1.3 STUDY METHODOLOGY
A reconnaissance-level field survey of the project site was conducted on March 20 and 21, 2025 by LOA biologist Natalie Neff. The survey consisted of a meandering walk and drive through the project site while identifying its principal land uses and the constituent plants and animals of each land use. The field survey conducted for this study was sufficient to assess the significance of possible biological impacts associated with the development plans for the project site.
LOA conducted an analysis of potential project impacts based on the known and potential biotic resources of the project site discussed in Section 2.0. Sources of information used in the preparation of this analysis included: (1) results of the March 2025 reconnaissance-level surveys, (2) the California Natural Diversity Data Base (CDFW 2025), (3) the Online Inventory of Rare and Endangered Vascular Plants of California (CNPS 2025), and (4) manuals, reports, and references related to plants and animals of the San Joaquin Valley region.
LOA’s field investigation did not include an aquatic resources delineation or focused surveys for special status species. The field survey was sufficient to generally describe those features of the project site that could be subject to the jurisdiction of the U.S. Army Corps of Engineers (USACE), California Department of Fish and Wildlife (CDFW), and/or the Regional Water Quality Control Board (RWQCB), and to assess the significance of possible biological impacts associated with development of the project site.
6 2.0 EXISTING CONDITIONS
2.1 REGIONAL SETTING
The project site is located in Pleasant Valley, which is itself situated in the southwestern portion of California’s San Joaquin Valley. The San Joaquin Valley is a large, nearly flat alluvial plain bordered by the Sierra Nevada to the east, the Tehachapi Mountains to the south, the California coast ranges to the west, and the Sacramento-San Joaquin Delta to the north.
Like most of California, the San Joaquin Valley experiences a Mediterranean climate. Warm dry summers are followed by cool moist winters. Summer temperatures range from 56 to 101 degrees Fahrenheit, and the relative humidity is generally very low. Winter temperatures range from 37 to 72 degrees Fahrenheit. Annual precipitation in the vicinity of the project is about 8.2 inches, almost 85% of which falls between the months of October and March. Nearly all precipitation falls in the form of rain (NOAA 2025).
The principal drainages of the project vicinity are Warthan Creek and Los Gatos Creek. Both creeks initiate in the Diablo Range, approximately 15 miles west of the project site, at an elevation of approximately 3,000 feet. Warthan Creek flows approximately 22 miles southeast toward Pleasant Valley where it enters Los Gatos Creek just west of the Coalinga WWTP. Los Gatos Creek is a historical channel that originally terminated in a delta in the trough of the San Joaquin Valley, and together with the Kings River delta, formed a sill that marked the northern boundary of the historic Tulare Lake in very wet years.
2.2 PROJECT SITE
The project site is situated within Coalinga city limits, and consists entirely of lands modified for human use. While centered primarily on municipal roads and the WWTP, it also contains portions of parking lots, a public park, fallow agricultural lands, and residential lots. The topography of the project site is relatively flat with elevations averaging 640 feet National Geodetic Vertical Datum (NGVD) at the WWTP and ranging from 655 to 690 feet NGVD in municipal Coalinga.
7 The project site contains six soil mapping units (NRCS 2025). These soils are summarized in Table 1 below.
TABLE 1: SOILS OF THE PROJECT SITE
Soil Mapping Unit Parent Material Drainage
Class
Hydric
Rating
412: Yribarren clay loam, 0 to 2 percent
slopes
Alluvium from calcareous
sedimentary rock
Well drained No
445: Excelsior sandy loam, 0 to 2 percent
slopes
Calcareous coarse-loamy alluvium
from sedimentary rock
Well drained No
447: Excelsior sandy loam, sandy
substratum, 0 to 2 percent slopes
Calcareous coarse-loamy alluvium
from sedimentary rock
Well drained No
451: Milham sandy loam, 0 to 2 percent
slopes MLRA 17
Alluvium from igneous and
sedimentary rock
Well drained No
478: Cerini sandy loam, 0 to 2 percent
slopes, MLRA 17
Alluvium from calcareous
sedimentary rock
Well drained No
981: Sewage Disposal Pond - - No
None of the site’s soil mapping units are considered hydric, meaning none have the propensity to pond water and support hydrophytic (water-loving) vegetation. Soils within the project site and surrounding lands have been subjected to decades of soil-disturbing activities associated with agricultural use, road and canal construction, and urban and rural development, and are not expected to exhibit their native soil characteristics or be particularly relevant to biological resource issues.
A list of vascular plants identified on the site is presented in Appendix A. A list of terrestrial vertebrates using or potentially using the project site is presented in Appendix B. Representative photos of the site are presented in Appendix C.
8 2.3 BIOTIC HABITATS / LAND USES
LOA identified three general land uses within the project site: urban, rural, and wastewater treatment facility (Figure 3). Within each land use were several different habitat types. The land uses and their constituent habitats are described in more detail in the following sections.
2.3.1 Urban
The sewer main work area is largely confined to municipal Coalinga and includes portions of streets, alleys, parking lots, residential and commercial properties, ruderal areas, and park lands that are collectively classified as “urban.” The streets, alleys, and parking lots are developed features that are in most cases paved and entirely barren of vegetation. The residential properties are characterized by homes, outbuildings, and ornamental vegetation including trees, shrubs, turf, and other landscaping features. The project site’s one commercial property is a motel; the portion of the property that falls within project boundaries is a landscaped strip with densely-spaced ornamental trees. The ruderal areas are disturbed roadside habitats that, at the time of LOA’s survey, were characterized by unmaintained turf and/or common weeds. The park land is a portion of George E. Olsen Memorial Park that, at the time of the survey, contained maintained turf, ornamental trees, and fencing.
The project site’s urban lands are of low habitat value for most native wildlife, given high levels of ambient disturbance and, in most areas, a lack of vegetative cover. Wildlife species expected to be found here would be those that are attracted to urban areas and/or tolerate disturbance, and those that are associated with adjacent lands and use or pass through urban areas incidentally.
Reptiles that could be found in the project site’s urban lands include the western fence lizard (Sceloporus occidentalisi), California alligator lizard (Elgaria multicarinata multicarinata), and gopher snake (Pituophis melanoleucus). Amphibians are unlikely due to an absence of nearby breeding habitat.
A number of disturbance-tolerant avian species are likely to forage and nest in the site’s urban lands. Trees and shrubs could support nesting by American robins (Turdus migratorius), Anna’s hummingbirds (Calypte anna), northern mockingbirds (Mimus polyglottos), and mourning doves Vantor
µ
0 0.25 0.5 1
Miles
LEGEND
Habitat / Land Use
Urban
Rural
Wastewater
Treatment Facility
W. Elm Ave.
State Route 33
Jayne Ave.
Warthan Creek
Biotic Habitats / Land Uses
04/30/2026 2887-01 3
Date Project # Figure #
City of Coalinga Sanitary Sewer Collection and
Wastewater Treatment Plant Improvements
Los Gatos Creek
Cambridge Ave.
10 (Zenaida macroura), among other species. Mourning doves may also nest in ground vegetation.
The site’s residential structures could potentially be used for nesting by the house finch (Haemorhous mexicanus). All of the aforementioned birds may also forage in the site’s urban lands, as could winter migrants such as the savannah sparrow (Passerculus sandwichensis) and yellow-rumped warbler (Dendroica coronata).
Small mammal species likely to occur in the project site’s urban lands include the deer mouse (Peromyscus maniculatus), house mouse (Mus musculus), and Norway rat (Rattus norvegicus), among others. Burrowing rodent activity is expected to be limited due to the preponderance of pavement in this land use type, as well as regular maintenance practices in most of the unpaved areas. Less-maintained areas could support California ground squirrels (Otospermophilus beecheyi) and Botta’s pocket gophers (Thomomys bottae).
Disturbance-tolerant mammalian predators such as raccoons (Procyon lotor) and striped skunks (Mephitis mephitis) are expected to occasionally forage on or pass through the site’s urban lands.
Various bat species may roost in trees and buildings within this land use type and may forage on or over these areas.
2.3.2 Rural
The sewer main work area also includes lands outside of municipal Coalinga that, while all human-altered in some form, experience lower levels of ambient disturbance than the urban land use type and are of higher value for native wildlife species. These include portions of ruderal or fallow fields, unpaved roads, an irrigation ditch, and the minimally maintained margins of these uses. While the roads were barren of vegetation, the fields and margins were characterized by sparse to dense growth of common weeds such as foxtail barley (Hordeum murinum), ripgut brome (Bromus diandrus), red-stemmed filaree (Erodium cicutarium), and cheeseweed (Malva parviflora), among others. Where the sewer main alignment crossed and then paralleled an irrigation ditch between urban Coalinga and the WWTP, several native trees including valley oak (Quercus lobata) and willow (Salix sp.) overhung the work area.
The project site’s rural lands may be used by a variety of native wildlife species associated with agricultural and other open habitats. Reptiles that could be found in the project site’s rural areas 11 include the side-blotched lizard (Uta stansburiana), western whiptail (Aspidoscelis tigris), common kingsnake (Lampropeltis californiae), and gopher snake. Common amphibians such as the Sierran treefrog (Pseudacris sierra) and western toad (Anaxyrus boreas) may breed in nearby irrigation ditches and subsequently disperse through the site’s rural lands.
Birds expected to nest within the project site’s rural lands include common ground-nesting species such as the western meadowlark (Sturnella neglecta), killdeer (Charadrius vociferus), and mourning dove. Foraging species would include the western kingbird (Tyrannus verticalis) in the summer, savannah sparrow and American pipit (Anthus rubescens) in the winter, and American crow (Corvus brachyrhynchos), and Brewer’s blackbird (Euphagus cyanocephalus) throughout the year. The site’s rural lands are also likely to be used for foraging by open country raptors such as the red-tailed hawk (Buteo jamaicensis) and American kestrel (Falco sparverius).
Trees within which these raptors could nest, while absent from the site’s rural lands, are found immediately outside of project boundaries in some of these areas.
Small mammal species likely to occur in the site’s rural lands include the deer mouse, California ground squirrel, Botta’s pocket gopher, California vole (Microtus californicus), and Audubon’s cottontail (Sylvilagus audubonii). Raccoons, striped skunks, and coyotes (Canis latrans) are likely to occur here from time to time. Various bat species may forage on or over the site’s rural lands; however, roosting habitat is absent.
2.3.3 Wastewater Treatment Facility
The WWTP work area consists of lands and facilities used for wastewater treatment. It includes two aerated lagoons, each approximately 3 acres in size; three stabilization ponds collectively encompassing approximately 13 acres; two asphalt-bottomed sludge drying beds; a network of access roads around the pond perimeters; and other ruderal upland areas. At the time of LOA’s field survey, most of these lands were highly maintained and barren of vegetation. Where present, vegetation consisted of patches of bermudagrass (Cynodon dactylon) and other nonnative grasses and forbs. A small portion of the work area is outside of the fenced facility and appears infrequently maintained; this area, located immediately to the west of the aerated lagoons, supported dense cover of non-native grasses and forbs including ripgut brome, foxtail barley, and Russian thistle (Salsola tragus).
12 The WWTP’s stabilization ponds are perennially inundated and support various wildlife species associated with aquatic environments. At the time of LOA’s field survey, southwestern pond turtles (Actinemys pallida) were detected in all three stabilization ponds; this is a California Species of Special Concern that is also proposed for federal listing as threatened. Several amphibian species are likely to occur in the stabilization ponds; these include the Sierran treefrog, western toad, and American bullfrog (Lithobates catesbeianus). The stabilization ponds support both waterfowl and shorebirds. Examples of the former observed during LOA’s survey include the ruddy duck (Oxyura amicensis), green-winged teal (Anas crecca), and mallard (Anas platyrhynchos), while examples of the latter include the great egret (Ardea alba), greater yellowlegs (Tringa melanoleuca), and black-necked stilt (Himantopus mexicanus). The ponds may serve as a source of mud for black phoebes and cliff swallows (Petrochelidon pyrrhonata) during nest-building, and black phoebes may also forage in flight over the ponds.
Upland areas of the WWTP may be utilized by basking turtles of the aforementioned species.
Killdeer and black-necked stilts could nest on the ground in these areas. California ground squirrels were observed in upland areas of the WWTP at the time of LOA’s survey, and other small mammals such as Botta’s pocket gophers, deer mice, and California voles may also occur here. Raccoons and striped skunks are likely to use or pass through these areas from time to time.
2.4 SPECIAL STATUS PLANTS AND ANIMALS
Many species of plants and animals within the state of California have low populations, limited distributions, or both. Such species may be considered “rare” and are vulnerable to extirpation as the state’s human population grows and the habitats these species occupy are converted to agricultural and urban uses. As described more fully in Section 3.0, state and federal laws have provided California Department of Fish and Wildlife (CDFW) and the U.S. Fish and Wildlife Service (USFWS) with a mechanism for conserving and protecting the diversity of plant and animal species native to the state. A sizable number of native plants and animals have been formally designated as threatened or endangered under state and federal endangered species legislation. Others have been designated as “candidates” for such listing. Still others have been designated as “species of special concern” by the CDFW. The California Native Plant Society (CNPS) has developed its own set of lists (i.e., California Rare Plant Ranks, or CRPR) of native 13 plants considered rare, threatened, or endangered (CNPS 2025). Collectively, these plants and animals are referred to as “special status species.”
The California Natural Diversity Data Base (CNDDB) was queried for special status plant and animal occurrences in the nine USGS 7.5-minute quadrangles containing and surrounding the project site (Joaquin Rocks, Domengine Ranch, Harris Ranch, Alcalde Hills, Coalinga, Guijarral Hills, Curry Mountain, Kreyenhagen Hills, and Avenal). A number of special status plants and animals were returned in the query and are summarized below in Table 1. Sources of information for this table included California’s Wildlife, Volumes I, II, and III (Zeiner et. al 1988-1990), California Natural Diversity Data Base (CDFW 2025), The Jepson Manual:
Vascular Plants of California, second edition (Baldwin et al 2012), the California Native Plant Society’s Inventory of Rare and Endangered Vascular Plants of California (CNPS 2025), Calflora.org, iNaturalist.org, and eBird.org.
14 TABLE 2. LIST OF SPECIAL STATUS SPECIES POTENTIALLY OCCURRING IN THE
PROJECT VICINITY
PLANTS
Species Listed under the State and/or Federal Endangered Species Act Species Status Habitat Occurrence on the Project Site
California Jewel-flower
(Caulanthus californicus)
FE, CE,
CRPR
1B.1
Occurs in chenopod scrub, pinyon
and juniper woodland, and sandy
valley and foothill grassland; blooms
February–May; elevation 250-3,300
ft.
Absent. Any suitable habitat that may
have once been present on the site has
been eliminated through conversion to
urban and agricultural uses. This species
was generally mapped to Coalinga in
1926, but the population is considered
extirpated due to habitat loss (CDFW
2025).
San Joaquin woolly threads
(Monolopia congdonii)
FE
CRPR
1B.2
Occurs in sandy grassland and
chenopod scrub in sandy soils of the
southwestern Central Valley between
200 and 2,625 feet in elevation.
Blooms February-May.
Absent. Any suitable habitat that may
have once been present on the site has
been eliminated through conversion to
urban and agricultural uses. This species
was generally mapped to Coalinga in
1935, but was not found during a 1988
site visit; the population is considered
possibly extirpated due to habitat loss
(CDFW 2025).
CNPS-listed Species
Lost Hills Crownscale
(Atriplex coronata var.
vallicola)
CRPR
1B.2
Found in chenopod scrub and valley
and foothill grasslands; alkaline soils;
blooms April-August; elevations
below 2,080 ft.
Absent. Any suitable habitat that may
have once been present on the site has
been eliminated through conversion to
urban and agricultural uses.
Brittlescale
(Atriplex depressa)
CRPR
1B.2
Occurs in chenopod scrub, valley and
foothill grassland, and wetland
habitats; blooms April-October;
elevations below 1,050 ft.
Absent. Any suitable habitat that may
have once been present on the site has
been eliminated through conversion to
urban and agricultural uses.
Lemmon’s Jewelflower
(Caulanthus lemmonii)
CRPR
1B.2
Occurs in grasslands, chaparral, and
scrubland. Blooms March-May,
elevation 260-3600 ft.
Absent. Any suitable habitat that may
have once been present on the site has
been eliminated through conversion to
urban and agricultural uses.
Hall’s Tarplant
(Deinandra halliana)
CRPR
1B.2
Occurs in chaparral habitats in rocky
soils; elevations 900-4,100 ft.
Blooms May-June.
Absent. The project site is below this
species’ elevational distribution, and
suitable habitat is absent.
Recurved Larkspur
(Delphinium recurvatum)
CRPR
1B.2
Occurs in poorly drained, fine,
alkaline soils in grassland and
Atriplex scrub; blooms March-June;
elevations up to 2,500 ft.
Absent. Any suitable habitat that may
have once been present on the site has
been eliminated through conversion to
urban and agricultural uses.
Eastwood’s Buckwheat
(Eriogonum
eastwoodianum)
CRPR
1B.3
Occurs in foothill woodlands, shale.
Blooms May-September; elevation
from 655 to 3,280 ft.
Absent. Any suitable habitat that may
have once been present on the site has
been eliminated through conversion to
urban and agricultural uses.
Diablo Range Hare-Leaf
(Lagophylla diabolensis)
CRPR
1B.2
Occurs in grassy openings in
woodlands in heavy clay. Blooms
April-July; elevation 1,150-3,300 ft.
Absent. The project site is below this
species’ elevational distribution, and
suitable habitat is absent.
Alkali-Sink Goldfields
(Lasthenia chrysantha)
CRPR
1B.1
Found in alkaline vernal pools below
approximately 650 feet in elevation.
Blooms February-April.
Absent. Any suitable habitat that may
have once been present on the site has
been eliminated through conversion to
urban and agricultural uses.
Pale-Yellow Layia
(Layia heterotricha)
CRPR
1B.1
Occurs in foothill woodlands, valley
grasslands, pinyon-juniper
woodlands, and wetland-riparian
areas in clay or sandy soils. Blooms
April- June; elevation 660-5,900 ft.
Absent. Any suitable habitat that may
have once been present on the site has
been eliminated through conversion to
urban and agricultural uses.
15 TABLE 2. LIST OF SPECIAL STATUS SPECIES POTENTIALLY OCCURRING IN THE
PROJECT VICINITY
PLANTS
CNPS-listed Species
Species Status Habitat Occurrence on the Project Site
Panoche pepper-grass
(Lepidium jaredii ssp. album)
CRPR
1B.2
Found on steep slopes associated
with alluvial fans and washes; valley
and foothill grassland association;
clay soils; elevations 600-2,450 ft.
Blooms February-June.
Absent. Any suitable habitat and
microsite conditions that may have once
been present on the site have been
eliminated through conversion to urban
and agricultural uses.
Showy Golden Madia
(Madia radiata)
CRPR
1B.1
Occurs in foothill woodlands or
grasslands in heavy clay. Blooms
March- May; elevations up to 6,000
ft.
Absent. Any suitable habitat that may
have once been present on the site has
been eliminated through conversion to
urban and agricultural uses.
Indian Valley Bushmallow
(Malacothamnus
aboriginum)
CRPR
1B.2
Found on granitic outcrops and sandy
bar soil within chaparral and
woodland habitats, often in burned
areas; elevations 500-5,600 ft.
Blooms April-October.
Absent. The project site does not contain
chaparral or woodland habitats, or any
recently burned areas.
Shining Navarretia
(Navarretia nigelliformis
ssp. radians)
CRPR
1B.2
Occurs in valley grassland, foothill
woodland, freshwater-wetlands, and
wetland-riparian between 525 and
1770 ft. in elevation. Blooms AprilJuly.
Absent. Any suitable habitat that may
have once been present on the site has
been eliminated through conversion to
urban and agricultural uses.
Panoche Navarretia
(Navarretia panochensis
CRPR
1B.3
Known from a few locations in the
Panoche region of Fresno and San
Benito Counties. Found in grassland
and scrub habitats in clay or gravelly
soils. Elevation 1,310- 2,130 ft.
Absent. The project site is below this
species’ elevational distribution, and
suitable habitat is absent.
Prostrate Vernal Pool
Navarretia
(Navarretia prostrata)
CNPS
1B.2
Occurs in wetlands of coastal scrub
and alkaline grassland habitats in the
western San Joaquin Valley and
Coast Ranges at elevations up to
2,300 ft. Blooms April – July.
Absent. Any suitable habitat that may
have once been present on the site has
been eliminated through conversion to
urban and agricultural uses.
Chaparral Ragwort
(Senecio aphanactis)
CRPR
2B.2
Occurs in coastal scrub, foothill
woodlands, alkali flats, and dry, open
rocky areas. Blooms February- May;
elevations up to 2,600 ft.
Absent. Any suitable habitat that may
have once been present on the site has
been eliminated through conversion to
urban and agricultural uses.
ANIMALS
Species Listed under the State and/or Federal Endangered Species Act Crotch’s bumble bee
(Bombus crotchii)
CCE Once common in the Central Valley,
this species is now largely absent
from this portion of its historic range
(CDFW 2019). Where present, it is
associated with open grassland and
scrub habitats, where it relies on food
plants of the Asclepias, Chaenactis,
Lupinus, Medicago, Phacelia, and
Salvia genera (Williams et al. 2014).
Unlikely. Although rural portions of the
project site contain some foraging
resources for the Crotch’s bumble bee,
this species is unlikely to occur in the
vicinity other than possible occasional
transient movements. Xerces et al. (2018)
reported no post-2002 detections of this
species in the western San Joaquin Valley
despite a relatively high sampling effort.
The CNDDB lists two occurrences of
Crotch’s bumble bee within 3 miles of the
site, but both are from more than 25 years
ago (CDFW 2025). There are no
iNaturalist or Bumble Bee Watch
observation records within 15 miles of the
project site (iNaturalist 2025, Bumble Bee
Watch 2025).
16 TABLE 2. LIST OF SPECIAL STATUS SPECIES POTENTIALLY OCCURRING IN THE
PROJECT VICINITY
ANIMALS
Species Listed under the State and/or Federal Endangered Species Act Species Status Habitat Occurrence on the Project Site
Monarch Butterfly
(Danaus plexippus)
FPT Overwinters in coastal California and
Baja California and breeds
throughout California in the spring
and summer along its annual
migration north and east. The adult
monarch lays its eggs on obligate
milkweed (Asclepias spp.) host
plants, which the resultant larvae
feed on before pupating and
emerging as adults. In addition to
milkweed, this species requires
abundant nectar resources to nourish
migrating adults, and trees for
roosting during migratory stopovers.
Possible. Monarchs have been reported
within Coalinga city limits, including a
2022 sighting in George E. Olson
Memorial Park, approximately 300 feet
south of the sewer main work area
(iNaturalist 2025). The project site
contains both flowering plants on which
monarchs could forage and trees within
which they could roost. LOA’s survey
was conducted early in the growing
season, at a time when locally-occurring
milkweeds may not be readily detectable.
While not observed, milkweed could
conceivably occur in the residential yards,
park land, and ruderal/fallow fields of the
sewer main work area, introducing some
potential for breeding in these areas.
Milkweed (and monarch reproduction) is
not expected in the degraded habitats of
the WWTP work area.
Vernal Pool Fairy Shrimp
(Branchinecta lynchi)
FT Found in vernal pools and swales,
basalt flow depression pools, and
depressions in sandstone rock
outcrops; can occur in roadside
ditches and puddles when in
association with vernal pools.
Absent. Suitable wetland habitat for this
species is absent from the project site and
adjacent lands.
California Tiger Salamander
(Ambystoma californiense)
FT, CT Found primarily in annual
grasslands; requires vernal pools for
breeding and rodent burrows for
aestivation. CTS are capable of
overland travel of up to 1.3 miles
(Orloff 2011).
Absent. The project site consists entirely
of urban, agricultural, and other highly
modified lands that would not attract or
support this species. Moreover, suitable
breeding habitat is absent from the site
and surrounding lands within a distance
that would enable CTS to access the site
for aestivation. The nearest CNDDB
occurrence of this species is nearly 20
miles from project boundaries (CDFW
2025).
Foothill Yellow-Legged Frog
-Central Coast DPS
(Rana boylii pop. 4)
FE, CE Found in or near rocky streams in a
variety of habitats. Use submerged
rocks and debris for cover. Requires
gravel or rocks in moving water near
stream margins for reproduction.
Absent. Suitable aquatic habitat is absent
from the project site and surrounding
lands. There is a historic (1941) CNDDB
occurrence of this species mapped
generally to a location approximately 2
miles west of Coalinga; however, the
species is considered extirpated from the
vicinity (CDFW 2025).
California Red-Legged Frog
(Rana draytonii)
FT Perennial rivers, creeks and stock
ponds of the Inner Coast Range
foothills, preferring deep pools with
overhanging vegetation.
Absent. Suitable aquatic habitat is absent
from the project site and surrounding
lands. The nearest CNDDB occurrence is
over 30 miles from project boundaries
(CDFW 2025).
17 TABLE 2. LIST OF SPECIAL STATUS SPECIES POTENTIALLY OCCURRING IN THE
PROJECT VICINITY
ANIMALS
Species Listed under the State and/or Federal Endangered Species Act Species Status Habitat Occurrence on the Project Site
Western Spadefoot
(Spea hammondii)
FPT, CSC Occurs in grasslands of San Joaquin
Valley, where it breeds in vernal
pools or other seasonal wetlands and
aestivates in underground refugia
such as rodent burrows. Baumberger
et al. (2019) recorded a maximum
distance of around 860 feet between
breeding and aestivation sites.
Absent. There is a historic (1941)
CNDDB occurrence of this species
mapped generally to a location
approximately 2 miles west of Coalinga.
While the western spadefoot may yet be
present in the larger project vicinity, the
project site itself consists entirely of urban
and agricultural lands that would not
attract or support this species. Suitable
breeding habitat is absent from the site and
surrounding lands within a distance that
would enable western spadefoot
individuals to access the site for
aestivation.
Southwestern Pond Turtle
(Actinemys pallida)
FPT,
CSC
Found in ponds, marshes, rivers,
streams, and irrigation ditches with
aquatic vegetation. Requires
partially submerged rocks or logs
for basking sites. Nesting takes
place in open areas, on a variety of
soil types, and up to ¼ mile away
from water. Overwintering and
summertime aestivation may include
use of upland habitat, generally with
leaf litter or other loose substrate for
burying themselves.
Present. This species is present at the
WWTP. At the time of LOA’s survey
effort, 36 pond turtles were observed in the
three existing stabilization ponds. Turtle
age/size varied, indicating that this is a
breeding population and not merely
sustained through immigration. While
highly maintained, upland portions of the
WWTP may support nesting by this
species, as has been observed at other such
facilities (M. Jennings, Rana Resources,
pers. comm.). The WWTP’s pond turtles
are likely to remain active through most of
the winter, but during the coldest periods
may overwinter underwater (M. Jennings,
Rana Resources, pers. comm.). Pond
turtles are not expected to occur in the
sewer main work area.
Blunt-Nosed Leopard Lizard
(BNLL)
(Gambelia sila)
FE, CE,
CP
Occurs in semiarid grasslands, alkali
flats, and washes. Avoids densely
vegetated areas. Inhabits the San
Joaquin Valley and adjacent valleys
and foothills north to southern
Merced County.
Unlikely. The BNLL was historically
known from the near vicinity. There is a
historic (1935) CNDDB record of this
species mapped to a general location 1.25
miles east of Coalinga, centered on the
present-day WWTP. A second record,
from 1989, documented several
individuals along Los Gatos Creek,
approximately 1 mile north of project
boundaries. Since that time, BNLL
sightings in the area have been scarce; the
closest post-2000 CNDDB occurrence is
located some 8 miles east of the site at a
CDFW ecological reserve. There are no
iNaturalist sightings within 20 miles of the
project site. The site consists entirely of
lands heavily modified by urban and
agricultural uses and is unlikely to attract
or support individuals of this species, even
if they do persist in the vicinity.
18 TABLE 2. LIST OF SPECIAL STATUS SPECIES POTENTIALLY OCCURRING IN THE
PROJECT VICINITY
ANIMALS
Species Listed under the State and/or Federal Endangered Species Act Species Status Habitat Occurrence on the Project Site
Temblor Legless Lizard
(Anniella alexanderae)
CCE,
CSC
A burrowing lizard that occurs in
alkali desert scrub and annual
grasslands of southwestern San
Joaquin Valley within Kern and
Fresno Counties. Consumes insects
and other small invertebrates.
Possible. There is a recent (2022)
CNDDB occurrence of this species from
Warthan Creek, approximately 0.3 mile
outside of Coalinga city limits and 1 mile
south of project boundaries. Although the
project site consists entirely of urban,
agricultural, and other highly modified
lands that do not constitute Temblor
legless lizard habitat, there is some
chance for individuals of this species to
occur along Warthan or Los Gatos Creeks
in the immediate vicinity and to
occasionally wander onto the WWTP
work area or rural portions of the sewer
main work area.
Burrowing Owl
(Athene cunicularia)
CCE Frequents open, dry annual or
perennial grasslands, deserts, and
scrublands characterized by lowgrowing vegetation. May also utilize cropland, foraging in fields and
roosting or nesting at field margins.
Dependent upon burrowing
mammals, most notably the
California ground squirrel, for nest
burrows.
Possible. Burrowing owls are not often
documented in the project vicinity; the
closest CNDDB record is approximately 3
miles northeast of the site, recorded at the
Coalinga airport in 2009, and the closest
eBird occurrence is approximately 9 miles
northeast, recorded near an Interstate 5
off-ramp in 1983 (CDFW 2025, eBird
2026). Nevertheless, this species has
some potential to forage and nest in rural
portions of the project site.
Swainson’s Hawk
(Buteo swainsoni)
CT This breeding migrant to California
nests in mature trees in riparian areas
and oak savannah, and occasionally
in lone trees at the margins of
agricultural fields. Requires adjacent
suitable foraging areas such as
grasslands or alfalfa fields supporting
rodent populations.
Likely. This species is fairly welldocumented in the project vicinity. There are three recent eBird sightings within 3
miles of project boundaries; two of these
were logged at George E. Olson
Memorial Park in Coalinga, between 300
and 700 feet from project boundaries
(eBird 2025). A historic (1941) CNDDB
record documented two Swainson’s hawk
nests in the general Coalinga area, while a
modern (2016) record describes a nest
along Jacalitos Creek, approximately 3.5
miles southeast of project boundaries.
This species has the potential to nest in
trees on or near the project site,
particularly outside of the urban core of
Coalinga, and to forage in rural portions
of the site.
California Condor
(Gymnogyps californianus)
FE, CE Found in chaparral and valley and
foothill grassland habitats; requires
vast expanses of open natural land to
meet its foraging needs. Nests in rock
crevices, on overhung cliff ledges,
and in old-growth conifers.
Absent. The project site lacks suitable
condor nesting and roosting habitat, and
does not contain or adjoin large blocks of
natural land that could support foraging
by this species.
19 TABLE 2. LIST OF SPECIAL STATUS SPECIES POTENTIALLY OCCURRING IN THE
PROJECT VICINITY
ANIMALS
Species Listed under the State and/or Federal Endangered Species Act Species Status Habitat Occurrence on the Project Site
Tricolored Blackbird
(Agelaius tricolor)
CT, CSC Breeds colonially near fresh water in
dense bulrush, cattails, or thickets of
willows or shrubs, and increasingly
in grain fields. Forages in grassland
and cropland areas.
Possible. This species may forage in rural
portions of the site, but nesting habitat is
absent. The CNNDB lists one occurrence
of this species in the project vicinity, a
2014 observation of a small nesting
colony at a gravel pit approximately 1
mile north of project boundaries (CDFW
2025).
San Joaquin Antelope
Squirrel
(Ammospermophilus
nelsoni)
CT Found in arid upland scrub
communities, and to a lesser extent
grasslands, along the western margin
of the San Joaquin Valley and in the
adjoining hills and plains. Occupies
modified kangaroo rat burrows or
self-constructed burrows. Not usually
found on steep slopes or in areas
prone to flooding.
Absent. The project site consists entirely
of urban, agricultural, and other highly
modified lands that would not attract or
support this species. There are four
CNDDB occurrences of the San Joaquin
antelope squirrel in the general vicinity,
located between 3 and 5 miles south of
the site in the Jacalitos Hills. All are from
more than 30 years ago and are associated
with natural lands typical of this species’
habitat preferences (CDFW 2025). The
nearest iNaturalist sightings are more than
20 miles from project boundaries
(iNaturalist 2025).
Giant Kangaroo Rat
(Dipodomys ingens)
FE, CE Historically occurred from Merced
County to Kern County and Carrizo
Plain and Cuyama Valley in San Luis
Obispo County, but has been reduced
to fragmented populations
encompassing only 5 percent of its
historic range (USFWS 2010).
Prefers annual grassland and
shrubland communities where
vegetation is sparse and soils are well
drained fine, sandy loams. Does not
inhabit areas where slopes exceed 10
percent or where water may pool.
Absent. The project site consists entirely
of urban, agricultural, and other highly
modified lands that would not attract or
support giant kangaroo rats. The nearest
CNDDB and iNaturalist records of this
species are more than 20 miles from
project boundaries (CDFW 2025,
iNaturalist 2025).
San Joaquin Kit Fox (SJKF)
(Vulpes macrotis mutica)
FE, CT Frequents desert alkali scrub and
annual grasslands and may forage in
adjacent agricultural habitats.
Utilizes enlarged ground squirrel
burrows as denning habitat. May
become adapted to urban
environments, as has occurred in the
cities of Bakersfield, Taft, and
Coalinga. Urban-adapted kit foxes
commonly use vacant lots, industrial
and commercial areas, parks, golf
courses, and lightly-disturbed rightsof-way such as canals and utility corridors. Residential areas are not
commonly used as they have high
levels of disturbance, numerous dogs,
and fences and other features that
limit movement (Cypher et al. 2012).
Possible. Coalinga is known to support a
population of urban-adapted SJKF
(Cypher et al. 2012). This species is also
fairly well documented in outlying areas,
with 12 CNDDB occurrences located
within 10 miles of project boundaries
(CDFW 2025). There is considerable
potential for the SJKF to forage and den
on the project site. Although this is a
theoretical possibility for any portion of
the site, Cypher et al. (2012)’s work
suggests a higher potential for SJKF
occurrence outside of Coalinga’s
residential neighborhoods.
20 TABLE 2. LIST OF SPECIAL STATUS SPECIES POTENTIALLY OCCURRING IN THE
PROJECT VICINITY
ANIMALS
State Species of Special Concern
Species Status Habitat Occurrence on the Project Site
Coast horned lizard
(Phrynosoma blainvillii)
CSC Ranges from the central and southern
California coast inland through the
western Sierra Nevada, where it is
found in grassland and open areas
within woodland and forest habitats.
Often found in sandy areas including
washes and floodplains.
Unlikely. The coast horned lizard is not
known from the near project vicinity.
There are several iNaturalist records in
the hills generally west of Coalinga, but
none from the Pleasant Valley floor
(iNaturalist 2025). The closest CNDDB
occurrences are more than 15 miles away
(CDFW 2025). The project site consists
entirely of lands heavily modified by
urban and agricultural uses and is
unlikely to attract or support individuals
of this species, even if they do occur in
the vicinity.
Northern California Legless
Lizard
(Anniella pulchra)
CSC Occurs in sparsely vegetated areas of
beach dunes, chaparral, pine-oak
woodlands, desert scrub, sandy
washes, and stream terraces with
sycamores, cottonwoods, or oaks.
Requires moist soils.
Unlikely. The northern California legless
lizard is not known from the near project
vicinity. The nearest iNaturalist records
are more than 9 miles southwest of
project boundaries, at undisclosed
locations in the Inner Coast Range
(iNaturalist 2025). The closest CNDDB
occurrence is approximately 7 miles
southwest in the Curry Mountain area
(CDFW 2025). The project site consists
entirely of lands heavily modified by
urban and agricultural uses and is
unlikely to attract or support individuals
of this species, even if they do occur in
the vicinity.
California glossy snake
(Arizona elegans
occidentalis)
CSC Inhabits arid scrub, rocky washes,
grasslands, and chaparral, where it
forages nocturnally, hiding in
underground burrows during the day.
Prefers loose, sandy soils.
Possible. This species has been
documented in the near project vicinity.
Two historic (1935 and 1951) CNDDB
records intersect the project site itself,
while two additional records are located
within 4 miles west and south of the
WWTP work area (CDFW 2025). There
are several iNaturalist records at
undisclosed locations in the general
project vicinity; at least one of these is
along Los Gatos Creek on the floor of
Pleasant Valley (iNaturalist 2025).
Although the project site consists entirely
of urban, agricultural, and other highly
modified lands that do not constitute
California glossy snake habitat, there is
some chance for individuals of this
species to occur along Warthan or Los
Gatos Creeks in the immediate vicinity
and to occasionally wander onto the
WWTP work area or rural portions of the
sewer main work area.
21 TABLE 2. LIST OF SPECIAL STATUS SPECIES POTENTIALLY OCCURRING IN THE
PROJECT VICINITY
ANIMALS
State Species of Special Concern
Species Status Habitat Occurrence on the Project Site
San Joaquin coachwhip
(Masticophis flagellum
ruddocki)
CSC Occurs in open, dry areas including
grassland and saltbush scrub. Takes
refuge in rodent burrows and under
shaded vegetation.
Possible. There are historical
observations of this species in the near
project vicinity. Two CNDDB records
from the 1980s are located between 1 and
2 miles from project boundaries.
Although the project site consists entirely
of urban, agricultural, and other highly
modified lands that do not constitute San
Joaquin coachwhip habitat, there is some
chance for individuals of this species to
occur along Warthan or Los Gatos
Creeks in the immediate vicinity and to
occasionally wander onto the WWTP
work area or rural portions of the sewer
main work area.
Long-eared Owl
(Asio otus)
CSC Nests in dense patches of trees or tall
shrubs and forages in adjacent open
habitats such as grassland, shrubland,
and fields. Utilizes nests built by
other birds, particularly those built by
corvids. Occurs year-round in
California.
Possible. Suitable nesting habitat for the
long-eared owl is absent from the project
site itself, but occurs immediately
adjacent to the WWTP work area along
Los Gatos Creek. This species could
forage over rural portions of the site.
There is a CNDDB nesting occurrence of
the long-eared owl along Los Gatos
Creek approximately 6 miles downstream
of the project site, logged in 2005, and an
eBird sighting from the last ten years that
is generally mapped to the Coalinga area
(CDFW 2025, eBird 2025).
Le Conte’s Thrasher
(Toxostoma lecontei)
CSC Occupies desert flats with scattered
low shrubs. Requires well-drained,
bare ground areas with litter layers
near shrubs for foraging. Primarily
eats insects but will occasionally eat
plant seeds, bird eggs, and small
lizards. Nests deep into dense shrubs
where direct sunlight rarely reaches.
Unlikely. The project site does not
contain suitable habitat for the Le
Conte’s thrasher. Although the dry
channels of Warthan and Los Gatos
Creeks may theoretically provide some
habitat value, the creeks in the project
vicinity are situated in a landscape highly
modified for anthropogenic use and are
therefore unlikely to support this species.
The only known occurrence in the
general vicinity is a historic (1934)
CNDDB nest sighting along Los Gatos
Creek, approximately 3 miles east of the
WWTP work area (CDFW 2025).
Yellow-headed Blackbird
(Xanthocephalus
xanthocephalus)
CSC Occurs in California primarily as a
breeding season migrant; however,
small numbers winter in the southern
Central Valley and the Imperial and
Colorado River Valleys. Requires
deepwater marshes and wetlands
with tall emergent vegetation such as
tules or cattails for breeding. Forages
in wetlands and surrounding
grasslands, croplands, and savanna.
Unlikely. The yellow-headed blackbird is
not known from the project vicinity; all
CNDDB, eBird, and iNaturalist
occurrence records are more than 15
miles from project boundaries (CDFW
2025, eBird 2025, iNaturalist 2025).
Suitable breeding habitat for this species
is absent from the project site and
surrounding lands.
22 TABLE 2. LIST OF SPECIAL STATUS SPECIES POTENTIALLY OCCURRING IN THE
PROJECT VICINITY
ANIMALS
State Species of Special Concern
Species Status Habitat Occurrence on the Project Site
Short-nosed Kangaroo Rat
(Dipodomys nitratoides
brevinasus)
CSC Historically occurred on the western,
southern, and extreme southeastern
sides of the San Joaquin Valley
typically above the valley floor.
Currently, fragmented populations
exist near Los Banos, Panoche and
San Joaquin Valleys, Kettleman
Hills, Antelope and Carrizo Plains,
and Cuyama Valley. Prefer friable
soils on flat or gently rolling terrain
in grassland and desert-scrub
vegetation.
Absent. The project site consists entirely
of urban, agricultural, and other highly
modified lands that would not attract or
support short-nosed kangaroo rats. There
are three CNDDB occurrences of this
species in the general vicinity; all were
recorded in 1992 between 3 and 4 miles
east and northeast of the WWTP work
area (CDFW 2025). While located on the
Pleasant Valley floor, all three of these
occurrences were in or immediately
adjacent to large blocks of natural land.
Tulare Grasshopper Mouse
(Onychomys torridus
tularensis)
CSC Known from arid shrubland
communities in hot, arid grassland
and scrub desert associations.
Intensive trapping surveys conducted
in the 1980s and 1990s suggest that
this species no longer occupies
fragmented native habitats, large or
small, on the floor of the San Joaquin
Valley (Bolster 1998).
Absent. The project site consists entirely
of urban, agricultural, and other highly
modified lands unsuitable for the Tulare
grasshopper mouse. There is a historic
(1905) CNDDB occurrence of this
species that is generally mapped to
Coalinga. The Tulare grasshopper mouse
is unlikely to have persisted in this area
following urban and intensive
agricultural development.
Townsend’s Big-eared Bat
(Corynorhinus townsendii)
CSC Found throughout California. Roosts
most frequently in caves and cavelike structures, but has also been reported to utilize bridges, buildings,
rock crevices, and hollow trees.
Occurs in a variety of habitats.
Possible. This species has some potential
to roost in buildings or trees within or
adjacent to the project site, and to forage
over the site.
Western Mastiff Bat
(Eumops perotis
californicus)
CSC Frequents open, semi-arid to arid
habitats, including conifer, and
deciduous woodlands, coastal scrub,
grasslands, palm oasis, chaparral and
urban. Roosts in cliff faces, high
buildings, and tunnels.
Possible. This species has some potential
to roost in buildings within or adjacent to
the project site, and to forage over the
site. There is a 1995 CNDDB occurrence
from central Coalinga, within a few
hundred feet of the sewer main work
area.
American Badger
(Taxidea taxus)
CSC Found in drier open stages of most
shrub, forest, and herbaceous habitats
with friable soils. Adult badgers are
primarily nocturnal, foraging at night
and remaining underground in
sleeping dens during the day.
Badgers mate in late summer to early
fall, and the young are born in natal
dens in March and April. While
badgers rarely remain in a sleeping
den for more than a day, natal dens
may be used for a period of 4-8
weeks as the female gives birth to
and raises her young.
Possible. This species has been
documented in the general vicinity; there
is a historic CNDDB occurrence
approximately 4 miles southwest of the
project site along Warthan Creek, and a
more modern (2005) occurrence
approximately 5 miles east of the site
along Los Gatos Creek. This wideranging species has some potential to den and forage in rural portions of the sewer
main work area. Degraded habitats and
high levels of ambient disturbance are
expected to preclude its occurrence from
the WWTP work area and urban portions
of the sewer main work area.
23 OCCURRENCE DESIGNATIONS AND STATUS CODES
Present: Species observed on the site at time of field surveys or during recent past.
Likely: Species not observed on the site, but it may reasonably be expected to occur there on a regular basis.
Possible: Species not observed on the site, but it could occur there from time to time.
Unlikely: Species not observed on the site, and would not be expected to occur there except, perhaps, as a transient.
Absent: Species not observed on the site and precluded from occurring there because habitat requirements not met.
STATUS CODES
FE Federally Endangered CE California Endangered
FT Federally Threatened CT California Threatened
FC Federal Candidate CCE California Candidate Endangered FPT Federal Proposed Threatened CFP California Fully Protected CSC California Species of Special Concern
CR California Rare
CRPR CODES
1A Plants Presumed Extinct in California 2B Plants Rare, Threatened, or Endangered in 1B Plants Rare, Threatened, or Endangered in California, but more common elsewhere California and elsewhere
2.5 JURISDICTIONAL WATERS
Jurisdictional waters are those rivers, creeks, drainages, lakes, ponds, reservoirs, and wetlands that are subject to the authority of the USACE, CDFW, and/or the RWQCB. In general, the USACE regulates navigable waters, tributaries to navigable waters, and wetlands with a continuous surface connection to these waters, where wetlands are defined by the presence of hydric soils, hydrophytic vegetation, and wetland hydrology. All waters under USACE jurisdiction are also regulated by the RWQCB as waters of the State. Additionally, the RWQCB asserts jurisdiction over certain isolated features disclaimed by the USACE. The CDFW has jurisdiction over waters that have a defined bed and bank. The regulation of jurisdictional waters is discussed in more detail in Section 3.9.
Waters subject to the jurisdiction of the USACE and CDFW are absent from the project site; however, the RWQCB may regulate activities within the site’s wastewater treatment ponds and the irrigation ditch crossed by the sewer main alignment between urban Coalinga and the WWTP.
2.6 DESIGNATED CRITICAL HABITAT
As will be discussed further in Section 3.0, the USFWS often designates areas of “critical habitat” when it lists species as threatened or endangered. Critical habitat is a specific 24 geographic area(s) that contains features essential for the conservation of a threatened or endangered species and that may require special management and protection.
Designated critical habitat is absent from the project site and surrounding lands. The nearest units of critical habitat are located some 30 miles from project boundaries in the Inner Coast Range, and are designated for the protection of the vernal pool fairy shrimp (Branchinecta lynchi) and California red-legged frog (Rana draytonii).
2.7 SENSITIVE NATURAL COMMUNITIES
California contains a wide range of natural communities, or unique assemblages of plants and animals. These communities have largely been classified and mapped by CDFW as part of their Vegetation Classification and Mapping Program (VegCAMP). Natural communities are assigned state and global ranks according to their rarity and the magnitude and trend of the threats they face. Any natural community with a state rank of 3 or lower (on a 1 to 5 scale) is considered “sensitive” and must be considered in CEQA review.
Sensitive natural communities are absent from the project site.
2.8 WILDLIFE MOVEMENT CORRIDORS
Wildlife movement corridors are routes that animals regularly and predictably follow during seasonal migration, dispersal from native ranges, daily travel within home ranges, and interpopulation movements. Movement corridors in California are typically associated with valleys, ridgelines, and rivers and creeks supporting riparian vegetation. Certain features of the project area have the potential to function as movement corridors for resident and migratory fish and wildlife species.
Wildlife movement corridors are absent from the project site itself, but Los Gatos Creek, immediately adjacent to the WWTP work area, is likely to function as an important movement corridor for locally-occurring wildlife.
25 3.0 RELEVANT GOALS, POLICIES, AND LAWS
3.1 CALIFORNIA ENVIRONMENTAL QUALITY ACT
In California, any project carried out or approved by a public agency that will result in a direct or reasonably foreseeable indirect physical change in the environment must comply with CEQA.
The purpose of CEQA is to ensure that a project’s potential impacts on the environment are evaluated and methods for avoiding or reducing these impacts are considered before the project is allowed to move forward. A secondary aim of CEQA is to provide justification to the public for the approval of any projects involving significant impacts on the environment.
According to Section 15382 of the CEQA Guidelines, a significant effect on the environment means a “substantial, or potentially substantial, adverse change in any of the physical conditions within the area affected by the project, including land, air, water, minerals, flora, fauna, ambient noise, and objects of historic or aesthetic interest.” Although the lead agency may set its own CEQA significance thresholds, project impacts to biological resources are generally considered to be significant if they would meet any of the following criteria established in Appendix G of the CEQA Guidelines:
• Have a substantial adverse effect, either directly or through habitat modifications, on any species identified as a candidate, sensitive, or special status species in local or regional plans, policies, or regulations, or by CDFW or USFWS.
• Have a substantial adverse effect on any riparian habitat or other sensitive natural community identified in local or regional plans, policies, or regulations or by CDFW or USFWS.
• Have a substantial adverse effect on state or federally protected wetlands (including, but not limited to, marsh, vernal pool, coastal, etc.) through direct removal, filling, hydrological interruption, or other means.
• Interfere substantially with the movement of any native resident or migratory fish or wildlife species or with established native resident or migratory wildlife corridors, or impede the use of native wildlife nursery sites.
• Conflict with any local policies or ordinances protecting biological resources, such as a tree preservation policy or ordinance.
26 • Conflict with the provisions of an adopted Habitat Conservation Plan, Natural Community Conservation Plan, or other approved local, regional, or state habitat conservation plan.
Furthermore, CEQA Guidelines Section 15065(a) requires the lead agency to make “mandatory findings of significance” if there is substantial evidence that a project may:
• Substantially degrade the quality of the environment, substantially reduce the habitat of a fish or wildlife species, cause a fish or wildlife population to drop below self-sustaining levels, threaten to eliminate a plant or animal community, or substantially reduce the number or restrict the range of an endangered, rare or threatened species. • Achieve short-term environmental goals to the detriment of long-term environmental goals.
• Produce environmental effects that are individually limited but cumulatively considerable, meaning that the incremental effects of the project are significant when viewed in connection with the effects of past projects, other current projects, and probable future projects.
3.2 NATIONAL ENVIORNMENTAL POLICY ACT
Projects that are proposed, funded, or authorized by federal agencies are generally subject to the provisions of NEPA. Signed into law in 1970 and amended by the Fiscal Responsibility Act of 2023, NEPA requires federal agencies to evaluate the environmental effects of their proposed actions prior to making decisions. Agencies must utilize systematic, interdisciplinary approach that includes the review of technically and economically feasible alternatives to the proposed action, and must ensure professional and scientific integrity in the environmental documents they prepare.
The level of NEPA review that is required is related to a project’s potential to cause “significant” environmental effects. Projects with reasonably foreseeable significant effects on the quality of the human environment require an Environmental Impact Statement (EIS). Among other elements, an EIS requires detailed analyses of the project’s environmental effects, development and study of a reasonable range of alternatives to the proposed action, and consideration of public comments received during the scoping process. Projects that do not have reasonably foreseeable significant effects on the quality of the human environment, and projects for which the significance of such effects is unknown, may meet their NEPA obligations with the 27 preparation of an Environmental Assessment (EA). An EA is a concise public document that either provides the basis for a federal agency’s finding of no significant impact or culminates in a determination that an EIS is necessary.
3.3 GENERAL PLAN POLICIES OF THE CITY OF COALINGA
In compliance with CEQA, the lead agency must consider conformance with applicable goals and policies of the General Plan of the City of Coalinga. The City of Coalinga General Plan was adopted in 2009 and was intended to guide planning decisions through 2025. It presents the City’s vision for long-term growth and development and establishes goals and policies to accomplish this vision. Current policies relevant to biological resources include (1) establishment/protection of a diverse network of open lands encompassing valuable natural and agricultural resources within and around urban Coalinga, (2) protection of streams, riparian corridors, and unique or sensitive habitats, (3) protection of special status plant and animal species and their habitats in accordance with local, state, and federal regulations, (4) preservation and enhancement of habitat linkages recognized by regulatory agencies and/or identified during the City’s development review process, and (5) protection of threatened and endangered species and their habitats addressed in the future Coalinga Habitat Conservation Plan (HCP).
3.4 THREATENED AND ENDANGERED SPECIES
In California, imperiled plants and animals may be afforded special legal protections under the California Endangered Species Act (CESA) and/or Federal Endangered Species Act (FESA).
Species may be listed as “threatened” or “endangered” under one or both Acts, and/or as “rare” under CESA. Under both Acts, “endangered” means a species is in danger of extinction throughout all or a significant portion of its range, and “threatened” means a species is likely to become endangered within the foreseeable future. Under CESA, “rare” means a species may become endangered if their present environment worsens. Both Acts prohibit “take” of listed species, defined under CESA as “to hunt, pursue, catch, capture, or kill, or attempt to hunt, pursue, catch, capture or kill” (California Fish and Game Code, Section 86), and more broadly defined under FESA to include “harm” (16 USC, Section 1532(19), 50 CFR, Section 17.3). The USFWS commonly interprets “take” to include the loss of habitat utilized by a listed species. 28 When state and federally listed species have the potential to be impacted by a project, the USFWS and CDFW must be included in the CEQA process. These agencies review the environmental document to determine the adequacy of its treatment of endangered species issues and to make project-specific recommendations for the protection of listed species. Projects that may result in the “take” of listed species must generally enter into consultation with the USFWS and/or CDFW pursuant to FESA and CESA, respectively. In some cases, incidental take authorization(s) from these agencies may be required before the project can be implemented.
3.5 MIGRATORY BIRDS
The Federal Migratory Bird Treaty Act (FMBTA: 16 USC 703-712) prohibits killing, possessing, or trading in any bird species covered in one of four international conventions to which the United States is a party, except in accordance with regulations prescribed by the Secretary of the Interior. The name of the act is misleading, as it actually covers almost all birds native to the United States, even those that are non-migratory. The FMBTA encompasses whole birds, parts of birds, and bird nests and eggs.
Native birds are also protected under California state law. The California Fish and Game Code makes it unlawful to take or possess any non-game bird covered by the FMBTA (Section 3513), as well as any other native non-game bird (Section 3800), even if incidental to lawful activities.
3.6 BIRDS OF PREY
Birds of prey are also protected in California under provisions of the State Fish and Game Code, Section 3503.5, 1992), which states that it is “unlawful to take, possess, or destroy any birds in the order Falconiformes or Strigiformes (birds of prey) or to take, possess, or destroy the nest or eggs of any such bird except as otherwise provided by this code or any regulation adopted pursuant thereto.” Construction disturbance during the breeding season could result in the incidental loss of fertile eggs or nestlings, or otherwise lead to nest abandonment. Disturbance that causes nest abandonment and/or loss of reproductive effort is considered “taking” by the CDFW.
29 3.7 NESTING BIRDS
In California, protection is afforded to the nests and eggs of all birds. California Fish and Game Code (Section 3503) states that it is “unlawful to take, possess, or needlessly destroy the nest or eggs of any bird except as otherwise provided by this code or any regulation adopted pursuant thereto.” Breeding-season disturbance that causes nest abandonment and/or loss of reproductive effort is considered a form of “take” by the CDFW.
3.8 HABITAT CONSERVATION PLANS AND NATURAL COMMUNITY
CONSERVATION PLANS
Section 10 of the federal Endangered Species Act establishes a process by which non-federal projects can obtain authorization to incidentally take listed species, provided take is minimized and thoroughly mitigated. A Habitat Conservation Plan (HCP), developed by the project applicant in collaboration with the USFWS and/or NMFS, ensures that such minimization and mitigation will occur, and is a prerequisite to the issuance of a federal incidental take permit.
Similarly, a Natural Community Conservation Plan (NCCP), developed by the project applicant in collaboration with CDFW, provides for the conservation of biodiversity within a project area, and permits limited incidental take of state-listed species.
3.9 WETLANDS AND OTHER JURISDICTIONAL WATERS
Section 404 of the federal Clean Water Act (CWA) regulates the discharge of dredged or fill material into “navigable waters” (33 U.S.C. §1344), defined in the CWA as “the waters of the United States, including the territorial seas” (33 U.S.C. §1362(7)). The CWA does not supply a definition for waters of the U.S., and that has been the subject of considerable debate since the CWA’s passage in 1972. A variety of regulatory definitions have been promulgated by the two federal agencies responsible for implementing the CWA, the Environmental Protection Agency (EPA) and USACE. These definitions have been interpreted, and in some cases, invalidated, by federal courts.
Waters of the U.S. are presently defined by the EPA and USACE’s joint 2023 Revised Definition of ‘Waters of the U.S.’ Rule (2023 WOTUS Rule), issued in January 2023 and amended in August 2023. Generally speaking, waters of the U.S. include:
30 • Waters which are currently used, or were used in the past, or may be susceptible to use in interstate or foreign commerce, including all waters which are subject to the ebb and flow of the tide
• The territorial seas
• Interstate waters
• Impoundments of waters otherwise defined as waters of the United States • Tributaries to other waters of the U.S. that are relatively permanent, standing or continuously flowing bodies of water
• Wetlands adjacent to other waters of the U.S. that have a continuous surface connection to those waters
The 2023 WOTUS Rule also defines a number of exclusions from the definition of waters of the U.S., many of which are longstanding exclusions from earlier regulatory regimes. These generally include:
• Waste treatment systems
• Prior converted cropland
• Ditches excavated wholly in and draining only dry land that do not carry a relatively permanent flow of water
• Certain artificial features, e.g. irrigation basins, swimming pools, borrow pits, and artificially irrigated areas
• Swales and erosional features characterized by low volume, infrequent, or short duration flow
All activities that involve the discharge of dredge or fill material into waters of the U.S. are subject to the permit requirements of the USACE. Such permits are typically issued on the condition that the applicant agrees to provide mitigation that result in no net loss of wetland functions or values.
Under the Porter-Cologne Water Quality Control Act of 1969, the State Water Resources Control Board (SWRCB) has regulatory authority to protect the water quality of all surface water and groundwater in the State of California (“waters of the State”). Nine RWQCBs oversee water quality at the local and regional level. The RWQCB for a given region regulates discharges of 31 fill or pollutants into waters of the State through the issuance of various permits and orders.
Discharges into waters of the State that are also waters of the U.S. require a Section 401 Water Quality Certification from the RWQCB as a prerequisite to obtaining a Section 404 Clean Water Act permit. Discharges into waters of the State that are not also waters of the U.S. require Waste Discharge Requirements (WDRs), or waivers of WDRs, from the RWQCB.
The SWRCB and RWQCBs also administer the federal National Pollution Discharge Elimination System (NPDES) program, which is concerned with the discharge of stormwater and other pollutants into water bodies. Projects that disturb one or more acres of soil must obtain coverage under the SWRCB’s current NPDES Construction Stormwater General Permit. A prerequisite for permit coverage is the development of a Storm Water Pollution Prevention Plan (SWPPP) by a certified Qualified SWPPP Developer. Other types of pollutant discharges into waters of the U.S., such as wastewater, may require coverage under a different NPDES general permit, and in some cases an individual permit.
CDFW has jurisdiction over the bed and bank of natural drainages and lakes according to provisions of Section 1601 and 1602 of the California Fish and Game Code. Activities that may substantially modify such waters through the diversion or obstruction of their natural flow, change or use of any material from their bed or bank, or the deposition of debris require a Notification of Lake or Streambed Alteration. If CDFW determines that the activity may adversely affect fish and wildlife resources, a Lake or Streambed Alteration Agreement will be prepared. Such an agreement typically stipulates that certain measures will be implemented to protect the habitat values of the lake or drainage in question. 32 4.0 IMPACTS AND MITIGATIONS
This impact assessment assumes that: (1) all project-related disturbance associated with sewer mains in roadways will be confined to the traveled way, (2) all project-related disturbance associated with sewer mains outside of roadways will be confined to a 20-foot-wide corridor centered on the pipe segment, (3) the entirety of the project site’s WWTP work area may be permanently or temporarily impacted by proposed activities at that location, (4) no tree or building removal will be required for any project component, and (5) where the sewer main alignment crosses an irrigation ditch between urban Coalinga and the WWTP, the ditch will not be physically disturbed because the pipe will be rehabilitated within its existing footprint using trenchless techniques.
4.1 POTENTIALLY SIGNIFICANT PROJECT IMPACTS
4.1.1 Project Impacts to Monarch Butterfly
Potential Impacts. As discussed, the monarch butterfly (Danaus plexippus) has some potential to reproduce, forage, and roost within the project site (see Table 2). Reproduction takes place solely on milkweed (Asclepias sp.) plants, which could conceivably be found in those portions of the sewer main work area that pass through residential yards or park land (urban land use type) or ruderal/fallow fields (rural land use type). Milkweed, and by extension breeding, is not expected in the highly degraded habitats of the WWTP work area. Foraging may take place in any vegetated portion of the project site; this includes portions of the WWTP work area that do not experience regular vegetation management. Finally, roosting is a possibility in the few trees of the sewer main work area.
If milkweed occurs in portions of the project site that are planned for impact, the project may result in mortality of monarch eggs, larvae, and pupae, as well as loss of monarch reproductive habitat. These are considered potentially significant impacts under CEQA and NEPA.
Project construction is not expected to adversely affect foraging or roosting monarchs. Monarchs are highly mobile while foraging and would presumably have the ability to avoid active construction zones. After construction, any habitats that provide nectar resources for monarchs 33 under existing conditions would be expected to naturally revegetate and return to their preproject level of suitability for this species. Because the project will not remove any trees, it will not impact any monarchs that happen to be roosting on site at the time of construction and will not result in loss of monarch roosting habitat.
Mitigation. The following measures will be implemented to reduce the magnitude of potential project impacts to the monarch butterfly.
Mitigation Measure 4.1.1a (Milkweed Survey). Prior to the start of construction, a qualified biologist will conduct a survey for milkweed plants in any portion of the sewer main work area that passes through residential yards, park land, ruderal/fallow fields, or other potentially suitable habitats. The survey will be conducted at a time of year when milkweed is readily identifiable. The objective of the survey will be to tally and map all milkweed plants that could potentially be impacted by project activities.
Mitigation Measure 4.1.1b (Construction Timing). If feasible, no milkweed plants will be removed during the period when monarchs may be breeding in the project vicinity, March 15-October 31 (The Xerces Society 2019).
Mitigation Measure 4.1.1c (Compensatory Mitigation). Any milkweed plants located within areas proposed for impact will be replaced at a 3:1 ratio in accordance with a revegetation plan prepared by a qualified biologist. The planting site(s) must be in similar or higher quality habitat to the habitat that was impacted, in area(s) that will not be treated with pesticides or herbicides.
Implementation of the above measures will reduce impacts to the monarch butterfly to a less than significant level under CEQA and NEPA.
4.1.2 Potential Project Impacts to the Southwestern Pond Turtle Potential Impacts. As discussed, the southwestern pond turtle (Actinemys pallida) is present at the WWTP. At the time of LOA’s survey, 36 individuals of this species were observed, evenly distributed among the three stabilization ponds. The turtles were of various growth stages, indicating that this is a breeding population. No turtles were observed in the aerated lagoons, and these features are presumably not suitable for this species due to surface turbulence and reduced water quality; the aerated lagoons represent an earlier stage of water treatment than the stabilization ponds. Pond turtles are likely to regularly bask in upland areas surrounding the three occupied ponds and may even nest within the fenced facility, as has been documented at 34 wastewater treatment facilities elsewhere in California (Davidson and Alvarez 2020; M.
Jennings, Rana Resources, pers. comm.). Water temperatures at the WWTP are likely warm enough that pond turtles would be able to remain active through much of the winter; however, during the coldest periods individuals may brumate underwater (M. Jennings, Rana Resources, pers. comm.).
During construction activities at the WWTP, resident pond turtles will be at considerable risk of direct injury or mortality, as well as disturbance leading to indirect mortality. Direct injury or mortality may result from heavy equipment operation in and around the occupied ponds.
Subterranean eggs or hatchlings may be crushed, and migrating turtles may be struck and killed.
Turtles may also respond to pond dewatering and construction-related noise and vibration by attempting to leave the area, making them vulnerable to predation and vehicle strikes.
Construction-related injury and mortality of southwestern pond turtles, both direct and indirect, is a potentially significant impact of this project under CEQA and NEPA.
During operation of the upgraded WWTP, pond turtles would not be at heightened risk of direct injury or mortality because operational activities will be similar to existing. However, indirect mortality is likely to be higher than under baseline conditions due to periodic dry-down of the percolation ponds. Following construction, any given percolation pond will receive treated effluent until percolation rates drop, at which point the pond will be allowed to dry down and will be disked prior to being placed back in service. Pond dry-down will force turtles on to land and potentially out of the WWTP facility altogether, increasing their vulnerability to predation and vehicle strikes. Indirect mortality of southwestern pond turtles during the operations phase is also a potentially significant impact of the project under CEQA and NEPA.
Proposed WWTP upgrades will increase the extent of potential aquatic habitat for the western pond turtle while decreasing its habitat value. Specifically, the project will convert approximately 12.5 acres of suitable, occupied ponds and approximately 6 acres of unsuitable, unoccupied ponds to approximately 18.5 acres of ponds with fluctuating suitability for southwestern pond turtles. On the one hand, the percolation ponds will have higher water quality than existing, with lower levels of biochemical oxygen demand (BOD), total suspended solids (NSS), and nitrogen. Improved water quality in the future percolation ponds may boost 35 invertebrate prey populations (M. Jennings, Rana Resources, pers. comm.) and otherwise benefit pond turtle fitness. On the other hand, unlike the stabilization ponds, the percolation ponds will not have a perennial inundation regime, but will cycle through inundated and dry periods based on percolation rates. At present, it is unknown how many months of the year any given pond will retain water. Habitat impacts are expected to have a net negative effect on southwestern pond turtles and are potentially significant under CEQA and NEPA.
Mitigation. The following measures will be implemented to reduce the magnitude of projectrelated impacts to the southwestern pond turtle.
Mitigation Measure 4.1.2a (Construction Timing). Construction activities at the WWTP will take place entirely between the months of November and March to avoid the typical timeframe for southwestern pond turtle nesting and egg incubation in this locality.
Mitigation Measure 4.1.2b (Preconstruction Survey). Within 24 hours prior to the start of construction at the WWTP, a qualified biologist will survey the WWTP work area to identify any locations of possible underground nests, as would be indicated by eggshells on the surface from predation. Because hatchlings sometimes overwinter underground in their nests, this survey is required even with the implementation of Mitigation Measure
4.1.2a above.
Mitigation Measure 4.1.2c (Environmental Awareness Training). Prior to the start of construction at the WWTP, construction personnel will be trained on the identification, behavior, and ecology of the southwestern pond turtle, and the project-specific measures adopted for its protection. Attendees will be given a handout that summarizes the training material and provides a photographic key to differentiating between the southwestern pond turtle and the common non-native red-eared slider. Attendance at all training sessions will be documented on sign-in sheets.
Mitigation Measure 4.1.2d (Refuge Ponds). Construction activities at the WWTP will be staged so that, at any given time, at least two ponds suitable for the southwestern pond turtles will be inundated to their full operational depth (“refuge ponds”). In the first stage, at least two of the existing stabilization ponds will remain inundated, as these (and not the aerated lagoons) are presently occupied by pond turtles. Construction activities may proceed at the remaining features. As any given feature is converted to a percolation pond and inundated to its full operational depth, it will become a refuge pond and one of the previous refuge ponds may be released for dewatering and construction.
Mitigation Measure 4.1.2e (Construction Monitoring). One or more qualified biologists will continuously monitor construction activities at the WWTP for the protection of southwestern pond turtles. The biologist(s) will look for pond turtles attempting to leave the ponds or otherwise traveling through upland areas of the WWTP, and will handcapture and relocate these individuals to the nearest refuge pond. Any red-eared sliders or 36 other introduced turtles that are discovered during this effort will be removed from the WWTP and either permanently rehomed or humanely dispatched. The biologist(s) will monitor all ground-disturbing activities in upland areas, looking for any subterranean nests or hatchlings that may be unearthed. The biologist(s) will have the authority to stop work if any nests or hatchlings are detected, and will appropriately secure the area before construction resumes. The number of biologists on site at any given time will be determined by the scope and extent of construction activities.
Mitigation Measure 4.1.2f (WWTP Operational Practices to Ensure No Net Loss of Aquatic Habitat). During operation of the upgraded WWTP, periodic dry-down and disking of the percolation ponds will be staged so that, at any given time, at least three ponds encompassing a minimum of 12.5 acres will be inundated to their full operational depth.
Mitigation Measure 4.1.2g (Habitat Enhancement). When inundated, each percolation pond will be equipped with at least three turtle basking structures. Such devices may consist of logs or floating boards, anchored with chains and weights, that can be removed during periods of dry-down and reinstalled once the pond is ready to be placed back in service.
Mitigation Measure 4.1.2h (Annual Monitoring). For the first five years postconstruction, a qualified biologist will conduct annual monitoring of the WWTP’s southwestern pond turtle population. Monitoring surveys will be conducted between May and July, when pond turtles are most active, and will target favorable weather conditions for basking. The biologist will assess aquatic habitat suitability by noting inundation levels, recording the species composition and cover of any emergent vegetation, conducting a dipnet survey for invertebrate food sources, and evaluating other parameters as appropriate. The biologist will record the number of all turtles observed by species and age class. An attempt will be made to capture any red-eared sliders or other introduced turtles that are discovered during annual monitoring; captured individuals will be removed from the WWTP and either permanently rehomed or humanely dispatched. The biologist will document their findings in an annual report, to be submitted to the City of Coalinga and other agencies as necessary. If any corrective actions are needed, they will be identified in the annual report and promptly implemented by the City.
Implementation of the above measures will reduce potential project impacts to the southwestern pond turtle to a less than significant level under CEQA and NEPA.
4.1.3 Potential Project Impacts to the Temblor Legless Lizard, California Glossy Snake, and San Joaquin Coachwhip
Potential Impacts. As discussed, three special status terrestrial reptiles, the Temblor legless lizard (Anniella alexanderae), California glossy snake (Arizona elegans occidentalis), and San Joaquin coachwhip (Masticophis flagellum ruddocki), have some potential to occur along the 37 Warthan and Los Gatos Creek corridors in the immediate project vicinity, and to wander onto the WWTP work area and/or rural portions of the sewer main work area from time to time. If any individuals of these species are present at the time of construction, they could be injured or killed by project activities. Construction-related injury or mortality of these three species is a potentially significant impact under CEQA and NEPA.
The project will not adversely affect the Temblor legless lizard, California glossy snake, or San Joaquin coachwhip through loss of habitat. The site consists of highly modified lands that do not constitute habitat for these special status reptiles but may nevertheless experience occasional use based on these species’ potential presence along the adjoining creek corridors. Nearly all project impacts will be temporary, with the sewer mains located belowground and any disturbed surface habitats expected to return to their pre-project level of suitability following project implementation. Considerable habitat of similar or higher quality for these species will remain available in the project vicinity. Project-related loss of habitat for the Temblor legless lizard, California glossy snake, and San Joaquin coachwhip is not considered a significant impact under CEQA and NEPA.
Mitigation. The following measures will be implemented to avoid and minimize constructionrelated impacts to the Temblor legless lizard, California glossy snake, and San Joaquin coachwhip.
Mitigation Measure 4.1.3a (Preconstruction Surveys). Within 24 hours prior to the start of construction activities at the WWTP and in rural portions of the sewer main work area, a qualified biologist will conduct preconstruction surveys for the Temblor legless lizard, California glossy snake, and San Joaquin coachwhip. The biologist will make an attempt to hand-capture any individuals of these species that are found and relocate them to suitable alternative habitat away from the work area.
Mitigation Measure 4.1.3b (Environmental Awareness Training). Prior to the start of construction at the WWTP and in rural portions of the sewer main work area, construction personnel will be trained on the identification, behavior, and ecology of the Temblor legless lizard, California glossy snake, and San Joaquin coachwhip, and the project-specific measures adopted for its protection. Attendees will be given a handout that summarizes the training material. Attendance at all training sessions will be documented on sign-in sheets.
Mitigation Measure 4.1.3c (Protective Measures During Construction). Workers will regularly inspect the work area for reptiles. At a minimum, this will include (1) checking 38 for reptiles under and around any parked vehicles or equipment prior to their operation, (2) scanning the ground for reptiles while operating vehicles or equipment, and (3) checking any open trenches or other excavations for trapped reptiles at the beginning and end of each work day. Any reptiles found during these inspections will be allowed to leave the area of their own volition, or will be captured and relocated out of harm’s way.
Implementation of these measures will reduce project-related impacts to the Temblor legless lizard, California glossy snake, and San Joaquin coachwhip to a less than significant level under CEQA and NEPA.
4.1.4 Potential Project Impacts to the Swainson’s Hawk
Potential Impacts. The Swainson’s hawk, a California Threatened species, is likely to forage in rural portions of the project site from time to time, and may also nest in mature trees on or near the site, particularly outside of the urban core of Coalinga. No trees will be removed by the project; therefore, there is no appreciable potential for direct injury or mortality of nesting Swainson’s hawks or their young. However, construction activities proximate to active nests may disturb the nests to the extent that the nests could fail or have reduced success. Project activities that injure, kill, or reduce the nesting success of Swainson’s hawks would violate state and federal laws and be considered a significant impact under CEQA and NEPA.
Swainson’s hawks would not be vulnerable to construction-related injury or mortality while foraging because they are highly mobile during this activity and are expected to avoid active work areas. The project is not expected to adversely affect this species through loss of foraging habitat. All impacts to potential Swainson’s hawk foraging habitat will be temporary, as the sewer mains will be buried and surface habitats will be allowed to return to pre-project conditions. Loss of habitat for the Swainson’s hawk is considered a less than significant impact of the project under CEQA and NEPA.
Mitigation. The following measures will be implemented to avoid and minimize constructionrelated impacts to Swainson’s hawk.
Mitigation Measure 4.1.4a (Construction Timing). If feasible, project construction will occur entirely outside of the March -September 15 Swainson’s hawk nesting season. 39 Mitigation Measure 4.1.4b (Protocol Nesting Surveys). If construction activities must occur between March 1 and September 15, then a qualified biologist will conduct protocol nesting surveys in accordance with the Swainson’s Hawk Technical Advisory Committee (SHTAC) 2000 Recommended Timing and Methodology for Swainson’s Hawk Nesting Surveys in California’s Central Valley. Surveys will be conducted in at least the two SHTAC-defined survey periods immediately preceding construction. The survey periods are Period 1: January-March 20, Period II: March 20-April 5, Period III:
April 5-20, Period IV: April 21-June 10, Period V: June 10-July 30.
Mitigation Measure 4.1.4c (Avoidance of Active Nests). Should any active nests be discovered within the survey area, an appropriate disturbance-free buffer will be established by the biologist based on local conditions and agency guidelines. Disturbance free buffers will be identified on the ground with flagging, fencing, or by other easily visible means and will be maintained until a qualified biologist has determined that the young have fledged and are capable of foraging independently.
Implementation of these measures will reduce project-related impacts to the Swainson’s hawk to a less than significant level under CEQA and NEPA and facilitate compliance with state and federal laws protecting this species.
4.1.5 Potential Project Impacts to the Burrowing Owl
Potential Impacts. Although LOA is not aware of any recent, nearby sightings of the burrowing owl, rural portions of the sewer main work area could potentially be used by individuals of this species if it occurs in the vicinity. Burrowing owls are particularly vulnerable to constructionrelated impacts while occupying underground burrows, either for nesting or roosting. In the unlikely event that one or more burrowing owls were to be occupying burrows within the project site at the time of construction, they could be injured or killed by construction activities, or, if nesting, could be disturbed such that they would abandon their eggs or young. Such an event would constitute a violation of the Migratory Bird Treaty Act and California Endangered Species Act, and would represent a significant impact of the project under CEQA and NEPA. Individuals of this species would not be vulnerable to construction-related injury or mortality while foraging because they are highly mobile foragers and would presumably avoid active work areas.
The project will not result in the loss of burrowing owl nesting or foraging habitat. All impacts to such habitats will be temporary, as the sewer mains will be buried and surface habitats will be allowed to return to pre-project conditions. Loss of habitat for the burrowing owl is considered a less than significant impact of the project under CEQA and NEPA. 40 Mitigation. The following measures will be implemented to avoid and minimize constructionrelated impacts to burrowing owls.
Mitigation Measure 4.1.5a (Take Avoidance Survey). A take avoidance survey for burrowing owls will be conducted by a qualified biologist within 14 days prior to the start of construction, following methods described in the Staff Report on Burrowing Owl Mitigation (CDFG 2012). The survey area will include all potential roosting and nesting habitat on or within 200 meters of the project site.
Mitigation Measure 4.1.5b (Avoidance of Active Burrows). If project activities are undertaken during the breeding season (February 1-August 31) and active nest burrows are identified within or near project impact areas, a 200-meter disturbance-free buffer will be established around these burrows. The buffers will be enclosed with temporary fencing to prevent construction equipment and workers from entering the setback area.
Buffers will remain in place for the duration of the breeding season. During the nonbreeding season (September 1-January 31), active burrowing owl burrows will be avoided by a minimum distance of 50 meters.
Mitigation Measure 4.1.5c (CDFW Consultation). If it is not feasible to avoid burrows by the setback distances specified above, the applicant will develop other measures to fully avoid take of burrowing owls in consultation with CDFW. If full take avoidance is not possible, the applicant will obtain a Section 2081 Incidental Take Permit (ITP) for this species. If an ITP is required, it would include minimization and mitigation measures including a passive relocation effort, construction monitoring, replacement burrow creation/enhancement, and/or other forms of compensatory mitigation.
Implementation of these measures will reduce potential project impacts to the burrowing owl to a less than significant level under CEQA and NEPA and facilitate compliance with state and federal laws protecting this species.
4.1.6 Potential Project Impacts to the San Joaquin Kit Fox Potential Impacts. Coalinga is known to support an urban-adapted population of the SJKF (Cypher et al. 2012). Individuals of this species have some potential to forage and den in both urban and rural portions of the sewer main work area, particularly outside of residential neighborhoods. SJKF are unlikely to occur within the fenced WWTP, but may occur within those portions of the WWTP work area outside of the fenceline. In the event that one or more SJKF individuals were to be occupying the project site at the time of construction, they could be injured or killed by construction activities. Such an event would constitute a violation of federal and state law and would represent a significant impact of the project under CEQA and NEPA. 41 The project will not result in the loss of denning or foraging habitat for this species. All impacts to such habitats will be temporary, as the sewer mains will be buried and surface habitats will be allowed to return to pre-project conditions. Loss of habitat for the SJKF is considered a less than significant impact of the project under CEQA and NEPA.
Mitigation. The applicant will implement the following measures derived from the USFWS 2011 Standardized Recommendations for Protection of the San Joaquin Kit Fox Prior to or During Ground Disturbance.
Mitigation Measure 4.1.6a (Pre-construction Surveys). Between 14 and 30 days prior to the start of any project activity that could potentially affect the SJKF, a qualified biologist will conduct preconstruction surveys for this species following the USFWS 2011 Standardized Recommendations for Protection of the Endangered San Joaquin Kit Fox Prior to or during Ground Disturbance (“Standardized Recommendations”). The primary objective will be to identify potential SJKF habitat features and evaluate their use by kit foxes.
Mitigation Measure 4.1.6b (Avoidance). Should one or more active kit fox dens be detected during preconstruction surveys, the USFWS and CDFW will be notified immediately. A disturbance-free buffer will be established around the dens in consultation with the USFWS and CDFW, to be maintained until an agency-approved biologist has determined that the dens have been abandoned.
Mitigation Measure 4.1.6c (Minimization). The applicant will implement all minimization measures presented in the USFWS Standardized Recommendations. Such measures include, but are not limited to: restriction of project-related vehicle traffic to established roads, construction areas, and other designated areas; measures to prevent the inadvertent entrapment of kit foxes in holes, trenches, and pipes; restriction of rodenticide and herbicide use; and proper disposal of food items and trash.
Mitigation Measure 4.1.6d (Environmental Awareness Training). A qualified biologist will provide training to all personnel who will be working on site. The training will include a description of the kit fox and its habitat needs; a report of the occurrence of kit fox in the project vicinity; an explanation of the status of the species and its protection under the Endangered Species Act; and a list of the measures being taken to reduce impacts to the species during project construction and implementation. A handout will be provided to all attendees that summarizes the information presented in the training and presents the contact name and number of a designated representative to contact in case SJKF individuals are observed in or near the work area during construction. 42 Implementation of these measures will reduce potential project impacts to the SJKF to a less than significant level under CEQA and NEPA and facilitate compliance with state and federal laws protecting this species.
4.1.7 Potential Project Impacts to the American Badger
Potential Impacts. Although badgers do not appear to be regularly sighted in the project vicinity, this wide-ranging species has some potential to pass through the area from time to time.
If present in the vicinity, then individuals could potentially forage and den in rural portions of the sewer main work area and/or in that portion of the WWTP work area outside of the fenceline.
Badgers are particularly vulnerable to construction-related impacts while in their dens. In the unlikely event that one or more badgers were to be occupying dens within the project site at the time of construction, they could be injured or killed by construction activities. Construction mortality of denning badgers is considered a potentially significant impact of the project under CEQA and NEPA. Individuals of this species would not be vulnerable to construction-related injury or mortality while foraging because they would presumably avoid foraging within active work areas, and because their nocturnal foraging behavior should prevent them from overlapping temporally with construction activities.
The project will not result in the loss of American badger denning or foraging habitat. All impacts to such habitats will be temporary, as the sewer mains will be buried and surface habitats will be allowed to return to pre-project conditions. Loss of habitat for the badger is considered a less than significant impact of the project under CEQA and NEPA.
Mitigation. The following measures will be implemented to avoid and minimize constructionrelated impacts to American badgers.
Mitigation Measure 4.1.7a (Preconstruction Surveys). A preconstruction survey for American badgers will be conducted by a qualified biologist within 7 days prior to the start of construction activities in rural portions of the sewer main work area and at the WWTP. The surveys will target all potential denning habitat on or within 50 feet of these areas.
Mitigation Measure 4.1.7b (Avoidance). Should an active sleeping den be identified during the preconstruction surveys, the den shall be identified in the field with brightlycolored fencing or flagging, and avoided until a qualified biologist has determined that it 43 has been abandoned. Should an active natal den be identified during the preconstruction surveys, a suitable disturbance-free buffer will be established around the den and maintained until a qualified biologist has determined that the cubs have dispersed or the den has been abandoned.
Implementation of the above measures will reduce potential project impacts to the American badger to a less than significant level under CEQA and NEPA
4.1.8 Potential Project Impacts to Nesting Migratory Birds and Raptors including the Long-eared Owl
Potential Impacts. The project site and adjoining lands have the potential to be used for nesting by a variety of migratory birds and raptors protected by the federal Migratory Bird Treaty Act and related state laws. This includes common species such as the mourning dove, killdeer, and American robin, but may also include several uncommon species. An example of the latter is the special status long-eared owl (Asio otus), which could nest immediately adjacent to the WWTP work area along the riparian corridor associated with Los Gatos Creek. If project construction takes place during the nesting season, birds nesting on the site could be injured or killed by construction activities, while birds nesting on or adjacent to the site could be disturbed such that they would abandon their nests. Construction-related mortality of nesting birds and disturbance leading to nest abandonment would violate state and federal laws and be considered a significant impact of the project under CEQA and NEPA.
The special status long-eared owl also has the potential to forage in rural portions of the project site. Individuals of this species would not be vulnerable to construction-related injury or mortality while foraging because they are highly mobile during this activity and because their nocturnal foraging behavior should prevent them from overlapping temporally with construction.
The project is not expected to adversely affect this species through loss of foraging habitat. All impacts to such habitats will be temporary, as the sewer mains will be buried and surface habitats will be allowed to return to pre-project conditions. Loss of habitat for the long-eared owl is considered a less than significant impact of the project under CEQA and NEPA.
Mitigation. The following measures will be implemented to avoid and minimize constructionrelated impacts to nesting migratory birds and raptors including the long-eared owl. 44 Measure 4.1.8a (Construction Timing). If feasible, project construction will occur entirely outside of the February 1-August 31 general avian nesting season.
Measure 4.1.8b (Preconstruction Surveys). If construction must occur between February 1 and August 31, a qualified biologist will conduct pre-construction surveys for active bird nests within 7 days prior to the start of any work within this period. The survey area will encompass the work area and surrounding lands within 250 feet for nesting migratory birds and 500 feet for raptors.
Measure 4.1.8c (Avoidance of Active Nests). Should any active nests be discovered in or near proposed construction zones, the biologist will identify a suitable construction-free buffer around the nest. The buffer distance will be determined based on species biology, site-specific conditions, and the level of project-related disturbance that is anticipated near the nest(s) in question. Buffers will be identified on the ground with flagging or fencing and will be maintained until the biologist has determined that the young have fledged and are capable of foraging independently.
Implementation of the above measures will reduce project impacts to nesting migratory birds and raptors, including the special status long-eared owl, to a less than significant level under CEQA and NEPA and facilitate compliance with state and federal laws.
4.2 LESS THAN SIGNIFICANT PROJECT IMPACTS
4.2.1 Project Impacts to Special Status Plant Species
Potential Impacts. Eighteen special status plant species have been documented in the regional vicinity of the project site (see Table 2). All are considered absent from the project site due to the absence of suitable habitat and/or the site’s being located outside of the species’ distribution. The project is not expected to affect individuals or regional populations of these 18 species because they have no appreciable potential to occur on site.
Mitigation. Mitigation measures are not warranted.
4.2.2 Project Impacts to Special Status Animal Species that Would Use the Site for Nonsensitive Activities Only Potential Impacts. Of the 13 special status animal species potentially occurring on site, one species, the tricolored blackbird (Agelaius tricolor) is not expected to use the site for sensitive activities such as breeding, nesting, or communal roosting, nor is it likely to breed, nest, or 45 communally roost close enough to the site that it would be vulnerable to construction-related disturbance during these activities (see Table 2). Any tricolored blackbird use of the site would be limited to foraging. Tricolored blackbirds are highly mobile during this activity and would be expected to simply avoid active work areas.
The project will not adversely affect tricolored blackbirds through loss of habitat. The site does not offer unique habitat for this species; similar and higher quality habitats are regionally abundant. Moreover, all impacts to potential tricolored blackbird foraging habitat will be temporary, as the sewer mains will be buried and surface habitats will be allowed to return to pre-project conditions. For these reasons, project-related impacts to the tricolored blackbird are considered less than significant under CEQA and NEPA.
Mitigation. Mitigation is not warranted.
4.2.3 Project Impacts to Roosting Bats including Townsend’s Big-eared Bat and Western Mastiff Bat
Potential Impacts. The project site’s trees and buildings have the potential to be used by roosting bats, possibly including the Townsend’s big-eared bat (Corynorhinus townsendii) and western mastiff bat (Eumops perotis californicus), both California Species of Special Concern.
No trees or buildings will be removed under current project design; therefore, roosting bats will not be at risk of construction-related injury or mortality.
The Townsend’s big-eared bat and western mastiff bat may also forage over the project site.
These species would not be vulnerable to construction-related injury or mortality while foraging because they are highly mobile during this activity and would be expected to simply avoid active work areas. Moreover, these species forage nocturnally, when construction will presumably not be taking place. The project will not adversely affect the Townsend’s big-eared bat and western mastiff bat through loss of habitat. The site does not offer unique habitat for these species; similar and higher quality habitats are regionally abundant. Nearly all project impacts will be temporary, with the sewer mains placed belowground and surface habitats allowed to return to pre-project conditions.
46 For these reasons, project-related impacts to roosting bats, including the Townsend’s big-eared bat and western mastiff bat, are considered less than significant under CEQA and NEPA.
Mitigation. Mitigation is not warranted.
4.2.4 Project Impacts to Special Status Animal Species Absent from, or Unlikely to Occur within, the Project Site
Potential Impacts. Of the 29 special status animal species that potentially occur in the general vicinity of the site, 16 are considered absent or unlikely to occur within the project site due to the absence of suitable habitat, and/or the project site’s being situated outside of the species’ known distribution (see Table 2). These are the Crotch’s bumble bee (Bombus crotchii), vernal pool fairy shrimp (Branchinecta lynchi), California tiger salamander (Ambystoma californiense), foothill yellow-legged frog (Rana boylii), California red-legged frog (Rana draytonii), western spadefoot (Spea hammondii), blunt-nosed leopard lizard (Gambelia sila), California condor (Gymnogyps californianus), San Joaquin antelope squirrel (Ammospermophilus nelsoni), giant kangaroo rat (Dipodomys ingens), coast horned lizard (Phrynosoma blainvillii), northern California legless lizard (Anniella pulchra), Le Conte’s thrasher (Toxostoma lecontei), yellowheaded blackbird (Xanthocephalus xanthocephalus), short-nosed kangaroo rat (Dipodomys nitratoides brevinasus), and Tulare grasshopper mouse (Onychomys torridus tularensis). The project has no appreciable potential to affect these species through construction mortality/disturbance or loss of habitat because there is little or no likelihood that they utilize the site.
Mitigation. Mitigation is not warranted.
4.2.5 Project Impacts to Riparian Habitat and Sensitive Natural Communities Potential Impacts. The project does not contain riparian habitat or any sensitive natural communities. There will be no impact to such resources.
Mitigation. Mitigation measures are not warranted.
47 4.2.6 Potential Project Impacts to Waters of the State and U.S.
Potential Impacts. The project site’s wastewater treatment ponds and irrigation ditch may be regulated by the RWQCB but do not meet the definition of a Water of the U.S. Although the treatment ponds will be impacted through the removal of clay liners and changed inundation regimes, the project is not expected to substantially alter the ecological function and value of these manmade features. The sewer main that crosses the irrigation ditch is proposed for rehabilitation using trenchless techniques; the ditch will not be physically disturbed. For these reasons, project impacts to Waters of the State are considered less than significant under CEQA and NEPA. The project will have no impact on Waters of the U.S.
Mitigation. Mitigation is not warranted.
4.2.7 Project Impacts to Wildlife Movement Corridors
Potential Impacts. As discussed, the project site itself does not contain any wildlife movement corridors, but Los Gatos Creek adjoins the WWTP work area and is likely to function as a regionally important corridor. The subject reach of Los Gatos Creek is likely to experience some amount of ambient disturbance under existing conditions, as WWTP operational activities include daily vehicular travel and occasional heavy equipment use. Noise disturbance during construction will exceed baseline levels, but for a relatively short period of time. Animals may temporarily shift their use of or movement along this reach of Los Gatos Creek while work is occurring, but following construction, wildlife use of the creek corridor is expected to return to baseline conditions. Project-related impacts to wildlife movement corridors are considered less than significant under CEQA and NEPA.
Mitigation. Mitigation is not warranted.
4.2.8 Project Impacts to Designated Critical Habitat
Potential Impacts. The project will have no effect on designated critical habitat because critical habitat is absent from the project site and adjacent lands.
Mitigation. Mitigation is not warranted.
48 4.2.9 Local Policies or Habitat Conservation Plans
Potential Impacts. It is assumed that the project will be implemented in a manner consistent with the City of Coalinga General Plan policies related to biological resources. No habitat conservation plans are known to pertain to the area containing the project site.
Mitigation. No mitigation is required.
4.3 SECTION 7 DETERMINATIONS FOR FEDERALLY LISTED SPECIES Table 3 below presents LOA’s preliminary FESA Section 7 effect determinations for federally listed and proposed species found on the USFWS IPaC list and CNDDB list generated for the project, based on currently available information and a level of analysis appropriate for a CEQA Mitigated Negative Declaration and/or NEPA Environmental Assessment. Candidate species are not included in Table 3 because they do not require Section 7 consultation.
TABLE 3: SECTION 7 EFFECT DETERMINATIONS FOR FEDERALLY LISTED SPECIES Species ESA Status Determination Rationale for the Determination California Jewelflower
(Caulanthus californicus)
Endangered No effect Species is absent (no suitable habitat) San Joaquin Woollythreads
(Monolopia congdonii)
Endangered No effect Species is absent (no suitable habitat) Monarch Butterfly
(Danaus plexippus)
Proposed
Threatened
No jeopardy This species may occur on site;
conservation measures will be
implemented to avoid take
Vernal Pool Fairy Shrimp
(Branchinecta lynchi)
Threatened No effect Species is absent (no suitable habitat) California Tiger
Salamander
(Ambystoma californiense)
Threatened No effect Species is absent (no suitable habitat) Foothill Yellow-legged Frog
(Rana boylii)
Threatened No effect Species is absent (no suitable habitat) California Red-legged Frog
(Rana draytonii)
Threatened No effect Species is absent (no suitable habitat) Western Spadefoot
(Spea hammondii)
Proposed
Threatened
No jeopardy Species is absent (no suitable habitat)
Southwestern Pond Turtle
(Actinemys pallida)
Proposed
Threatened
No jeopardy This species occupies the WWTP
work area; conservation measures
will be implemented to avoid take
49 TABLE 3 (CONT’D)
Species ESA Status Determination Rationale for the Determination Blunt-nosed Leopard
Lizard
(Gambelia sila)
Endangered No effect No appreciable potential for species to occur on site (landscape-level
factors, unsuitable habitat)
California Condor
(Gymnogyps californianus)
Endangered No effect Species is absent (no suitable habitat) Giant Kangaroo Rat
(Dipodomys ingens)
Endangered No effect Species is absent (no suitable habitat) San Joaquin Kit Fox
(SJKF)
(Vulpes macrotis mutica)
Endangered May affect, not
likely to
adversely affect
This species may occur on site;
conservation measures will be
implemented to avoid take
50 5.0 LITERATURE REFERENCED
Baldwin, B.G., D.H. Goldman, D.J. Keil, R. Patterson, T.J. Rosatti, and D. G. Wilken, editors. 2012. The Jepson Manual: Vascular Plants of California, second edition. University of California Press, Berkeley.
Baumberger, K. L., M. V. Eitzel, M. E. Kirby, and M. H. Horn. 2019. Movement and habitat selection of the western spadefoot (Spea hammondii) in southern California. PLoS ONE 14(10): e0222532. Available at: https://doi.org/10.1371/journal.pone.0222532 Calflora. 2025. Calflora: An online database of plant identification and distribution [web application]. Calflora, Berkeley, California. Available: http://www.calflora.org.
California Department of Fish and Wildlife (CDFW). 2025. California Natural Diversity Database. The Resources Agency, Sacramento, CA.
________. 2002. California Fish and Game Code. Gould Publications. Binghamton, NY.
California Native Plant Society. 2025. Inventory of Rare and Endangered Vascular Plants of California. Available online at: http://cnps.site.aplus.net/cgi-bin/inv/inventory.cgi.
California Soil Resource Lab. 2008. Streaming, seamless interface to USDA-NCSS SSURGO and STATSGO Soil Survey Products.
Cypher, B., C. Van Horn Job, and S. Phillips. 2012. Conservation strategies for San Joaquin kit foxes in urban environments. Prepared for the U.S. Bureau of Reclamation Agreement No. R11AP20502.
Davidson, K. A. and J. A. Alvarez. 2020. A review and synopsis of nest site selection and site characteristics of western pond turtles. Western Wildlife 7:42-49. eBird. 2025. eBird: An online database of bird distribution and abundance [web application]. eBird, Cornell Lab of Ornithology, Ithaca, New York. Available: http://www.ebird.org. iNaturalist. 2025. Available: https://www.inaturalist.org/ Natural Resources Conservation Service. 2011. National Hydric Soils List by State, California.
U.S. Department of Agriculture.
Swainson’s Hawk Technical Advisory Committee. 2000. Recommended Timing and Methodology for Swainson’s Hawk Nesting Surveys in California’s Central Valley. 5 pp.
The Xerces Society. 2019. A Quick Guide to Monarch Habitat on Farms in California’s Central Valley. Publication 19-033_01.
U.S. Fish and Wildlife Service. 2025. IPaC Resource List, Information for Planning and Consultation (IPaC). Available: https://ecos.fws.gov/ipac. 51 USFWS. 2010. Giant Kangaroo Rat (Dipodomys ingens) 5-year Review: Summary and Evaluation. Sacramento Fish and Wildlife Office, Sacramento, CA.
Wetland Training Institute, Inc. 1991. Federal Wetland Regulation Reference Manual. B.N.
Goode and R.J. Pierce (eds.) WTI 90-1. 281pp.
Zeiner, David C., William F. Laudenslayer, Kenneth E. Mayer and Marshal White. Ed. 1988.
California’s wildlife, volume I, amphibians and reptiles, volume II, birds, and volume III, mammals. Department of Fish and Game. Sacramento, CA. Online:
http://www.dfg.ca.gov/biogeodata/cwhr/cawildlife.aspx
52 APPENDIX A: VASCULAR PLANTS OF THE PROJECT SITE
53 APPENDIX A: VASCULAR PLANTS OF THE PROJECT SITE
The plant species listed below were observed on the project site during surveys conducted by Live Oak Associates, Inc. on March 20 and 21, 2025. The wetland indicator status of each plant, derived from the USACE-administered National Wetland Plant List for the Arid West Region, has been shown following its common name if available.
OBL - Obligate
FACW - Facultative Wetland
FAC - Facultative
FACU - Facultative Upland
UPL - Upland
NR - No review
NA - No agreement
NI - No investigation
ANACARDIACEAE – Sumac Family
Schinus molle Peppertree FACU
Searsia lancea African Sumac UPL
APOCYNACEAE – Dogbane Family
Nerium oleander Oleander UPL
ARALIACEAE – Ginseng Family
Hedera helix English Ivy FACU
ARECACEAE – Palm Family
Washingtonia filifera California Fan Palm FAC
Washingtonia robusta Mexican Fan Palm FACW
ASTERACEAE – Sunflower Family
Helianthus annus Sunflower FACU
Lactuca serriola Prickly Lettuce FACU
Matricaria discoidea Pineappleweed
Senecio vulgaris Common Groundsel FAC
Sonchus oleraceus Sowthistle UPL
BETULACEAE – Birch Family
Alnus rhombifolia White Alder FACW
BRASSICACEAE – Mustard Family
Brassica spp. Mustard UPL
Capsella bursa-pastoris Shepherd’s Purse FACU
Sisymbrium irio London Rocket UPL
BUXACEAE – Box Family
Buxus spp. Boxwood UPL
CACTACEAE – Cactus Family
Opuntia spp. Prickly Pear UPL
CHENOPODACEAE – C Family
Salsola tragus Russian Thistle FACU
CUPRESSACEAE – Cypress Family
54 Calocedrus decurrens Incense Cedar UPL
Juniperus californica California Juniper FACU
FABACEAE – Bean Family
Albizia julibrissin Mimosa Tree UPL
Ceratonia siliqua Carob UPL
Cercis occidentalis California Redbud UPL
FAGACEAE – Oak Family
Quercus spp. Oak
Quercus lobata Valley Oak FACU
Quercus suber Cork Oak UPL
Quercus wislizeni Interior Live Oak UPL
GERANIACEAE – Geranium Family
Erodium cicutarium Redstem Filaree UPL
JUGLANDACEAE – Walnut Family
Carya illinoinensis Peacan FAC
LYTHRACEAE – Mahogany Family
Lagerstroemia spp. Crepe Myrtle UPL
Punica granatum Pomegranate UPL
MAGNOLIACEAE – Magnolia Family
Magnolia spp. Magnolia UPL
MALVACEAE – Mallow Family
Malva parviflora Cheeseweed UPL
MELIACEAE – Mahogany Family
Melia azedarach Chinaberry UPL
MORACEAE – Fig Family
Ficus carica Fig UPL
Morus alba White Mulberry FACU
MYTACEAE – Myrtle Family
Eucalyptus spp. Eucalyptus
Myrtus communis Common Myrtle UPL
OLEACEAE – Olive Family
Olea europaea Olive UPL
Ligustrum lucidum Glossy Privet
PINACEAE – Pine Family
Cedrus deodara Deodar Cedar UPL
Pinus brutia Turkish Pine UPL
Pinus halepensis Aleppo Pine UPL
Pinus sabiniana Foothill Pine UPL
Pinus spp. Pine
POACEAE – Grass Family
Bromus diandrus Ripgut Brome UPL
Bromus rubens Red Brome UPL
Cynodon dactylon Bermuda Grass FACU
Echinochloa crus-galli Barnyard Grass FACW
Hordeum murinum Foxtail Barley FACU
Poa annua Lawn Grass FAC
55 ROSACEAE – Rose Family
Prunus sp. Stone Fruit
Prunus cerasifera Cherry Plum
Pyrus calleryana Bradford Pear UPL
Rosa spp. Ornamental Rose
RUTACEAE – Citrus Family
Citrus x sinensis Orange UPL
Citrus x limon Lemon UPL
SALICACEAE – Willow Family
Populus fremontii Fremont’s Cottonwood FAC
Populus nigra Italian Poplar FAC
Salix spp. Willow
SAPINDACEAE – Soapberry Family
Acer spp. Maple
Acer palmatum Japanese Maple
TAMARICACEAE – Tamarisk Family
Tamarix ramossima Saltcedar Tamarisk FAC
ULMACEAE – Elm Family
Ulmus parvifolia Chinese Elm UPL
VITACEAE – Elm Family
Vitis spp. Grape
56 APPENDIX B: TERRESTRIAL VERTEBRATE SPECIES THAT POTENTIALLY
OCCUR ON THE PROJECT SITE
57 APPENDIX B: TERRESTRIAL VERTEBRATE SPECIES THAT POTENTIALLY
OCCUR ON THE PROJECT SITE
The species listed below are those that may be expected to routinely and predictably use or pass through the project site during some or all of the year. The list was not intended to include birds that are vagrants or occasional transients. Terrestrial vertebrate species observed on or adjacent to the project site during surveys conducted by Live Oak Associates, Inc. on March 20 and 21, 2025 have been noted with an asterisk.
CLASS: AMPHIBIA (Amphibians)
ORDER: SALIENTIA (Frogs and Toads)
FAMILY: BUFONIDAE (True Toads)
Western Toad (Bufo boreas)
FAMILY: HYLIDAE (Treefrogs and relatives)
Sierran Treefrog (Pseudacris sierra)
FAMILY: RANIDAE (True Frogs)
Bullfrog (Lithobates catesbeianus)
CLASS: REPTILIA (Reptiles)
ORDER: TESTUDINES (Turtles)
SUBORDER: CRYPTODIRA (Hidden-neck Turtles)
FAMILY: EMYDIDAE
*Southwestern Pond Turtle (Actinemys pallida)
Red-eared Slider (Trachemys scripta)
ORDER: SQUAMATA (Lizards and Snakes)
SUBORDER: SAURIA (Lizards)
FAMILY: PHRYNOSOMATIDAE
Western Fence Lizard (Sceloporus occidentalis)
Side-blotched Lizard (Uta stansburiana)
SUBORDER: SERPENTES (Snakes)
FAMILY: COLUBRIDAE (Colubrids)
Pacific Gopher Snake (Pituophis catenifer catenifer)
Common Kingsnake (Lampropeltis getulus)
Common Garter Snake (Thamnophis sirtalis)
FAMILY: VIPERIDAE (Vipers)
Western Rattlesnake (Crotalus viridis)
CLASS: AVES
ORDER: ANSERIFORMES (Ducks, Geese, and Swans)
FAMILY: ANATIDAE (Ducks, Geese, and Swans)
*Mallard (Anas platyrhynchos)
Gadwall (Anas strepera)
*American Wigeon (Mareca americana)
*Cinnamon Teal (Anas cyanoptera)
*Northern Shoveler (Anas crecca)
*Green-winged Teal (Anas cyanoptera)
58 Ring-necked Duck (Aythya collaris)
Lesser Scaup (Aythya affinis)
Bufflehead (Bucephala albeola)
*Ruddy Duck (Oxyura jamaicensis)
ORDER: PELECANIFORMES (Wading Birds)
FAMILY: ARDEIDAE (Herons)
*Great Egret (Ardea alba)
Snowy Egret (Egretta thula)
ORDER: ACCIPITRIFORMES (Hawks, Eagles, Vultures, and Kites) FAMILY: CATHARTIDAE (New World Vultures)
Turkey Vulture (Cathartes aura)
FAMILY: ACCIPITRIDAE (Hawks, Eagles, Kites, Old World Vultures, and Harriers) Cooper’s Hawk (Accipiter cooperi)
*Red-tailed Hawk (Buteo jamaicensis)
Red-shouldered Hawk (Buteo lineatus)
Swainson’s Hawk (Buteo swainsoni)
FAMILY: FALCONIDAE (Caracaras and Falcons)
Merlin (Falco columbarius)
*American Kestrel (Falco sparverius)
ORDER: GALLIFORMES (Megapodes, Currassows, Pheasants, and Relatives) FAMILY: ODONTOPHORIDAE (New World Quails)
California Quail (Callipepla californica)
FAMILY: PHASIANIDAE (Pheasants, Chickens, Turkeys and Allies) Domestic Chicken (Gallus gallus domesticus)
ORDER: GRUIFORMES (Cranes and Rails)
FAMILY: RALLIDAE (Rails, Gallinules, and Coots)
American Coot (Fulica americana)
ORDER: CHARADRIIFORMES (Shorebirds, Gulls, and relatives) FAMILY: CHARADRIIDAE (Plovers and relatives)
*Killdeer (Charadrius vociferus)
FAMILY: RECURVIROSTRIDAE (Stilts and Avocets)
*Black-necked Stilt (Himantopus mexicanus)
American Avocet (Recurvirostra americana)
FAMILY: SCOLOPACIDAE (Sandpipers and Allies)
Wilson’s Snipe (Gallinago delicata)
*Greater Yellowlegs (Tringa melanoleuca)
*Least Sandpiper (Calidris minutilla)
ORDER: CUCULIFORMES (Cuckoos)
FAMILY: CUCULIDAE (Cuckoos)
*Greater Roadrunner (Geococcyx californianus)
ORDER: COLUMBIFORMES (Pigeons and Doves)
FAMILY: COLUMBIDAE (Pigeons and Doves)
*Rock Pigeon (Columba livia)
*Mourning Dove (Zenaida macroura)
*Eurasian Collared Dove (Streptopelia decaocto)
ORDER: STRIGIFORMES (Owls)
59 FAMILY: TYTONIDAE (Barn Owls)
Barn Owl (Tyto alba)
ORDER: APODIFORMES (Swifts and Hummingbirds)
FAMILY: TROCHILIDAE (Hummingbirds)
Black-chinned Hummingbird (Archilochus alexandri)
Anna’s Hummingbird (Calypte anna)
ORDER: PASSERIFORMES (Perching Birds)
FAMILY: TYRANNIDAE (Tyrant Flycatchers)
*Black Phoebe (Sayornis nigricans)
Say’s Phoebe (Sayornis saya)
Western Kingbird (Tyrannus verticalis)
FAMILY: CORVIDAE (Jays, Magpies, and Crows)
California Scrub Jay (Aphelocoma coerulescens)
*American Crow (Corvus brachyrhynchos)
Common Raven (Corvus corax)
FAMILY: ALAUDIDAE (Larks)
Horned Lark (Eremophila alpestris)
FAMILY: HIRUNDINIDAE (Swallows)
Cliff Swallow (Petrochelidon pyrrhonota)
Barn Swallow (Hirundo rustica)
Northern Rough-winged Swallow (Stelgidopteryx serripennis) FAMILY: AEGITHALIDAE (Titmice)
*Oak Titmouse (Baeolophus inornatus)
FAMILY: AEGITHALIDAE (Bushtits)
Bushtit (Psaltriparus minimus)
FAMILY: TURDIDAE (Thrushes)
Western Bluebird (Sialia mexicana)
American Robin (Turdus migratorius)
FAMILY: MIMIDAE (Mockingbirds and Thrashers)
*Northern Mockingbird (Mimus polyglottos)
FAMILY: PARULIDAE (Wood Warblers and Relatives)
Yellow-rumped Warbler (Dendroica coronata)
FAMILY: STURNIDAE (Starlings and Allies)
*European Starling (Sturnus vulgaris)
FAMILY: MOTACILLIDAE (Wagtails and Pipits)
*American Pipit (Anthus rubrescens)
FAMILY: EMBERIZIDAE (Sparrows)
*Savannah Sparrow (Passerculus sandwichensis)
*White-crowned Sparrow (Zonotrichia leucophrys)
Golden-crowned Sparrow (Zonotrichia atricapilla)
California Towhee (Pipilo crissalis)
FAMILY: ICTERIDAE (Blackbirds, Orioles and Allies)
Western Meadowlark (Sturnella neglecta)
Red-winged Blackbird (Agelaius phoeniceus)
Great-tailed Grackle (Quiscalus mexicanus)
*Brewer's Blackbird (Euphagus cyanocephalus)
60 Brown-headed Cowbird (Molothrus ater)
Bullock’s Oriole (Icterus bullockii)
FAMILY: FRINGILLIDAE (Finches)
*House Finch (Haemorhous mexicanus)
*Lawernce’s Goldfinch (Spinus lawrencei)
Lesser Goldfinch (Carduelis psaltria)
FAMILY: PASSERIDAE (Old World Sparrows)
*House Sparrow (Passer domesticus)
CLASS: MAMMALIA
ORDER: DIDELPHIMORPHIA (Marsupials)
FAMILY: DIDELPHIDAE (Opossums)
Virginia Opossum (Didelphis virginiana)
ORDER: INSECTIVORA (Shrews and Moles)
FAMILY: TALPIDAE (Moles)
Broad-footed Mole (Scapanus latimanus)
ORDER: CHIROPTERA (Bats)
FAMILY: VESPERTILIONIDAE (Vespertilionid Bats)
Pale Big-eared Bat (Corynorhinus townsendii pallescens) Big Brown Bat (Eptesicus fuscus)
Yuma Myotis (Myotis yumanensis)
California Myotis (Myotis californicus)
Western Pipistrelle (Pipistrellus hesperus)
FAMILY: MOLOSSIDAE (Free-tailed Bat)
Brazilian Free-tailed Bat (Tadarida brasiliensis)
ORDER: LAGOMORPHA (Rabbits, Hares, and Pikas)
FAMILY: LEPORIDAE (Rabbits and Hares)
*Audubon’s Cottontail (Sylvilagus audubonii)
Black-tailed Jackrabbit (Lepus californicus)
ORDER: RODENTIA (Rodents)
FAMILY: SCIURIDAE (Squirrels, Chipmunks, and Marmots)
*California Ground Squirrel (Otospermophilus beecheyi)
FAMILY: GEOMYIDAE (Pocket Gophers)
Botta’s Pocket Gopher (Thomomys bottae)
FAMILY: MURIDAE (Mice, Rats and Voles)
Western Harvest Mouse (Reithrodontomys megalotis)
Deer Mouse (Peromyscus maniculatus)
Norway Rat (Rattus norvegicus)
House Mouse (Mus musculus)
California Vole (Microtus californicus)
FAMILY: HETEROMYIDAE (Kangaroo Rats)
Heermann’s Kangaroo Rat (Dipodomys heermanni)
ORDER: CARNIVORA (Carnivores)
FAMILY: CANIDAE (Foxes, Wolves, and Relatives)
Red Fox (Vulpes vulpes)
Coyote (Canis latrans)
61 *Domestic Dog (Canis familiaris)
FAMILY: PROCYONIDAE (Raccoons and Relatives)
Raccoon (Procyon lotor)
FAMILY: MUSTELIDAE (Weasels and Relatives)
Striped Skunk (Mephitis mephitis)
FAMILY: FELIDAE (Cats)
*Feral Cat (Felis catus)
62 APPENDIX C: SELECTED SITE PHOTOGRAPHS
63 Photo 1 (above): Urban portion of the sewer main work area, showing a paved street. Photo 2 (below): Urban portion of the sewer main work area, showing an alley. 64 Photo 3 (above): Urban portion of the sewer main work area, showing park land. Photo 4 (below): Urban portion of the sewer main work area, showing a parking lot. 65 Photo 5 (above): Rural portion of the sewer main work area, showing unpaved road. Photo 6 (below): Rural portion of the sewer main work area, facing west along fallow field (center/right) and irrigation ditch (left). The irrigation ditch is outside of project boundaries at this location, but is crossed by the sewer main alignment farther to the west. 66 Photo 7 (above): Existing stabilization ponds at the WWTP; pictured are the two easternmost ponds. Photo 8 (below): Existing aerated lagoons at the WWTP. 67 Photo 9 (above): Disturbed uplands of the WWTP work area, inside fenced facility. Photo 10 (below): Disturbed uplands of the WWTP work area, outside fenced facility. 68 Photo 11 (above): Southwestern pond turtle observed at one of the existing stabilization ponds in March 2025.
69 APPENDIX D: USFWS INFORMATION FOR PLANNING AND CONSULTATION
OFFICIAL SPECIES LIST
IPaC resource list
This report is an automatically generated list of species and other resources such as critical habitat (collectively referred to as trust resources) under the U.S. Fish and Wildlife Service's (USFWS) jurisdiction that are known or expected to be on or near the project area referenced below. The list may also include trust resources that occur outside of the project area, but that could potentially be directly or indirectly affected by activities in the project area. However, determining the likelihood and extent of effects a project may have on trust resources typically requires gathering additional site-specific (e.g., vegetation/species surveys) and project-specific (e.g., magnitude and timing of proposed activities) information.
Below is a summary of the project information you provided and contact information for the USFWS office(s) with jurisdiction in the defined project area. Please read the introduction to each section that follows (Endangered Species, Migratory Birds, USFWS Facilities, and NWI Wetlands) for additional information applicable to the trust resources addressed in that section.
Location
Fresno County, California
Local office
Sacramento Fish And Wildlife Office
(916) 414-6600
(916) 414-6713
Federal Building
IPaC U.S. Fish & Wildlife Service
2800 Cottage Way, Room W-2605
Sacramento, CA 95825-1846
Endangered species
This resource list is for informational purposes only and does not constitute an analysis of project level impacts.
The primary information used to generate this list is the known or expected range of each species.
Additional areas of influence (AOI) for species are also considered. An AOI includes areas outside of the species range if the species could be indirectly affected by activities in that area (e.g., placing a dam upstream of a fish population even if that fish does not occur at the dam site, may indirectly impact the species by reducing or eliminating water flow downstream). Because species can move, and site conditions can change, the species on this list are not guaranteed to be found on or near the project area. To fully determine any potential effects to species, additional sitespecific and project-specific information is often required.
Section 7 of the Endangered Species Act requires Federal agencies to "request of the Secretary information whether any species which is listed or proposed to be listed may be present in the area of such proposed action" for any project that is conducted, permitted, funded, or licensed by any Federal agency. A letter from the local office and a species list which fulfills this requirement can only be obtained by requesting an official species list from either the Regulatory Review section in IPaC (see directions below) or from the local field office directly.
For project evaluations that require USFWS concurrence/review, please return to the IPaC website and request an official species list by doing the following:
1. Draw the project location and click CONTINUE.
2. Click DEFINE PROJECT.
3. Log in (if directed to do so).
4. Provide a name and description for your project.
5. Click REQUEST SPECIES LIST.
Listed species and their critical habitats are managed by the Ecological Services Program of the U.S. Fish and Wildlife Service (USFWS) and the fisheries division of the National Oceanic and Atmospheric Administration (NOAA Fisheries ).
Species and critical habitats under the sole responsibility of NOAA Fisheries are not shown on this list. Please contact NOAA Fisheries for species under their jurisdiction.
1. Species listed under the Endangered Species Act are threatened or endangered; IPaC also shows species that are candidates, or proposed, for listing. See the listing status page for more information. IPaC only shows species that are regulated by USFWS (see FAQ).
2. NOAA Fisheries, also known as the National Marine Fisheries Service (NMFS), is an office of the National Oceanic and Atmospheric Administration within the Department of Commerce. 1 2
The following species are potentially affected by activities in this location:
Mammals
Birds
Reptiles
Amphibians
NAME STATUS
Giant Kangaroo Rat Dipodomys ingens
Wherever found
No critical habitat has been designated for this species. https://ecos.fws.gov/ecp/species/6051
Endangered
San Joaquin Kit Fox Vulpes macrotis mutica
Wherever found
No critical habitat has been designated for this species. https://ecos.fws.gov/ecp/species/2873
Endangered
NAME STATUS
California Condor Gymnogyps californianus
There is final critical habitat for this species. Your location does not overlap the critical habitat.
https://ecos.fws.gov/ecp/species/8193
Endangered
NAME STATUS
Blunt-nosed Leopard Lizard Gambelia silus
Wherever found
No critical habitat has been designated for this species. https://ecos.fws.gov/ecp/species/625
Endangered
Northwestern Pond Turtle Actinemys marmorata
Wherever found
No critical habitat has been designated for this species. https://ecos.fws.gov/ecp/species/1111
Proposed Threatened
NAME STATUS
Insects
Crustaceans
Flowering Plants
California Red-legged Frog Rana draytonii
Wherever found
There is final critical habitat for this species. Your location does not overlap the critical habitat.
https://ecos.fws.gov/ecp/species/2891
Threatened
California Tiger Salamander Ambystoma californiense
There is final critical habitat for this species. Your location does not overlap the critical habitat.
https://ecos.fws.gov/ecp/species/2076
Threatened
Foothill Yellow-legged Frog Rana boylii
There is proposed critical habitat for this species. Your location does not overlap the critical habitat.
https://ecos.fws.gov/ecp/species/5133
Threatened
Western Spadefoot Spea hammondii
Wherever found
No critical habitat has been designated for this species. https://ecos.fws.gov/ecp/species/5425
Proposed Threatened
NAME STATUS
Monarch Butterfly Danaus plexippus
Wherever found
There is proposed critical habitat for this species. Your location does not overlap the critical habitat.
https://ecos.fws.gov/ecp/species/9743
Proposed Threatened
NAME STATUS
Vernal Pool Fairy Shrimp Branchinecta lynchi
Wherever found
There is final critical habitat for this species. Your location does not overlap the critical habitat.
https://ecos.fws.gov/ecp/species/498
Threatened
NAME STATUS
Critical habitats
Potential effects to critical habitat(s) in this location must be analyzed along with the endangered species themselves.
There are no critical habitats at this location.
You are still required to determine if your project(s) may have effects on all above listed species.
Bald & Golden Eagles
California Jewelflower Caulanthus californicus
Wherever found
No critical habitat has been designated for this species. https://ecos.fws.gov/ecp/species/4599
Endangered
San Joaquin Wooly-threads Monolopia (=Lembertia)
congdonii
Wherever found
No critical habitat has been designated for this species. https://ecos.fws.gov/ecp/species/3746
Endangered
Bald and Golden Eagles are protected under the Bald and Golden Eagle Protection Act and the Migratory Bird Treaty Act (MBTA) . Any person or organization who plans or conducts activities that may result in impacts to Bald or Golden Eagles, or their nests, should follow appropriate regulations and implement required avoidance and minimization measures, as described in the various links on this page.
The data in this location indicates that no eagles have been observed in this area. This does not mean eagles are not present in your project area, especially if the area is difficult to survey. Please review the 'Steps to Take When No Results Are Returned' section of the Supplemental Information on Migratory Birds and Eagles document to determine if your project is in a poorly surveyed area.
If it is, you may need to rely on other resources to determine if eagles may be present (e.g. your local FWS field office, state surveys, your own surveys).
Additional information can be found using the following links:
Eagle Management https://www.fws.gov/program/eagle-management 2 1
Bald & Golden Eagles FAQs
What does IPaC use to generate the potential presence of bald and golden eagles in my specified location?
The potential for eagle presence is derived from data provided by the Avian Knowledge Network (AKN). The AKN data is based on a growing collection of survey, banding, and citizen science datasets and is queried and filtered to return a list of those birds reported as occurring in the 10km grid cell(s) which your project intersects, and that have been identified as warranting special attention because they are an eagle (Bald and Golden Eagle Protection Act requirements may apply).
Proper interpretation and use of your eagle report
On the graphs provided, please look carefully at the survey effort (indicated by the black vertical line) and for the existence of the "no data" indicator (a red horizontal line). A high survey effort is the key component. If the survey effort is high, then the probability of presence score can be viewed as more dependable. In contrast, a low survey effort line or no data line (red horizontal) means a lack of data and, therefore, a lack of certainty about presence of the species. This list is not perfect; it is simply a starting point for identifying what birds have the potential to be in your project area, when they might be there, and if they might be breeding (which means nests might be present). The list and associated information help you know what to look for to confirm presence and helps guide you in knowing when to implement avoidance and minimization measures to eliminate or reduce potential impacts from your project activities or get the appropriate permits should presence be confirmed.
How do I know if eagles are breeding, wintering, or migrating in my area? To see what part of a particular bird's range your project area falls within (i.e. breeding, wintering, migrating, or resident), you may query your location using the RAIL Tool and view the range maps provided for birds in your area at the bottom of the profiles provided for each bird in your results. If an eagle on your IPaC migratory bird species list has a breeding season associated with it (indicated by yellow vertical bars on the phenology graph in your “IPaC PROBABILITY OF PRESENCE SUMMARY” at the top of your results list), there may be nests present at some point within the timeframe specified. If "Breeds elsewhere" is indicated, then the bird likely does not breed in your project area.
Interpreting the Probability of Presence Graphs
Each green bar represents the bird's relative probability of presence in the 10km grid cell(s) your project overlaps during a particular week of the year. A taller bar indicates a higher probability of species presence. The survey effort can be used to establish a level of confidence in the presence score.
How is the probability of presence score calculated? The calculation is done in three steps:
Measures for avoiding and minimizing impacts to birds
https://www.fws.gov/library/collections/avoiding-and-minimizing-incidental-take-migratory-birds Nationwide avoidance and minimization measures for birds https://www.fws.gov/sites/default/files/documents/nationwide-standard-conservationmeasures.pdf Supplemental Information for Migratory Birds and Eagles in IPaC https://www.fws.gov/media/supplemental-information-migratory-birds-and-bald-and-goldeneagles-may-occur-project-action The probability of presence for each week is calculated as the number of survey events in the week where the species was detected divided by the total number of survey events for that week. For example, if in week 12 there were 20 survey events and the Spotted Towhee was found in 5 of them, the probability of presence of the Spotted Towhee in week 12 is 0.25.
To properly present the pattern of presence across the year, the relative probability of presence is calculated.
This is the probability of presence divided by the maximum probability of presence across all weeks. For example, imagine the probability of presence in week 20 for the Spotted Towhee is 0.05, and that the probability of presence at week 12 (0.25) is the maximum of any week of the year. The relative probability of presence on week 12 is 0.25/0.25 = 1; at week 20 it is 0.05/0.25 = 0.2.
The relative probability of presence calculated in the previous step undergoes a statistical conversion so that all possible values fall between 0 and 10, inclusive. This is the probability of presence score.
Breeding Season ()
Yellow bars denote a very liberal estimate of the time-frame inside which the bird breeds across its entire range.
If there are no yellow bars shown for a bird, it does not breed in your project area.
Survey Effort ()
Vertical black lines superimposed on probability of presence bars indicate the number of surveys performed for that species in the 10km grid cell(s) your project area overlaps.
No Data ()
A week is marked as having no data if there were no survey events for that week.
Survey Timeframe
Surveys from only the last 10 years are used in order to ensure delivery of currently relevant information. The exception to this is areas off the Atlantic coast, where bird returns are based on all years of available data, since data in these areas is currently much more sparse.
Migratory birds
The Migratory Bird Treaty Act (MBTA) prohibits the take (including killing, capturing, selling, trading, and transport) of protected migratory bird species without prior authorization by the Department of Interior U.S. Fish and Wildlife Service (Service). The incidental take of migratory birds is the injury or death of birds that results from, but is not the purpose, of an activity. The Service interprets the MBTA to prohibit incidental take.
1. The Migratory Birds Treaty Act of 1918.
2. The Bald and Golden Eagle Protection Act of 1940.
Additional information can be found using the following links:
Eagle Management https://www.fws.gov/program/eagle-management Measures for avoiding and minimizing impacts to birds
https://www.fws.gov/library/collections/avoiding-and-minimizing-incidental-take-migratory-birds Nationwide avoidance and minimization measures for birds 1 Measures for Proactively Minimizing Migratory Bird Impacts Your IPaC Migratory Bird list showcases birds of concern, including Birds of Conservation Concern (BCC), in your project location. This is not a comprehensive list of all birds found in your project area. However, you can help proactively minimize significant impacts to all birds at your project location by implementing the measures in the Nationwide avoidance and minimization measures for birds document, and any other project-specific avoidance and minimization measures suggested at the link Measures for avoiding and minimizing impacts to birds for the birds of concern on your list below.
Ensure Your Migratory Bird List is Accurate and Complete If your project area is in a poorly surveyed area, your list may not be complete and you may need to rely on other resources to determine what species may be present (e.g. your local FWS field office, state surveys, your own surveys). Please review the Supplemental Information on Migratory Birds and Eagles document, to help you properly interpret the report for your specified location, including determining if there is sufficient data to ensure your list is accurate.
For guidance on when to schedule activities or implement avoidance and minimization measures to reduce impacts to migratory birds on your list, see the "Probability of Presence Summary" below to see when these birds are most likely to be present and breeding in your project area.
Review the FAQs
The FAQs below provide important additional information and resources.
BREEDING SEASON
Supplemental Information for Migratory Birds and Eagles in IPaC https://www.fws.gov/media/supplemental-information-migratory-birds-and-bald-and-goldeneagles-may-occur-project-action NAME
Belding's Savannah Sparrow Passerculus sandwichensis
beldingi
This is a Bird of Conservation Concern (BCC) only in particular Bird Conservation Regions (BCRs) in the continental USA
https://ecos.fws.gov/ecp/species/8
Breeds Apr 1 to Aug 15
Nuttall's Woodpecker Dryobates nuttallii
This is a Bird of Conservation Concern (BCC) only in particular Bird Conservation Regions (BCRs) in the continental USA
https://ecos.fws.gov/ecp/species/9410
Breeds Apr 1 to Jul 20
Yellow-billed Magpie Pica nuttalli
This is a Bird of Conservation Concern (BCC) throughout its range in the continental USA and Alaska.
https://ecos.fws.gov/ecp/species/9726
Breeds Apr 1 to Jul 31
Probability of Presence Summary
The graphs below provide our best understanding of when birds of concern are most likely to be present in your project area. This information can be used to tailor and schedule your project activities to avoid or minimize impacts to birds. Please make sure you read "Supplemental Information on Migratory Birds and Eagles", specifically the FAQ section titled "Proper Interpretation and Use of Your Migratory Bird Report" before using or attempting to interpret this report.
Probability of Presence ( )
Each green bar represents the bird's relative probability of presence in the 10km grid cell(s) your project overlaps during a particular week of the year. (A year is represented as 12 4-week months.) A taller bar indicates a higher probability of species presence. The survey effort (see below) can be used to establish a level of confidence in the presence score. One can have higher confidence in the presence score if the corresponding survey effort is also high.
How is the probability of presence score calculated? The calculation is done in three steps:
1. The probability of presence for each week is calculated as the number of survey events in the week where the species was detected divided by the total number of survey events for that week. For example, if in week 12 there were 20 survey events and the Spotted Towhee was found in 5 of them, the probability of presence of the Spotted Towhee in week 12 is 0.25.
2. To properly present the pattern of presence across the year, the relative probability of presence is calculated. This is the probability of presence divided by the maximum probability of presence across all weeks. For example, imagine the probability of presence in week 20 for the Spotted Towhee is 0.05, and that the probability of presence at week 12 (0.25) is the maximum of any week of the year. The relative probability of presence on week 12 is 0.25/0.25 = 1; at week 20 it is 0.05/0.25 = 0.2.
3. The relative probability of presence calculated in the previous step undergoes a statistical conversion so that all possible values fall between 0 and 10, inclusive. This is the probability of presence score.
To see a bar's probability of presence score, simply hover your mouse cursor over the bar.
Breeding Season ( )
Yellow bars denote a very liberal estimate of the time-frame inside which the bird breeds across its entire range. If there are no yellow bars shown for a bird, it does not breed in your project area.
Survey Effort ( )
Vertical black lines superimposed on probability of presence bars indicate the number of surveys performed for that species in the 10km grid cell(s) your project area overlaps. The number of surveys is expressed as a range, for example, 33 to 64 surveys.
To see a bar's survey effort range, simply hover your mouse cursor over the bar.
No Data ( )
probability of presence breeding season survey effort no data A week is marked as having no data if there were no survey events for that week.
Survey Timeframe
Surveys from only the last 10 years are used in order to ensure delivery of currently relevant information. The exception to this is areas off the Atlantic coast, where bird returns are based on all years of available data, since data in these areas is currently much more sparse.
SPECIES JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC Belding's
Savannah
Sparrow
BCC - BCR
Nuttall's
Woodpecker
BCC - BCR
Yellow-billed
Magpie
BCC Rangewide
(CON)
Migratory Bird FAQs
Tell me more about avoidance and minimization measures I can implement to avoid or minimize impacts to migratory birds.
Nationwide Avoidance & Minimization Measures for Birds describes measures that can help avoid and minimize impacts to all birds at any location year-round. When birds may be breeding in the area, identifying the locations of any active nests and avoiding their destruction is one of the most effective ways to minimize impacts. To see when birds are most likely to occur and breed in your project area, view the Probability of Presence Summary.
Additional measures or permits may be advisable depending on the type of activity you are conducting and the type of infrastructure or bird species present on your project site.
What does IPaC use to generate the list of migratory birds that potentially occur in my specified location?
The Migratory Bird Resource List is comprised of Birds of Conservation Concern (BCC) and other species that may warrant special attention in your project location, such as those listed under the Endangered Species Act or the Bald and Golden Eagle Protection Act and those species marked as “Vulnerable”. See the FAQ “What are the levels of concern for migratory birds?” for more information on the levels of concern covered in the IPaC migratory bird species list.
The migratory bird list generated for your project is derived from data provided by the Avian Knowledge Network (AKN). The AKN data is based on a growing collection of survey, banding, and citizen science datasets and is queried and filtered to return a list of those birds reported as occurring in the 10km grid cell(s) with which your project intersects. These species have been identified as warranting special attention because they are BCC species in that area, an eagle (Bald and Golden Eagle Protection Act requirements may apply), or a species that has a particular vulnerability to offshore activities or development.
Again, the Migratory Bird Resource list includes only a subset of birds that may occur in your project area. It is not representative of all birds that may occur in your project area. To get a list of all birds potentially present in your project area, and to verify survey effort when no results present, please visit the Rapid Avian Information Locator (RAIL) Tool.
Why are subspecies showing up on my list?
Subspecies profiles are included on the list of species present in your project area because observations in the AKN for the species are being detected. If the species are present, that means that the subspecies may also be present. If a subspecies shows up on your list, you may need to rely on other resources to determine if that subspecies may be present (e.g. your local FWS field office, state surveys, your own surveys).
What does IPaC use to generate the probability of presence graphs for the migratory birds potentially occurring in my specified location?
The probability of presence graphs associated with your migratory bird list are based on data provided by the Avian Knowledge Network (AKN). This data is derived from a growing collection of survey, banding, and citizen science datasets.
Probability of presence data is continuously being updated as new and better information becomes available. To learn more about how the probability of presence graphs are produced and how to interpret them, go to the Probability of Presence Summary and then click on the "Tell me about these graphs" link.
How do I know if a bird is breeding, wintering, or migrating in my area? To see what part of a particular bird's range your project area falls within (i.e. breeding, wintering, migrating, or resident), you may query your location using the RAIL Tool and view the range maps provided for birds in your area at the bottom of the profiles provided for each bird in your results. If a bird on your IPaC migratory bird species list has a breeding season associated with it (indicated by yellow vertical bars on the phenology graph in your “IPaC PROBABILITY OF PRESENCE SUMMARY” at the top of your results list), there may be nests present at some point within the timeframe specified. If "Breeds elsewhere" is indicated, then the bird likely does not breed in your project area.
What are the levels of concern for migratory birds?
Migratory birds delivered through IPaC fall into the following distinct categories of concern:
1. "BCC Rangewide" birds are Birds of Conservation Concern (BCC) that are of concern throughout their range anywhere within the USA (including Hawaii, the Pacific Islands, Puerto Rico, and the Virgin Islands);
2. "BCC - BCR" birds are BCCs that are of concern only in particular Bird Conservation Regions (BCRs) in the continental USA; and
3. "Non-BCC - Vulnerable" birds are not BCC species in your project area, but appear on your list either because of the Bald and Golden Eagle Protection Act requirements (for eagles) or (for non-eagles) potential susceptibilities in offshore areas from certain types of development or activities (e.g. offshore energy development or longline fishing).
Although it is important to avoid and minimize impacts to all birds, efforts should be made, in particular, to avoid and minimize impacts to the birds on this list, especially BCC species. For more information on avoidance and minimization measures you can implement to help avoid and minimize migratory bird impacts, please see the FAQ “Tell me more about avoidance and minimization measures I can implement to avoid or minimize impacts to migratory birds”.
Details about birds that are potentially affected by offshore projects For additional details about the relative occurrence and abundance of both individual bird species and groups of bird species within your project area off the Atlantic Coast, please visit the Northeast Ocean Data Portal. The Portal also offers data and information about other taxa besides birds that may be helpful to you in your project review. Alternately, you may download the bird model results files underlying the portal maps through the NOAA NCCOS Integrative Statistical Modeling and Predictive Mapping of Marine Bird Distributions and Abundance on the Atlantic Outer Continental Shelf project webpage.
Proper interpretation and use of your migratory bird report The migratory bird list generated is not a list of all birds in your project area, only a subset of birds of priority concern. To learn more about how your list is generated and see options for identifying what other birds may be in your project area, please see the FAQ "What does IPaC use to generate the migratory birds potentially occurring in my specified location". Please be aware this report provides the "probability of presence" of birds within the 10 km grid cell(s) that overlap your project; not your exact project footprint. On the graphs provided, please look carefully at the survey effort (indicated by the black vertical line) and for the existence of the "no data" indicator (a red horizontal line). A high survey effort is the key component. If the survey effort is high, then the probability of presence score can be viewed as more dependable. In contrast, a low survey effort bar or no data bar means a lack of data and, therefore, a lack of certainty about presence of the species. This list does not represent all birds present in your project area. It is simply a starting point for identifying what birds of concern have the potential to be in your project area, when they might be there, and if they might be breeding (which means nests might be present). The list and associated information help you know what to look for to confirm presence and helps guide implementation of avoidance and minimization measures to eliminate or reduce potential impacts from your project activities, should presence be confirmed. To learn more about avoidance and minimization measures, visit the FAQ "Tell me about avoidance and minimization measures I can implement to avoid or minimize impacts to migratory birds".
Interpreting the Probability of Presence Graphs
Each green bar represents the bird's relative probability of presence in the 10km grid cell(s) your project overlaps during a particular week of the year. A taller bar indicates a higher probability of species presence. The survey effort can be used to establish a level of confidence in the presence score.
How is the probability of presence score calculated? The calculation is done in three steps:
The probability of presence for each week is calculated as the number of survey events in the week where the species was detected divided by the total number of survey events for that week. For example, if in week 12 there were 20 survey events and the Spotted Towhee was found in 5 of them, the probability of presence of the Spotted Towhee in week 12 is 0.25.
To properly present the pattern of presence across the year, the relative probability of presence is calculated.
This is the probability of presence divided by the maximum probability of presence across all weeks. For example, imagine the probability of presence in week 20 for the Spotted Towhee is 0.05, and that the probability of presence at week 12 (0.25) is the maximum of any week of the year. The relative probability of presence on week 12 is 0.25/0.25 = 1; at week 20 it is 0.05/0.25 = 0.2.
The relative probability of presence calculated in the previous step undergoes a statistical conversion so that all possible values fall between 0 and 10, inclusive. This is the probability of presence score.
Breeding Season ()
Yellow bars denote a very liberal estimate of the time-frame inside which the bird breeds across its entire range.
If there are no yellow bars shown for a bird, it does not breed in your project area.
Survey Effort ()
Vertical black lines superimposed on probability of presence bars indicate the number of surveys performed for that species in the 10km grid cell(s) your project area overlaps.
No Data ()
A week is marked as having no data if there were no survey events for that week.
Survey Timeframe
Surveys from only the last 10 years are used in order to ensure delivery of currently relevant information. The exception to this is areas off the Atlantic coast, where bird returns are based on all years of available data, since data in these areas is currently much more sparse.
Facilities
Wildlife refuges and fish hatcheries
Refuge and fish hatchery information is not available at this time Wetlands in the National Wetlands Inventory
(NWI)
Impacts to NWI wetlands and other aquatic habitats may be subject to regulation under Section 404 of the Clean Water Act, or other State/Federal statutes.
For more information please contact the Regulatory Program of the local U.S. Army Corps of Engineers District.
Please note that the NWI data being shown may be out of date. We are currently working to update our NWI data set. We recommend you verify these results with a site visit to determine the actual extent of wetlands on site.
This location overlaps the following wetlands:
FRESHWATER POND
PUBKx
LAKE
L2UBKx
RIVERINE
R4SBA
R4SBC
NOTE: This initial screening does not replace an on-site delineation to determine whether wetlands occur. Additional information on the NWI data is provided below.
Data limitations
The Service's objective of mapping wetlands and deepwater habitats is to produce reconnaissance level information on the location, type and size of these resources. The maps are prepared from the analysis of high altitude imagery. Wetlands are identified based on vegetation, visible hydrology and geography. A margin of error is inherent in the use of imagery; thus, detailed on-the-ground inspection of any particular site may result in revision of the wetland boundaries or classification established through image analysis.
The accuracy of image interpretation depends on the quality of the imagery, the experience of the image analysts, the amount and quality of the collateral data and the amount of ground truth verification work conducted. Metadata should be consulted to determine the date of the source imagery used and any mapping problems.
Wetlands or other mapped features may have changed since the date of the imagery or field work. There may be occasional differences in polygon boundaries or classifications between the information depicted on the map and the actual conditions on site.
Data exclusions
Certain wetland habitats are excluded from the National mapping program because of the limitations of aerial imagery as the primary data source used to detect wetlands. These habitats include seagrasses or submerged aquatic vegetation that are found in the intertidal and subtidal zones of estuaries and nearshore coastal waters.
Some deepwater reef communities (coral or tuberficid worm reefs) have also been excluded from the inventory.
These habitats, because of their depth, go undetected by aerial imagery.
Data precautions
Federal, state, and local regulatory agencies with jurisdiction over wetlands may define and describe wetlands in a different manner than that used in this inventory. There is no attempt, in either the design or products of this inventory, to define the limits of proprietary jurisdiction of any Federal, state, or local government or to establish the geographical scope of the regulatory programs of government agencies. Persons intending to engage in activities involving modifications within or adjacent to wetland areas should seek the advice of appropriate Federal, state, or local agencies concerning specified agency regulatory programs and proprietary jurisdictions that may affect such activities.
R5UBF
A full description for each wetland code can be found at the National Wetlands Inventory website Appendix D
Cultural Resources Survey
Draft
CLASS III INVENTORY/PHASE I SURVEY,
COALINGA SANITARY SEWER COLLECTION
SYSTEM AND WASTEWATER TREATMENT PLANT
IMPROVEMENTS PROJECT FRESNO COUNTY,
CALIFORNIA
Prepared for:
Travis Crawford
Crawford & Bowen Planning, Inc.
113 N. Church Street, Suite 3
Visalia, CA 93291
Prepared by:
Dustin Merrick, MA, RPA,
Madeline Gonzalez, MA,
and
Sarah Stringer-Bowsher, MA, RPH
ASM Affiliates
4800 Stockdale Hwy, Ste 405
Bakersfield, CA 93309
July 2026
PN 36790.19
Table of Contents
Coalinga Sanitary Sewer Collection System and WWTP Improvements Project i
TABLE OF CONTENTS
Chapter Page
MANAGEMENT SUMMARY ..........................................................................................v
1. INTRODUCTION AND REGULATORY CONTEXT....................................................1
1.1 PROJECT LOCATION ...................................................................................................... 1
1.2 PROJECT DESCRIPTION AND AREA OF POTENTIAL EFFECTS......................................... 5
1.2.1 Sewer Main Replacement..................................................................................... 5
1.2.2 Sewer Main Rehabilitation.................................................................................... 5
1.2.3 Proposed Improvements to Wastewater Treatment Plant.................................. 6
1.2.4 Area of Potential Effect......................................................................................... 7
1.3 REGULATORY CONTEXT ................................................................................................ 7
1.3.1 National Historic Preservation Act Section 106.................................................... 7
1.3.2 California Environmental Quality Act.................................................................... 8
1.3.3 Eligibility Criteria for Wastewater Treatment Facilities in California ................... 9
2. ENVIRONMENTAL AND CULTURAL BACKGROUND ...........................................17
2.1 GEOARCHAEOLOGICAL SENSITIVITY AND ENVIRONMENTAL BACKGROUND ............ 17
2.1.1 Environmental Setting......................................................................................... 17
2.1.2 Geology and Geomorphology ............................................................................. 17
2.1.3 Soils ..................................................................................................................... 20
2.1.4 Buried Site Sensitivity.......................................................................................... 20
2.2 ETHNOGRAPHIC BACKGROUND.................................................................................. 20
2.3 PRE-CONTACT ARCHAEOLOGICAL BACKGROUND...................................................... 22
2.4 HISTORICAL BACKGROUND......................................................................................... 25
2.4.1 Drinking Water and Wastewater Treatment Facilities in California................... 25
2.4.2 Coalinga Wastewater Treatment Plant Operations............................................ 97
2.4.3 Coalinga Wastewater Treatment Plant............................................................... 99
2.4.4 Site Specific History........................................................................................... 102
2.5 Historic-Era Archaeology: Refuse Deposits............................................................... 114
3. RECORDS AND SACRED LANDS FILE SEARCHES...............................................119
3.1 RECORDS SEARCH ..................................................................................................... 119
3.2 TRIBAL OUTREACH.................................................................................................... 122
4. METHODS AND RESULTS ...............................................................................123
4.1 FIELD METHODS........................................................................................................ 123
4.2 SURVEY RESULTS....................................................................................................... 123
4.2.1 Archaeological Results...................................................................................... 123
4.2.2 Built Environment Results................................................................................. 129
5. SUMMARY, ASSESSMENT OF EFFECTS, AND RECOMMENDATIONS ................165
5.1 SUMMARY................................................................................................................. 165 Table of Contents
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5.2 ASSESSMENT OF EFFECTS ......................................................................................... 166
5.3 RECOMMENDATIONS ............................................................................................... 166 REFERENCES ............................................................................................................169 CONFIDENTIALAPPENDICES...........................................................................................
Table of Contents
Coalinga Sanitary Sewer Collection System and WWTP Improvements Project iii
LIST OF FIGURES
Page
Figure 1. Coalinga Sanitary Sewer Collection System and WWTP Improvements Project, Fresno County, California. ......................................................................... 3 Figure 2. Coalinga Sanitary Sewer Collection System and WWTP Improvements Project Geology Map ............................................................................................ 19 Figure 3. Portion of 1944 USGS Topographic Map Coalinga Quadrangle. Surveyed in 1935-1936 and 1940-1941.................................................................................. 103 Figure 4. Portion of 1956 USGS Topographic Map Coalinga Quadrangle. Aerial Photographs taken 1953..................................................................................... 104 Figure 5. 1967 historic aerial photograph of the Coalinga WWTP. Source: USGS ............ 105 Figure 6. The Coalinga WWTP as depicted in the 1979 drawings by John Carollo Engineers............................................................................................................. 107 Figure 7. Detail of the plant area of the WWTP as depicted in the 1979 drawings by John Carollo Engineers........................................................................................ 108 Figure 8. The Coalinga WWTP as depicted in the 1990 drawings by James Montgomery Consulting Engineers. ................................................................... 109 Figure 9. Detail of the plant area of the WWTP as depicted in the 1990 drawings by James Montgomery Consulting Engineers. ........................................................ 110 Figure 10. Photograph of the construction occurring at the Coalinga WWTP, dated May 28, 1991. The clarifier is visible in the foreground, and the animal shelter building is visible in the background. ..................................................... 111 Figure 11. Photograph of the construction occurring at the Coalinga WWTP, dated May 28, 1991. This photograph depicts the materials that were removed for the modernization and expansion of the facility. ......................................... 112 Figure 12. Photograph of the construction occurring at the Coalingag WWTP, dated May 28, 1991. The clarifier structure is depicted, and the primary pump station is visible under construction................................................................... 113 Figure 13. Project APE overview along Van Ness Street, facing east. ................................. 124 Figure 14. Project APE overview along Cherry Lane, facing west. ...................................... 124 Figure 15. WWTP APE infrastructure overview, facing east................................................ 125 Figure 16. WWTP APE infrastructure overview, facing northwest...................................... 125 Figure 17. Northwestern WWTP APE overview, facing southwest. .................................... 126 Figure 18. WWTP-SITE-1 overview, facing north................................................................. 128 Figure 19. WWTP-SITE-1 refuse scatter............................................................................... 128 Figure 20. Location Map of Coalinga WWTP APE and potential WWTP historic district boundary............................................................................................................. 131 Figure 21. Aerial map that identifies the components of the Coalinga WWTP and the potential WWTP historic district boundary. ....................................................... 133 Figure 22. Building One, the Operations Building. Primary façade, view toward east. ...... 138 Figure 23. Building One, the Operations Building. Side and primary façade, view toward southwest............................................................................................... 138 Table of Contents
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Figure 24. Building One, the Operations Building. Rear façade, view toward west............ 139 Figure 25. Building One, the Operations Building. Side and primary façade, view toward northeast. ............................................................................................... 139 Figure 26. Detail of the plaque on the primary façade of Building One, the Operations Building. .............................................................................................................. 140 Figure 27. Building Two, the Animal Shelter Building. Rear and side façade, view toward southwest............................................................................................... 143 Figure 28. Building Two, the Animal Shelter Building. Rear and side façade, view toward northwest. .............................................................................................. 143 Figure 29. Building Two, the Animal Shelter Building. View of concrete pad and pathway. View toward east. ............................................................................... 144 Figure 30. Building Two, the Animal Shelter Building. Primary façade, view toward east...................................................................................................................... 144 Figure 31. Building Three, the Primary Pump Station. Rear and side façade, view toward northwest. .............................................................................................. 147 Figure 32. Building Three, the Primary Pump Station. Primary and side façade, view toward northeast. ............................................................................................... 147 Figure 33. Building Three, the Primary Pump Station. Rear façade, view toward west. ............................................................................................................................. 148 Figure 34. Building Four, the Shed. View toward south. ..................................................... 151 Figure 35. Building Four, the Shed. Rear façade, view toward southwest.......................... 152 Figure 36. Building Four, the Shed. Primary façade, view toward northeast...................... 152 Figure 37. Building Four, the Shed. Detail of interior. ......................................................... 153 Figure 38. Structure One, Digester Tank. View toward northwest. Building Four visible in background. .................................................................................................... 154 Figure 39. Structure One, Digester Tank. View toward southwest. .................................... 155 Figure 40. Structure One, Digester Tank. View toward southeast. ..................................... 155 Figure 41. Structure Two, Clarifier Tank. View toward southeast....................................... 158 Figure 42. Structure Two, Clarifier Tank. View toward north. Structure One visible in background. ........................................................................................................ 158 Figure 43. Showing exposed ditch feature within the Pipelines APE. ................................. 166
LIST OF TABLES
Page
Table 1. Proposed Sewer Main Replacement....................................................................... 5 Table 2. Proposed Sewer Main Rehabilitation ..................................................................... 5 Table 3. Proposed Evaporation/Percolation Pond Characteristics ...................................... 7 Table 4. Previous Reports within 0.5 mi. of the APE ........................................................ 119 Table 5. Previously Recorded Resources.......................................................................... 121 Management Summary
Coalinga Sanitary Sewer Collection System and WWTP Improvements Project v
MANAGEMENT SUMMARY
This report documents the results of an intensive Class III inventory/Phase I survey for the Coalinga Sanitary Sewer Collection System and Wastewater Treatment Plant Improvements Project (Project) Fresno County, California.
The Project is within the city of Coalinga in Fresno County. This places the Project on the open flats of the San Joaquin Valley, directly east of the Coast Range. Specifically, the Project is within Sections 31, 33, 34, Township 20 South, Range 17 East (T20S/R15E) and Section 4 and 5 T21S/ R15E, Mount Diablo Base and Meridian (MDBM), as illustrated on the Coalinga USGS 7.5- minute topographic quadrangle. The proposed Project site consists of developed infrastructure including a water treatment facility, unpaved and paved roads throughout the city of Coalinga, as well as agricultural fields. Elevations within the Project area, which is mostly flat, range from 640 feet (ft.) above mean sea level (amsl) to 690 ft. amsl. The Area of Potential Effect (APE) for the Project was defined as the area of potential ground surface disturbance. The horizontal APE for the Project totals approximately 174.7 acres (ac.) and contains all construction areas, staging and laydown areas, and access roads. The vertical APE, defined as the maximum depth of excavation of the Project, is not expected to exceed 10 ft. below ground surface.
ASM Affiliates (ASM) conducted this study, with Senior Archaeologist Dustin Merrick, MA, RPA, serving as principal investigator and main author of this report. Associate Archaeologist Robert Azpitarte, BA, and Assistant Archaeologist Margarita Medina Lemus, BA, conducted the fieldwork. Geoarchaeologist Maya Klinger, MA, RPA, prepared the geoarchaeological sensitivity and environmental background. Architectural Historian Madeline Gonzalez, MA, prepared the evaluation of the built environment resources under National Register of Historic Places (NRHP) and California Register of Historic Resources (CRHR) criteria. Sarah Stringer-Bowsher, MA, RPH, was the peer reviewer of the built environment evaluations. The study was undertaken to assist with compliance with Section 106 of the National Historic Preservation Act (NHPA) of 1966, as amended, and the California Environmental Quality Act (CEQA).
To determine whether the Project APE had been previously surveyed for cultural resources, and/or whether any such resources were known to exist within or near to it, staff of the Southern San Joaquin Valley Information Center (SSJVIC) conducted an archival records search on May 29, 2024. According to the SSJVIC, six previous studies have been conducted within the Project APE, and 31 previous studies were identified within a 0.5-mile (mi.) buffer. Based on SSJVIC data, approximately 30 percent of the Project APE has been previously surveyed. Dates for previous studies in the APE range from 1995 to 2016 with the majority of studies being greater than 20 years old. The SSJVIC results identified a single previously recorded cultural resource (P-10- 003930) within the APE. An additional 17 resources were identified within the 0.5-mi. buffer.
Geoarchaeological review of the project indicates the deposits within the APE(s) formed between the historical era/modern times (<150 years before present [YBP]), and latest Holocene (2000– 150 YBP). Whereas the Pipelines APE is marked by high buried site potential, the Waste Water Treatment Plant (WWTP) APE is marked as having low buried site potential (Meyer et al. 2010:140, Table 18). Historic aerial and topographic map review shows the project APE has been Management Summary
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heavily disturbed by agricultural activities and industrial development as far back as the midtwentieth century.
As part of the CEQA process, a search of the Native American Heritage Commission (NAHC) Sacred Lands File was completed on May 9, 2024. Based on the NAHC records, the APE is negative for sacred sites or traditional cultural places. Outreach letters were sent on July 23, 2024, to tribal organizations on the NAHC contact list. Follow-up emails were sent on April 16, 2024.
On August 12, 2024, Table Mountain Rancheria responded stating the Project was out of their area of interest. No other responses were received as a result of this outreach.
The Class III inventory/Phase I survey of the Project APE was conducted from August to September 2024. Parallel survey transects spaced at maximum intervals of 15 meters (m) apart were employed for pedestrian survey of the 174.7-ac. Project APE, which consists of two areas referred to as the Pipeline APE and the WWTP APE. The proposed Project consists of improvements to a water treatment plant first constructed in 1963 and its associated pipelines. The Pipeline APE consists largely of paved roads. As such, the vast majority of the Pipeline APE has been hardscaped over. Approximately 1,700 ft. of the Pipeline APE, along both O Street and 16th Street, is undeveloped. Visibility within undeveloped areas was good (approximately 75 percent).
The majority of the WWTP APE was developed between 1963 and 1991. The visibility within the water treatment facility was excellent (approximately 90 percent) outside of developed areas.
Diffuse modern refuse was observed throughout the APE. Non-native vegetation inhibited visibility in undeveloped areas.
One previously recorded resource, a segment of the Southern Pacific Railroad (P-10-003930), was observed within the Pipeline APE, and is described in Section 4.2.1. The Project proposes trenchless drilling under P-10-003930. As such, it is outside of the APE. No other previously recorded resources and no further cultural resources were identified within the Pipeline APE.
ASM was tasked with the evaluation of all buildings and structures within the WWTP APE. In this report, buildings and structures that were constructed more than 45 years ago are individually evaluated for their eligibility for the NRHP, CRHR, and as CEQA historical resources, and buildings and structures that were constructed less than 45 years ago were considered under NRHP Criterion Consideration G. ASM additionally considered the potential for a historic district associated with the Coalinga WWTP. ASM considered the possibility of a historic district within the WWTP APE, but there is no historic district. The buildings and structures within the WWTP APE are recommended not individually eligible for the NRHP and CRHR. Therefore, the buildings and structures are not considered historic properties pursuant to the NHPA, and they are not considered historical resources pursuant to CEQA. These resources are further described in Section
4.2.1. ASM was not tasked with the evaluation of the pipelines within the Pipelines APE.
Based on the above analyses and findings, the proposed Coalinga Sanitary Sewer Collection System and WWTP Improvements Project will not result in adverse effects to historic properties or significant impacts to historical resources. ASM recommends a determination of no adverse effect under Section 106 and no significant impact under CEQA. It is further recommended that, in the unlikely event that previously unrecorded cultural resources are identified during Project Management Summary
Coalinga Sanitary Sewer Collection System and WWTP Improvements Project vii construction, work be halted within a 100-ft. radius of the find and a qualified archaeologist be contacted to evaluate the newly discovered resource.
1. Introduction and Regulatory Context
Coalinga Sanitary Sewer Collection System and WWTP Improvements Project 1
1. INTRODUCTION AND REGULATORY
CONTEXT
ASM Affiliates (ASM) was retained by Crawford & Bowen Planning, Inc. to conduct an intensive Class III inventory/Phase I survey for the Coalinga Sanitary Sewer Collection System and Wastewater Treatment Plant (WWTP) Improvements Project (Project) Fresno County, California (Figure 1). The study was undertaken to assist with compliance with Section 106 of the National Historic Preservation Act (NHPA) of 1966, as amended, and the California Environmental Quality Act (CEQA). The investigation was conducted, specifically, to ensure that significant impacts or adverse effects to historic properties or historical resources do not occur as a result of Project construction.
This current study included:
• A background records search and literature review to determine if any known cultural resources were present in the project zone and/or whether the area had been previously and systematically studied by archaeologists;
• An on-foot, intensive inventory of the Project site to identify and record previously undiscovered cultural resources and to examine known sites; and • A preliminary assessment of any such resources found within the subject property.
Senior Archaeologist Dustin Merrick, MA RPA, served as principal investigator and main author of this report. Associate Archaeologist Robert Azpitarte, BA, and Assistant Archaeologist Margarita Medina Lemus, BA, conducted the fieldwork. Geoarchaeologist Maya Klinger, MA, RPA, prepared the geoarchaeological sensitivity and environmental background. Architectural Historian Madeline Gonzalez, MA, prepared the evaluation of the built environment resources according to NRHP and CRHR criteria. Sarah Stringer-Bowsher, MA, RPH, was the peer reviewer of the built environment evaluations.
This document constitutes a report on the Class III inventory/Phase I survey. Subsequent chapters provide background to the investigation, including historic context studies; the findings of the archival records search; a summary of the field surveying techniques employed; and the results of the fieldwork. We conclude with management recommendations for the Project.
1.1 PROJECT LOCATION
The Project is within the city of Coalinga (City) in Fresno County, spanning throughout the city.
This places the Project on the open flats of the San Joaquin Valley, directly east of the Coast Range.
Specifically, the Project is within Sections 31, 33, 34, Township 20 South, Range 17 East (T20S/R15E) and Section 4 and 5 T21S/ R15E, Mount Diablo Base and Meridian (MDBM), as illustrated on the Coalinga USGS 7.5-minute topographic quadrangle. The proposed Project site consists of developed infrastructure including a water treatment facility, unpaved and paved roads throughout the city of Coalinga, as well as agricultural fields. Elevations within the Project area, which is mostly flat, range from 640 feet (ft.) above mean sea level (amsl) to 690 ft. amsl.
1. Introduction and Regulatory Context
Coalinga Sanitary Sewer Collection System and WWTP Improvements Project 3 Figure 1. Coalinga Sanitary Sewer Collection System and WWTP Improvements Project, Fresno County, California.
1. Introduction and Regulatory Context
Coalinga Sanitary Sewer Collection System and WWTP Improvements Project 5
1.2 PROJECT DESCRIPTION AND AREA OF
POTENTIAL EFFECTS
Based on the condition assessment conducted, the recommended improvements for the City’s sewer collection system are summarized in the following paragraphs.
1.2.1 Sewer Main Replacement
CCTV inspection conducted on 104,618 linear feet (LF) of the City’s sewer collection system revealed several defects in portions of the collection system. Defects found in the sewer mains included root intrusion, fractured and broken pipe, cracked pipe, sags greater than 60 percent, defective and intruding laterals, joint displacements, and attached deposits (grease and concrete).
The segments of the sewer collection system recommended for replacement have been selected based on sorted NASSCO ratings and the condition of the existing sewer mains. For this proposed Project, it is recommended that approximately 41,073 LF of gravity sewer mains be replaced with new sewer pipes before failure occurs. Table 1 provides a summary of the sewer mains that will be replaced using the conventional construction method of dig and replace.
Table 1. Proposed Sewer Main Replacement
Parameter Total Length (ft)
6” PVC Pipe 13,838
8” PVC Pipe 4,226
10” PVC Pipe 1,738
Total 19,802
1.2.2 Sewer Main Rehabilitation
Trenchless sewer rehabilitation is recommended where applicable to reduce surface disturbance over traditional dig and replace methods, reduce the number of traffic and pedestrian detours, spare tree removal, decrease construction noise, and reduce air pollution from construction equipment.
Table 2 provides a summary of the sewer mains that will be rehabilitated using the trenchless construction method known as cured-in-place (CIP).
Table 2. Proposed Sewer Main Rehabilitation
Parameter Total Length (ft)
6” PVC Pipe 15,914
8” PVC Pipe 7,297
10” PVC Pipe 2,071
15” PVC Pipe 2,558
18” PVC Pipe 2,975
Total 30,815
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1.2.3 Proposed Improvements to Wastewater Treatment
Plant
The existing aerated lagoons and stabilization ponds will be decommissioned for the construction of percolation ponds. In this proposed project, an extended aeration system with biological nutrient removal with filtration and disinfection will be constructed. For this proposed project, Aero Mod extended aeration system was selected. The moving aeration chains are equipped with diffuser and provide efficient mixing of the basin contents as well as high oxygen transfer at low energy usage.
Aeration will be provided by aeration blowers, which will be operated by VFDs. Mixed liquor will flow across the aerated tank reactor and will enter a distribution box that will split flow between two clarifiers. One clarifier will be required to handle the plant’s design flow of 1.34 MGD, while the other will be provided for redundancy. Mixed liquor will settle in the clarifier, and clear liquid will overflow into a peripheral weir channel and into the RAS/WAS pumpstation. Settled sludge will be recirculated back to the aeration basin or wasted to a sludge-drying bed. Treated effluent will be conveyed to the facility’s new percolation ponds that will be constructed.
Extended Aeration and Biological Nutrient Removal
The proposed aeration tank will be constructed in the existing WWTP facility. Aero-Mod SEQUOX for biological nutrient removal offers the benefits of sequencing aeration and continuous clarification. Flow enters through an anoxic tank, where the raw sewage is combined with returned activated sludge (RAS) from the clarifiers. The combination of cyclical aeration in the four basins creates excellent aerobic conditions for BOD and ammonia removal when aerating. When the air is off, the nitrate laden MLSS settles and becomes oxygen deprived, creating anoxic conditions for the nitrates to become the oxygen source and allow for denitrification to occur. The plug flow process repeats this cyclical on/off aeration several times as the liquid mass progresses through the SEQUOX process and on to the clarifier. The effluent quality is achieved with TN levels as low as 3 milligrams per liter (mg/L). The process is energy efficient, has a small footprint, and does not require recycling pumps or mixers. Table 3 contains the required dimensions for the aerated treatment system.
Clarifier
The SEQUOX process often incorporates the ClarAtor clarifier where the biomass is settled and returned to the selector tank. The clarified effluent is withdrawn and discharged. This technology is low maintenance, featuring stainless steel and fiberglass components with no moving parts below the water, while its unique flow-regulation system provides in-basin surge storage. For this proposed project, a center configuration will be used for influent entering the secondary clarifier.
Mixed liquor will be carried to the center of the clarifier, which will radially distribute flow from the top of the basin. A peripheral weir will collect effluent, and a surface skimmer will collect floating scum.
Effluent Disposal
The purpose of upgrading the existing WWTP to an extended aeration activated system with biological nutrient removal facility is to lower the nitrogen concentration of the effluent before it is discharged to percolate the underground aquifer. Nitrogen is a nutrient normally present in domestic wastewater at a concentration that can degrade groundwater quality. Currently, the
1. Introduction and Regulatory Context
Coalinga Sanitary Sewer Collection System and WWTP Improvements Project 7 existing WWTP is not protective of the current beneficial use of the groundwater and is not consistent with RWQCB’s policy of beneficial reuse. By upgrading the WWTP to include secondary/tertiary treatment and discharging the higher effluent quality to percolation ponds on site, the City will provide an incidental recharge of the groundwater aquifer, which will ultimately help demonstrate groundwater sustainability. By removing nitrogen, treated effluent will be allowed to percolate and be protective of the groundwater’s beneficial uses. The City would need to decommission the existing aerated lagoons and stabilization ponds to construct five percolation ponds to increase the facility’s disposal capacity. According to the water balance calculations, a total percolation area of 18.34 acres would allow the City to dispose 1.34 MGD. Table 3 displays the surface areas and estimated volumes of each percolation pond.
Table 3. Proposed Evaporation/Percolation Pond Characteristics Pond No Top Surface Area (ac.) Depth (ft.) Volume (ac. ft.) Volume (gallon) Pond 1 3 6 18 5,866,200
Pond 2 3 6 18 5,866,200
Pond 3 2.45 5 12.25 3,992,275
Pond 4 4.83 5 24.15 7,870,485
Pond 5 5.06 5 25.30 8,245,270
Total 18.34 - 97.7 31,840,430
1.2.4 Area of Potential Effect
The Area of Potential Effect (APE) for the Project was defined as the area of potential groundsurface disturbance. The horizontal APE for the Project totals approximately 174.7 ac. and contains all construction areas, staging and laydown areas, and access roads. The vertical APE, defined as the maximum depth of excavation for sewer replacement for the Project, is not expected to exceed 10 ft. below ground surface.
1.3 REGULATORY CONTEXT
1.3.1 National Historic Preservation Act Section 106
NHPA Section 106 is applicable to federal undertakings, including projects financed or permitted by federal agencies regardless of whether the activities occur on federally managed or privately owned land. Its purpose is to determine whether adverse effects will occur to significant cultural resources, defined as “historical properties” that are listed in or determined eligible for listing in the National Register of Historic Places (NRHP). The criteria for NRHP eligibility are defined at 36 CFR § 60.4 as follows:
The quality of significance in American history, architecture, archaeology, engineering, and culture is present in districts, sites, buildings, structures, and objects that possess integrity of location, design, setting, materials, workmanship, feeling, and association, and that:
(A) are associated with events that have made a significant contribution to the broad patterns of our history; or
(B) are associated with the lives of persons significant in our past; or
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(C) embody the distinctive characteristics of a type, period, or method of construction, or that represent the work of a master, or that possess high artistic values, or that represent a significant and distinguishable entity whose components may lack individual distinction; or
(D) have yielded or may be likely to yield, information important in prehistory or history.
There are, however, restrictions on the kinds of historical properties that can be NRHP listed.
These have been identified by the Advisory Council on Historic Preservation (ACHP), as follows:
Ordinarily cemeteries, birthplaces, or graves of historical figures, properties owned by religious institutions or used for religious purposes, structures that have been moved from their original locations, reconstructed historic buildings, properties primarily commemorative in nature, and properties that have achieved significance within the past 50 years shall not be considered eligible for the National Register. However, such properties will qualify if they are integral parts of districts that do meet the criteria or if they fall within the following categories:
(a) A religious property deriving primary significance from architectural or artistic distinction or historical importance; or
(b) A building or structure removed from its original location but which is significant primarily for architectural value, or which is the surviving structure most importantly associated with a historic person or event; or (c) A birthplace or grave of a historical figure of outstanding importance if there is no appropriate site or building directly associated with his productive life. (d) A cemetery which derives its primary significance from graves of persons of transcendent importance, from age, from distinctive design features, or from association with historic events; or
(e) A reconstructed building when accurately executed in a suitable environment and presented in a dignified manner as part of a restoration master plan, and when no other building or structure with the same association has survived; or (f) A property primarily commemorative in intent if design, age, tradition, or symbolic value has invested it with its own exceptional significance; or (g) A property achieving significance within the past 50 years if it is of exceptional importance. (ACHP n.d.)
1.3.2 California Environmental Quality Act
CEQA is applicable to discretionary actions by state or local lead agencies. Under CEQA, lead agencies must analyze impacts to cultural resources. Significant impacts under CEQA occur when “historically significant” or “unique” cultural resources are adversely affected, which occurs when such resources could be altered or destroyed through project implementation. Historically significant cultural resources are defined by eligibility for or by listing in the California Register of Historical Resources (CRHR). In practice, the federal NRHP criteria (below) for significance
1. Introduction and Regulatory Context
Coalinga Sanitary Sewer Collection System and WWTP Improvements Project 9 applied under Section 106 are generally (although not entirely) consistent with CRHR criteria (see PRC § 5024.1, Title 14 CCR, Section 4852 and § 15064.5(a)(3)).
Significant cultural resources are those archaeological resources and historical properties that:
(1) Are associated with events that have made a significant contribution to the broad patterns of California’s history and cultural heritage; (2) Are associated with the lives of persons important in our past; (3) Embody the distinctive characteristics of a type, period, region, or method of construction, or represent the work of an important creative individual, or possess high artistic values; or
(4) Have yielded, or may be likely to yield, information important in prehistory or history.
Unique resources under CEQA, in slight contrast, are those that represent:
An archaeological artifact, object, or site about which it can be clearly demonstrated that, without merely adding to the current body of knowledge, there is a high probability that it meets any of the following criteria:
(1) Contains information needed to answer important scientific research questions and that there is a demonstrable public interest in that information. (2) Has a special and particular quality such as being the oldest of its type or the best available example of its type.
(3) Is directly associated with a scientifically recognized important prehistoric or historic event or person (PRC § 21083.2(g)).
Preservation in place is the preferred approach under CEQA to mitigating adverse impacts to significant or unique cultural resources.
1.3.3 Eligibility Criteria for Wastewater Treatment Facilities in California
In 2023, JRP Historical Consulting LLC in conjunction with the State Water Resources Control Board prepared the Drinking Water and Wastewater Treatment Facilities in California Historic Context and Research Design for National Register Evaluation. This report identified Wastewater Treatment Plants as a distinct Property Type and presented evaluation procedures and processes for the identified property types. Relevant sections from the report are reproduced below:
Property Type: Wastewater Treatment Plants
Municipal wastewater treatment plants resemble drinking water treatment facilities in many respects, and they use much of the same equipment for screening, clarifying, filtering, and disinfecting water. The wastewater plants differ chiefly in their use of biological methods during secondary treatment that have no parallel for drinking water systems. Wastewater plants are classified by the level of treatment that they offer. Older plants might offer only primary treatment, using clarifiers to decrease the quantity of suspended matter. All modern plants will also include secondary treatment with trickling filters or activated sludge tanks, and
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disinfection by chlorine contact. Some plants will include tertiary treatment for nutrient and contaminant removal using filters or modifications to the activated sludge tanks. As with drinking water plants, separate process chains handle effluent purification and the processing and disposable of sedimentation sludge. And, as always, most major equipment is duplicated to provide flexible capacity and to allow for treatment to continue while one piece of hardware is serviced. The Yountville Wastewater Reclamation Facility that is used as a case study in this project offers a typical example of small-sized municipal plant combining historic-aged components with modern tertiary treatment refinements.
Application of Criteria
Drinking water and wastewater systems or components may be found eligible under any of the NRHP/CRHR criteria, although some criteria are more commonly relevant than others. These systems are more likely to have significance under Criterion A/1 (events) and C/3 (type or style of construction), while Criterion B/2 (people) and D/4 (information potential) will apply in fewer cases. More than one of the criteria may apply to a system or feature, for example when a treatment plant is eligible under both A/1 and C/3 for its association with important events and its engineering values.
Criterion A/1
A drinking water or wastewater system may qualify for listing in the national and/or state register under Criterion A/1 if it has a demonstrably significant association with an important historic event, trend, or theme. Like other kinds of public-works facilities, sanitary water systems are inherently important to the communities they serve, providing infrastructure essential for municipal development. Such value, however, does not necessarily equate to historical significance under Criterion A/1, lest every treatment plant, pumping station, and the like be judged historically important. Rather, this type of infrastructure is best evaluated for significance based on its impact relative to other comparable, contemporaneous systems. This requires determining if a water system feature had historic importance above and beyond fulfilling its ordinary role of purifying water or disposing of sewage as was done by similar systems in innumerable communities.
A wastewater or drinking water facility may have significance if it introduced or proved the efficacy of an important new technology (may also be applicable under Criterion C/3, see below), public health measure, or environmental treatment standard; if it is closely associated with the creation of a type of political organization, such as a municipal utility district, that itself has importance in comparison to earlier organization models; or if it was the clearly identified focus of important social or political conflicts.
This document has established historic contexts for these themes at a state-wide level, but other events may also be significant, and evaluators will need to consider the potential for local historic importance.
Mere coexistence with an important historic trend is not enough to grant a resource significance. Rather, the property must be an important example of the trend or theme. Thus, for example, a plant that provided chlorination of a drinking water supply is not automatically significant merely because disinfection was an important public health advancement. The plant
1. Introduction and Regulatory Context
Coalinga Sanitary Sewer Collection System and WWTP Improvements Project 11 must have fulfilled an important role in the introduction of chlorination by being a site of experimentation, quelling a major disease outbreak, validating a new regulatory regime, or similar such measure. A resource such as a cistern or pumping station might be eligible under Criterion A/1 if it was important to providing a significant new public service.
If a water or sewer system is evaluated as having significance, it is further required to determine what parts of the system are most directly associated with the significant contribution. A program of drinking water chlorination requires a treatment plant but also watermains, laterals, service connections, and a source of supply. Not all of these are equally important to the chlorination program. The waterlines are necessary for disinfection, but they are not by themselves sufficient for disinfection, as the mere existence of waterlines does not presuppose chlorination treatment. Conversely, the chlorination equipment is both necessary and sufficient for disinfection as the existence of a treatment plant does presuppose a functioning water supply and distribution system. Therefore, while all the parts of the water system—supply, treatment, and distribution—participate in the historically significant introduction of chlorination, as used in this example, only the treatment plant itself might have direct and important association with that significance necessary for individual eligibility under these criteria. Other components could demonstrate a direct, significant association if, for example, they were constructed at the same time and as part of a single program of modernization. An evaluator needs to use judgement in assessing how broadly or narrowly to ascribe direct association with a significant innovation, but should avoid bringing in unrelated system components.
The technologies of drinking water and wastewater purification involve the engineering of both physical structures (mixing basins, sedimentation tanks, etc.) and biological and chemical components (nutrient-digesting microorganisms and flocculants, for example). Engineering innovation is generally recognized under Criterion C/3, but that applies principally to the physical features of a property. If the engineering innovation was primarily of a biological or chemical nature, and the physical structure shows few specific modifications, the innovation might be better recognized under Criterion A/1 if, for example, it demonstrably changed patterns of development of the community it served. A property may qualify under both sets of criteria if the engineering combined structural and biochemical elements.
Criterion B/2
A drinking water or wastewater system that is closely associated with an individual of historic importance may be found eligible for listing in the national and/or state register under Criterion B/2. Standards of significance under Criterion B/2 are very specific and relatively few properties meet them. Eligible properties must be associated with the productive life of the historically important individual and must be the best representation of the person’s historic contributions. NRHP guidelines emphasize that Criterion B is only applicable to the achievements of individuals, not groups of persons. Further, if an individual’s association with a property was through his or her role in its engineering design, this would be better captured under Criterion C/3 as the work of a master engineer.
A drinking water or wastewater system feature may have significance under this criterion if it is directly associated with a scientific, public policy, or social change that best represents the
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productive life of an historically important individual. This historic context has specifically identified individuals of importance within the context of the development of water sanitation including Thomas Logan, Charles Hyde, Wilfred Langelier, Chester Gillespie, and C. E.
Grunsky, though other pioneering or influential individuals in the field may certainly exist.
The association of one of these individuals with a property could confer historical significance under Criterion B/2 if their involvement was primarily in the realm of science or policy, rather than engineering, and if the property was an important one within the context of their career and contributions to their profession or field. Individuals must also be considered for importance at a local level and might be recognized for such actions as campaigning to extend sanitary services to a neglected community or adding protection for a natural resource.
Drinking water and wastewater systems do not commonly have strong, direct association with single individuals. They are instead usually the creation of municipal governments where credit and responsibility for the planning and construction of infrastructure are diffused among elected officials, city managers, and public works departments.
Criterion C/3
A drinking water or wastewater system or water system feature that exhibits important engineering or design characteristics may qualify for listing in the national and/or state register under Criterion C/3. A property can qualify either by being an important representative example of its type, period, or method of construction, or by having unique value as the work of a master or one that possesses high artistic value.
A water system feature may qualify if it is the earliest, best preserved, or a rare surviving example of its type; if it introduced a design innovation; or if it represents a transition between different expressions of the property type. Examples could include a nineteenth-century sewerage pipe if it is of a type that survives in few locations; an early trickling filter that shows transition between fill-and-drain practices and later continual spray methods; or the first water softening plant constructed in the state. Trade press publications can help to determine if a property was innovative for its time or exceptional for its size, expense, design challenges, unique combination of features, or in some other way. To be considered a good representative of its type, a property must possess “distinctive characteristics” that illustrate either a pattern of features common to the type or an important variation on the common features. It should be kept in mind that many water systems followed standard designs that were widely constructed.
It is thus necessary to compare the subject property to other similar surviving examples to establish its importance as a representative of its type.
A water system feature can be significant as the work of a master if it was designed by a figure of acknowledged greatness in the field and is an important example of their work. The individuals listed in Criterion B/2 above were all major figures in the field of sanitary engineering who worked at times as consultants in designing drinking water and wastewater systems. Research will reveal other designers whose importance is evident by the number and types of projects they engaged in or by the testimony of their contemporaries. Not every building or structure designed by a master has historic importance, and it is necessary to situate the evaluated property within the context of the individual’s body of work to determine if it was one of their highest achievements or marked an important phase of their career.
1. Introduction and Regulatory Context
Coalinga Sanitary Sewer Collection System and WWTP Improvements Project 13 A property with high artistic value is one that articulates a particular concept of design so well that it expresses an aesthetic ideal. While many water systems features were of utilitarian design, it was not uncommon for municipalities to carefully consider issues of architectural style when constructing buildings and structures that required considerable public investment and represented a commitment to the civic good. In general, the styling of water systems followed architectural trends employed in other contemporaneous public or utility buildings, using, for example, Neoclassical design around the turn of the century, the Art Deco style in the 1930s, and Modern styles in the 1940s and later. A water system feature might have significance for its design if it expressed one of these styles with a purity of form and a level of sophistication that exceeded that used in other comparable buildings. A property would not qualify if it made superficial use of a style or was of only average execution.
Not all features of drinking and wastewater systems are equally likely to possess significance under this criterion. Some water system components perform routine functions that remain consistent across treatment eras without showing more than incremental refinement. These include such features as sewer lines, waterline laterals, service connections, and wells.
Technological innovation is more likely to be found in the principal components of treatment plants and in such property types as large water storage towers. Ubiquitous property types that were constructed using common designs and materials for their era are highly unlikely to be significant for their engineering. Note, however, that if the significance was for architectural styling, then even the most common storage shed could share in the design and contribute to the property’s significance. Additionally, these features may contribute to the significance of a larger historic property (such as a historic district; see below) comprised of multiple elements working in concert as part of a larger system.
Criterion D/4
Drinking water and wastewater systems may be eligible for listing under Criterion D/4 if they are likely to yield information important to the study of history or prehistory. The properties most commonly found eligible under Criterion D/4 are archaeological sites, though historic built-environment features might also qualify for their information potential. These properties must be situated within an appropriate historic context, and they must possess the potential to answer specific important research questions through a study of their physical features.
Potentially relevant research issues for water system features include those related to vernacular practices and construction methods and might apply to indigenous, Spanish, Mexican, and early Euro-American systems. For instance, remnants of drinking and wastewater infrastructure from nineteenth century California may exhibit a local variation of a standard construction technique and provide insight into the availability of materials or construction expertise at a time when drinking and wastewater infrastructure were more localized and potentially non-standard. In order to make such a determination, construction dates would need to be ascertained using either the built-environment or archaeological record to identify associated temporally sensitive architectural elements of standing resources, documentation in primary sources, and/or temporally sensitive artifacts.
Certain water sanitation systems may possess research value for their associations with other types of resources. As the use of water and disposal of waste are essential to every form of
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settlement and most economic activities, establishing the location and time period of a water feature’s use may aid in the broader study of a region’s development.
However, oftentimes the archaeological remnants of water and waste disposal features or the material culture of the people that operated these systems, do not contain enough data to impart new knowledge about the design or operation of a facility.
Integrity
Working drinking water and wastewater systems will almost invariably have been altered to meet expanded demand, incorporate new technologies, replace worn-out components, and comply with changing regulations. Over time, these incremental changes leave most working systems with few original components that have not been modified or expanded. It is thus critical that evaluators carefully consider the integrity of historically significant systems and components under consideration. Even when systems meet one or more NRHP/CRHR criteria for significance, they will be ineligible for listing by state and federal standards if they do not retain the integrity needed to convey the significance they may once have possessed.
To retain historic integrity, a system must possess at least several, and usually most, of the seven aspects of integrity: location, design, setting, materials, workmanship, feeling, and association. Determining which of these aspects are most critical to a property requires clearly defining why the property is important and the time period (period of significance, see below) of that importance. The evaluator must weigh the cumulative loss of integrity across the seven aspects, balancing each by its relative importance, and arrive at a conclusion to what is ultimately a yes-or-no question: Does the resource retain adequate integrity to its period of significance to convey its significance? An answer of “yes” makes a significant resource eligible for listing in the NRHP and/or CRHR, while a “no” answer means that the resource is ineligible for listing in either register despite having historical significance.
As with other types of historic properties, the fundamental test of the integrity of a drinking water or wastewater system consists of the relationship between its current appearance and its appearance during the period of significance, which the evaluator will establish after placing the resource in its appropriate historic context and determining which significance criterion or criteria it meets. Integrity will not be lost as the result of modifications made during the system’s period of significance, and indeed, these alterations may actually contribute to its importance if they illustrate the adaptability and evolving role of the property. Modifications made after the period of significance may adversely affect the resource’s integrity. However, these modifications must be assessed to determine if they are of a scope, scale, and nature sufficient to cause the loss of one or more aspects of integrity.
It will not always be possible to assess the integrity of underground resources. Construction plans or other documentary materials may record the type, age, and materials of below-ground pipes, vaults, and other such features, but it might not be possible to determine if the original items have been replaced or altered without exposing the resource through excavation. The evaluation may then contain language to indicate the uncertainty, noting that the resource would contribute to the significance of the larger property if it was constructed during the period of significance and maintains historic integrity to the period.
1. Introduction and Regulatory Context
Coalinga Sanitary Sewer Collection System and WWTP Improvements Project 15 Not all alterations made to a system are of equal importance in assessing integrity. Changes that result from routine maintenance are usually less detrimental to integrity than are alterations made to the plant’s fundamental processes, and especially so when the changes affect only smaller, secondary components such as motors, pumps, electronic sensors, and computer systems. However, it is necessary to consider the cumulative effect of various additions and alterations over time. At the other extreme, replacing a major component of the treatment process, for example, replacing a septic tank with a separate clarifier and sludge digestor, would greatly degrade resource integrity of design and would likely disqualify it for listing in state and national registers.
Historic Districts
Drinking water and wastewater features may be evaluated as independent resources or as contributors to a historic district composed of related elements. A historic district consists of a significant concentration, linkage, or continuity of sites, buildings, structures, or objects that are interrelated visually or by function. A district may contain resources that are also individually eligible for listing or consist entirely of resources that lack individual distinction, but which achieve significance when grouped as a whole. A drinking water system district might consist of a treatment plant and related support features such as pumping stations and storage tanks, or of a series of wells that are united by common design and function. A district usually consists of a definable geographic area that is distinguishable from surrounding properties, but it may also be discontiguous (composed of two or more areas separated by nonsignificant areas) if the elements are spatially discrete and the space between them is not significant to the district. A discontiguous district may work well for a water system where the piped connections between resources are below ground and not of visual or historic importance to the district. Note, however, that if the district was significant for its engineering achievement and the subsurface pipe configuration or materials were an important part of that accomplishment, then the district might need to include the non-visible pipes within the property boundaries.
Drinking water features may also contribute to historic districts that are significant for reasons unrelated to water development. Indeed, the majority of California water features that have been determined eligible for listing in the NRHP and/or CRHR are of this type and owe their significance to the role they played in a larger enterprise rather than for their merits as engineered water features per se. Examples of this include the water system and sewage treatment plant within the Sonoma State Home Historic District and the water treatment plant in the Presidio National Historic Landmark District. It is thus always necessary to consider how water or sewage infrastructure was used in the pursuit of other economic, social, and cultural ends and to assess if the larger context has independent historic importance.
2. Environmental and Cultural Background
Coalinga Sanitary Sewer Collection System and WWTP Improvements Project 17
2. ENVIRONMENTAL AND CULTURAL
BACKGROUND
2.1 GEOARCHAEOLOGICAL SENSITIVITY AND
ENVIRONMENTAL BACKGROUND
2.1.1 Environmental Setting
The Project area is located within/near the city of Coalinga in Fresno County, California. Located approximately 0.40 mi. apart, the APE consists of two discontinuous parcels: 1) Pipelines APE and 2) WWTP APE (see Figure 1). Whereas the Pipelines APE is associated with the city of Coalinga, the WWTP APE is associated with Coalinga’s Wastewater Treatment Plant (see Figure 1). The Pipelines APE is west of the WWTP APE, and the parcels are bisected by Warthan Creek.
Elevations within the APE range between 640 ft. and 690 ft. amsl, with slopes ranging between zero and two percent. Both parcels are bounded to the north by Los Gatos Creek, which coalesces with Warthan Creek near the Project area. As outlined below, the APE consists of alluvial fans and historical era/modern anthropogenic deposits.
2.1.2 Geology and Geomorphology
The Project area is located within Pleasant Valley, which consists of a small valley within the southern Diablo Range. Pleasant Valley is technically part of the San Joaquin Valley but is separated from San Joaquin Valley proper via the Guijarral Hills and Anticline Ridge, which is bisected by Los Gatos Creek (Figure 2). Coalinga is partially surrounded by oil fields, with the first oil production beginning in 1890 (Hughes et al. 1990:399). These oil fields, as well as the city of Coalinga, were damaged by a magnitude 6.7 earthquake originating from Anticline Ridge in 1983 (Rymer and Ellsworth 1990). The earthquake engendered several thousand landslides, some of which occurred along the cutbanks paralleling Los Gatos Creek (Harp and Keefer 2017:344).
The APE is located within the southwestern portion of Pleasant Valley and is marked by extensive alluvial fans originating from adjacent hillslopes. The APE consists of (Qa) deposits composed of surficial sediments (i.e., alluvial gravel, sand and clay of valley areas; includes gravel and sand of stream channels) (see Figure 2).
2. Environmental and Cultural Background
Coalinga Sanitary Sewer Collection System and WWTP Improvements Project 19 Figure 2. Coalinga Sanitary Sewer Collection System and WWTP Improvements Project Geology Map
2. Environmental and Cultural Background
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2.1.3 Soils
Soils in the APE were identified through the US Department of Agriculture’s National Resource Conservation Service (USDA-NRCS 2019) Soil Survey Geographic (SSURGO) soil data. The Pipelines APE is mapped as the Excelsior soil series, which formed during the latest Holocene (2000–150 cal YBP) and consists of mixed alluvium originating from igneous and calcareous sedimentary rocks (Meyer et al. 2010: Appendix C). In contrast, the WWTP APE is mapped as “Sewage Disposal Pond” and dates to the historical era/modern times (<150 YBP) (Meyer et al. 2010: Appendix C). Although SSURGO does not list the native soil type(s) associated with the WWTP APE, the surrounding soils predominantly consist of the Excelsior series. Soil types accounting for less than six percent of the APE were not included. Soil map units are as follows:
Pipelines APE
• Excelsior; (latest Holocene; 2000–1000 cal YBP)
WWTP APE
• Sewage Disposal Pond; (historical era/modern times; <150 cal YBP) Soils in the APE(s) consist of young to very young soils formed in alluvium originating from adjacent areas of higher elevation. Although both parcels are marked by anthropogenic disturbances, the WWTP APE is mapped entirely as “Sewage Disposal Pond” which Meyer et al. (2010: Appendix C) confirms is a historical era/modern (<150 cal YBP) deposit.
2.1.4 Buried Site Sensitivity
As outlined above, the deposits within the APE(s) formed between the historical era/modern times (<150 YBP), and latest Holocene (2000–150 YBP). Whereas the Pipelines APE is marked by high buried site potential, the WWTP APE is marked as having low buried site potential (Meyer et al. 2010:140, Table 18). It should be noted that areas within the WWTP APE lacking modern disturbances via the construction of Coalinga’s Wastewater Treatment Plant would be classified as having high buried site potential, as it likely is marked as the Excelsior soil series.
2.2 ETHNOGRAPHIC BACKGROUND
Penutian-speaking Yokuts tribal groups occupied the southern San Joaquin Valley region and much of the nearby Sierra Nevada. Ethnographic information about the Yokuts was collected primarily by Powers (1971, 1976 [originally 1877]), Kroeber (1925), Gayton (1930, 1948), Driver (1937), Latta (1977) and Harrington (n.d.). For a variety of historical reasons, existing research information emphasizes the central Yokuts tribes who occupied both the valley and particularly the foothills of the Sierra. The northernmost tribes suffered from the influx of Euro Americans during the Gold Rush and their populations were in substantial decline by the time ethnographic studies began in the early twentieth century. In contrast, the southernmost tribes were partially removed by the Spanish to missions and eventually absorbed into multi-tribal communities on the Sebastian Indian Reservation (on Tejon Ranch), and later the Tule River Reservation and Santa Rosa Rancheria to the northeast. The result is a scarcity of ethnographic detail on southern Valley tribes, especially in relation to the rich information collected from the central foothills tribes where native speakers of the Yokuts dialects are still found. Regardless, the general details of indigenous
2. Environmental and Cultural Background
Coalinga Sanitary Sewer Collection System and WWTP Improvements Project 21 lifeways were similar across the broad expanse of Yokuts territory, particularly in terms of environmentally influenced subsistence and adaptation and with regard to religion and belief, which were similar everywhere.
Following Kroeber (1925: Plate 47), the Project APE most likely lies in Tachi territory. The closest village to the APE for this group was Udjiu, northeast of the APE.
The Yokuts settlement pattern was largely consistent, regardless of the specific tribe involved.
Winter villages were typically located along lakeshores and major stream courses (as these existed circa 150 YBP), with dispersal phase family camps located at elevated spots on the valley floor and near gathering areas in the foothills.
Most Yokuts groups, again regardless of specific tribal affiliation, were organized as a recognized and distinct tribelet, a circumstance that almost certainly pertained to the tribal groups noted above.
Tribelets were land-owning groups organized around a central village and linked by shared territory and descent from a common ancestor. The population of most tribelets ranged from about 150 to 500 people (Kroeber 1925).
Each tribelet was headed by a chief who was aided by a variety of assistants, the most important of whom was the winatum, a herald or messenger and assistant chief. A shaman also served as a religious officer. While shamans did not have any direct political authority, as Gayton (1930) has illustrated, they maintained substantial influence within their tribelet.
Shamanism is a religious system common to many Native American tribes. It involves a direct and personal relationship between the individual and the supernatural world enacted by entering a trance or hallucinatory state (usually through the ingestion of psychotropic plants, such as jimsonweed or more typically native tobacco). Shamans were considered individuals with an unusual degree of supernatural power, serving as healers or curers, diviners, and controllers of natural phenomena (such as rain or thunder). Shamans also produced the rock art of this region, depicting the visions they experienced in vision quests believed to represent their spirit helpers and events in the supernatural realm (Whitley 1992, 2000).
The centrality of shamanism to the religious and spiritual life of the Yokuts was demonstrated by the role of shamans in the yearly ceremonial round. The ritual round, performed in the same manner each year, started in the spring with the jimsonweed ceremony, followed by rattlesnake dance and (where appropriate) first salmon ceremony. After returning from seed camps, fall rituals began in the late summer with the mourning ceremony, followed by first seed and acorn rites, and then bear dance (Gayton 1930:379). In each case, shamans served as ceremonial officials responsible for specific dances involving a display of their supernatural powers (Kroeber 1925).
Subsistence practices varied from tribelet to tribelet based on the environment of residence.
Throughout Native California, and Yokuts territory in general, the acorn was a primary dietary component, along with a variety of gathered seeds. Valley tribes augmented this resource with lacustrine and riverine foods, especially fish and wildfowl. As with many Native California tribes, the settlement and subsistence rounds included the winter aggregation into a few large villages, where stored resources (like acorns) served as staples, followed by dispersal into smaller camps,
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often occupied by extended families, where seasonally available resources would be gathered and consumed.
Although population estimates vary and population size was greatly affected by the introduction of Euro-American diseases and social disruption, the Yokuts were one of the largest, most successful groups in Native California. Cook (1978) estimates that the Yokuts region contained 27 percent of the aboriginal population in the state at the time of contact; other estimates are even higher. Many Yokuts people continue to reside in the southern San Joaquin Valley today.
2.3 PRE-CONTACT ARCHAEOLOGICAL BACKGROUND
The southern San Joaquin Valley region has received minimal archaeological attention compared to other areas of the state. In part, this is because the majority of California archaeological work has been concentrated in the Sacramento Delta, Santa Barbara Channel, and central Mojave Desert areas (see Moratto 1984). Although knowledge of the region’s prehistory is limited, enough is known to determine that the archaeological record is broadly similar to south-central California as a whole (see Gifford and Schenk 1926; Hewes 1941; Wedel 1941; Fenenga 1952; Elsasser 1962; Fredrickson and Grossman 1977; Schiffman and Garfinkel 1981). Based on these sources, the general prehistory of the region can be outlined as follows.
Initial occupation of the region occurred at least as early as the Paleoindian Period, or prior to about 10,000 YBP. Evidence of early use of the region is indicated by characteristic fluted and stemmed points found around the margin of Tulare Lake, in the foothills of the Sierra, and in the Mojave Desert proper.
Both fluted and stemmed points are particularly common around lake margins, suggesting a terminal Pleistocene/early Holocene lakeshore adaptation similar to that found throughout far western North America at the same time; little else is known about these earliest peoples. More than 250 fluted points have been recovered from the Witt Site (CA-KIN-32), located along the western shoreline of ancient Tulare Lake south of the APE, demonstrating the importance of this early occupation in the San Joaquin Valley specifically (see Fenenga 1993). Additional finds consist of a Clovis-like projectile point discovered in a flashflood cut-bank near White Oak Lodge in 1953 on Tejon Ranch (Glennan 1987a, 1987b). More recently, a similar fluted point was found near Bakersfield (Zimmerman et al. 1989), and a number are known from the Edwards Air Force Base and Boron area of the western Mojave Desert. Although human occupation of the state is well-established during the Late Pleistocene, relatively little can be inferred about the nature and distribution of this occupation with a few exceptions. First, little evidence exists to support the idea that people at that time were big-game hunters, similar to those found on the Great Plains.
Second, the western Mojave Desert evidence suggests small, very mobile populations that left a minimal archaeological signature. The evidence from the ancient Tulare Lake shore, in contrast, suggests much more substantial population and settlements which, instead of relying on big-game hunting, were tied to the lacustrine lake edge. Variability in subsistence and settlement patterns is thus apparent in California, in contrast to the Great Plains.
Substantial evidence for human occupation across California, however, first occurs during the middle Holocene, roughly 7500 to 4000 YBP. This period is known as the Early Horizon, or
2. Environmental and Cultural Background
Coalinga Sanitary Sewer Collection System and WWTP Improvements Project 23 alternatively as the Early Millingstone along the Santa Barbara Channel. In the south, populations concentrated along the coast with minimal visible use of inland areas. Adaptation emphasized hard seeds and nuts with tool kits dominated by mullers and grindstones (manos and metates).
Additionally, little evidence for Early Horizon occupation exists in most inland portions of the state, partly due to a severe cold and dry paleoclimatic period occurring at this time, although a site deposit dating to this age has been identified along the ancient Buena Vista shoreline in Kern County to the south (Rosenthal et al. 2007). Regardless of specifics, Early Horizon population density was low with a subsistence adaptation more likely tied to plant-food gathering than hunting.
Environmental conditions improved dramatically after about 4000 YBP during the Middle Horizon (or Intermediate Period). This period is known climatically as the Holocene Maximum (circa 3800 YBP) and was characterized by significantly warmer and wetter conditions than previously experienced. It was marked archaeologically by large population increase and radiation into new environments along coastal and interior south-central California and the Mojave Desert (Whitley 2000). In the Delta region to the north, this same period of favorable environmental conditions was characterized by the appearance of the Windmiller culture which exhibited a high degree of ritual elaboration (especially in burial practices) and perhaps even a rudimentary mound-building tradition (Meighan, personal communication, 1985). Along with ritual elaboration, Middle Horizon times experienced increasing subsistence specialization, perhaps correlating with the appearance of acorn-processing technology. Penutian-speaking peoples (including the Yokuts) are also posited to have entered the state roughly at the beginning of this period and, perhaps, to have brought this technology with them (cf. Moratto 1984). Likewise, it appears the so-called “Shoshonean Wedge” in southern California, the Takic-speaking groups that include the Gabrielino/Fernandeño, Tataviam, and Kitanemuk, may have moved into the region at that time (Sutton 2009), rather than at about 1500 YBP as first suggested by Kroeber (1925).
Evidence for Middle Horizon occupation of interior south-central California is substantial. For example, in northern Los Angeles County along the upper Santa Clara River, to the south of the San Joaquin Valley, the Agua Dulce village complex indicates occupation extending back to the Intermediate Period, when the population of the village may have been 50 or more people (King et al n.d.). Similarly, inhabitation of the Hathaway Ranch region near Lake Piru, and the Newhall Ranch near Valencia, appears to date to the Intermediate Period (W&S Consultants 1994). To the west, little or no evidence exists for pre-Middle Horizon occupation in the upper Sisquoc and Cuyama River drainages; populations first appear there at roughly 3500 YBP (Horne 1981). The Carrizo Plain, the valley immediately west of the San Joaquin, experienced a major population expansion during the Middle Horizon (W&S Consultants 2004; Whitley et al. 2007), and recently collected data indicates the Tehachapi Mountains region was first significantly occupied during the Middle Horizon (W&S Consultants 2006). A parallel can be drawn to the inland Ventura County region where a similar pattern has been identified (Whitley and Beaudry 1991), as well as the western Mojave Desert (Sutton 1988a, 1988b), the southern Sierra Nevada (W&S Consultants 1999), and the Coso Range region (Whitley et al. 1988). In all of these areas a major expansion in settlement, the establishment of large site complexes, and an increase in the range of environments exploited appear to have occurred sometime roughly around 4,000 years ago. Although most efforts to explain this expansion have focused on local circumstances and events, it is increasingly apparent this was a major occurrence throughout southern California, and any explanation must
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be sought at a larger level of analysis (Whitley 2000). Additionally, evidence from the Carrizo Plain suggests the origins of the tribelet level of political organization developed during this period (W&S Consultants 2004; Whitley et al. 2007). Whether this same demographic process holds for the southern San Joaquin Valley, including the Project APE, is yet to be determined.
The beginning of the Late Horizon is set variously at 1500 and 800 YBP, with a growing archaeological consensus for the shorter chronology. Increasing evidence suggests the importance of the Middle-Late Horizons transition (AD 800 to 1200) in the understanding of south-central California prehistory. This corresponds to the so-called Medieval Climatic Anomaly, followed by the Little Ice Age, and this general period of climatic instability extended to about A.D. 1860. It included major droughts matched by intermittent “mega-floods,” and resulted in demographic disturbances across much of western North America (Jones et al. 1999). It is believed to have resulted in major population decline and abandonments across south-central California, involving as much as 90 percent of the interior populations in some regions, including the Carrizo Plain (Whitley et al. 2007). It is not clear whether site abandonment was accompanied by a true reduction in population or an agglomeration of the same numbers of peoples into fewer but larger villages in more favorable locations. Population along the Santa Barbara coast appears to have spiked at about the same time that it collapsed on the Carrizo Plain (ibid). Along Buena Vista Lake, in Kern County, population appears to have been increasingly concentrated toward the later end of the Medieval Climatic Anomaly (Culleton 2006), and population intensification also appears to have occurred in the well-watered Tehachapi Mountains during this same period (W&S Consultants 2006).
What is then clear is that Middle Period villages and settlements were widely dispersed across the south-central California landscape, including in the Sierra and the Mojave Desert. Many of these sites are found at locations that lack existing or known historical freshwater sources. Late Horizon sites, in contrast, are typically concentrated in areas where fresh water was available during the historical period, if not currently.
One extensively studied site that shows evidence of intensive occupation during the Middle-Late Horizons transition (~1500 – 500 YBP) is the Redtfeldt Mound (CA-KIN-66/H), located south of the current APE, near the north shore of ancient Tulare Lake. There, Siefkin (1999) reported on human burials and a host of artifacts and ecofacts excavated from a modest-sized mound. He found that both Middle Horizon and Middle-Late Horizons transition occupations were more intensive than Late Horizon occupations, which were sporadic and less intensive (Siefkin 1999:110-111).
The Late Horizon can then be understood as a period of recovery from a major demographic collapse. One result is the development of regional archaeological cultures as the precursors to ethnographic Native California, suggesting that ethnographic lifeways recorded by anthropologists extend roughly 800 years into the past.
The position of southern San Joaquin Valley prehistory relative to patterns seen in surrounding areas is still somewhat unknown. The presence of large lake systems in the valley bottoms appears to have mediated some of the desiccation seen elsewhere. But, as the reconstruction of Soda Lake in the nearby Carrizo Plain demonstrates (see Whitley et al. 2007) environmental perturbations had serious impacts on lake systems too. Identifying certain prehistoric demographic trends for the
2. Environmental and Cultural Background
Coalinga Sanitary Sewer Collection System and WWTP Improvements Project 25 southern San Joaquin Valley, and determining how these trends (if present) correlate with those seen elsewhere, is a current important research objective.
2.4 HISTORICAL BACKGROUND
2.4.1 Drinking Water and Wastewater Treatment Facilities in California
JRP Historical Consulting, LLC and AECOM prepared the historic context below:1
1. The Pre-Treatment Era: Sanitation in the Nineteenth Century The mid-nineteenth century saw the emergence of the first social-reform “Sanitarians” in England and America who linked cleanliness and good health. The reformers lacked a specific causal mechanism to explain waterborne disease transmission, but they succeeded in creating state and local boards of health with limited powers to enforce hygienic measures. No practical method for treating drinking water or sewage yet existed, so municipal engineers simply sought to direct sewage away from populated areas as rapidly as possible and to secure safe drinking water drawn from deep wells or remote mountain streams. The ad hoc nature of water procurement and sewer construction meant these efforts frequently failed, and cholera and typhoid fever took a frightful toll on urban populations through the century.
Knowledge
Modern sanitary sewage and drinking water systems first emerged in mid-nineteenth-century England. Prior to that time, systems of water supply and waste disposal were local in nature with limited public oversight. Individuals were responsible for procuring their own water and disposing of their own waste. So long as population densities remained low, these traditional methods functioned satisfactorily. However, as urbanization and industrialization took hold in Victorian England, the streams of human and industrial waste began to overwhelm the limited physical and legal infrastructure that governed the flows of pure and soiled waters. London, Birmingham, and Manchester choked on their own filth and suffered through regular epidemics that the medical theories of the day could neither explain nor ameliorate.
In the 1830s, English social reformers—the so-called Sanitarians—began to link dirt, disease, and moral disorder. A cholera epidemic of 1831–1832 killed great numbers of people and particularly devastated the poorest and dirtiest districts of London. A nascent reform movement that aimed to improve living conditions for the laboring class seized on the moment to promote the idea that cleanliness and health were inextricably linked. Theorists began to conceive of the city as an organic entity that depended upon a regular flow of clean water for nourishment and as an aid in the disposal of waste. They pressed for improved public health systems, with a focus on securing clean sources of drinking water and, to a lesser extent, providing public sewerage systems.
The sanitarian position was associated with miasmic theory, the then-dominant medical model.
Miasmic theory held that disease arose from the putrefaction of organic wastes and was transmitted through the inhalation of contaminated airs (miasmas) such as vapors arising from stagnant ponds or sewer gases leaking through a storm grate. Scientists debated the exact nature of miasmas, but 1 ASM did not include any of the mentioned figures, and Table 2 has been excluded. Please see original source.
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were in general agreement that they arose from a combination of warm temperatures, damp environments, and an overabundance of organic matter. A physician’s proper duties thus extended beyond individual care to encompass social reform of the unsanitary conditions that endangered public health. Because many of the illnesses that the Sanitarians first combatted were intestinal in nature—cholera, dysentery, typhoid fever—their environmental campaigns produced real improvements that vouched for the theory among scientists, politicians, and the public. However, the miasmic theory always remained vague about the precise vectors of contagion, and by the end of the nineteenth century it had been largely replaced by the germ theory that identified bacterial pathogens as the agents responsible for spreading disease.
Edward Chadwick was the great popularizer of sanitary ideas. A lawyer by profession, Chadwick led several government investigations of epidemics that established firm connections between poor sanitary conditions and disease outbreaks. His 1842 Report on the Sanitary Conditions of the Labouring Population of Great Britain was widely read, selling more copies than any prior government publication. Chadwick argued that improving sanitary conditions required a strong centralized authority with the power to construct comprehensive public works systems that integrated water deliveries and sewage removal. He was too impatient to accept the more limited political realities of his time, and none of his proposals ever achieved full implementation.
However, his forceful advocacy of sanitarian ideas shifted the public debate. His work brought together for the first time an environmental context for public health, an argument for the role of government in improving conditions for the greater good, and the identification of infrastructure technologies that could realize those goals.
Sanitarian ideas crossed the Atlantic in the mid-1840s. A small but influential group of American physicians had closely followed developments in Europe and were eager to apply the new environmental models of health to their own country, which was then in the midst of its first great wave of urban expansion. John H. Griscom, the New York City Inspector at the time, corresponded with Chadwick and in 1845 published The Sanitary Conditions of the Laboring Population of New York that was modeled on Chadwick’s report. Among other proposed reforms, the study called for an expanded public drinking water system and the construction of underground sewers. Griscom joined with other physicians in organizing the New York Academy of Medicine that made sanitarian reform one of its chief objectives.
The American Medical Association (AMA) established a committee on public hygiene in 1848.
The committee took a broad view of public health that included infrastructure improvements alongside quarantine laws, smallpox vaccinations, temperance advocacy, vital statistics gathering, pure food and drink measures, and mental health programs. The group urged the creation of state and local boards of health and called for medical schools to include instruction in the sanitary sciences. In 1857, the AMA staged the first national sanitary convention in Philadelphia, with annual meetings following in Baltimore, New York, and then Boston in 1860. The outbreak of the Civil War interrupted the gathering momentum of the American sanitarian movement, but public health had established itself as a key element in progressive medical thought.
Political Organization
For all the gains that sanitarian ideas made among physicians and social reformers, the movement realized far fewer practical achievements. Americans shrank from accepting the sort of centralized authority that Chadwick and Griscom believed was needed to implement sanitarian reforms. State
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Coalinga Sanitary Sewer Collection System and WWTP Improvements Project 27 and local governments largely assumed public health responsibilities only when compelled to by an epidemic and the resulting regulations were typically allowed to lapse once the crisis had passed. Local governments lacked clear authority to do more even if they had so desired. A lack of definite knowledge about the causes of illness contributed to this reluctance as most early efforts at halting the spread of epidemics proved futile and divisive.
A few Northeastern cities broke from this general pattern of passivity to take an active role in passing sanitary ordinances and establishing public health bodies. The city leaders of Boston in 1634 prohibited the dumping of fish or garbage near the common docks in what was apparently the first formal sanitary law in the American colonies. The city authored quarantine regulations in 1647 and began to regulate the construction of privies five years later. In 1797, Boston established the first permanent local board of health in the nation, though the body had limited formal powers and was staffed by political appointees. The New York state legislature in 1866 passed the New York Metropolitan Health Law that established the Metropolitan Board of Health. This was the first effective board of health in a major city, and it provided a model for subsequent developments.
Massachusetts created the first state-level board of health in 1869. Still, few states immediately followed the lead of New York and Massachusetts, and as late as 1875 many major cities had no permanently empowered health departments.
Rather than adopting formal ordinances to regulate sanitary matters, most cities and states chose to rely on broad but vaguely articulated nuisance laws. The State of California later defined a public nuisance as “anything which is injurious to health, or is indecent, or offensive to the senses, or an obstruction to the free use of property, so as to interfere with the comfortable enjoyment of life or property.”10In most circumstances, noxious odors and unsightly trash dumps posed more of an annoyance than a serious public health threat. However, because these sorts of nuisances were commonly limited to individual properties, they could be more easily addressed than systemic problems. And critically, the courts, rather than politicians, took the lead in enforcing nuisance laws. Americans were willing to accept litigation in private property disputes more so than government-imposed regulations. Thus, public nuisance lawsuits and abatement orders played the chief role through the nineteenth century in protecting water purity.
Nineteenth-Century California
Nineteenth-century California was progressive in establishing public health organizations, but lagged in constructing effective infrastructure. While California generally followed national trends in sanitation and looked towards the Northeastern states and Western Europe for its models, the peculiarities of the Gold Rush in the late 1840s and early 1850s shaped the state’s early experiences with water and sewage systems. The mass movement of population and the sudden emergence of urban centers, especially in San Francisco and Sacramento, fueled pandemics that galvanized early public health campaigns. Physicians strenuously advocated for improved sanitary conditions, but the actual development of water and sewage systems occurred in a piecemeal fashion that befit an era of limited governments. Systems constructed for the “instant cities” of the 1850s remained in use a half century later despite obvious inadequacies. Only in the twentieth century did California emerge as a national leader in sanitation matters.
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Boards of Health
The public health systems of nineteenth-century California emerged in response to the severe disorder that accompanied the Gold Rush. The surge of hundreds of thousands of global migrants into a region almost entirely lacking in public health infrastructure produced a calamitous series of disease outbreaks, including most notably the cholera epidemic of 1850. Cholera struck horror wherever it appeared in the nineteenth century. The intestinal illness, transmitted by food and water contaminated with fecal matter, caused violent vomiting and diarrhea that left victims with an unquenchable thirst and dehydration so severe that the skin pulled taut around skeletal features.
Nearly half of cases resulted in death, often within hours of the onset of symptoms.
Cholera arrived in San Francisco aboard an unquarantined ship in early October 1850. Within a week and a half, the disease had spread to Sacramento, where it had its most devastating impact.
No authority then existed to keep a reliable count of the dead, but an estimated 800 to 1000 people, roughly 15 percent of Sacramento’s population, are thought to have perished during the monthlong outbreak. Of the 40 physicians based in Sacramento, 17 died while tending to the ill, one of the highest mortality rates ever recorded among medical first responders. This encounter with cholera and subsequent waves of smallpox, diphtheria, typhoid fever, and other communicable illnesses deeply impressed upon the state’s physicians the need to organize in support of quarantine laws and public sanitation measures.
Sacramento physician Thomas M. Logan took a leading role in establishing the institutions of public health. Born and educated in South Carolina, Logan spent a year of study in Britain and France during a cholera epidemic that allowed him to learn firsthand the latest in sanitary science.
Back in the United States, he served as a university lecturer, authored a compendium on surgery, and accepted a hospital appointment in New Orleans before the Gold Rush lured him to California in time for the 1850 cholera epidemic. Logan began compiling statistics on mortality in Sacramento and was ahead of his time in insisting that the control of disease depended largely upon the sanitation of the community. He took an active role in organizing the Sacramento Medical Society in 1855, the California Medical Society in 1856, and the Sacramento Society for Medical Improvement in 1868. Logan regularly served as corresponding secretary for these organizations, and he ranked among the most prolific writers of medical literature in the state.
Logan and the medical societies campaigned for the organization of boards of health that would place matters of sanitation and quarantine under the direction of medical school-trained physicians rather than political patronage appointees. Both San Francisco and Sacramento established local boards in the mid-1860s, closely following the example set by New York Metropolitan Board of Health. Logan served as a charter member and secretary for the Sacramento board.
Local boards held responsibility for a complex array of health matters. The enacting legislation charged the boards with managing quarantine procedures at the ports; keeping records of birth, deaths, and interments; supervising the sanitary conditions of all public hospitals, jails, almshouses, and schools; providing guidance on the location and staffing of hospitals; and establishing “pest houses” for isolating contagious disease. While the boards held general authority to make and enforce any sanitary regulation deemed necessary, in practice their involvement with municipal water and sewage systems was limited to ordering the abatement of nuisances. The boards did not take a hand in planning such systems or in supervising their construction, which
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Coalinga Sanitary Sewer Collection System and WWTP Improvements Project 29 remained the purview of private developers and municipal engineers. The boards could order an individual source of pollution from a tenement house or butcher shop cleaned up at the owner’s expense, but the larger failures common in the ad hoc construction of sewage networks remained unaddressed.
In 1870, Logan authored legislation to establish the California State Board of Health.
Massachusetts had created the nation’s first state board of health only a year prior in 1869, and California was the second state to take the consequential step. Logan had been frustrated by the smallpox epidemic of 1868-69, when popular resistance to vaccinations cost hundreds of lives that might otherwise have been saved. He desired a strong state board that could coordinate the efforts of mandatory local health boards but accepted that politics required a less powerful organization.
The law he crafted created a board of seven physicians, appointed by the governor and hailing from throughout the state. Logan was the first appointee to the board and served as secretary. In his opening address to the newly formed body, he stressed that the board would avoid sanitary measures that “might press too heavily on the individual and lessen too much the freedom of personal action.” “Our duties are not executive, but advisory,” he declared, and in most all cases, “the observation of our sanitary rules will be voluntary and not compulsory.” As one of its first orders of business, the state board drafted the “Act for Sanitary Purposes,” by which it hoped to empower local boards of health to construct and manage sewage collection systems. As drafted, the act would have compelled every incorporated city and town to establish a local board of health staffed by medical professionals. These local boards were to have sole authority over the management of sewage and drainage pipes. All new buildings constructed within incorporated towns would be required to complete sewers that either drained to the sea or connected to a sewage collection system if one were within 100 feet of the building. Those outside of 100 feet from an existing system would need to install privies and covered cesspools with the construction overseen by local health officials “for the preservation of the purity of streams and springs, or other sources of fresh water.”
The California Legislature declined to enact such an ambitious bill, and instead merely authorized (rather than required) city governments to appoint boards of health or health officers as they saw fit. County supervisors might likewise appoint boards of health, but only as a temporary measure during epidemics. Few cities immediately availed themselves of their appointment authority and only Stockton and Oakland created new boards to join those previously existing in San Francisco and Sacramento. In 1878, the legislature amended the law to make the formation of a local board of health mandatory for incorporated communities. Enforcement of the measure was limited, and many cities delayed appointing a board that might shift power away from city councilmembers.
By the mid-1880s, a total of 19 local boards of health existed, representing less than one third of the 60 incorporated cities and towns in the state. In 15 counties, no incorporated towns existed and therefore there were no boards of health.
The local boards of health had executive power to enforce nuisance abatement laws, but only a few cities had ordinances specific to sanitation. Serving on a health board was generally a thankless task that invited hostility from those who were served with abatement orders, so most boards acted only after receiving a formal complaint. The state board attempted to prompt the local boards into taking greater responsibility for their drinking water and sewage systems by sending out periodic
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questionnaires that asked for an assessment of current conditions and plans. However, the survey results tended to be more dispiriting than motiving. Of the 23 cities that responded to an 1879 survey, only one was judged to have a complete sewerage system, while seven others had partial systems that left out many neighborhoods. The remaining cities had no integrated systems but included disconnected sections of sewage pipe that were constructed by private interests to serve individual buildings or small developments. The state board concluded that the responses showed “an absence of a spirit of enterprise to overcome obstacles, and an apparent want of appreciation of the real importance of the subject.”
Professorships of Hygiene
In 1873, the regents of the University of California (UC) created a Professorship of Hygiene within the medical school at Berkeley, the fourth such position in the nation, and they appointed Thomas Logan, the founder and secretary of the State Board of Health, to the role. Logan had achieved national prominence in the years following the 1870 creation of the state board. He arranged for the 1871 annual convention of the AMA to be held in San Francisco, and he used his address to the body to tout the state’s achievements and urge the nation’s 37 medical schools to appoint chairs of hygiene. Logan was elected president of the AMA for the 1872 year. Although the UC regents appointed a leading man of medicine with a record of scientific and administrative innovation to head the new course of study, Logan died three years later without leaving a permanent, substantive plan of research and instruction.
The University of California, Stanford University, and the University of Southern California all created professorships of hygiene or sanitary science in the nineteenth century, but the broad program of instruction gave limited attention to matters of drinking water supply or sewage management. Courses focused largely on what might be termed healthy living, covering such subjects as diet, exercise, sexual relations, and mental health. There was thus little university research conducted on public sanitation in nineteenth-century California that might have shaped the infrastructure being created.
Nineteenth-Century Technology Waterworks
Prior to the 1870s, only about half of American towns had any sort of public water system and these were concentrated in the larger cities of the Northeast. In all other areas, individuals procured their daily water supplies for drinking, cooking, and bathing in essentially the same manner as had European peasants for centuries. They dipped pails in surface streams, drew groundwater from springs or wells, and collected rainwater in cisterns. What public systems did exist, with a few exceptions, were nearly as crude. A town might dig an open ditch from a nearby river or enclose a hillside spring and run a log pipe to a community trough. More commonly, town leaders simply excavated a large central well. The Spanish and Mexican settlements of pre-1850 California made use of such public systems as the Zanja Madre (Mother Canal) in the Los Angeles pueblo and artesian wells and small dams at the missions to meet both agricultural and domestic needs.
Some of these early Spanish and Mexican-period systems included rudimentary treatment facilities; such as the filtration building (“El Caballo”) at San Buenaventura Mission, where aqueduct water flowed through layers of sand and charcoal to purify the drinking water. Few towns had any sort of distribution system, so households had to carry their water in buckets or purchase a daily supply from water carriers who hauled water by wagon or hand. Consequently, most
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Coalinga Sanitary Sewer Collection System and WWTP Improvements Project 31 individuals limited themselves to between three and five gallons of water per day, equivalent to a few flushes of a modern toilet.
These local systems functioned adequately so long as populations remained low, but any town looking to grow needed a supply of abundant, reasonably pure water for domestic and industrial consumption as well as firefighting purposes. The challenge of obtaining such a supply frequently served as the catalyst for organizing a municipal government, and for many towns the construction of a public water system was their first and largest financial undertaking. In states dominated by rural legislatures, towns were frequently constrained in their abilities to tax citizens or finance infrastructure projects through debt. Municipal government thus commonly turned to private companies that could borrow from capital markets. In nineteenth-century California, only Sacramento developed a water system that was predominantly publicly owned; all other cities and towns relied on private enterprise to meet their supply needs. Governments regulated the water companies through the granting of franchises. The companies were offered access to water supplies, use of public rights-of-way, monopoly control over distribution networks, the right to exercise eminent domain in constructing their systems, and certain tax privileges. In exchange, the government could specify terms of service to include the distribution area and minimum water pressure requirements, as well as exercise a measure of control over pricing. Franchises also generally required that water be provided free for fire hydrants and public parks.
Selecting a water source required weighing expense, convenience, safety, and palatability. The English River Pollution Commission ranked water supplies with respect to their comparative wholesomeness, palatability, and general fitness for drinking and cooking. Springs, deep wells, and mountain streams or lakes provided the most desirable supply, while lowland rivers and shallow wells were both hazardous to health and undesirable for consumption. Throughout California, wells were the most common source of water and most were relatively shallow at 35 feet of depth or less. Water from such wells was essentially surface water that had been lightly filtered by percolating through the soil. This removed the larger contaminants and the water was generally clear and cool, though shallow filtration did not capture the smaller microorganisms that caused disease. In trickling through stone, the water also acquired quantities of dissolved calcium and magnesium that rendered it hard and alkaline. This decreased the water’s palatability and made it less effective in laundering and some industrial uses. In an era when water purity was assessed directly through the senses, the off-putting odor and flavor of hard water suggested contamination to many consumers. Where feasible, towns made use of deep wells, and deep artesian wells remained common in the nineteenth century through such locations as the Santa Clara Valley and the Los Angeles Basin. When located within a reasonable distance of mountains, cities diverted pure water from upland sources and ran it through earthen ditches to reservoirs for distribution.
Infiltration galleries offered one practical method for improving the safety of non-mountainous surface water sources. Infiltration galleries consisted of perforated pipes, generally of concrete construction, that ran horizontally through the sand and gravel bedding that surrounded and lay beneath watercourses. The pipes collected the subsurface river flow and then discharged it by gravity at a lower point or carried it to a pumping station for lifting to the surface. Percolating through the sand and gravel naturally filtered the subsurface flows. This cleansed the water of most organic matter and improved its safety, though the addition of dissolved minerals increased the water hardness and diminished its palatability. Los Angeles constructed an early gallery system in
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1886, consisting of two 3,656-foot-long pipes installed 10 to 15 feet beneath the Los Angeles River through the Glendale Narrows, north of downtown. The city expanded the existing system and completed additional galleries in 1904, 1905, and 1906. The largest of these burrowed through bedrock 115 feet beneath the riverbed. Nine vertical wells connected the bedrock tunnel to the river and collected the subsurface flow through their perforated linings. Collectively, these systems drained so much underground flow that the Los Angeles River routinely ran dry at the surface. The improved water quality, however, allowed the city to abandon several chlorine treatment stations that had proven expensive and inefficient to operate.
Diverted water generally flowed first to a service reservoir or water tower before entering the distribution network. This provided a reserve of water for use in firefighting, allowed for pumps to shut down overnight to save on fuel and labor costs, and helped to balance pressure through the distribution system. A typical design for a small municipal system was to place reservoirs at opposite ends of the distribution system, with a main reservoir near the source supply and an elevated tank at the other end of town. Water was pumped overnight across town into the tower, and then during the day water was available at both ends of the distribution system. This prevented a loss of pressure for users at the far end of town. Some small, early water systems dispensed with reservoirs in favor of direct-pressure systems (discussed below), but these fell in popularity as populations increased and towns opted for the flexibility offered by storage. Reservoirs also helped to deal with variable surface-stream turbidity (water clarity) as towns could fill their storage while a stream ran clear and then draw from that supply after a storm when river turbidity increased.
Some larger suspended solids might also fall out of the water while in a reservoir, though the regular in and out flow prevented the water from calming enough to deposit the smaller bits of clay and organic matter that caused the most problems with turbidity and off-putting colors and odors.
Reservoir design balanced cost versus storage capacity. Ideally, the system could store several days of water supply, but this required a large area and high construction costs. Earthen reservoirs were serviceable, but they benefitted from being lined on bottoms and slopes to make them watertight. Early linings were principally of puddle, a mixture of clay and sand, with dry stone paving reinforcing the slopes. As concrete quality improved over the nineteenth century, engineers increasingly used it for lining, though the large sheets were subject to cracking if exposed to temperature changes when a reservoir was drained for maintenance. Covering the concrete with asphalt improved its watertightness, and asphalt could also be applied over a brick lining as a sealant. Roofing the reservoir protected it from contamination and freezing during severe weather.
Large city reservoirs sometimes featured elaborate groined arches to support roof structures, but simpler construction of brick, wood, or iron was more common. A standpipe was a contained tank, constructed of concrete or steel, that stood at ground level rather than being elevated. The distinction between a reservoir and standpipe was one of relative dimensions: a storage tank that was taller than it was wide was commonly classified as a standpipe while one wider than it was tall was identified as a reservoir.
Water tanks replaced reservoirs in level terrain that lacked an elevation suitable for a storage basin, or where the needed supply was small enough that the expense of a tank was favorable compared to land acquisition and construction costs of an in-ground reservoir. Early tanks were wood barrels set on rooftops or girder platforms. The tanks were constructed of vertical staves bound by steel
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Coalinga Sanitary Sewer Collection System and WWTP Improvements Project 33 hoops, with the hoops more tightly spaced towards the tank bottom where the pressure was greatest. Wood tanks were common features on rooftops in older urban areas through the midtwentieth century and they continue to serve today in small water systems. Riveted or bolted steel replaced wood for larger municipal tanks beginning in the 1890s. These usually consisted of a steel cylindrical tank with a conical roof mounted on a steel girder platform. A riser pipe delivered water to and from the tank and a ladder provided maintenance access. Enclosing the base of the tower with wood or masonry material improved the tank appearance. Some communities transformed their water towers into monumental works of architecture with Gothic, Neoclassical, or other stylistic design elements. While this practice was more common in the East and Midwest than in California, some examples such as the 1894 tank in Fresno are found in the state.
The construction of a distribution network for delivering water by pipe to individual users was among the first improvements made to any water system. Main lines carried water through the public streets and connected to homes by service pipes. A variety of materials have been used over the decades for manufacturing pipes for municipal use in drinking water and wastewater systems.
Table X below includes the major materials used with an approximate date range for their period of peak popularity.
Table 1. Pipe materials and approximate date range of primary usage in United States.
Material Approximate Date Range of Peak Use
Wood 1600s–1800s
Clay 1800s–present
Lead 1800s–1920s
Cast Iron Early 1800s–1960s
Wrought Iron 1850s–1930s
Copper 1850s–present
Concrete 1900s–present
Steel Early 1900s–present
Asbestos Cement 1930s–1980s
Ductile Iron 1950s–present
Thermoplastics (PVC, HDPE) 1950s–present
Early watermains were made principally from bored and charred logs. Later pipes used milled timber of selected dimensions. Wire wrapped spirally along the pipe length added strength, and rings of iron fit around the pipe ends limited splitting. The pipes could be dipped in hot tar and sanded to add a protective coating. Wood pipes were reasonably durable in well-drained soil, but they were bulky, difficult to join, and generally came in only short lengths. Larger banded stave pipes (Figure 5) were introduced around 1850 and these later came into common use in the West for watermains and sewage outfalls, as well as on large irrigation and hydroelectric projects. Stave pipes constructed of redwood continued to be used occasionally for new construction in California into at least the 1930s.
Cast iron pipes were introduced in England around 1800 and began to replace wood pipes for watermains. Philadelphia made the first use of cast iron watermains in the United States in 1807, but the city needed to import the pipe from Great Britain. Iron pipe casting involved considerable technical challenge and the early pipes manufactured domestically were prone to inconsistencies in thickness and strength.
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Most pipe continued to be imported from Scotland prior to the Civil War, after which major foundries emerged in Pennsylvania, New Jersey, Ohio, and Kentucky. Pipe from these foundries remained relatively expensive until the financial Panic of 1873; the concomitant reduction in railroad construction caused a steep drop in iron prices and made distribution systems increasingly affordable. The durability, ease of manipulation, and comparatively low cost of cast iron pipe made it the standard product for water distribution by the end of the nineteenth century. As a protection against corrosion, manufacturers commonly dipped pipe in a hot bath of coal tar, asphalt, and linseed oil to create a smooth, hard, glossy coating. Techniques for galvanizing the iron or lining it with concrete or lead were introduced later in the nineteenth century. A confusing and often incompatible variety of pipe thicknesses, dimensions, and connection styles came into use during the following decades of growth before the American Water Works Association finally adopted standardized measurements in 1908. Improvements in the metallurgy of cast iron in the 1940s led to the introduction of ductile iron pipe in the 1950s. Under pressure, this more flexible material would deform slightly rather than cracking, making it more durable. Ductile iron pipe is distinguishable from older cast iron pipe by its smoother texture, gray versus black color, and the ringing sound it produces when struck by a hammer, versus the dull thud of cast iron.
Initially, use of cast iron pipe was rare on the West Coast as no regional foundries existed and transportation costs were prohibitive. Hydraulic mining in California demanded a metal pipe capable of withstanding great pressure, so local manufacturers substituted wrought iron sheets riveted into tubes. When lined internally with concrete or asphalt, these pipes could be used for watermains. Wrought iron bands connected adjacent sections of pipe and a coating of cement mortar encased the whole exterior surface of the pipes. Hermann Schussler drew upon these mining experiences when he laid out the San Francisco Water-Works in the 1860s using concrete-lined wrought iron pipes. The pipes were serviceable but lacked durability as water pressure frequently eroded the poorly-mixed concrete and eventually rusted the metal shell.
Techniques for welding, rather than riveting, wrought iron sheet into pipes developed gradually over the nineteenth century and started to enter common usage in the 1880s. These pipes were light, easily handled, resistant to damage, and came in lengths of up to 20 feet. Their smooth interiors presented low frictional resistance so that a welded pipe could carry more water than a cast iron or riveted pipe of the same diameter. The early joints were formed from iron sleeves welded into place, but these were later replaced by butt weld joints that directly connected two pipe sections. California manufacturers commonly coated the pipes with asphalt, but chemical processes also existed to oxidize the metal or plate it with copper to prevent further corrosion.
Steel sheets were rolled and riveted to form pipes beginning in the 1850s, but the low tensile strength of the early steel limited its application. Manufacturers began successfully welding steel sheets into pipes in the 1880s. Gradual refinements to the process brought down costs and improved consistency, so that by the 1930s welded steel pipes largely replaced earlier riveted steel and welded iron for use in transmission and distribution mains.
Clay pipes appeared frequently in sewerage systems but were less common in drinking water systems as they were susceptible to breaking under higher pressures. Manufacturers produced a variety of natural clay pipes that differed chiefly by the firing temperature in the kiln. When fired at comparatively low temperatures (below1,800 degrees Fahrenheit), the material produced was known as earthenware pipe. The material remained somewhat porous and would absorb water,
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Coalinga Sanitary Sewer Collection System and WWTP Improvements Project 35 making it useful for drainage systems but less so for sewage and drinking water systems. Higher firing temperature, up to around 2,300 degrees Fahrenheit, caused the clay to vitrify (turn to glass), making it a dense, durable, corrosion-resistant, non-porous material that was widely used in sewage, irrigation, and drainage systems. This material was generally known as stoneware or as vitrified clay pipe when a specialized mixture of clay and shale was used in manufacturing. To maintain water tightness, bands of wrought iron were wrapped around the joints between pipe segments, and as clay pipes were generally short, the joints needed to be spaced frequently. This increased the amount of friction in the pipes and therefore reduced their carrying capacity.
Concrete pipe was used in sewage systems, storm drains, and agricultural irrigation, but was comparatively rare in drinking water distribution systems. While concrete pipes were inexpensive, easy to maintain, and could be constructed without skilled labor, the pipes could not well withstand the high water pressures of the distribution system and tended to leak. The pipes were also difficult to repair and generally required replacement if damaged. In the 1920s, manufacturers began mixing asbestos fibers into the cement slurry to form composite asbestos-cement pipes, also known as transite. This made for a stronger and more durable material that was resistant to chemical erosion. With the ability to withstand high pressures, asbestos-cement pipes were more widely used for drinking-water mains. A growing recognition of the health effects of asbestos exposure led to declining use in the 1960s and 1970s, until the material was largely phased out in the 1980s.
Because of cost and their physical properties, lead pipes did not appear in main distribution systems, but were used extensively for service connections that linked individual homes and tenement buildings to street mains (Figure 6). These are now commonly referred to as lead service lines. Lead pipe was more expensive than the iron or steel alternatives, but it offered advantages in durability and flexibility. Lead provided superior protection against exterior soil corrosion and was second only to cement-lined iron pipe in guarding against interior corrosion. A line that rusted from the inside could clog, and as no practical means existed for flushing lines prior to 1910, stopped pipes needed to be excavated and manually cleaned or replaced. To avoid such costly and disruptive repairs, many municipalities opted for the higher upfront cost of building with lead pipe.
Lead’s malleability also favored its use in dense urban areas where water pipes needed to be routed around existing gas and sewer lines and other obstructions. In the early twentieth century, manufacturers introduced lead lining for iron pipes that combined the greater corrosion resistance of lead with the lower cost of iron. Lead pipe was also widely used for household plumbing and in the solder used to connect iron pipes.
The material advantages of lead pipe led to its wide adoption, particularly in large cities. By the end of the nineteenth century, about half of all American municipalities and 70 percent of cities with populations greater than 30,000 used lead service connections either exclusively or in combination with some other pipe type. By contrast, two-thirds of communities with fewer than 8,000 people made no use of lead service connections. Large cities had both the financial resources needed to make an upfront investment in more expensive lead piping and the complicated infrastructure that made the durability and flexibility of the material attractive. Small towns were less likely to have paved roads and could more readily access the buried pipes and handle the occasional failure of an iron service connection. Public water companies were also more likely to invest in lead pipes than were private utility companies, and such public utilities were also more common in large cities.
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The chief objection to the use of lead pipe, as was understood at the time, was its potential to contribute to lead poisoning. In low doses, lead exposure produced subtle symptoms that were difficult to diagnosis such as headaches, dizziness, and hypertension. At higher exposures, lead poisoning produced joint and muscle pain, gastro-intestinal distress, infertility, difficulties with memory and concentration, and mood disorders. Extreme levels could cause seizures and death.
Children were particularly vulnerable to lead poisoning and could experience serve developmental delays, hearing loss, and a general failure to thrive. Despite this knowledge, most nineteenthcentury physicians worried little about the potential for lead poising through the drinking water supply, but focused instead on occupational exposures and the use of lead tubing in distilleries.
The sheer ubiquity of lead pipes in major cities and the difficulty in recognizing the signs of lowlevel lead exposure led many to assume that no major problem existed. Recent studies, however, suggest that the use of lead piping in nineteenth century cities increased stillbirth and infant mortality rates by as much as 400 percent. Effects varied between communities based on the acidity of the water supply and age of the pipes, as older lines developed a protective coating of corrosion that limited the leaching of lead. Upgrading water systems to add filtration and chlorination could increase water acidity, and when combined with new lead pipelines, the results could be disastrous.
Lowell and Milton, Massachusetts, for example, overhauled their water systems around the turn of the twentieth century, leading to a sudden increase in lead levels that caused several deaths and multiple documented cases of nerve damage and cognitive disability. These widely publicized cases helped to discourage the use of lead pipe in new construction going into the twentieth century. Copper piping offered the chief alternative, with tin and brass following. Like lead pipe, copper pipe is more expensive and harder to work with that its alternatives, but its strength, corrosion resistance, and heat tolerance make it a common material for household plumbing and the smaller-diameter service lines that connect individual buildings to watermains.
For all the improvements made by water companies, distribution networks remained highly inequitable through the nineteenth century. Frequently, central business districts and wealthy residential neighborhoods were the first to receive pipe service, while Black, immigrant, and working-class districts were more likely to continue to draw water from polluted wells. Even when distribution networks were run to more neighborhoods, individual expense was required to connect the public pipe end to private plumbing fixtures. Tenement owners rarely undertook such efforts, so renters continued to haul buckets of water up steep stairwells from the streetside taps.
Water pressure through distribution networks was also inconsistent, owing to the leaky nature of early piping and plumbing. Many homeowners thus constructed water tanks in their attics or on rooftops to regulate the flow. The tanks would fill with water overnight and then the resident would release it for household use during the day when the distribution system pressure was at its lowest.
These tanks, however, were troubling subjects for sanitarians as they often contained decaying organic matter and served as breeding grounds for mosquitos Urban water systems began to proliferate in the 1870s owing largely to the promotional efforts of water-works equipment manufactures. Birdsill Holly of Lockport, New York, was the leading figure in this transition. The Holly Company manufactured steam-powered rotary and gang pumps that injected water at pressure directly into a town’s watermains without need for a reservoir. This allowed pipes to maintain a desired pressure with relative consistency, facilitating firefighting and simplifying the
2. Environmental and Cultural Background
Coalinga Sanitary Sewer Collection System and WWTP Improvements Project 37 overall waterworks systems, though the lack of flexibility in handling variable demands led to the obsolescence of direct-pressure systems by the end of the nineteenth century.
Holly canvased for towns lacking in water systems and offered to complete waterworks in exchange for an annual payment based on the number of fire hydrants provided. The practical and financial success of his system inspired other manufacturers to follow his example. Increased competition, in turn, spurred rapid innovations in waterworks technology, financing, and promotion, inducing many small towns to install their first public water systems.
Throughout the nineteenth century, most cities had water supplies that were separate from sewage discharges, with the exception being communities that relied entirely upon shallow wells or which were located along major interior rivers downstream from other population centers. In the era before effective water filtration, the usual solution to pollution was simply to go further afield in tapping a supply. The largest cities could accomplish this, such as New York City, which in 1842 completed the Groton Aqueduct which carried water by gravity for 41 miles. Most communities, however, lacked the political and financial power to create such systems.
In California, pollution concerns were particularly acute in Sacramento. The upstream towns of Redding, Red Bluff, Chico, Colusa, Marysville, and Yuba City all sat along the Sacramento River or its tributaries north of the capitol city, and all discharged raw sewage into the waterways. The agricultural land immediately north of Sacramento also posed hazards as dead hogs were routinely disposed of in the river and washed up on sandbars to rot in the heat of summer. The State Board of Health held Folsom Prison responsible for “probably the most flagrant pollution of potable waters in California,” as it discharged the raw sewage of several thousand convicts into the American River at a point only 22 miles above Sacramento to the east.52Logan, as board secretary, had recommended constructing a well into the gravels of the Sacramento River so that the water might be at least filtered before being collected by a Holly pump for distribution to the city.
However, to his great frustration, the residents of the city expressed a clear preference for softer, if more hazardous, river water over hard well water. The city thus continued to consume surface water from the Sacramento and American rivers, while the State Board of Health redirected its attention to limiting pollution from Folsom Prison and other upriver sources.
Wastewater
Municipal officials paid little attention to waste disposal prior to the mid-nineteenth century. Even as towns began to develop drinking water systems, they saw no need to construct parallel systems for disposing of the wastewater. The ancient civilizations of Babylon, Mesopotamia, and Rome had constructed sophisticated systems of drainage, but these practices had all but vanished in Medieval Europe. Primitive, folk methods of waste management, with an emphasis on individual responsibility, prevailed through the seventeenth and eighteenth centuries, and these habits were reproduced in the American colonies. These practices centered around the so-called “cesspool– privy vault system” (discussed below). The rapid growth of cities in the nineteenth century and particularly the introduction of water closets eventually overwhelmed the system by flooding the cesspools and privies beyond capacity.
While the terms cesspool and privy vault were sometimes used interchangeably, the two structures were intended for different waste types and were designed accordingly. Privy vaults handled
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human fecal and urine waste (what is today termed blackwater), while cesspools received graywater from kitchens, laundries, and animal stalls. Cesspools were large pits constructed in the yard or cellar of a building. They were commonly lined with brick or stone, but mortar generally was not used so that the water might leach into the surrounding soil, leaving kitchen scraps behind to decompose. In areas too underdeveloped for cesspools, liquid household waste might be piped to a nearby drainage or merely be cast upon the ground.
Privy vaults were little more than shallow holes dug in the ground, usually without lining. In rural areas, the privy would be covered with soil when filled and a new hole could be dug. In denser settlements, it was necessary to periodically empty privies to keep them in use. Individuals either did this work for themselves or contracted with private scavengers. Later, specialized collection companies employed odorless excavators to rapidly suction privies. Many cities required that privies be emptied only at night, giving rise to “night soil” as a euphemism for human waste. The collected material might be sold to outlying farmers for fertilizer or be dumped in a convenient waterway or refuse pile. In built-up neighborhoods, privies posed a danger to nearby wells as waste leached through the soil. The problems were compounded when heavy rains caused privies to overflow through a neighborhood, mixing their raw waste with the general flooding.
Sewers were uncommon before the mid-nineteenth century, and where they existed, they were used primarily for carrying storm runoff. Early sewers were largely of private construction without any systematic planning. Open ditches or brick-lined street gutters carried away rainwater and allowed for the drainage of cellars. Later the ditches were covered with brick, creating the first partially enclosed sewers. Municipalities began to specify construction techniques and the division of costs among neighbors in the 1820s, and commonly prohibited the dumping of solid waste, and particularly fecal matter, into the systems. However, these regulations were frequently ignored, and the surface sewers frequently carried kitchen waste, offal, manure, and the industrial byproducts of dye works or tanneries.
The introduction of piped water seriously disrupted the cesspool–privy vault system. The availability of freely running water at the household tap led to a surge in per capita use, increasing from the prior three to five-gallon range to between 50 and 100 gallons per day. This increase alone threatened to overwhelm cesspools, but the problem was compounded by the introduction of water closets. Flush toilet technology had been around for some time, but it required the wide availability of piped water to make the system practical. Water closets were introduced in England around 1810 and the first models were patented in the United States in 1833. Affluent homeowners quickly adopted the modern technology which promised greater convenience and sanitation than outhouses and privies. By 1880, approximately one-third of urban households had installed water closets.
The increased flow into cesspools and privy vaults overwhelmed the ability of the soil to absorb the leach water. In city after city through the late nineteenth century, the old regime of waste management collapsed before a new system could be put in place. Cites attempted to order homeowners to empty their cesspools and privies more frequently, but compliance was poor. Many households constructed surreptitious connections to the city sewer system, illegally draining their water closets into pipes that were not designed for the task of carrying off human waste. Fecal matter began to spread over large areas, posing particular problems for low-lying neighborhoods
2. Environmental and Cultural Background
Coalinga Sanitary Sewer Collection System and WWTP Improvements Project 39 that were generally populated by the poor and immigrants. Ironically, the piped water and water closet technologies that had been sold with the promise of improved sanitary health had the opposite effect. Incidents of waterborne disease surged as overflowing privies became a ubiquitous feature of urban life.
Sanitarians proposed as a remedy a system of “water carriage,” in which waste would be transported by hydraulic flow through a network of self-cleaning sewer lines. This meant abandoning privies and cesspools and repurposing the storm sewers to carry wastewater in addition to rain runoff. New interceptor lines needed to be constructed to tie together the patchwork of existing sewer lines. Brooklyn completed the first American combined sewage–stormwater system in 1857, followed by Chicago in 1859. These sewerage systems dumped the untreated waste into nearby riverways, where it was presumed that dilution would render the stream water safe. It was then widely believed among sanitarians and others that running water was self-purifying, though experiences in London with the highly polluted Thames River had already called that convenient assumption into doubt. The issue was largely a moot one anyway as no practical form of sewage treatment was yet available. (As a term, “sewerage” referred to the drainage and disposal of waste without treatment; when treatment was later introduced, the term “sewage system” was commonly used for the combined process of collection, treatment, and disposal).
As an alternative to the combined sewer system, some engineers proposed constructing separate lines for stormwater and sewage. In England, a great debate over the relative merits of the combined and separate systems had raged since the 1840s, but the separate system got a toehold in America only in 1880, when Memphis, Tennessee, constructed the first such system of large scale in the country. The presumed advantage of the separate system was that it could more quickly evacuate waste from a city, so that the sewage left the populated area in fresh condition before putrefaction of organic material reached a critical point of giving off miasmic gases. The system attracted considerable attention but was not widely duplicated as the National Board of Health held that both combined and separate systems were of equal sanitary value and that the selection of one system over the other depended upon local circumstances. As most cities already had storm sewers, it was less expensive to construct a combined system. Only when sewage treatment became more widely adopted in the late nineteenth century did separate sewage systems begin to be constructed, as it was far easier to treat sewage that was separated from stormwater.
Unlike drinking water systems that were largely constructed by private industry, municipal governments were almost solely responsible for building and operating sewers. Private utility companies naturally gravitated towards services that generated revenue such as providing drinking water, electricity, telegraph or telephone lines, and streetcars or railroads. Non-revenue generating activities such as refuse disposal, street construction, firefighting, and code enforcement remained principally the domain of government. Private industry participated in building sewerage systems as construction contractors and the manufacturers of pipe. Later, industry played important roles as engineering consultants and as patent holders on various mechanical devices and biochemical processes.
California Sewerage
Early sewerage construction in California occurred piece by piece, completed primarily by private interests in an unplanned, unsystematic fashion. At least 59 Californian cities constructed sewerage
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systems in the nineteenth century, and while many made efforts to bring order to their network of public and private pipes, few achieved anything more than patchwork solutions. Sanitarians and municipal engineers might have envisioned comprehensive systems that collected and disposed of sewage in an orderly manner, but the reality was far messier. F. Walton Todd, a state board member from Stockton, wryly summarized the usual course of development:
A drain is made from somebody’s hotel, and another from a livery stable is allowed to connect with it, and so on until an interest is established that has weight in a Common Council, and thus, from step to step, a system grows up altogether vicious, which sooner or later, and always after large sums of money have been spent, has to give way to another, the work of a competent engineer, but not until some serious damage has been inflicted, which the engineer, Board of Health, and Common Council combined cannot repair.
Table 2. Year of construction for nineteenth-century California sewerage works.
Year City Year City
1850 San Francisco 1895 Belmont
1850 (circa) Sacramento 1895 Emeryville
1863 (circa) Los Angeles 1895 Fort Bragg
1869 (circa) Oakland 1895 Ontario
1876 San Buenaventura 1896 (circa) Martinez
1877 San Jose 1896 Piedmont
1878 Alameda 1896 San Mateo
1879 Napa 1896 Ukiah
1880 (circa) San Rafael 1897 Hollister
1880 Santa Barbara 1897 Modesto
1880 (circa) Suisun 1897 Salinas
1880 Vallejo 1897 Santa Rosa
1885 Coronado 1898 Red Bluff
1887 San Diego 1899 Belvedere
1888 Berkeley 1899 Ferndale
1888 Santa Cruz 1899 Palo Alto
1890 Fresno 1899 Paso Robles
1890 Redding 1899 Ross
1890 Redlands 1899 San Anselmo
1890 Redwood City 1899 Watsonville
1890 San Bernardino 1900 Beverly Hills
1890 Santa Ana 1900 (circa) Daly City
1890 Woodland 1900 (circa) Monterey
1892 San Luis Obispo 1900 Nevada City
1893 Auburn 1900 Pomona
1893 Los Gatos 1900 (circa) Porterville
1893 Stockton 1900 (circa) Sonora
1894 Mount Shasta 1900 Visalia
1894 Richmond 1900 (circa) Wheatland
1894 Riverside n/a n/a
At the end of the century, the eminent civil engineer C. E. Grunsky surveyed sewage systems throughout the state and found that most remained a tangled web of pipes of various ages, materials, and designs. He concluded that nearly all the works operated by “a haphazard method that is really beyond all comprehension [as quoted from Grunsky 1901].”
2. Environmental and Cultural Background
Coalinga Sanitary Sewer Collection System and WWTP Improvements Project 41 Most of the early California sewer systems were of the combined sewage–stormwater variety. It made little sense, at an early date, to construct separate conduits for stormwater runoff as these would receive little use through the long dry season. Combined systems also allowed for subsoil drainage in low-lying areas like the Mission Flats district of San Francisco and downtown Sacramento. This drainage improved public health by limiting the formation of stagnant pools and made cellar storage feasible. The combined sewage pipes were necessarily large to handle winter runoff. The main pipes in Oakland, for example, were five feet wide by five and one-half feet high, while the San Francisco pipes were occasionally wide enough to drive a wagon through. The larger size also allowed sewage workers to physically enter pipes and move through them in a stooped position or by crawling so as to remove the sediment that invariably entered the combined pipes.
Cities began to construct separate sewage systems in the final decades of the nineteenth century.
These systems were more common in Southern California where urban development occurred later and rainfall totals averaged lower than in the northern part of the state. San Diego, Los Angeles, Santa Barbara, and San Luis Obispo all had separate sewage systems by the 1890s, as did the campus of Stanford University on the San Francisco Peninsula. These systems utilized smaller pipes, with the main line in San Diego, for instance, being 24 inches in diameter.
Main combined sewer lines were customarily constructed of brick because of their large size. Early construction used whatever bricks and mortar were readily available, but too often these eroded away as sand and silt washed through the pipes. Later work called for hard, thoroughly burnt bricks with smooth surfaces to reduce frictional drag. Where cost was an overriding consideration, common brick might be used on the sides and upper arch of the sewer as these were less subject to wear and tear. Blocks of terra-cotta or stoneware were frequently used at the bottom of the sewer for their enhanced durability and smoothness. Termed “invert blocks,” these came in both solid and hollow forms. The hollow blocks helped drain subsoil moisture during construction, but were weaker than solid forms and builders sometime filled them with cement at the conclusion of work.
An egg shape was most frequently used in the main sewer lines as the profile placed low volume flows in the constricted bottom width to maintain velocity while widening above to increase capacity in large flow events.
The smaller branch lines were generally constructed of vitrified clay or concrete, though specially curved bricks could be used for small diameter pipes. Concrete and vitrified clay were favored for their economy, durability, water tightness, and smooth internal surfaces (Figure 10). Concrete pipes could be manufactured locally and allowed for patch repairs in a way that vitrified clay pipes did not, but care had to been taken to ensure that contractors correctly mixed the concrete as a poorly constructed concrete line quickly eroded. Vitrified clay pipes had the smoothest surfaces and were the easiest to work with, but into the 1870s the best quality pipe still had to be imported from Scotland. Redwood pipes were less durable over the long term, but received wide-spread use owing to the ubiquity of the material and low cost. Wooden pipes were also useful where sewer lines crossed marshy terrain as heavier brick sewer lines would require constructing piling foundations. Cast iron pipes were used nationally in sewerage systems in the mid-nineteenth century, but the extent of their employment in California is not well documented.
Manholes were placed at regular intervals along sewer lines to allow for maintenance and the clearing of obstructions. In most cases, this permitted repair work to be done without requiring the expensive and disruptive excavation of roadways. Manholes were generally constructed on a
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circular plan, being approximately three to five feet in diameter at bottom and tapering towards the surface, with brickwork lining the manhole well. Square manholes were used occasionally where larger entrances were needed, but these required additional brickwork and were thus more expensive to provide. Smaller lamp holes were added along lines to assist in locating and removing stoppages (Figure 11). A sewer worker would suspend a light in a lamp hole and then enter the adjacent manhole. He would know the obstruction had been cleared when he could see the lamp light shining down the pipe. Manholes also provided a means of ventilating the sewers through the holes left in the manhole covers, though these frequently clogged with dirt and manure on busy streets.
Combined sewer lines required manual clearing or periodic flushing during periods of low rainfall.
The low volume of fluid passing through a large pipe during the summer could not generate adequate velocity to clear accumulated silt and organic matter. The problem was compounded by the irregularities of nineteenth-century construction that caused velocities to vary through a sewer line owing to changes in grade, pipe diameter, surface friction, and other variables. The simplest system of flushing involved directing a hose from a fire hydrant into openings that were constructed along the sewer line. The water of several hydrants was combined to flush the main line. Sacramento, as a typical example, constructed flush holes at the head of every branch line and periodically along larger lines. Once or twice a month, maintenance workers began flushing at the bottom of the system and worked their way towards the heads.
Automated flushing systems allowed for daily clearance of the lines and reduced the required labor but involved greater initial expense. These systems consisted of a network of tanks installed at the head of the sewer lines. Taps running from watermains slowly filled the tubs. The fill rate could be adjusted to provide for flushing intervals ranging from every two hours to twice per day. Once full, the tank tipped under its own weight, emptied its contents, and returned to the upright position to fill again. Alameda purchased 130 of these flushing tanks in the late 1880s to clear its 41 miles of sewage line. Each tank held 50 gallons of water and dumped every six hours. The tanks were installed just below sidewalk grade, in brick receptables covered by iron lids, to provide easy access for adjusting the flushing frequency.
More elaborate flushing systems were proposed in San Francisco and implemented in Oakland.
San Francisco suffered from particularly bad problems of pooling sewage that ordinary fire hydrant flushing could not clear. In the early 1870s, State Board of Health member A. B. Stout proposed constructing a series of reservoirs along the ridges and hilltops above the city and filling these with salt water pumped from the bay. Great volumes of water could then be released to clear obstructions before flowing back to the sea. City officials never constructed the expensive proposal, but it remained under consideration through the end of the century. In Oakland, City Engineer T. W. Morgan designed an ingenious system that caused waters from Lake Merritt, then still connected to the bay tidelands, to flush the line twice daily. Floodgates in a dam at the bottom of the lake permitted water to enter on the flood tide, but prevented it flowing out with the ebb.
Workers manually opened a gate at the head of the main sewer line to send a scouring burst of stored water through the sewer and back to the tidelands. Oakland thus treated Lake Merritt like the tank on a toilet bowl that was flushed and refilled by the regular motion of the earth beneath the moon.
2. Environmental and Cultural Background
Coalinga Sanitary Sewer Collection System and WWTP Improvements Project 43 Engineers during this same period devoted considerable attention to finding means of venting sewer gases. Indeed, because of the influence of miasma theory, sanitarians regularly gave greater priority to the control of vapors than to the disposal of liquid waste. When homeowners caught a whiff of sewage coming up from a kitchen sink, they worried about the illnesses that their neighbors might be transmitting to them through the shared sewer lines. Despite intense study, however, sanitarians developed no practical method for dispersing sewer gas. Experiments were made with air vacuums, blowers, furnaces, and charcoal filters, but none were economical to deploy at scale. Oakland considered building towers through the city to vent gases above the rooflines, but never pursued the idea. Attention thus focused on simply keeping the gas out of homes and businesses through the use of drain traps. These basic U-shaped traps were installed beneath sinks and water closets to retain a small quantity of water in the pipe after draining. The trapped water formed a seal against rising gases and odors. While simple drain traps had been in use since the eighteenth century, the design continued to evolve through a great number of patented forms as the quantity and types of drains in households multiplied.
Sewage Farms
The disposal of sewage on land offered the only practical alternative in the nineteenth century to the dumping of raw waste into bodies of water. The practice variously termed “sewage farming,” “sewage irrigation,” or “broad irrigation” both prevented river pollution and allowed for sewage effluent to be put to beneficial use as fertilizer. Sewage farming proved particularly well adapted to the arid American West, and Californians adopted the practice on a wider scale than did any other state. At least 50 California cities and 39 public and private institutions made use of sewage farms over a span of half a century between the late 1880s and World War II.
Sanitarians were almost universally in favor of the use of sewage farms. The British reformer Edwin Chadwick advocated the practice beginning in the 1840s and argued that the entire cost of municipal sewer systems could be paid for through selling the output to farms. The Massachusetts Sanitary Commission echoed the recommendation in the 1850s, and by the 1870s American scientific journals and the popular press were regularly running articles on the practice. Sewage farming even showed up in the utopian writings of Victor Hugo and Edward Bellamy. The California State Board of Health joined the call for sewage farming beginning with its second annual report in 1873 and remained in support of the method into the 1930s.
The use of human and animal waste on farms to boost productivity was, of course, an ancient practice. The Romans used human waste as fertilizer and the tradition remained common throughout Europe well into the nineteenth century. Particularly refined methods of gardening with night soil were in use in China, Japan, and Korea for centuries. These early methods utilized the waste of privies and cesspools. Scavengers with ladles and buckets or service companies with odorless excavators collected the waste and sold it either directly to farmers for depositing on the land or to processing plants for conversion into compost or fertilizer.
The introduction of water carriage sewer systems (discussed above) in the nineteenth century required a change in practices. By one contemporary estimate, the sewage from a water carriage system consisted of 998 parts water, one part mineral matter, and one part organic matter. The intent of sewage farming was to neutralize that one-thousandth part organic matter while retaining its valuable nitrogen, phosphorous, and potash. The chief challenge was finding a way to dispose
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of the water, which could easily run to tens of thousands of gallons a day from even a mid-sized town. The land selected for a sewage farm should be well drained with a sandy or gravelly subsoil, accessible by gravity flow, and of low cost. The character of the surrounding habitations needed to be considered to avoid complaints about nuisance odors, although sewage farming advocates claimed the smells were no worse than those arising from pigsties and barnyards. The practice was particularly valued in the western states because low summer river flows made instream disposal an unbearable nuisance and there was always high demand for any irrigation source.
The method of irrigating with sewage did not differ greatly from ordinary irrigation practices. A somewhat greater degree of care was needed to minimize direct contact between the sewage and growing plants and to control the ponding of sewage when effluent was placed on saturated soils during winter rains. Pipes were generally used to carry sewage to the farming grounds, but then the effluent could be run through ordinary, unlined, earth ditches. The land was leveled and prepared with furrows and ridges for row crops or divided into check basins for flood irrigation.
As irrigation was not required during the winter months, it was necessary to set aside some land for uncropped infiltration. Most any crop could be grown by sewage farming, though in 1918 the State Board of Health issued regulations prohibiting the use of sewage on garden vegetables intended to be eaten raw. Fruit trees, melons, grains, and vegetables intended for cooking or canning all remained permissible.
Public institutions were the first to use sewage farming in the United States, beginning in the 1870s.
Asylums, prisons, alms houses, and reformatories could supply labor without expense and had a built-in market for the crops produced. Pullman, Illinois, was the first municipality to employ a sewage farm to dispose of its waste in 1881, though the practice did not long endure there owing to the heavy clay soils and natural abundance of rain. Pasadena in 1888 was the second American city to establish a sewer farm and it became a model for many of the other municipal programs that followed. By the early 1890s, municipal sewage farms were operating in Redding, Santa Rosa, Stockton, Fresno, and Los Angeles.
The Redding sewage farm provides a typical example of a medium-scaled municipal operation.
The city constructed a separate sewage system in 1889, designed by the city engineer. The system, serving a population of around 2,000, included 2.9 miles of line and seven 112-gallon automatic flushing tanks. The city had intended to dispose of its waste into the Sacramento River, but objections from the State Board of Health led to a search for alternatives. The city called for bids on a contract to dispose of the waste for a 40-year period at a beginning payment of $300 yearly, to be increased in proportion to the community’s growth. L. F. Bassett, the former Sacramento city engineer, secured the contract and purchased 100 acres of land at the city fairgrounds, about a mile south of Redding, in the location of today’s civic center (Figure 13). About 10 acres were initially prepared for irrigation by leveling the land and running furrows. Bassett laid a 12-inch-diameter pipe through the racetrack grounds and excavated open ditches to carry the sewage to the prepared land. The sewage irrigated a variety of crops including asparagus, turnips, beets, and potatoes, but was used primarily for raising fruit trees as nursery stock. The acreage had a soil of loamy sand underlain with a deep bed of gravel and did not require a separate system of drainage.
Rather than run the sewage continually, Bassett constructed a 75,000-gallon reservoir—equal to one day’s average flow—to hold the material overnight. In the morning, the reservoir gate was
2. Environmental and Cultural Background
Coalinga Sanitary Sewer Collection System and WWTP Improvements Project 45 opened and the sewage flowed onto the land for two to four hours before the gate was again closed.
The reservoir was covered by a wood lid and included a 60-foot-tall timber chimney to disperse odors and prevent the site from becoming a nuisance to the adjacent county road. A screen above the irrigated lands removed any large objects that might obstruct the irrigation ditches. During the winter, when no crops were growing, it was necessary to run the sewage onto one piece of land for several days and then to plough it under when the ground had sufficiently dried. The greatest odor occurred at this time as the sewage ponded before being absorbed into the saturated soil.
The construction and operation of the sewage farm was not without opposition. Neighboring landowners objected to the approval of the farm prior to its completion, and in 1892 they had Bassett arrested for maintaining a public nuisance. The courts, however, sided with the sewage farm, and the local press also offered support. The State Board of Health added its endorsement later in the year when a delegation visited the Redding sewage farm to ascertain its impact on the Sacramento River. Pleased with what they found, they declared the system satisfactory and “commendable to that progressive city [as quoted from State Board of Health 1901].” Nationally, sewage farming achieved its peak popularity in the 1890s and then declined. The adoption of new and generally superior technologies for sewage treatment around the turn of the century, including septic tanks, chemical precipitation, and sprinkling filters, was the chief cause of the decline. Advocates of sewage farming claimed that these new methods wasted the nutritional and economic value of sewage, but sanitary engineers countered that the fertilizing power of sewage had always been overrated. The large volume of water applied in sewage farming in many cases leached nutrients from the soil quicker than they could accumulate. Public health concerns about applying raw sewage to edible crops had been relatively muted when no better sewage treatment option was available, but the increase in alternatives brought greater attention to the problems. Rising land values on the margins of towns, where sewage farms were initially constructed, also favored abandoning the older plants. Sewage farming remained a viable option only in locations where irrigation water was in great demand, as in much of Southern California.
The practice continued there in adjunct to other treatment methods, so that sewage was first processed by a septic tank or sprinkling filter before the treated effluent was discharged as irrigation water. In this way, the method prefigured the later practice of using reclaimed wastewater for irrigating roadsides and other public lands.
2. The Era of Sanitary Engineering, 1900–1949
The first half of the twentieth century witnessed rapid advances in sanitation science and technology, but slower progress in policy. The creation of two new academic and regulatory bodies epitomized the era. In 1905, the University of California established a department of sanitary engineering at Berkeley, headed by Charles Gilman Hyde, and a decade later, the State Board of Health created the Bureau of Sanitary Engineering, led by Hyde’s former student, Chester Gillespie. The careers of both men extended into the late 1940s and coincided with the emergence of modern sanitary engineering practices.
The first decades of the twentieth century saw the creation of nearly all the major processes and pieces of infrastructure employed at drinking water and wastewater treatment plants today. These included the processes of chlorine disinfection and rapid sand filtration for drinking water, and the biological wastewater treatment methods used in trickle filters and activated sludge tanks. These
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advances largely halted the scourge of typhoid fever except in locations that lacked modern services because of their remoteness or economic marginality. Still, the laxness of state regulations meant that few municipalities constructed modern sewage treatment plants prior to World War II.
The newest and most sophisticated systems tended to be constructed in Southern California, where communities were young and growth rapid, while Northern California employed more legacy systems from the nineteenth century.
Knowledge
Germ Theory
By 1900, the germ theory of disease, more formally known as bacteriology, had replaced the earlier miasma theory in sanitary planning. Among public health professionals it became accepted fact that it was not filth in general that caused disease, but the presence of particular microorganisms.
Expectations faded for the sort of broad social reforms that had animated the sanitarian movement and were replaced with the more narrowly focused task of ridding public water supplies of diseasecausing organisms. The application of this knowledge, particularly through the chlorination of drinking water, produced sharp drops in death rates from typhoid fever and other intestinal illnesses. Ironically, the decline in disease led to greater tolerance for sewage dumping as the public came to see pollution as a mere nuisance rather than a public health crisis. It was only when officials later began to worry about the economic impacts of pollution that they again made efforts to limit raw sewage discharges.
At its core, germ theory held that discrete, microscopic organisms penetrated bodies and caused disease through their growth and reproduction. These pathogens, or “germs,” could be bacterial, viral, or fungal. Ideas related to the germ theory had been in circulation for centuries, but they gained dominance among medical professionals only in the late nineteenth century. The investigations of Louis Pasteur and Robert Koch between the 1860s and 1880s were the first to identify specific organisms responsible for disease and to demonstrate conclusively the shortcomings of alternative theories. Still, the theory was slow to find full acceptance. Most physicians were flexible in their thinking and for decades continued to freely combine the germ theory with their long-standing beliefs about miasmas and the influences of climate and topography on health.
The impact of germ theory on public health measures was thus initially subtle, but it ultimately proved transformative. Physicians shifted their focus from society to the individual and from preventing disease to curing it. Medical practitioners and engineers grew irritable with the efforts of sanitarian reforms, which while well-meant and often at least indirectly beneficial, seemed to miss the essential scientific point. “Smells are not dangerous,” claimed San Francisco engineer Ernest McCullough. “They are rarely, if ever, a cause of illness. They are simply unpleasant to our modern sense of what is right and proper.” Local boards of health shifted their efforts from supervising sanitary systems to measures that more directly aligned with the new science such as vaccination campaigns and inspecting health conditions among the increasing immigrant population. By the First World War, municipal health departments had largely turned over their former responsibility for water and sewage systems to engineers and public works departments.
2. Environmental and Cultural Background
Coalinga Sanitary Sewer Collection System and WWTP Improvements Project 47 Sanitary Engineering
Sanitary engineering emerged as a distinct professional field at the start of the twentieth century.
The field had its roots in the larger English sanitarian movement, and the term “sanitary engineer” was first used in the 1870s to describe anyone with a concern for using technology to clean the environment, including plumbers, building contractors, asylum superintendents, and municipal engineers. Over the remainder of the nineteenth century, the field gradually shed its association with the building trades and came to define itself as a science-based profession. The series of technological triumphs that emerged from the field in the early twentieth century, from the chlorination of water supplies to the activated sludge treatment of sewage, allowed sanitary engineers to displace physicians and sanitarian reformers as the chief figures in public health.
In 1887, the Massachusetts State Board of Health founded the Lawrence Experiment Station that was transformative to the practice of sanitary engineering in the United States. The station brought together experts in engineering, chemistry, and biology to conduct basic research across disciplines related to water filtration and sewage treatment. The station biologist, William T. Sedgwick, also headed the Department of Biology at the Massachusetts Institute of Technology (MIT). He introduced a public health orientation to his department that drew heavily on the new field of bacteriology, but he knew that applying that knowledge required engineering skill. Engineers had always constructed sanitary systems, but they had taken their direction largely from their clients and built basic systems for water or sewage collection and transport. Sedgwick desired to train engineers in the sciences of biology and chemistry so that they might innovate solutions to the problems of treatment. In 1892, MIT started the first sanitary engineering program in the nation.
The University of Illinois followed a year or two later, and in 1905 the University of California president, Benjamin Ide Wheeler, organized the nation’s third department of sanitary engineering at Berkeley.
Wheeler hired Charles Gilman Hyde to head the newly created program, and Hyde—the recognized “Dean of Sanitary Engineering of the West”—exercised a profound influence on the development of the field in California. Hyde graduated in the first class of sanitary engineers to emerge from the MIT program in 1896. He worked as an assistant engineer with the Massachusetts State Board of Health for four years and then in Pennsylvania on major water supply projects for the cities of Philadelphia and Harrisburg. When Hyde moved to Berkeley in 1905, he was the first well-trained and experienced sanitary engineer to locate on the Pacific Coast. He remained at UC Berkeley through 1944 except for two years spent with the US Army Sanitary Corps during the First World War. He closely mentored two generations worth of students, and “Hyde’s boys” went on to fill major positions in government, industry, research, and education.
Hyde served as Engineering Consultant to the California State Board of Health and advocated for the establishment of a State Bureau of Sanitary Engineering that was then headed by his student Chester Gillespie. He also worked as an industry consultant and designed wastewater and drinking water treatment plants in Sacramento, San Francisco, the East Bay, Los Angeles, San Diego, and beyond. His colleagues remembered him as “an engineer’s engineer – a designer, a builder, and an innovator.
To teach the necessary chemistry courses, Hyde recruited Wilfred Langelier in 1916 from the Illinois Water Survey where Langelier had been involved in pioneering work in chlorine
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disinfection. The two men comprised almost the entirety of the UC Berkeley sanitary engineering program through World War II and earned a reputation as one of the most effective engineerchemist teams in the evolving field. Water chemistry was then a neglected subject among municipal engineers, limited to little more than water testing, and Langelier was able to make fundamental advances in the field. In an attic laboratory, Langelier developed methods to “jar test” coagulation procedures that allowed for careful control of variables and became standard scientific practice. His study of the corrosive potential of water is still recognized today through use of the Langelier Saturation Index. And in his work with Hyde in the early 1920s on designing the Sacramento water filtration plant, he developed a process for inducing flocculation (removal of colloidal particles from a suspension to form a sediment) through agitation with mechanical paddles that soon became standard in plants worldwide. In addition to teaching chemistry courses within the specialty, Langelier lectured architectural students on plumbing practices (including future modernist architect William Wurster with whom he later designed the San Leandro Filtration Plant) and taught a basic sanitation class to women students within the gender-segregated Domestic Science program.
Professional organizations emerged concurrently with the creation of the university programs. The American Society of Sanitary Engineers was founded in 1906, though it reflected an earlier understanding of the field in accepting plumbers and building contractors for membership. The American Public Health Association created a sanitary engineering section in 1911, and the US Public Health Service granted civil service classification status to the title “Sanitary Engineer.” Finally, in 1922, the American Society of Civil Engineers (ASCE) organized a Sanitary Engineering Division with 526 initial members, offering full recognition of the standing of the field.
Biological Treatment of Sewage
The introduction of biological sewage treatment methods in the 1890s revolutionized sanitary practices, and today’s secondary treatment methods all trace their origins to that turn of the century moment. Biological treatment methods were discovered more or less independently on four occasions, giving rise to different technologies. In the early 1890s, the Lawrence Experiment Station in Massachusetts performed the initial studies that led eventually to the trickling filter, while William Joseph Dibdin, chief chemist for the London Metropolitan Board of Works, developed the contact filter. In 1896, Donald Cameron, City Surveyor for Exeter, England, invented the septic tank. And finally, in 1912, a group of scientists and engineers associated with the University of Manchester and the Manchester Disposal Works introduced the activated sludge process, the most advanced of the biological treatment techniques. This section deals with the new knowledge that informed and arose from the experiments; for specifics on the various treatment methods.
Biological treatment methods employed microorganisms to digest (decompose) organic matter within sewage in an orderly and controlled fashion. This largely eliminated the pathogens that cause disease and rendered the effluent safe for discharge. These methods differed fundamentally from prior sewerage techniques that had simply evacuated waste as rapidly as possible from populated areas so as to avoid decomposition and the production of miasmic gases. The greater knowledge of microbiology that developed towards the end of the nineteenth century allowed for a better understanding of both the causes of disease and the biochemical processes of
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Coalinga Sanitary Sewer Collection System and WWTP Improvements Project 49 decomposition. While the microorganisms necessary to digest organic wastes occurred naturally within sewage, researchers learned that their numbers and effectiveness could be greatly increased by providing them with a favorable environment. The biological treatment methods thus consisted principally of supplying the proper living conditions for the desired organisms (largely bacteria) by regulating the food supply, oxygen saturation, temperature, pH levels, and other variables.
Digestion occurred both in the presence of oxygen (aerobic) and in its absence (anaerobic).
Anaerobic digestion liquefied organic solids, greatly reducing the volume of waste while producing methane gas as a byproduct. Aerobic digestion allowed for more complete decomposition as it could reduce large organic polymers such as cellulose to carbon dioxide and water, whereas anaerobic processes left behind more complex, partially digested substances.
Complete digestion required both aerobic and anaerobic conditions, and sewage treatment plants thus commonly divided the digestion process into two or more parts with each devoted to a particular class of microbes. Biological treatment altered the character of the organic matter in sewage, but it did not necessarily remove the material, and in some circumstances the discharged treated water might contain more suspended matter than the raw influent, though the material had been rendered safe for disposal. Treatment plants thus commonly used additional clarifiers at the end of the treatment process to settle out the remaining material and produce a final, clear effluent.
A sewage farm provided a basic form of biological treatment, though it was not understood as such prior to the late nineteenth century. Sanitarians recognized that filtering sewage through soil cleansed it of some of its organic material. However, they could not agree as to whether this was simply a matter of the soil particles mechanically screening the sewage or if there was some “essence” of the soil that participated in the process. Work conducted at the Lawrence Experiment Station began to demonstrate that the process was essentially a biological one, driven by living microorganisms in the soil. If the soil within an experimental plot was sterilized, for example, it lost its capacity for cleansing organic matter from sewage, though there had been no alteration to its character as a mechanical filter
Near simultaneous work by William Didbin on the Thames River started to develop a practical understanding of the conditions required to nurture populations of beneficial microorganisms.
According to historian Christopher Hamlin, Didbin began his experiments without any real understanding of the biology involved or with any conviction that bacteria could effectively deal with the immense stream of pollution flowing from London. Rather, he was under enormous political and legal pressure to show that the city was making efforts to address its problems, and his experiments bought him time without generating costs his employers would be unwilling to pay Didbin placed various filter media (sand, gravel, baked clay, coke) within sewage basins and intermittently filled and drained them, measuring the change in quantities of organic matter and bacteria. He came to recognize that an inverse relationship existed between the two: greater quantities of bacteria meant lower levels of organic matter. And he learned that he could influence the size of the bacterial populations by regulating the rate at which they were fed waste and controlling how often the tanks were reoxygenated by draining the liquid sewage. This led to the realization that the successful use of the contact beds relied entirely upon nurturing and sustaining beneficial bacteria. The bacteria did the real work and the sanitary engineer became a sort of zookeeper, tending to the wants and needs of his microorganisms.
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While the work by Didbin and the Lawrence Experiment Station focused primarily on aerobic processes, Donald Cameron discovered the capacity for anaerobic digestion to consume the sludge that accumulated at the bottom of sedimentation tanks. Anaerobic bacteria developed within the tank over a period of a couple weeks to several months, and then worked continuously on digesting the organic matter of the sludge into gases of methane, carbon dioxide, and nitrogen as well as finely divided organic compounds. This greatly reduced the volume of sludge and thus the expense and difficulty involved in disposing of it. Cameron named his invention the “septic tank” to emphasize its reliance on bacteria and to contrast it with the deliberately antiseptic systems that proceeded it. To showcase his discovery, Cameron constructed an observation chamber in the City of Exeter tank so that visiting engineers could descend into the belly of the device and watch the digestion in action through a porthole. Large modern treatment plants use separate sludge digestion tanks, rather than septic tanks, for anaerobic digestion, but the fundamental process remains the same.
In contact or trickling filters, the biological treatment occurred in a narrow film that surrounded the filter particles. The bacteria and algae physically lived upon the bits of stone, plastic, or other media that filled the beds. The breakthrough of the activated sludge process was to realize that the microorganisms could live suspended within the sewage itself, feeding and reproducing rapidly in a highly oxygenated environment. Experiments with aerating sewage had been conducted since the 1870s but without great success. In 1912, Gilbert Fowler of the University of Manchester observed one such experiment at the Lawrence Experiment Station, and he persuaded Edward Ardern and W. T. Lockett, engineers with the Manchester Disposal Works, to add oxygenation to research they were doing on using retained sludge to treat fresh influent.
When sludge from a prior treatment was retained, decanted of its liquid, and returned to a tank of fresh sewage, it arrived preloaded (“activated”) with a high concentration of aerobic bacteria that seeded the treatment tank. Blowers or paddles supplied the bacteria with copious oxygen to enhance its metabolism and thoroughly mix it through the sewage. The bacteria attached themselves to bits of suspended matter and served as a flocculant, causing the organic matter to clump together and fall out of suspension. After the sludge was separated in a sedimentation tank, the remaining effluent was clear, odorless, and safe for discharge. A portion of the separated sludge was then returned to the aeration tank, beginning the process anew. A landmark 1914 publication announced the discovery of the activated sludge process and attracted immediate attention. The outbreak of World War I shortly thereafter suspended additional research within Europe and allowed American engineers to take the lead in further developing the process.
The refinement of the biological treatment process, from simple sewage farming to sophisticated activated sludge plants, allowed for ever smaller plants to treat ever greater volumes of sewage.
The need to conserve real estate was an overriding concern that justified the higher energy inputs and greater technical skill required to operate the more complex processes. Sewage farming had the advantage of simplicity, but it required access to more land than any decent-sized community could reasonably provide. Turn-of-the-century Berlin, for instance, operated the most efficient sewage farms in all of Europe, but at 23,000 acres, the sewage farms were larger than the city itself.
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Coalinga Sanitary Sewer Collection System and WWTP Improvements Project 51 The adoption of biological treatment methods marked a shift towards a more scientific approach to wastewater management as it required a greater degree of process control and an ever-evolving understanding of microbiology. It spurred the introduction of new technologies in the form of pumps, aeration equipment, and tools for laboratory testing. On the downside, biological treatment methods were vulnerable to greater disruption. Bacteria are living organisms that behave in sometimes unpredictable manners. A cold snap or the inadvertent introduction of a toxic chemical could cause a collapse of bacterial populations. Recovery from such a disaster was slow as the colony needed to rebuild itself organically. Particularly in the early years, when biological knowledge remained limited, many communities were reluctant to embark upon such a potentially perilous course and loose regulations did not require them to make the risky investment. The practical adoption of biological treatment methods thus lagged behind the rapid pace of scientific advancement.
Political Organization
Federal Drinking Water Oversight
The federal government established the first national water quality standards in 1914 when the US Public Health Service (USPHS) set requirements for the water used on common carriers in interstate travel, including ships and trains crossing state lines. The standards initially applied only to bacteriological agents associated with contagious diseases, but they were later revised and expanded in 1925, 1946, and 1962 to cover broader criteria. Every state eventually adopted the standards with minor modifications. By the 1930s, USPHS was certifying nearly a hundred California water supply systems per year to allow for their use in interstate transportation. Even local inspections adhered to the federal standards, so that for decades all water analyses performed in California included a statement about the sample’s conformity with USPHS standards for drinking water.
State Oversight
The State of California also increased its oversight of sanitary matters during the first decades of the twentieth century and granted the State Board of Public Health its first formal permitting powers over water and sewage systems. The board had passed through a period of reduced activity at the end of the nineteenth century as it turned largely to managing the state hospital system. The 1906 San Francisco earthquake revived state interest in sanitary issues as a wave of epidemics afflicted the displaced population. The Public Health Act of 1907 required communities to receive a permit from the State Board of Health for new sewage system construction. The Sanitary Water Systems Act of 1913 extended the permit system to water systems having 200 or more connections or supplying a hotel or labor camp. However, the permitting was done on a case-by-case basis rather than establishing general standards that all dischargers had to meet, and it depended on whatever review the underfunded and understaffed board could provide. Permits also applied only to new construction so that systems that predated the 1907 law were not subject to state review.
The state elections of 1910 and 1911 launched California to the forefront of progressive reform.
Hiram Johnson was elected governor in 1910 on a promise to end corporate and municipal corruption, and in 1911 the voters approved a sweeping array of progressive voting reforms including women’s suffrage, ballot initiatives, referendum, and recall. Collectively these measures displayed an eagerness to have the state tackle issues that previously had been accepted as
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intractable. Additional funding and staffing allowed the State Board of Health to expand its reach, and it created six new bureaus or divisions between 1911 and 1920, including the Bureau of Sanitary Engineering. A reorganization of the state government in 1927 to reflect its expanded scope promoted the board to become the Department of Public Health.
The staff of the state board began performing regular sanitary inspections of towns and private establishments in 1913. The inspections aimed at nuisance abatement without making pretext to proposing systematic improvements to water or sewage systems. A typical inspection from 1914 examined conditions at the Gregory Hotel outside of Fresno:
Said premises consist of a large frame building used as a hotel. The toilet facilities were complained of. They consist of one modern water flushed toilet, located in the building for the women, which discharges into a dilapidated cesspool in the barn yard about three hundred feet from the hotel, also a dilapidated privy in the yard about twenty feet from the building, close to the county road, which is open to flies, etc. and it is in filthy condition, and one urinal inside of the building which discharges into the vault of the privy. The refuse water from the sinks, bathtubs, etc. is being disposed of by means of open wooden drains, which discharge in the yard.
The state inspectors had authority to examine public accommodations and to make recommendations (in the case of the Gregory Hotel to demolish the privy, construct a sealed cesspool, and add a flush toilet for men) but lacked any enforcement powers. Only local authorities could compel the proprietor to comply with the recommendations.
The Progressive Era also saw the state centralize control over utility regulations. The Public Utilities Act of 1911 extended the authority of the California Railroad Commission to cover all private utility and transportation companies. In 1946, the agency was renamed the California Public Utilities Commission to better reflect its expanded scope of authority. Commission approval was required for rate increases, service area expansions, mergers, and changes to service. This effectively replaced the municipal franchise system and reduced the chances for local corruption or favoritism to interfere with the rational development of services. Private water companies generally favored the transition as they expected better, more scientific management from state officials. They also hoped that increased regulation would temper demands for public ownership of water systems. Because state regulation did not extend to municipal systems, the new order conversely provided an incentive for local governments to reassert their authority by taking ownership of utilities.
Municipal Reforms
The multiple impulses of reform that pulsed through Progressive Era California transformed the character of municipal government and its relationship to the delivery of sanitary services. No single, overall plan guided the reform movements and different causes regularly acted at cross purposes to one another. Efforts to strengthen municipal governments, for example, clashed with competing impulses to centralize power in state bureaus. And every water dispute in California came deeply enmeshed in local rivalries with their own idiosyncratic histories that defy easy generalization. More than 700 municipal water and sewage systems operated in California by 1936, along with approximately one hundred smaller institutional systems. Each system had its own distinct set of local circumstances and trajectory of development. Nonetheless, several broad
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Coalinga Sanitary Sewer Collection System and WWTP Improvements Project 53 patterns of change can be identified through the early twentieth century that led to greater public ownership of water supplies, the increased professionalization of municipal utility services, and the creation of special districts to serve multiple communities.
Nineteenth-century Californians largely welcomed private water companies, viewing them as an efficient means of developing resources without high taxation. However, that support gave way to distrust and dissatisfaction in the early twentieth century. The politics of Progressive Era California were largely shaped by opposition to the monopoly powers of the Southern Pacific Railroad and the heavy-handed ways in which it intervened in state and local politics. Anti-monopoly politics then broadened to include resistance to a wide array of corporate interests that were seen as conspiring against the public good. Private water companies found themselves on the defensive as they sought to prevent their systems being forced into competition with public utilities. For decades, the companies were largely successful in that fight as they held monopoly control of local water rights, but they faced rising discontent among consumers as their aging systems struggled to provide water in adequate quantity and quality at a reasonable price.
In the early twentieth century, the largest cities in California all outgrew the local creeks and wells that had fed their water systems. This required them to reach further afield for water sources and opened the possibility for creating new, publicly owned water systems. Los Angeles seized control of the Owens River and later tapped the Colorado River; San Francisco developed the Tuolumne River behind the Hetch Hetchy Dam; and the East Bay communities of Oakland, Berkeley, and Richmond turned to the Mokelumne River in the Sierra Nevada foothills. Each of these farreaching systems originated through public ownership, financed with municipal bonds. The private water companies that served these cities recognized that a transition had occurred and they generally sold their remaining systems to the public. Many smaller cities followed the example in acquiring private water systems, though not every campaign for public ownership was successful as many voters continued to view local government as more inclined to corruption and ineptitude than was private enterprise.
Ironically, providing better service—making abundant pure water conveniently and cheaply available—led to a surge in demand that frequently exceeded planning expectations for the new municipal water systems. This inevitably produced disappointment among citizens and fueled accusations of political incompetency. To protect vital services from the corrupting influences of patronage politics, many communities transferred control of their systems from politicians to engineers. Progressive reforms had introduced the city manager form of government to California and increasingly a nonpartisan, technocratic class of sanitary workers had responsibility for managing municipal systems and advocating for their improvement.
The expanded reach of water and sewer systems beyond traditional city boundaries led to the creation of regional utility districts. The East Bay Municipal Utility District (EBMUD), organized by Oakland, Berkeley, and Richmond in 1923, and the Metropolitan Water District of Southern California, established in 1928, typified the new organizational model. This trend reflected a national movement towards the creation of special districts in the decades between 1880 and 1930 to provide a wide variety of services from fire protection and flood control to port management and mosquito abatement. Districts enjoyed substantial administrative and financial independence from county or municipal governments in pursuit of a narrowly defined set of functions, and
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seemed to offer the best hope for professional, science-based management. Because state law limited cities to bonded debt equal to 15 percent of a community’s assessed valuation, independently funded districts appealed to small, fast-growing towns that had many competing needs to meet. Regional districts could also better match services to the natural boundaries that governed the distribution of water and disposal of sewage, rather than requiring a wasteful duplication of services within artificial political boundaries.
Bureau of Sanitary Engineering
The State Board of Health established the Bureau of Sanitary Engineering in 1915 following the advocacy of Charles Hyde. Chester Gillespie, one of “Hyde’s Boys” from the class of 1907, headed the bureau and he remained as chief until 1947. The early bureau had a two-year budget of $30,000 and consisted of Gillespie, two sanitary engineers, and a couple of stenographers. The group operated out of the UC Berkeley civil engineering building in an office adjacent to Hyde’s and they shared the attic laboratory space with Langelier. The bureau remained on the UC Berkeley campus until 1942 when it moved two blocks west to Shattuck Square. Bureau staff were responsible for reviewing the water and sewage plants plans submitted by cities, conducting field inspections, and making recommendations on permits to the State Board of Health. They also had responsibilities for inspecting shellfish production, mosquito control, and other assorted issues.
The bureau contributed to professionalizing municipal utility operations. Gillespie recognized early on that operating personnel were not advancing in their knowledge as rapidly as was the complexity of sewage science and technology. The turnover rate among sanitary engineers was a problem as those drawn to the field soon mastered the issues and left to find few more meaningful challenges and job prospects. In 1928, Gillespie took the lead in organizing the California Sewage Works Association to encourage the sharing of information among municipal sewage workers and managers. The association began publishing the California Sewage Works Journal. Nationally, the Federation of Sewage Works Association formed in the same year and published Sewage Works Journal.
Typhoid Fever
The Bureau of Sanitary Engineering’s strong focus through its first five years was combatting typhoid fever. Chlorinating the public water supply was the chief tool for reducing typhoid fever and was highly effective. Secondarily, bureau staff inspected sewage systems to locate and correct potential sources of cross contamination between sewage and water services. This was the case, for example, during a 1924 outbreak in Santa Ana that was among the worst of the twentieth century in California. An undersized sewer line habitually overflowed on Mondays, the local washday, and the runoff made its way into an open drinking water reservoir, carrying raw sewage with it. Expanding and relocating the line solved the problem. Other practices for reducing outbreaks included pasteurizing milk, improving general sanitation habits, and identifying carriers of typhoid fever through medical examination.
Typhoid fever death rates dropped dramatically with the effort. In 1906, the death rate was calculated at 34.9 per 100,000 population, a number that was somewhat elevated by the aftermath of the San Francisco earthquake. The following year the rate was a more typical 27.9. By 1920, the rate had fallen to 4.9 and it continued a downward trajectory to 1.7 in 1930 and finally below
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0.9 in 1937. Within years of starting the campaign, the efforts were saving in excess of a thousand Californian lives annually and municipal water systems had been rendered almost entirely safe.
Still, smaller outbreaks of typhoid fever continued to occur nearly every year in a few specific locations, particularly among the farm labor camps of the Sacramento-San Joaquin Delta and Imperial County. The camps, both temporary and semi-permanent, tended to be located along levees, and irrigation ditches served as both sewers and drinking water sources. The droughts of the 1930s compounded the problem as the Sacramento River fell so low that sewage did not wash out to sea but sloshed back and forth with the tides through an 8–12 mile stretch below the city of Sacramento. The Bureau of Sanitary Engineering installed emergency chlorination units at sites with identified problems, but too many labor camps were remotely located and all but unknown to authorities.
The bureau was inclined to blame the sanitary habits of the farm laborers for these outbreaks, writing in 1938 that “it is not always easy to obtain the cooperation of the some of the foreignborn races in the observance of preventative measures.” However, as legal scholar Camille Pannu has demonstrated, many rural communities made deliberate decisions to exclude labor camps from municipal water and sewer systems in order to keep laborers dependent upon farm owners for essential services and to discourage permanent settlement by Dust Bowl migrants or ethnic minority groups. As late as 1971, the Tulare County General Plan continued to argue for underinvestment as a strategy of population removal:
Public commitments to communities with little or no authentic future should be carefully examined before final action is initiated. These non-viable communities would, as a consequence of withholding major public facilities such as sewer and water systems, enter a process of long term, natural decline as residents depart for improved opportunities in nearby communities.
In 1938, the bureau noted with pride that 94 percent of the population within incorporated cities or service district boundaries had sewage systems. That figure, however, excluded precisely the sort of unincorporated communities on the margins of agricultural towns that were intentionally left beyond the reach of municipal services. Because of de jure and de facto segregation, those communities were largely populated by ethnic minorities. The Central Valley today still has more than 450 unincorporated communities, many of which are a legacy of pre-World War II settlement patterns, and these areas remain among the least well provided with essential sanitary services.
Environmental Pollution
In contrast to the successful campaign against typhoid fever, California’s Bureau of Sanitary Engineering had decidedly more limited success in combatting the environmental pollution of streams, rivers, lakes, and bays. This effort took the bureau beyond the immediate issue of public health and was met with resistance from the cities that were being urged to clean up their sewage discharges. Tax funds spent on sewage treatment provided little immediate return to the community making the investment, but instead benefitted downstream areas. Most municipalities thought that the solution to river pollution was for every town to treat their drinking water while cleaning up only the most noxious sources of nuisance dumping. This attitude changed only when economically valuable tourism or industry were directly impacted.
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When Gillespie assumed his position as bureau chief in 1915, he found conditions along many of the state’s rivers to be deplorable. The Merced River, he wrote, was “receiving sewage in the heart of Yosemite”; Tuolumne River “was a source of endless complaint”; Truckee River “was useless even for fishing”; the upper Sacramento River “was notorious for the piles of sewage along its edge”; Sonoma Creek “was a source of stench through a famous vacation belt”; and Napa River reeked of “offensive odors [that] prevented picnicking on its banks.” Many of the state’s famous beaches needed to be closed regularly for quarantines. In Northern California, communities dumped untreated sewage into the shallow water of bays and harbors.
Conditions in Southern California were somewhat better as outflows were commonly into deep ocean water where currents could disperse the waste. Most southland cities also provided at least preliminary sewage treatment with sedimentation or screening. San Diego, Long Beach, and the San Pedro Harbor were exceptions, as they continued to use short outfalls into the late 1930s. And even where deep water outfalls existed, regular breaks in the lines meant that sewage periodically washed up onto beaches.
The sanitary bureau had its greatest success in halting environmental pollution where it originated in relatively small institutions, most of which were state or federally operated. Folsom Prison, Sonoma State Home, Patton State Hospital, Yosemite National Park, Weimer Sanitarium, and UC Davis all installed trickling filters or activated sludge plants in the 1910s or 1920s that provided a high level of sewage treatment. Success was also possible in areas valued for their recreational potential. The bureau cooperated closely with the National Forest Service to clean up formerly squalid campgrounds and received support from Lake Tahoe resorts to end the practice of running sewers directly into the lake. Elsewhere, the bureau had to accept partial improvements. Towns such as Gilroy, Watsonville, and Yuba City replaced river dumping with sewage farms, but still provided limited treatment. Ukiah, St. Helena, Winters, and Paso Robles used land disposal during the summer months of low river flow, but continued to dump minimally processed effluent into rivers during the winter. And large areas through the Mother Lode and the California Delta dumped raw sewage into rivers year-round along with large quantities of unprocessed industrial waste from wineries, dairies, and fruit canneries.
Regional Variation
Distinct regional variation in the sophistication of water and sewage systems emerged in the early twentieth century. These systems developed through path-dependent processes so that decisions made in the mid-nineteenth century had an outsized influence on subsequent events well into the middle of the twentieth century. A divide thus opened between the older population centers of Northern California and the newer cities of Southern California that grew out of the oil, citrus, and real estate booms of the early twentieth century. Neither region was monolithic and in both halves of the state the fastest growing communities were most likely to embrace new technologies while outlying areas continued to accept older solutions as adequate. Nonetheless, real differences existed between the cutting-edge practices common in Los Angeles and the creeping progress that was made around the San Francisco Bay.
The location of sewage disposal—whether into freshwater, saltwater, or on land—was important in influencing how rapidly a community advanced its level of sewage treatment and drinking water
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Coalinga Sanitary Sewer Collection System and WWTP Improvements Project 57 chlorination. Few new systems for disposing of raw sewage into freshwater streams were constructed after 1920, and many existing freshwater systems began treating their sewage. Land disposal at sewage farms remained common through the 1920s, though increasing regulation meant that most added partial or advanced treatment methods. The chlorination of drinking water supplies advanced most rapidly in communities that drew their water from wells within groundwater basins that included sewage farms. Treatment advances were slowest in areas that discharged their waste to seawater. Two-thirds of the new disposal projects involving raw sewage through 1930 discharged into bays or sloughs, mostly in Northern California. No advanced treatment of sewage was applied at any seawater location, though partial treatment became the norm along Southern California’s recreational beaches.
Physical and economic realities underlay the different trajectories of the regions, but Gillespie and others also saw issues of human psychology playing a major role. In older areas, people had grown accustomed to disposing of raw sewage and it was difficult to persuade them to abandon familiar practices. Older communities through the Mother Lode and the San Joaquin Valley, Gillespie wrote, proved “to be the most refractory cases with which the sanitarian has to deal.” Conversely, new cities took it for granted that they would need to treat their sewage before disposing of it, and “once a community puts in sewage treatment, no matter how meager, it has been a psychological truth that the people there are ready for further sewage treatment when plausible reasons appear. “Naturally, the areas most open to change attracted the engineers and managers who were prepared to deliver it.
Southern California
The national idealization of California shifted around the turn of the century so that images of Los Angeles’s pristine beaches and suburban orange groves replaced the earlier gold fields and timber empires of the north state. Fitting its reputation as a land of health, Southern California assumed a position of national leadership in innovating practices of drinking water treatment and sewage disposal.
Los Angeles led the state in providing chlorination treatment for drinking water supplies. The region’s success was built upon a robust network of public health laboratories that continually monitored water supplies and fine-tuned chlorination levels. The Los Angeles County Health Department alone maintained 11 full-time public health laboratories from the San Fernando Valley to Pomona. There were additionally three city health departments with their own laboratories in Los Angeles, Pasadena, and Long Beach. This contrasted with a single laboratory serving the City and County of San Francisco and four laboratories in the East Bay.
The state’s southern region also innovated methods for improving the palatability of drinking water. In part, this was driven by necessity as Southern California could not draw upon pure mountain river water with the same ease as the north state. Large parts of the Los Angeles Basin relied upon well water as their primary supply, and as groundwater levels sank the remaining waters carried high concentrations of minerals that imparted undesirable tastes and appearances.
Colorado River water imported into the basin after 1939 also required extensive treatment for its hardness and turbidity. Private water companies experimented with sand and carbon filters to improve the palatability of the supply, and in 1941 the Metropolitan Water District constructed the
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world’s largest water softening plant in La Verne, with an ultimate capacity of 400 million gallons a day.
In sewage treatment, the southland was particularly active in creating joint sewerage projects that channeled the waste of multiple communities to a central treatment facility. By 1936, nine treatment plants handled the sewage of 43 separate communities. So, while Southern California had built only about one-third of all the high-grade treatment plants in the state, those served onehalf of all the communities in the state receiving the top level of sewage processing. Exemplary of this trend was the City of Los Angeles’s Hyperion plant near Santa Monica that treated the combined waste from seven cities and several unincorporated communities. The Los Angeles County Sanitation Districts, organized 1923-1925, handled waste from 32 other incorporated cities located through the county, treating most of the sewage at an activated sludge plant near the Palos Verdes Peninsula.
These joint plants had the financial resources to experiment with innovative technologies. The TriCity plant serving Pasadena, South Pasadena, and Alhambra enjoyed a national reputation as a proving ground for new sewage treatment practices, and the facility constructed an activated sludge pilot plant in 1917, the first in the state. The Los Angeles City Hyperion plant was the first in the state to employ fine sewage screens and its 12-foot-diameter drums were then the largest in the nation.
The cities of Southern California also paid unusual attention to the beautification of their water and sewage treatment plants. The Pasadena Tri-City plant was among the first sewage treatment facilities in the nation to landscape its grounds with lawns and ornamental trees. The City of Beverly Hills water filtration and softening plant, constructed in the mid-1920s, was a particularly ornate example Nicknamed the “Public Water Cathedral,” the building resembled a SpanishRomanesque church and had a soaring Moorish-style bell tower that disguised a chimney used for burning off sulfur above roof level of the surrounding neighborhood. Landscape architect Seymour Thomas designed the grounds in a hacienda layout to serve as a public park for visitors. No longer in use for water treatment, the building now houses a library and film archives for the Academy of Motion Picture Arts and Sciences.
The rapid progress made in drinking water and sewage treatment through Southern California resulted not from a genial consensus about the need for high standards, but from intense conflict between neighboring communities. Pasadena in the nineteenth century operated what was widely regarded as a model sewage farm, but the conversion of surrounding citrus groves into suburban tracts led to increasing odor complaints. The city added a septic tank in 1910 to treat the sewage prior to irrigation, and an Imhoff tank (a two-story septic tank with separate chamber, discussed further below) was completed in 1913. Among sanitary engineers, these improvements were believed to satisfactorily address the problem, but the neighbors were not appeased. In 1916, the areas surrounding the sewage farm incorporated as the City of Monterey Park and promptly passed an ordinance prohibiting sewage treatment facilities within city limits. It was this action that forced the Tri-City partners into developing the activated sludge treatment plant. Later, a plan to dump the dried sludge in Alhambra led 6,000 residents to sign a protest to the Los Angeles County Board of Supervisors and necessitated the addition of a kiln drier that converted the sludge to marketable fertilizer.
2. Environmental and Cultural Background
Coalinga Sanitary Sewer Collection System and WWTP Improvements Project 59 Similar conflicts occurred through the southland in the first decades of the twentieth century. When Anaheim began searching for territory for a sewage farm in 1911, the Speaker of the California State Assembly and local resident, Philip Stanton, led an effort to block the project by incorporating 16 square miles of rural land as the community of Stanton. Succeeding in their efforts, the community later disincorporated in 1924 in order to receive state funding for road improvements. West Covina, with a population of less than 1,000, incorporated in 1923 to block Covina from building a sewage project. West Covina later annexed additional territory to frustrate a second proposed plant. The organization of the Los Angeles County Sanitation Districts was in part a response to opposition against local sewage disposal in Compton, Watts, and Huntington Park. Similar experiences in Glendale, Burbank, and among the beach communities from Santa Monica to Hermosa drove the planning of the Los Angeles City Hyperion plant.
As Gillespie wrote in 1936, “Just why this Los Angeles area should be so universally sewered and at the same time be so violently opposed to sewage disposal forms an interesting subject on which to muse.” He credited the suburban boom that attracted great numbers of Midwestern migrants who came seeking a better and more modern way of life than what they had left behind. Escalating land values made every corner of the coastal plains a potential subdivision gold mine if the proper utility and transportation connections could be managed. And each subdivision required a sewer system, and yet no developer could tolerate a disposal plant next door. The result was a pattern of growth that consolidated sewage treatment into fewer and fewer plants, while demanding a continually higher level of odor control and facility beautification.
The great sensitivity to sewage and the escalating levels of treatment was a phenomenon largely confined to the major metropolitan areas. In more outlying areas, people adjusted themselves to the realities of sewage disposal and lived at peace with conditions that elicited bitter conflict among suburbanites. There, Gillespie concluded, “the pattern of sewage disposal will probably continue along its present course with sewer farming the rule, accompanied by high grade plants in critical neighborhoods, and cheaper plants elsewhere.
San Francisco Bay Area
The progress made in Southern California was not matched by the communities around the San Francisco Bay. Cities there largely remained tied to antiquated combined sewage systems without treatment plants. On the eve of World War II, some one million people continued to dump raw sewage through short outfalls into the Bay’s harbors, sloughs, and mudflats. That accounted for 80 percent of all the raw sewage disposed of by California’s urban population. An estimated 205 municipal sewer outlets discharged into the Bay, while oil refineries, industrial manufacturers, and innumerable fruit canneries used it indiscriminately as a dumping ground. Surveys of the Bay shores found them littered with vegetable scraps, chemical slicks, and floating fecal matter. A putrescent sludge covered the mudflats, and on warm days the smell of sewage carried several miles inland.
Still, there were few immediate health problems associated with the sewage and local concerns focused predominately on the economic impacts. The Bay Area drinking water supply was entirely separated from the saltwater sewage disposal, with much of the water being piped in from the Sierra Nevada mountains, and the cold waters of the San Francisco Bay did not attract bathers as
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did the beaches of Southern California. The pollution was instead seen as an impediment to industrial development. Hydrogen sulfide that arose from the anerobic digestion of waste caused corrosive damage to ships, buildings, and harbor structures. The oxygen-deprived waters starved nearshore habitats of life, and sewage threatened to contaminate shellfish, making them a potential source of cholera, hepatitis, and other infectious diseases. Trade organizations and local boosters also worried that the foulness of the Bay made the region appear backwards in comparison with their rivals in Southern California.
San Francisco was the largest offender in sewage production, but the city also did the most to address the problem. The first, relatively small, advanced treatment plant was constructed in Golden Gate Park in 1932 using New Deal relief funding Raw sewage had previously been used in the early twentieth century to irrigate the western portion of the park. After odor complaints, a septic tank was installed in 1912 and the treated effluent filled the ornamental lakes of the park. A lawsuit forced the abandonment of that practice in 1931, leading to the construction of the activated sludge plant the following year. The plant operated only during the irrigation season, running from mid-February to November, and produced around 500,000 gallons of treated effluent daily as well as dried sludge for fertilizer. Fitting its location in Golden Gate Park, the facility was beautified with flowerpots and landscaping. The plant (decommissioned in 1982) has been recognized as the first recycled water facility in California.
In 1933, the citizens of San Francisco voted approval for issuing $2.6 million in Public Works Administration (PWA) bonds to improve the sewer network and construct limited sewage treatment plants. When C. E. Grunsky undertook a study of sewage conditions in 1899, he found 125 separate sewer outlets and his plan called for consolidating those into six main outlets. In the intervening years, the expenditure of $17.5 million allowed for the total number of outlets to be reduced to 31, with 19 discharging to the Bay, 11 to the Golden Gate Strait, and one to the Pacific Ocean. With the WPA funds, the city hired a board of consulting engineers that included Charles Hyde of UC Berkeley to prepare a plan for improvement. The board recommended construction of three treatment plants, but had funding adequate to complete only the Richmond-Sunset facility.
The 15 million-gallons-a day (mgd) plant was completed in 1939 and provided only basic treatment with an Imhoff tank and sludge digester. Chlorination of raw sewage was used ahead of the tank for odor control year-round, and the final effluent was chlorinated for bacterial disinfection when the beaches were in use. The bulk of the city’s sewage, however, remained untreated.
The East Bay communities appreciated the need for sewage improvements, but could not find a way to coordinate their efforts prior to World War II. EBMUD was the obvious agency to manage a joint venture, but the district directors believed they lacked the authority to create special subdivisions for sewage disposal. Only after the state legislature amended its authorizing act in 1941 did the district feel enabled to engage in sewage planning, but then the outbreak of war delayed any further efforts. Nine individual East Bay cities made attempts to apply for WPA funding, but the inability of the applicants to reach agreement on essential issues prevented any of them from receiving funding.
Along the San Mateo Peninsula, Burlingame, Redwood City, and Palo Alto installed limited treatment plants, largely funded with WPA grants, to remove suspended solids from the sewage
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Coalinga Sanitary Sewer Collection System and WWTP Improvements Project 61 before discharging effluent onto mud flats or sloughs. Marin County did the same north of the Golden Gate. These plants, combined with those in San Francisco, provided basic treatment for the sewage of some 230,000 people, less than 20 percent of the region’s population. This fell far short of what the Bureau of Sanitary Engineers regarded as minimal conditions, which should include sedimentation, with or without chemicals, and sufficiently long outfalls to reach ocean currents. Grease removal would be required to prevents slicks, and to minimize land use, sludge should be disposed of by digestion and compact mechanical filters.
In reviewing the minimal progress made in the San Francisco Bay Area, Gillespie was sympathetic to challenges faced by the communities. The legacy sewer lines were expensive to operate and maintain. Merely mapping the lines was a challenge and attempting to link them required extensive construction in heavily built-up areas. Treatment plants necessarily needed to be located along the shores, as that was where gravity carried the waste. This meant acquiring expensive real estate and competing with industry for the land. The historic reliance on combined sewer lines also made it impractical to fully treat the flow during winter months and required that some overflow be tolerated. Gillespie was willing to accept lower standards of treatment for Bay pollution over freshwater streams, both because of the lower health hazard posed and because the heavy ship traffic made a certain level of pollution inevitable.
Still, Gillespie saw a dark cloud on the horizon in 1940 in the lack of preparation for dealing with industrial expansion. Already, studies in the East Bay indicated that the organic waste from industry, primarily canneries, was twice as great as that from human sewage. The refineries and heavy manufactures introduced chemical waste that was little understood in terms of effects or potential treatments. And of course, World War II would vastly increase the scale of industry in the San Francisco Bay Area and throughout the state.
Technology
Sewage and water treatment technologies advanced rapidly at the start of the twentieth century, giving rise to most of the processes that are still in use today. Chlorination was introduced for drinking water treatment in 1908 and rapid sand filtration entered common use in the 1920s. The era saw the beginning of the biological treatment of sewage with the introduction of trickling filters around the turn of the century and the activated sludge process in 1914. The biological treatment of sewage marked a shift to a more scientific process as they required a greater degree of control and an understanding of microbiology. It required new technologies in the form of pumps, aeration equipment, and tools for laboratory testing. Still, the technology was adopted only gradually, hindered by the slower rate of regulatory change, and as late as 1929 fewer than 20 percent of all sewage treatment plants used the activated sludge process.
Water Works
Most of the fundamental processes of modern drinking water treatment emerged during a brief period at the beginning of the twentieth century. The years between 1909 and 1916 saw the adoption of three major advances: the application of chlorine for disinfection; the use of rapid sand filters for treating turbidity; and the employment of the zeolite or ion exchange process for reducing water hardness. These techniques allowed municipalities to effectively treat drinking water for the first time, rather than just seeking out ever-more-remote sources of uncontaminated supply. By 1936, nearly 150 Californian communities provided at least some form of water
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treatment, predominately chlorine disinfection, and 36 cities had constructed full-scale filtration plants that treated surface waters for public use.
The common methods of water treatment consisted of disinfection, coagulation, sedimentation, filtration, aeration, and softening. The type and level of water treatment provided depended ultimately upon the source of supply. Coagulation, sedimentation, and filtration worked together to reduce turbidity and were used in treating surface waters at large filtration plants. Groundwater extracted by wells, the most common municipal water source, required comparatively little treatment beyond disinfection and thus needed little infrastructure. A chlorinator could fit into a small room at a pumphouse or be located at a centralized collection and distribution facility. If the water had a high mineral content, it might benefit from additional softening and aeration to improve palatability and remove minerals that could interfere with industrial processes. Surface water treatment required a larger investment in infrastructure than did groundwater because of the issues with turbidity, but it generally benefited from greater gravity flow and thus had lower on-going energy demand and pumping costs.
Water distribution systems, in contrast to water treatment, changed only modestly from the nineteenth into the twentieth century. The physical infrastructure benefited from incremental improvements in materials and energy sources. Pipes of galvanized steel, reinforced concrete, asbestos cement (transite), and ductile iron gradually replaced cast iron pipes, leading to greater durability and lower costs. Thermoplastic pipes, including those of Polyvinyl Chloride (PVC) and later High-Density Polyethylene (HDPE), began being manufactured in the 1930s and entered water system usage from the 1950s onward. The plastic pipes were light weight, corrosion resistant, versatile, and inexpensive and soon found many applications in drinking water and wastewater systems. Electricity replaced steam and oil in operating most pumps, allowing for smaller engines and plant footprints. Of greater direct consequence, engineers improved distribution networks to remove potential sources of contamination. Many of these occurred in factories or institutions that made primary use of a public municipal water supply but maintained a private auxiliary supply of untreated water for backup purposes. If a connection between the two systems lacked an air gap it was possible for untreated, contaminated water to find its way into the public supply. The Bureau of Sanitary Engineering identified and removed more than 1,000 such cross-connections through the first half of the twentieth century. This painstaking and laborintensive service received little public recognition, though it was essential to ensuring safe municipal water supplies and guaranteeing public health.
Chlorination
The permanent, continual chlorination of American drinking water supplies beginning in 1908 was one of the great public health achievements of the twentieth century. Chlorine is a strong oxidizing agent that, when applied in the correct dosage, can quickly kill the microorganisms that cause cholera, dysentery, typhoid fever, and other illnesses, without causing adverse effects in humans.
The introduction of chlorination promptly saved tens of thousands of lives that waterborne illnesses would otherwise have claimed. Chlorination also improved the efficiency and palatability of water systems by reducing the mold, algae, and slime that grew in water intakes and distribution systems.
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Coalinga Sanitary Sewer Collection System and WWTP Improvements Project 63 The first experiments in using chlorine compounds to disinfect water occurred in the late nineteenth century. British and German sanitarians in the 1890s used bleaching powder to sterilize watermains and other equipment following outbreaks of typhoid fever and cholera. These shortterm efforts succeeded in preventing reoccurrences of the epidemics, but they did not attempt to provide continual disinfection of the water supply. In 1905, officials again used chlorine to halt a typhoid epidemic in Lincoln, England, but then as a precautionary measure they continued a slow feed of chloride solution for a period of years until a new water source became available. This marked the first continual disinfection of a public water system and prompted further experimentation in Europe and America.
The earliest American efforts at continual disinfection occurred in 1908. Wilfred Langelier of the Illinois Water Survey and later professor of chemistry at UC Berkeley participated in the first experiment at the Union Stock Yards of Chicago. The engineers selected the site as only animals would be affected, and the heavily contaminated water supply made an ideal test case. The introduction of a minute quantity of chlorine continually fed into the supply line almost completely sterilized the stockyard water, leaving it in better condition than Chicago’s municipal supply.
Shortly after, the same engineers applied the technique to the drinking water of Jersey City, with chlorination beginning on September 26, 1908. The city received many complaints about the odor and taste of chlorine, which could not yet be administered with precise control, but the results were so promising that the objections were overruled. In the years immediately following the experiments, sanitary officials constructed many emergency chlorination plants in areas affected by flooding or disease outbreaks.
The introduction of improved chlorine gas feeders around 1913 allowed the process to spread into wide municipal use. Compressing chlorine gas under pressure converted it into a liquid that could be stored and transported in tightly sealed metal containers. A British officer in the Indian Medical Service was the first to use liquified chlorine gas on a small scale in 1903. The US Army experimented with the technology in the Philippines in the early 1910s, and a Niagara Falls plant began using liquid chlorine for temporary treatment in 1912. Philadelphia installed the first permanent liquid chlorine plant in 1913. The Wallace & Tiernan Company of New Jersey designed nearly all the early chlorinators that allowed for the controlled application of dosages, and according to Langelier, many of the first graduates of the UC Berkeley sanitary engineering program found employment with the firm.
All large treatment plants used liquefied chlorine gas as it was the most economical option.
However, as the gas is highly toxic, it could be difficult to safely store and an accidental release would endanger employees and nearby communities. Smaller plants therefore sometimes used chlorine in a powdered bleach form. In either case, the chemical was administered through chlorinators of various and evolving designs that connected to the water main with non-corrosive tubing. The chlorine and water mixed within a baffled chlorine contact basin for a specified period of time to produce effective disinfection. Duplicate equipment allowed chlorination to continue in the event of a failure of the primary apparatuses. The chlorine and dosing equipment occupied a dedicated room so that any leaks could be isolated. This room commonly had a separate entrance from the building exterior and no direct connection between it and any other room in the treatment plant or pumping house. Good ventilation facilitated repairs in case of a minor leak. Because liquified chlorine was commonly delivered in large steel cylinders weighing up to a ton,
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chlorination rooms generally included loading docks built to truck bed height for easy on and off loading.
Sedimentation
Sedimentation is an ancient technology used to clarify muddy waters. Most surface waters carry quantities of clay, silt, and sand that are too fine to catch on a screen. Allowing the water to stand in or pass slowly through a settlement basin causes much of the suspended matter to settle to the bottom of the reservoir. This process of plain sedimentation could greatly improve water clarity, and in some cases was sufficient in and of itself to prepare the water for public consumption.
However, the finest particles of clay and silt did not settle readily and could remain in suspension even after months of storage. It was therefore more common to use sedimentation as a preliminary treatment step preparatory to more thorough filtration. The addition of coagulating chemicals aided sedimentation, especially in highly turbid waters.
Sedimentation at its most basic required a bare minimum of infrastructure. Any natural or artificial basin with enough capacity to retain water for several hours could remove some portion of the suspended matter. These simple reservoirs could be left as exposed earth or be lined with stone, brick, asphalt, or concrete. The primitive basins lacked means for removing deposited settlement and thus required periodic draining and clearing. Gillespie recalled that, prior to 1915, such “small weed grown settling basins” provided the only form of water treatment through most of California.
More sophisticated sedimentation basins (also known as sedimentation tanks or clarifiers) allowed for greater process control. Early, purpose-built sedimentation basins followed the fill-and-draw method in which tanks were filled, held for a specified retention period, and then drained and cleaned. This method was labor intensive, and managers soon abandoned it in favor of the continual flow method with inlets and outlets always open. The concrete basins came in rectangular, square, and circular forms. Rectangular basins used baffles of concrete, wood, or metal to prevent water flowing directly from the inlet to outlet. A circuitous route ensured an adequate retention time and limited the formation of eddies that would inhibit sedimentation. In circular basins, untreated water entered the center of the tank from below and passed through a perforated baffle. Flow velocities declined rapidly away from the middle of the tank, so most materials fell out into a sump near the tank center. The cleaned water flowed out over an overflow weir that circled the tank and connected to an outlet pipe. As with most items in treatment plants, sedimentation basins generally came in pairs so that one basin could continue to operate while the other was taken offline for cleaning, repair, or maintenance. The use of sedimentation basins increased with the introduction of mechanical equipment for automatically removing sedimentation around 1919. In rectangular basins, chain loops dragged scrapers in a straight line down the tank towards a collection sump and then returned the scrapers raised above the tank bottom. In circular tanks, a series of arms with bottom scrapers revolved around a central axis. In both cases, the scrapers moved at barely perceptible speed to avoid disturbing the calmed water.
Numerous patented variations on mechanical cleaning equipment existed to meet different specific needs.
The addition of coagulating chemicals facilitated sedimentation by causing suspended matter to clump together, forming a jelly-like precipitate known as floc. The clumped floc readily settled to the tank bottoms. Sanitary engineers experimented with many chemicals, using the jar test
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Coalinga Sanitary Sewer Collection System and WWTP Improvements Project 65 developed by Langelier, to ascertain their coagulating properties under different conditions. The most widely used substance through the twentieth century was aluminum sulfate, also known as alum. Ferrous sulfate, ferric chloride, ferric sulfate, and chlorinated copperas were common substitutes. The chemicals functioned most efficiently within narrow pH limits, and the addition of soda ash, lime, or similar helped to fine tune acidity.
Small mixing basins, located ahead of the sedimentation tanks, served to thoroughly mix the coagulates and raw water. The basins employed a range of methods for mixing the chemicals including baffles located within the flow stream, mechanical stirring paddles, and air blowers. The simple baffles generally worked adequately, but equipment manufacturers patented and marketed more complex apparatuses that promised some particular advantage.
Sand Filters
British sanitarians began experimenting with sand filters in the early nineteenth century. In 1829, a private water company constructed a sand filter to serve their customers in the London area, creating the world’s first treated municipal water supply. These British sand filters, also known as slow sand filters, differed in design and operation from the later rapid sand filters that became dominant in America in the early twentieth century, but they provided a model for subsequent developments.
A slow sand filter consisted of a large watertight basin, generally of concrete, that contained a layer of sand of uniform small size over a bed of gravel with drainage tiles below. The sand layer had a minimum depth of 12 inches up to a maximum of around 40 inches. The slow percolation of water through the sand caused suspended materials to settle out, depositing a thin layer of sediment on the surface of the sand bed. As the sediment layer increased in thickness, it produced increasing resistance to infiltration and operators thus needed to increase the depth of the water above to maintain an even filtration rate. When the sediment layer became too thick, the operators drained the tank, scraped off the top layer of sand, and began the process again with a fresh bed. The layer of sediment, known as shmutzedecke (German for “dirty skin”), functioned as a biofilm that digested organic matter in the water, serving to purify as well as clarify it, though the nature of this biological treatment was not understood in the nineteenth century. Because of their creeping rate of infiltration, slow sand filters required large basins of at least a quarter acre in size, with a half-acre or full acre more common.
Americans constructed their first slow sand filter in 1872 in Poughkeepsie, New York, and completed a number of similar plants through New England over the following decades. However, the design proved ill adapted for American conditions where rivers were far more turbid than the sedate English streams. The filters rapidly filled and choked on sediment, making them inefficient and uneconomical. In the 1890s, the eminent sanitary engineer George Fuller experimented with rapid sand filtration techniques in Louisville, Kentucky, to treat Ohio River water. By introducing a coagulant immediately prior to the sand filter, Fuller was able to process a large quantity of water in a relatively small tank. However, the great quantity of floc that settled on the sand bed required more frequent cleaning than did British slow sand filters, up to several times a day versus a monthly cleaning. To address this problem, Fuller adopted a system of backwashing that forced water under pressure up through the sand layer to cleanse it. This combination of features—small basin size,
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use of a coagulant, and backwashing—distinguished the American rapid sand filter from the predecessor models.
Several decades of incremental improvement gradually refined Fuller’s process until it operated with enough consistency and efficiency to be widely adopted. Much of the effort focused on improving the backwashing process to avoid forming mudballs that could clog the filter. In the 1920s, John Baylis developed a system of auxiliary scour that used horizontal water spray from a grid of pipes to enhance the cleaning action during backwashing. A decade later, the introduction of rotary sweeps improved the cleansing of the sand bed surface. Both scour types allowed for using aerated water, with air injected under pressure to enhance the scrubbing action. Researchers also adjusted the ordering of the filtration process, adding sedimentation basins ahead of the filtering, and thus reduced the required frequency of cleaning. By the late 1920s, the treatment chain of chemical coagulation, mixing, flocculation, sedimentation, and then filtration became known as “conventional treatment” and was used wherever muddy surface rivers were a principal water source.
The layout of municipal rapid sand filtration plants followed some general conventions, even as the particulars responded to the individual demands of the site, water source, available funding, and the decisions of the designer. Most large plants grouped small, rectangular, concrete tanks into two rows and placed a pipe gallery between the rows and beneath the floor of the tanks. During normal operations, the water level in the beds stood above the top of the lateral half pipe troughs.
After trickling through the sand, gravel, and underdrains, the water filled a reservoir or clear-water well below the beds. During backwashing, water from an elevated tank was forced up through the filter beds and drained through the troughs. The plant operators generally piped the removed sludge to a drying basin, where the water content was drawn down prior to disposal. Small plants were more likely to use circular units of concrete or steel, and equipment manufacturers sold many such patented apparatuses ready for rapid assembly and use.
A pressure filter was a variation of rapid sand filter that contained the process within an air-tight cylindrical shell and functioned by virtue of water pressure rather than gravity flow (Figure 25).
The small cylinders could operate vertically or horizontally and required little space. With their limited capacity, pressure filters were suited for industrial use or on small private or public water systems with low turbidity sources. Engineers commonly designed such water systems with a single set of pumps that removed water at its source, forced it through a pressure filter, and conveyed it to the point of consumption. When used in combination with chlorine disinfection, pressure filters allowed for small-scale water systems to operate safely and economically. Light weight pressure filters replaced the sand media with engineered fabric or paper filters. These systems lacked durability, but were suited for temporary installation at labor and military camps or the like.
Aeration and Water Softening
Groundwater drawn from certain geological formations by wells could contain high quantities of dissolved minerals including iron, calcium, and magnesium. These dissolved solids make water hard, which detracts from its palatability and interferes with industrial uses by forming scales in boilers and other equipment and requiring greater quantities of soap in laundry applications. Water softening is the process of removing these hardening minerals. The iron from an anaerobic well
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Coalinga Sanitary Sewer Collection System and WWTP Improvements Project 67 occurred in an invisible, soluble form, but as it oxidized following exposure to the atmosphere, it produced rust that gave the water an unappealing color, clogged distribution lines, and made it unfit for some industrial purposes.
Aeration provided the simplest means of oxidizing and removing dissolved iron. Aerators came in a variety of forms as there were many methods of exposing water to air. Spray nozzles could throw water into the air ahead of a storage basin, or a series of baffles, steps, or protruding stones could be placed within a shallow channel leading to the basin. A tray-type aerator (Figure 26) distributed water to the top of a series of shallow trays with perforated bottoms, allowing the water to aerate as it dripped between levels. The trays commonly contained coke or rock on which a coating formed that sped the process of oxidation. A number of patented devices employing nozzles, paddles, and propellers were also available.
Two different techniques existed for softening water: the lime-and-soda-ash process and the zeolite ion-exchange process. Lime and soda ash acted through a series of chemical reactions to convert soluble compounds of calcium and magnesium into insoluble forms that either precipitated out through sedimentation or were removed by filtration. The process was similar to that used in rapid sand filtration. Operators added lime and soda ash to raw water either separately or in combination, and thoroughly stirred the materials together in a mixing basin to produce flocculation. The heaviest material settled out in a sedimentation tank. The partially treated water was then recarbonized by injecting carbon dioxide gas into the water as it flowed from the sedimentation tank towards the filter. The carbon dioxide interacted with any excess lime to form soluble bicarbonates which helped to minimize the buildup of calcium carbonates deposits in the filter and distribution system. A final pass through a filter removed most of the remaining coagulant and prepared the water for consumption.
The zeolite process used ion exchange to replace the soluble calcium and magnesium in water with sodium. Ions are molecules that have acquired a net electrical charge as the result of gaining or losing electrons. As opposite charges attract, positively charged ions, known as cations, will adhere to their negatively charged anion partners. In ion exchange, molecules within solution are swapped with like-charged particles that are adhering to an oppositely charged solid that is immersed in the solution. Ion exchange is a common, natural process that is fundamental to soil fertility as the negative charges of clay soil and organic matter attract and hold plant nutrient cations such as potassium, calcium, and magnesium. British soil scientists in the mid-1840s were the first to study the ion exchange process and to recognize that any single cation in the soil could be replaced with any other cation by saturating the soil with water rich in the replacement nutrient.
European chemists began experimenting with ion exchange using zeolites in the 1850s, but without immediately recognizing the material’s potential for water softening. The term zeolite refers to a group of natural materials (and today, synthetic products) that combined iron, aluminum, and sodium in a silicate form. Greensand, a marine sandstone, was the most common natural zeolite.
When hardwater ran through a bed of zeolite, it exchanged its calcium and magnesium cations for the sodium cations adhering to the zeolite until the sodium was exhausted. Flooding the zeolite with a brine solution then reversed the process, releasing the calcium and magnesium for disposal and replenishing the sodium for another softening cycle. Coating the zeolite with manganese dioxide allowed it to also strip the water of iron. The potential to use zeolites for water softening
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was recognized by the early twentieth century, and the German scientist Robert Gans patented the process in 1906.
Over the next two decades, small zeolite softeners found their way into many industrial processes as they demineralized water for use in steam boilers, laundry plants, pulp mills, and the like. A zeolite softening unit was essentially a rapid sand filter but with a bed of zeolite replacing the sand quartz and with a special lining to protect against corrosion caused by the brines used in regeneration. Depending on the size of the operation, the units could be either of the gravity-fed basin type or pressurized steel tanks. The plant then blended the fully treated water with raw or partially treated water to produce a finished product with a desired level of hardness. The Ohio Valley Water Company constructed the first municipal softening plant below Pittsburgh in 1926.
The company added a second plant in 1929, and the area served as a working laboratory for experimenting with the zeolite process on a large scale. The plants entered wide use in the 1930s, appearing in every part of the country. In 1941, the Metropolitan Water District of Southern California constructed its large water softening plant in La Verne using a combination of lime treatment and zeolite filter beds. After a later expansion, the La Verne facility had the distinction of being the largest zeolite softening plant in the world.
Reservoirs
The design and construction of water tanks and reservoirs evolved in the early twentieth century to make more efficient use of materials. In 1894, Horace E. Horton of the Chicago Bridge & Iron Works constructed the first steel plate water tank with a full hemispherical bottom. The curved shape required less steel and was more watertight than a flat-bottomed tank, and because the rigid bottom was self-supporting, it did not need to sit on a platform. By the early twentieth century, this had become the dominant type of elevated water-storage structure in the United States. In 1905, George T. Horton, son of Horace Horton, created the first tank with an elliptical bottom, which had a shallower profile than the hemispherical form. The ellipsoidal form became nearly flat at its center and allowed for using larger risers that provided greater support. Further innovation in 1922 allowed for using the ellipsoidal shape for both the top and bottom of the tank. This eliminated the need for the interior trusses that supported a conical roof and gave a more pleasing, modern form.
In 1928, Chicago Bridge & Iron (CBI) introduced the first true spherical tank. Set on single pedestal supports, these small tanks, trademarked under the name Watersphere, looked like golf balls sitting on tees. The use of welding, rather than riveting, to join tank plates beginning in 1933 allowed for greater flexibility in design and led to larger forms, including a 100,000-gallon capacity Watersphere introduced in 1939. The Watersphere became the most popular elevated tank design in the 1940s and were especially common for small systems with low storage needs. Other CBI advances allowed for constructing high-capacity tanks holding up to two million gallons.
These design types included radial-cone and toro-spherical tanks, both of which placed the convex steel plates under tension to allow for the use of thinner materials.
The tubular steel legs that supported the large tanks also required less material than prior truss support systems. Central towers under the tanks housed risers, overflow pipes, and ladders for access. By World War II, tanks in these modern forms and several other variations became
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Coalinga Sanitary Sewer Collection System and WWTP Improvements Project 69 common on large systems. Form followed function for elevated steel tanks, and while they were frequently painted with town names or high school mascots, they rarely had architectural decoration beyond their own striking industrial forms.
Sewage Works
Public sewerage systems for collecting household waste became nearly universal among incorporated Californian communities in the first half of the twentieth century, while the treatment of sewage advanced somewhat less rapidly. By the eve of World War II, 95 percent of the state’s urban population and about three-quarters of the total population benefited from public sewerage systems. However, nearly four in ten of those systems, including most of the older legacy works of Northern California, continued to discharge raw sewage without treatment. Where people had grown accustomed to disposing of raw sewage, state officials found it difficult to persuade them to abandon existing practices. Conversely, newer cities took it for granted that they would need to treat their sewage before disposing of it, and 80 percent of systems constructed after 1913 included treatment from the outset. Naturally, the communities most open to improvement attracted the engineers and managers who were prepared to deliver it.
The location of sewage disposal—whether into freshwater, saltwater, or on land—was important in determining how rapidly a community advanced in sewage treatment. By 1920, state and local officials well understood the hazards of disposing of raw waste into freshwater streams. Nearly every new freshwater-discharge system included treatment, and many existing systems were overhauled to add treatment options. Land disposal at sewage farms remained common through the 1920s, although increasing regulation meant that most added partial or advanced treatment methods. Communities that discharged their waste to seawater were the slowest to advance. Twothirds of the new disposal projects involving raw sewage through 1930 discharged into bays or sloughs, mostly in Northern California. No seawater location added advanced biological treatment methods prior to 1930, although partial treatment by screening or septic tanks became the norm along Southern California’s recreational beaches.
Sanitary engineers experimented with a wide variety of treatment methods as they sought practical means of implementing the scientific advances occurring in the field of microbiology. Septic tanks and the related two-chamber Imhoff tanks dominated the first decades of the twentieth century, but options soon diversified. The era of advanced biological treatment began with two designs by the Bureau of Sanitary Engineering for a trickling filter in Reedley in 1915 and an activated sludge plant at Folsom Prison in 1917. In 1929, Gillespie compiled an inventory of the various treatment plants in operation across the state.
Imhoff and septic tanks were by far the most common, although Gillespie described these as “mostly relics of the past.” Trickling filters were the most common advanced treatment option, producing a fully digested final effluent. While only six activated sludge plants were online, these were largely in joint sewerage plants that handled the waste of multiple communities. The somewhat older technologies of sand filters, contact beds, and fine screen continued to exist but in shrinking numbers. The survey did not include sewage farms, though a number remained in use in 1929. “All in all,” Gillespie noted, “California has adopted practically everything that has appeared on the horizon for sewage treatment.”
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Private consultants and equipment manufacturing firms played an increasingly important role in designing sewage treatment systems as their complexity advanced, even as the system remained in municipal or institutional ownership. Academic researchers worked extensively as consultants in the early period because there were few other practitioners experienced in the specialized design of water and sewage treatment plants. Professor Hyde, in particular, consulted on numerous treatment plants throughout the state. Eventually Hyde’s students organized their own consulting firms, with Clyde Kennedy (class of 1911) and Harry Jenks (class of 1917) being among the most prominent in Northern California. The larger equipment manufacturers, such as the Dorr Company, employed consulting engineers who could draw plant plans for small towns or institutions that utilized the company’s equipment.
The reliance on private consultants had the disadvantage of pushing municipalities towards technologies that benefited patent holders more than the communities. Professor Harold Gray of UC Berkeley noted a tendency for sewage treatment methods to cycle in and out of fashion in a manner unrelated to obvious changes in knowledge or technology. Activated sludge treatment found favor in the late 1930s, followed by increased interest in chemical precipitation and then later a revival in trickling filters. Gray linked this pattern to changes in patent status. Several patents for activated sludge treatment, for instance, ran out around the time that the trend away from it began, while the rediscovered interest in trickling filters coincided with the issuing of new patents for particular filter features.
A P. Banta of the Los Angeles County Sanitation Districts commented drolly on the persistence of equipment salesmen, even as he relied upon their services:
Larger treatment plants are the Mecca of budding inventive genius. Scarce a week goes by but that some gentleman or salesman arrives with a new panacea of sewage treatment. Sometimes it is the addition of tons of newspaper, or some patented chemical, or some mysterious settling media, or perhaps it is the simpler matter of just distilling the sewage. Paint and building material exponents are legion. Wonder-last-forever metals are nearly as common, and one must expect to have the lubrication system experted [sic] several times a year by all the oil companies.
The following sections highlight the major treatment technologies that came into widespread use during the first half of the twentieth century.
Sewage Pumps
Communities resorted to sewage pumping plants, also called lift stations, in any situation where sewage needed to be lifted above where gravity flow would naturally carry it. This could occur in hilly cities where isolated low-lying districts could not be served by gravity flow outlets. All the sewage through the district would then be collected at a single convenient location and pumped through a force main to join a higher sewer main operating under gravity flow. In flat topography, the need to maintain an adequate grade for flow velocities required excavating continually deeper towards the sewage outlet. In some situations, it proved less expensive to raise the sewage by pumping at one or more places rather than to do deep excavation over long stretches. Pumping stations were also commonly used immediately ahead of treatment plants in order to generate adequate head for plant operation.
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Coalinga Sanitary Sewer Collection System and WWTP Improvements Project 71 A sewage pumping station consisted of a storage well, two or more pumps, and the engines required to operate them. Storage was necessary as pumps operated at a continual rate while sewage inflow varied with the time of day, day of the week, and other factors. Adequate storage capacity also allowed for pumps to be taken offline for maintenance. Pumps could be submerged within the storage well, but it was often preferable to locate them in an adjacent dry well to facilitate servicing.
Screens at the sewage inlets removed large materials that could clog or damage pumps, but smaller materials including toilet paper and organic solids were allowed to pass through as these created odor problems at the stations if retained. Centrifugal pumps were favored over reciprocating pumps as they were less likely to clog from the smaller bits of trash. Any type of motor could be used to operate the pump, but electrical motors became standard as they were the easiest to automate
Sewage pumps generally operated automatically by way of a switch connected to a float within the storage well. When the sewage rose above a certain level, the rising float started the pump, and it operated continually until the sewage fell back below the trigger level. If the sewage continued to rise during pumping, another float would trigger a second pump into operation. A third pump might be present as an emergency reserve and to add additional pumping capacity along lines with high peak flows.
A properly maintained sewage pump plant would produce little odor and thus could be located wherever most convenient. Smaller plants could be contained in below ground vaults, while larger plants frequently had a motor room above ground and pumps below. Early pumping stations were crude, consisting of a wood or brick-lined tank, with a pump mounted on a platform above, and the whole system enclosed in a corrugated metal building. Greater attention was given to the stations as they started to encroach on residential neighborhoods. Some pumping stations constructed in the 1920s adhered to the City Beautiful movement and often featured Neoclassical or period revival design elements and landscaped grounds to emphasize the dignity of municipal service. One design manual argued that “such structures tend to remove the popular prejudice from sewerage and to arouse interest in sewerage questions.” In other cases, pump stations were designed to blend in with their surroundings. A pump station of the Los Angeles County Sanitation Districts near the Palos Verdes Peninsula, for example, was set below ground and landscaped above with a pergola that hid ventilation outlets. Likewise, when Long Beach constructed 14 new pump stations, the city disguised some as common stucco bungalows and built another into the central pier of a canal bridge.
Screens
Coarse or fine screens physically removed large items and some portion of the smaller suspended solids from sewage flows. Coarse screening was the first step in nearly all sewage treatment as it was necessary to remove large material—rags, timber, golf balls, and the like—that could clog or damage machinery. A bar screen, composed of parallel iron bars of one-quarter to one-half-inch thickness with openings of between one-half and six inches, was the simplest device. The screen was set with the bars oriented vertically and at an angle of between 30 and 60 degrees so that captured materials were pushed up the screen for easier removal. The screen was cleaned either
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periodically by manual raking or continually by automated processes of various sorts. Chain loops on sprocket wheels pulled a rake up the face of the screen and dumped collected materials into a receptacle for later disposal. Medium-sized mesh screens of galvanized wire fabric provided filtering for smaller objects such as toilet paper and leaves preparatory to passing sewage through reciprocating pumps, trickling filters, or other machinery that were readily clogged.
Fine screens provided a basic form of sewage treatment by removing a portion of the suspended organic solids. Long Beach was the first to use fine screens for sewage treatment in 1915, followed by Santa Barbara in 1916 and Stockton in 1919. Most fine screens consisted of perforated metal plates, rather than wire mesh, for greater strength and ease of replacement in the machines. The perforations ranged between 1/32 and 1/14 of an inch wide by 2 to 4 inches long. Fine screens were estimated to remove approximately 20 percent of suspended organic materials, though results varied with circumstances and the screens often underperformed expectations. For planning purposes, they were used only for treatment requiring less than 10 percent removal of suspended solids. That low level of cleaning was considered sufficient when sewage was discharged into an environment where it would be diluted quickly, such as at the Santa Cruz screening plant designed by Charles Hyde that discharged into the ocean.
Screens were also widely used for industrial waste at pulp mills or fruit canneries where the finer organic material that passed through the screen did not pose an immediate health risk. Because screens removed fewer suspended solids than did sedimentation, there was less sludge requiring disposal, and this could be an advantage where land use was at a premium.
Fine screens operated continuously and were cleaned while in motion by brushes or jets of air, water, or steam. Equipment manufacturers marketed a wide variety of patented screen systems.
Among the most common in the United States were the disc and drum types, though many variations existed. In large treatment plants, the fine screens were major pieces of equipment, with sizes ranging from 8–12 feet in length or diameter. Electric motors powered the screen as well as operated sewage pumps and water or air compressors. A dedicated operator was generally required to ensure smooth functioning.
The materials removed by screening were disposed of by incineration or burial. The materials were sometimes dewatered by rolling presses or centrifugal units before disposal. The Hyperion plant in Los Angeles, for example, removed 30 tons of wet screenings per day which dried down to 4.2 tons requiring incineration. Alternately, the screened materials could be sent through a shedder or grinder. Small shredders reduced organic matter to a pulp that could then be fed back into the raw influent, while harder inorganic materials were separated for disposal. Large grinders used toothed disks or swinging hammers to reduce even the hardest matter into particles small enough to be discharged with the effluent. In some cases, grinders were used in lieu of screens so that everything entering the plant was pulverized prior to treatment.
Golf Chambers
In combined storm-sewage systems, large quantities of sand entered the pipes and needed to be removed to avoid clogging the system. Early grit chambers were crude retention basins located along the sewer lines that allowed sand and some organic matter to settle out of suspension.
Because organic waste would putrefy in these chambers, they produced considerable odor and
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Coalinga Sanitary Sewer Collection System and WWTP Improvements Project 73 needed to be cleaned regularly. Later refinements allowed for greater control of the flow velocity, maintaining a current of around one foot per second, so that only the heaviest mineral materials settled out.
In sewage treatment plants, grit chambers were generally located immediately behind bar screens at the entrance to the plant. The velocity of the influent was reduced through the grit chamber by gradually flaring the sides and bottom of the channel to increase its width and depth. Grit settled out to the depths of the chamber which was set below the bottom level of the incoming and outgoing pipes. To maintain proper velocity, two or more chambers could be constructed in parallel. During times of low flow, a single chamber was used and the other chambers were put into use as flows increased.
Grit chambers needed to be cleaned periodically and particularly after storms. This could be done manually by temporarily taking the chamber out of service. Apparatuses for mechanical cleaning were introduced in 1927 and became common in the 1930s. Most of these consisted of a scraping device that ran over the bottom of the chamber and a moving rake or elevator that raised the material on an incline while agitating it to wash out any organic matter. Grit that retained any organic waste needed to be buried. Clean grit could be used as fill material or dumped as convenient.
Septic Tanks
The septic tank was the dominant sewage treatment technology of the early twentieth century, from 1900 to approximately 1913, after which it was superseded by the related Imhoff tank.
Donald Cameron introduced the septic tank in England in 1896 and received a US patent in 1899.
He organized the Cameron Septic Tank Company to license use of the technology in America at a fee of five percent of construction costs. However, Cameron immediately encountered resistance from engineers who objected to his effort to patent the septic process itself rather than a particular tank design. Municipalities refused his royalty demands on the grounds that the septic process was a natural one that relied upon anaerobic bacteria that was already in the sewage itself. The municipal engineers initially prevailed in the ensuing lawsuits, winning a 1907 court decision that generated a boom in septic tank construction, but an appeals court later reversed the ruling and declared the septic process patentable. The drawn-out suit and the uncertainty and animosity that surrounded it caused engineers to ultimately shy away from the technology and welcome the emergence of the Imhoff tank (see below) as an alternative. Only in 1919 did Cameron settle the final outstanding claims, but by then numerous competing technologies existed in the marketplace.
The municipal septic tank was a one-story, continuous-flow sedimentation tank through which sewage was permitted to slowly pass so that suspended matter would settle to the bottom and undergo anaerobic decomposition. The tanks were designed to hold sewage from 6 to 12 hours before discharging the effluent. The tanks thus needed a volume equivalent to a quarter or halfday’s average flow. If the tanks were too large and the sewage remained overlong in the chamber, undesirable levels of anaerobic activity would give the effluent an objectionably dark appearance and offensive odor. Too short of a stay and not enough organic matter would settle out of the effluent. As the volume of sewage flows varied, it was desirable to have two or more tanks so that capacity could be added or removed to match flows. Most small plants lacked that flexibility and thus produced results that were less than satisfactory.
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Septic tanks were constructed of wood, brick, or concrete in all different sizes and plans. They could be rectangular, square, or circular; deep or shallow; roofed or open-topped. The bottoms could be horizontal, sloping, or contain hoppers for settled sludge. The chief concern in design was to reduce the velocity of flow through the tank and prevent material from moving directly from inlet to outlet. Effluent passed over weir ‘c’ into the siphon chamber ‘d’, from which it was discharged by automatic pump ‘e’ into the outlet pipe ‘f’. A baffle near the inlet slowed the sewage entering the tank, while a scum bar near the weir extended 6 to 18 inches below the surface to prevent floating materials from escaping the tank.
Anaerobic bacteria developed within a new septic tank over a period of a couple weeks to several months. It would then work continuously on the layer of sludge that settled to the tank bottom, digesting organic matter into gases of methane, carbon dioxide, and nitrogen as well as finely divided organic compounds that entered solution and left the tank with the effluent. Some organic matter resisted decomposition and formed a permanent layer on the bottom of the tank that needed to be drained or pumped out roughly once or twice a year. The effluent discharged from a septic tank had between 25 to 50 percent less suspended matter than raw sewage, including the bulk of the material that was most inclined to putrefaction and thus public offense. Septic tanks were used both as the sole sewage treatment prior to discharge or as a preparatory stage for further treatment.
In California, Willits of Mendocino County was the first to employ a municipal septic tank in 1904, while Bishop, Santa Rosa, and Fresno added tanks the following year. The municipal use of septic tanks declined after the introduction of the Imhoff tank, though they remained in use for longer at institutions and small treatment works. Septic tanks remain ubiquitous in rural areas without sewage systems. Modern septic tanks are manufactured of concrete, plastic, or fiberglass.
They generally operate in connection with a drain field in which subsurface perforated pipes discharge effluent into a porous underlayer.
Imhoff Tanks
Karl Imhoff developed his namesake tank in Germany in 1907 to address a chief failing of the septic tank. As the sludge at the bottom of a septic tank decomposed, it gave off gases that bubbled up through the sludge layer and liquid sewage. During the heat of summer, the bubbling could become vigorous enough to stir up the sludge and mix it into the effluent. This greatly increased the quantity of suspended solids and prevented effective sedimentation.
The Imhoff tank (also known as an Emscher tank) operated by dividing sedimentation and digestion into separate chambers across a two-story structure so that gases, scum, and regurgitate particles from the decomposing sludge could not agitate or reenter the flowing sewage above. The upper sedimentation chambers were long, narrow basins through which the liquid influent flowed at a rate of around a foot per minute, giving a retention period of two to three hours. The chambers had a maximum length of around 100 feet and a relatively narrow width to avoid creating crosscurrents in the flow. Angled bottoms on the sedimentation chambers sloped down to a narrow slot through which the deposited solids fell into the lower digestion chamber. The slot was designed in such a manner to prevent gas from entering from below. Concrete was favored for construction as its smoothness assisted the sludge in slipping down the sedimentation chamber walls. Still, it was necessary to include a walkway on top of the tanks so that workers could scrape
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Coalinga Sanitary Sewer Collection System and WWTP Improvements Project 75 the side walls of accumulated deposits twice a week or so. Two or more sedimentation chambers were sometimes used over a single digestion chamber to avoid the depths required by the long sloping of a single chamber.
The digestion chambers stored sludge for between six and 12 months, with longer times required in small plants or during cold weather. It was desirable to make the digestion chamber as deep as possible as this improved decomposition by maintaining more uniform temperatures. This desire had to be balanced against the increased cost of deep excavation, and tanks generally had a maximum depth of 30 to 35 feet. Gas and scum produced by digestion bubbled up into spaces surrounding the exterior of the sedimentation tanks. Vents of various designs allowed the gas to escape. Digested sludge was removed from the bottom of the tank by gravity where feasible or more commonly by pumping. The bottom of the digestion chamber was in the form of a hopper.
A vertical sludge pipe drew digested sludge from the hopper bottom and fed it into a horizontal pipe that led to sludge drying beds. A valve opened the pipe and pressure from the water above forced the digested sludge through the pipes. Operators closed the valve as soon as the emerging sludge showed signs of not being fully digested. The sludge produced by Imhoff tanks was generally in better condition that than from traditional septic tanks and was more easily dried.
Imhoff tanks gained quick popularity in America because of increasing dissatisfaction with septic tanks and weariness of the protracted patent litigation. Fullerton, Hanford, Mill Valley, and Winters constructed the first four tanks in California in 1912. The effluent released from an Imhoff tank was in most circumstances superior to that from septic tanks and lacked dark coloring and offensive odors. The improved quality of digested sludge also made Imhoff tanks attractive to municipalities that hoped to sell the material as fertilizer to partially recoup operating costs.
However, the tanks had several notable drawbacks. Because of their great depth, Imhoff tanks required deep excavation during constructing, which made them more expensive than alternatives (Figure 41). Operating costs were also generally higher than for other tank types as Imhoff tanks could not be neglected for more than a few days at a time without detrimental results. The tanks tended to be temperamental and they sometimes failed to produce adequate digestion or generated excessive quantities of scum without clear cause. Imhoff tanks also lacked means of heating the sludge to aid digestion and the fixed relationship between settling capacity and sludge digestion space limited their flexibility. Some very large Imhoff tanks were constructed in the United States, including a 472 mgd tank in Chicago, but they eventually fell out of favor for all but small treatment plants, replaced by plain sedimentation tanks with separate digestors.
Clarifies
Clarifiers or plain sedimentation tanks followed the same basic principle inherent in septic or Imhoff tanks in using a controlled, slow flow of sewage to cause mineral and organic solids to settle out of suspension. They differed in that the sediments were removed before septic conditions could develop and the sludge was digested separately. Settlement basins (also called settling basins) were a basic technology that had been used in the nineteenth century to treat turbidity in drinking water and to provide minimal treatment of sewage before discharge. However, they did not come into wide use until after 1919 when mechanical equipment for removing sludge and grease from the tanks was introduced in the United States. In comparison to Imhoff tanks, clarifiers were simple to operate as they did not require scraping or manual skimming and the separate digestion could be more readily controlled with less unpredictable foaming or digestive failures.
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A primary clarifier unit was used with raw sewage at the start of treatment, while a secondary or final clarifier unit was sometimes required to provide additional settlement at the end of treatment following a trickling filter or activated sludge tank. Sludge from final clarifiers was frequently returned by pipe back to the primary clarifier where it again settled and was removed.
Early clarifier-style settlement tanks operated on an intermittent fill-and-drain schedule, but by 1904 it was known that a continual flow in, through, and out of the basin provided just as good results and with increased throughput capacity. Settlement periods were commonly between one and three hours. Less retention time was required ahead of trickling filters and more might be used on a small system with relatively fresh sewage and no secondary treatment. Settlement tanks for sewage systems followed similar designs to those used in drinking water treatment (see above section) and came in rectangular and circular plans. Square tanks featured rounded corners to facilitate sludge collection, but these proved difficult to fully clean and the design fell from favor A wide variety of devices for mechanical sludge collection were available that promised savings in construction, labor, and maintenance, or particular advantages with different types of sewage.
These devices generally consisted of scrapers and skimmers that moved sludge and scum respectively towards collection points. In some designs, a scraper moved across the bottom of the tank from end to end before being raised on a chain loop and returning along the top of the tank as a skimmer. Rotary skimmers sometimes used jets of water rather than physical blades to collect fats from the surface. The collectors could operate continuously or could be used once or twice a day for around half an hour at a time. The collection sumps were pumped at least daily, and pumping continued until sewage started to flow through the outlet pipe.
Intermittent Sand Filters and Contact Beds
Neither intermittent sand filters nor contact beds ever found wide use in California, though both were important transition technologies in introducing biological treatment methods. Intermittent sand filtration offered a refinement on sewage farming in which the wastewater flowed onto specially prepared beds of sand, gravel, or other porous materials.
The practice was first developed in England in the late 1860s and was further studied at the Lawrence Experiment Station in 1886-87. The sand filter treatment area was commonly divided into three or more beds so that sewage distribution could be rotated between fields. This allowed beds to dry out and reabsorb oxygen between uses. Compared to sewage farming, intermittent filters could support ten times the population on the same amount of land, but required more intensive management. Workers needed to carefully grade and rake the beds to ensure even distribution. Organic waste that dried onto the surface of the soil needed to be scraped and removed periodically. In some cases, it was necessary to install drainage tiles beneath the bed surface. The tiles of hard-baked clay admitted water at their joints and removed excess moisture. Intermittent filtration was used extensively on the East Coast and particularly in New England where natural sand beds were abundant, but it was not widely adopted elsewhere in the United States and examples in California are limited. Redlands in San Bernardino County began disposing of raw sewage on natural sand filter beds in 1890, and Monrovia, Manteca, Kingsburg, and Ojai all later disposed of septic, Imhoff tank, or trickling filter effluent on sand beds.
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Coalinga Sanitary Sewer Collection System and WWTP Improvements Project 77 The contact bed, developed by William Didbin in early-1890s London, involved a water-tight basin, four to eight feet deep, that was filled with particles ranging in size from a pea to a walnut.
The maximum basin size was around one-half acre as anything larger required too much time to fill. On the bottom of the basin, a network of drains led to an outlet pipe. Experiments were made with a wide variety of filter materials including coal, slag, cinder, gravel, burnt clay, glass, and broken bricks. Roughness, porosity, and small size were desired to increase the surface area to volume, though material that was too small led to clogging. The beds operated on cycles, allowing, for example, an hour for filling, two hours of standing full, an hour to drain, and four hours to stand empty. A degree of sedimentation occurred during the period of slow filling, followed by a degree of anerobic decomposition while the pool was full. The majority of the digestion occurred aerobically on the wet surfaces of the filter materials while the tank stood empty. Aerobic digestion could be increased by operating basins in pairs and passing the effluent from the first-contact filter into a second-contract filter. An experimental plant in Marion, Ohio, achieved a high level of treatment by having sewage receive primary treatment in septic tanks prior to flowing in sequence into two contract beds followed by a final cleaning in a sand filter. Gillespie recorded a total of four contact beds constructed across California, with the first being a 1910 plant in Roseville, followed by Dixon in 1911. Only one contact bed remained in use by 1930.
Trickling Filter
The trickling filter, also known as “trickle filter,” “sprinkling filter,” or “biofilter,” was the most common secondary treatment method employed in California prior to World War II. The method differed from a contact bed in that there was no period where the basin filled with sewage and engaged in anaerobic digestion. Tests at the Lawrence Experiment Station demonstrated that better results were obtained by maintaining a consistent environment that favored aerobic microbes.
Early efforts were made at distributing sewage over a contact bed at a slow, trickling pace by use of troughs, but uniform and consistent distribution could not be obtained. Joseph Corbett of Salford, England, first made use of spray jets to create a true trickling filter in 1893. Madison, Wisconsin, constructed the first such filter in the United States for institutional use in 1901, and Redding, Pennsylvania, completed the first municipal plant in 1908. California’s Bureau of Sanitary Engineering designed the first trickling filter in the state in Reedley in 1915.
Early trickling filters were built in much the same fashion as a contact bed. Concrete basins were constructed with depths between six and ten feet and filled with rough, hard, and angular particles, between 1.5 and 3 inches in size, over a drainage system. Multiple units were generally constructed in series to provide flexibility in operation.
The exterior dimensions of the tanks varied with local circumstances and needs. The tanks could be recessed in the ground or built up, as at the plant in Lemoore. The practice at early plants was to provide rest periods between applications of sewage. This required large surface areas as parts of the plant were regularly taken out of use. Later studies showed that the trickling filters could be used continuously around the clock, which allowed for higher rates of throughput and consequently smaller basins. Much of the innovation of design in trickling plants involved the nozzles and the quest to provide even spray coverage. Revolving distributors on circular tanks eventually replaced stationary nozzles in most plants. The distributors could be motorized to revolve or be propelled by the force of the spray emitted from the nozzles.
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Trickling filters generally operated in conjunction with automatic dosing tanks to ensure an even spray distribution over the bed. The tanks filled with influent and automatically discharged through a siphon when full. Small air-lock piping (not depicted in the figure) opened and closed the siphon at set levels. The sides of the tanks were angled to cause the head to decline at a rate calculated for even spray distribution. Dosing tanks were usually paired so that one tank was filling while the other was discharging.
Activated Sludge Process
San Marcos, Texas, constructed the first American activated sludge plant shortly after the technology debuted in 1914. The first plant in California followed three years later when the Pasadena Tri-City facility completed an experimental pilot project in January 1917.
Partitions divided the 9-by-20-foot aerating tank (also called an aeration tank) to produce 60 feet of channel for sewage to flow through, while blowers at the bottom of the tank mixed and aerated the liquid. Experiments showed promising bacterial reduction rates between 96 and 99.6 percent.
The Bureau of Sanitary Engineering constructed the first full-scale treatment plant at Folsom Prison later in 1917. As the bureau lacked experience with activated sludge treatment, they hired Ralph Hilscher away from the Illinois Water Survey. The prison plant answered the long-standing concern of the Bureau of Public Health with having minimally processed sewage dumped into the American River upstream from the state capitol. Municipal plants followed in Turlock (1921), Lodi (1923), Pasadena (1924—expansion of the pilot project), Los Angeles County Sanitation Districts (1928), and the City of Los Angeles (1930).
The activated sludge process was innovative in its biochemical approach but relatively simple in the required physical infrastructure. Sewage first passed through a primary clarifier or fine screen to remove the largest suspended solids before arriving in a concrete aeration tank. Activated sludge equal to about 20 percent of the sewage volume was added to the partially clarified sewage. Air blowers or (less commonly) mechanical agitators then mixed and aerated the sewage over a retention period of several hours. The concrete aeration tanks came in various shapes and sizes but usually included multiple chambers that could operate in series or independently. An air blower was located near the tanks, sometimes contained within a separate blower house. Perforated pipes or diffuser plates along the sides or bottoms of the chambers maintained a continual flow of air that generated a rotational motion in the liquid sewage.
When these were used in rectangular tanks, the longitudinal flow of the sewage through the tank combined with the rotational motion to produce a spiral flow pattern that mixed the sewage and prevented sludge from accumulating on the tank bottoms. After the prescribed period of aeration, sewage flowed to a secondary clarifier to remove the large volume of sludge generated in the process. A portion of the activated sludge was then returned to the aeration tank to seed the next batch of influent while the remainder was sent to a sludge digestion tank or drying bed for further treatment and disposal.
Sludge Treatment and Disposal
Early sewage management practices focused principally on the liquid effluent that was discharged at the end of treatment and gave comparatively little attention to the sludge that accumulated at the bottom of sedimentation tanks. The goal at most plants was simply to dispose of sludge as quickly
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Coalinga Sanitary Sewer Collection System and WWTP Improvements Project 79 and cheaply as possible, generally by burying it on land or dumping it at sea. Plants could manage this so long as the volume of sludge remained low. However, as operators gained efficiency in removing a larger share of suspended organic solids from liquid sewage, they invariably produced more sludge. The activated sludge process in particular produced very large quantities of waste that required treatment and disposal. Sanitary engineers thus turned towards developing more effective methods of digesting and drying sludge.
Sludge emerged from a sedimentation, Imhoff, or septic tank as a semiliquid slurry with a moisture content of around 95 percent and a strong, offensive odor. Basic treatment required dewatering the sludge to reduce the moisture content to 70 percent or lower, at which point it could be handled as a solid. Plants could then dispose of it through incineration, burial, dumping at sea, or by marketing it as fertilizer. Sludge drying beds, also called sand beds, were the essential tool for dewatering sludge and they remained common at smaller plants. Drying beds have the advantage of low capital costs and require little skill to operate, but need a large amount of land and are labor intensive to empty. In a conventional sand bed, a layer of sand approximately 12 to 24 inches thick lay over a bed of course gravel 6 to 8 inches deep that was drained from below by tile pipes. The walls of the bed could be of earth, wood, or concrete. The area of the bed would depend upon the population served, the characteristics of the sludge, and the local climate. In more recent practice, the beds are divided into multiple cells. Sludge was spread over the sand bed in a layer 8 to 12 inches thick to dry by drainage from below and evaporation from above. The organic matter continued to putrefy during this process and gave off strong odors, so a remote location was required.
Greenhouse covers were sometimes installed over the beds to increase heat, keep out rain, and contain the odors. Drying times depended upon the weather. During cold, damp winters, sludge could take months to dry, while two weeks might suffice during summer. Workers could remove the sludge as soon as it was dry enough to be handled by a rake or fork. Sludge drying beds could also be paved with cement. Paved beds required more area than conventional sand beds, but involved lower maintenance costs and allowed for heavy equipment to be used in mixing the sludge for drying and for removing the dried cake.
Mechanical devices aided dewatering, though some time on a drying bed was still generally required. These devices consist of three basic types: presses, centrifuges, and vacuum filters. A sludge press consisted of metal plates that could be hand-tightened by screws or compressed by machine to force water out of sludge. Centrifuges placed wet sludge within a metal tub lined with porous cloth and then spun the tub at high rotation to force the liquid through the cloth. Centrifuges also made use of hollow drums lined with porous cloth but used vacuum pressure to pull liquid from the sludge.
Various chemicals including sulfuric acid, sulfur dioxide, alum, peat, lime, and bone ash could be added to the sludge prior to treatment to aid in drying. With all the processes, the removed liquid was returned to the plant influent for further treatment while the sludge went to the sand beds or drying basin. Manufacturing fertilizer required an exceptionally dry sludge and gas-powered heat dryers helped to reduce the moisture below 10 percent.
Sludge digestion tanks allowed for a more thorough processing of the sludge. Anaerobic bacteria reduced the volume of sludge by liquifying organic matter and producing methane gas. Digestion shrank the sludge layer at the bottom of the tank to about a third of its original volume, while the
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liquid that bubbled to the top—referred to as “supernatant liquor”—accounted for most of the remaining two-thirds. The supernatant liquor overflowed the tank as new sludge entered and was piped back to the primary sedimentation tank for further treatment. In some cases, it was necessary to pretreat the liquor by running it through a sand bed filter or adding aluminum sulfate or other chemicals. The byproduct gasses of anerobic digestion, being between 60 and 80 percent methane, collected in a dome at the top of the tank. Plants commonly used the gas as fuel to heat the digestion tanks or to operate gas powered engines.
Early sludge digestion tanks took a variety of forms, including rectangular or square, though circular tanks later became the norm. Tanks were usually covered to minimize odors and allow for greater control. Floating covers helped to maintain a constant, uniform gas pressure and became increasingly common.
Heating and stirring the sludge aided digestion. Heating coils wrapped around the interior walls of the tank and were fed by water heated through the burning of the captured methane gas. Partially or fully burying the tanks helped to maintain uniform temperatures. Because heating increased the speed of digestion, smaller tanks could be used while still maintaining the same volume of processing. In cold climates, heating could reduce the tank size by around half, but gains were less significant in mild winter environments as prevailed through Southern California. A variety of mechanical stirring devices kept the sludge in circulation and ensured even heating and digestion.
A two-stage digester divided the process between primary and secondary tanks. The primary tank handled approximately three-quarters of the digestion and most of the gas production before passing the partially digested sludge through a pipe to the secondary tank. Secondary tanks were larger than the primary tanks but were generally unheated. This allowed for a slow but economical digestion that produced a cleaner final product with lower disposal costs.2
3. The Era of Advanced Treatment, 1950 – c.1980
Regulatory policy evolved rapidly in postwar America, catching up with the technological advances made in the first half of the century. The emergence of environmentalism as a political force compelled higher standards of water and sewage treatment that were codified in state and federal law. By the end of the era, secondary treatment was required for nearly all municipal wastewater discharges and most plants met this standard by using technologies that had been created in the early twentieth century. New environmental and health threats posed by synthetic nutrients and industrial toxins led to advanced wastewater treatment methods that processed effluent to near potable standards. These new processes largely built upon existing biological treatment methods, adding new bacterial populations or coagulating chemicals, rather than representing a fundamental break from established methods.
Knowledge
Environmentalism
Environmental concerns largely supplanted public health as the principal driver of sanitation policy in postwar America. Environmentalism emerged as a major force in popular culture in the early 1960s as it gave form to shifting attitudes about the economic, recreational, scientific,
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Coalinga Sanitary Sewer Collection System and WWTP Improvements Project 81 aesthetic, and spiritual values of nature. It coalesced as a mass political movement in the 1970s and found expression in a series of state and federal acts that provided the basis for modern natural resource policy. For the managers of public drinking water and wastewater systems, this required meeting more exacting standards of chemical and biological purity and led to a greater degree of uniformity across systems. Still, the American public and policy makers continued to trust science and technology to overcome the problems of pollution, and the focus was on improving existing treatment methods to meet rising demands, rather than challenging deeply held ideals of economic growth and material progress.
Environmental policy, as it related to water treatment systems, reflected changing understandings of health risks and new insights from the study of ecology. The advances of the early twentieth century had largely eliminated waterborne disease as an issue for public water systems. Focus thus shifted from biological contaminants to chemical toxins. Canneries, refineries, foundries, and chemical manufacturers had long dumped their waste products into coastal waters and interior rivers, but the scope and scale of industry expanded dramatically leading up to and during America’s entry into World War II in 1941. Aircraft plants in Southern California and shipyards around the San Francisco Bay introduced novel chemicals into the water supply with little monitoring or regulation, owing to the emergency nature of wartime production. The thick, acidic smog that filled the Los Angeles basin in the late war years was the most visible sign of increasing pollution, but the problem was also evident in tests of surface and groundwater quality. The eutrophication (excessive growth of aquatic plants) of inland waterways, caused by an excess of synthetic plant nutrients, produced striking evidence of environmental harm in the form of reoccurring toxic algae blooms and fish kills.
Cancer became the defining illness in the new era, replacing typhoid fever as the primary waterquality health concern among the public. By the late 1970s, it was estimated that one in four Americans would contract cancer during their lifetimes and two-thirds of those would die from it.
Studies showing cancer rates to be twice as high in cities as in rural districts pointed to the polluted environment as a chief cause. For decades, federal and state authorities were unable to gather even basic data about the chemicals being released into waterways. Industrial interests strenuously resisted disclosing information about their chemical use for fear that it would reveal trade secrets and make them liable for cleanup efforts. Only with the passage of the Clean Water Act in 1972 did the federal government gain legal power to require reporting by industrial dischargers. Court action by the Natural Resources Defense Council later compelled the Environmental Protection Agency (EPA) to begin actively regulating toxic pollutants, and amendments to the Clean Water Act in 1977 established a list of toxins that were subject to strict control on a set timeline.
The science of ecology, which matured during the postwar era, allowed for an intellectual understanding of the threat through its study of natural cycles and complex biological and chemical webs. The 1962 publication of Rachael Carson’s Silent Spring on the danger of synthetic pesticides crystalized these concerns and alerted the public to the ability of persistent toxics to accumulate through the food chain. Support for environmental protection cut across partisan and demographic lines, but was strongest among the young, well-educated residents of New England and the Pacific Coast states. California, with its booming population and unrivaled natural riches, emerged as an obvious leader of the movement. The state pioneered environmental legislation including creating air pollution control districts in Los Angeles (1947) and the San Francisco Bay counties (1955);
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passing the nation’s first automobile anti-smog law (1960); organizing regional planning bodies such as the San Francisco Bay Conservation and Development Commission (1965) and Coastal Zone Conservation Commission (1972); and enacting both the California Endanger Species Act and California Environmental Quality Act in 1970. The key water quality acts, the Dickey Water Pollution Act (1949) and Porter-Cologne Water Quality Control Act (1969), are discussed further below. Federal legislation often coincided with or followed the lead of California, including the Clean Air Act (1963), National Environmental Policy Act (1969), Clean Water Act (1972), and the Endangered Species Act (1973).
Sanitary engineers struggled at times to keep up with the shifting focus. In the 1920s and 1930s, engineers had generally been ahead of the public in advocating for high standards of purity in the state’s waterways. By the 1960s, however, the situation had reversed. The public treated almost all forms and quantities of pollution as illegitimate while engineers worried over the economic cost of rigid standards. Wilfred Langelier, the UC Berkeley chemist, expressed what he felt was a common belief among scientists that the public could not appreciate “the exorbitant cost” involved in attempting to remove “the last few degrees of pollution.”269Advanced wastewater treatment methods (discussed below) were effective at removing heavy metals, excess nutrients, pathogens, and other potential toxins, but came with high chemical, energy, and construction costs. Langelier and others of his generation regarded environmentalists as lacking in the cleareyed pragmatism needed to confront the problems.
Some younger sanitary engineers, however, found a new center of identity for the discipline in environmentalism. They critiqued the energy- and chemical-intensive methods required for conventional wastewater treatment and advocated for processes more integrated with ecological cycles. They developed an assortment of treatment systems using aquatic plants, natural or constructed wetlands, and various types of lagoons. The Arcata Marsh and Wildlife Sanctuary in Humboldt County is exemplary of this new approach. The City of Arcata and Humboldt State University began experimenting with wastewater aquaculture in 1969 and determined that juvenile salmon and trout could develop in mixtures of partially treated wastewater and seawater, demonstrating that wastewater could enhance wildlife habitat rather than presenting merely a problem of disposal. Between 1979 and 1983, the city and associated partners developed a test program for using constructed wetlands to treat wastewater in a cost-effective and environmentally sound manner. By 1986, the city had completed 100 acres of freshwater and salt marshes, brackish ponds, tidal sloughs, and estuaries that received treated effluent from the adjacent existing wastewater treatment plant. The marshes further clarified the effluent while providing habitat for fish and wildlife. The wildlife sanctuary is now recognized as one of the premiere locations for seeing migratory birds along the Pacific Coast, and the innovative system has become an international model for ecologically responsible wastewater reuse.
Advanced Wastewater Treatment
Advanced wastewater treatments target nutrients and contaminants that conventional primary and secondary treatments cannot fully remove. These treatments aim at two principal goals: preventing eutrophication in inland waters through the removal of nitrogen and phosphorous, and allowing for the reclamation of wastewater effluent by cleansing it of heavy metals, organic chemicals, inorganic salts, and pathogens. Advanced treatments differ in their specifics from conventional
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Coalinga Sanitary Sewer Collection System and WWTP Improvements Project 83 treatment but largely employ familiar processes of chemical coagulation, biological digestion, and mechanical filtration. While advanced treatment methods are sometimes identified as “tertiary treatments,” the two terms are not strictly synonymous. Advanced treatments may follow secondary biological treatment in a plant’s flow, but they may also consist of a modification or replacement of an existing conventional treatment step so that they operate concurrently with primary or secondary treatment. Research into advanced treatment methods began in the early 1960s and pilot plants were in operation by mid-decade in the most environmentally sensitive locations such as Lake Tahoe. The tightening of state and federal environmental standards, combined with improved technology and knowledge, spurred wider construction of full-scale plants in the late 1970s and 1980s.
Nutrient Removal
Nitrogen and phosphorous are the primary culprits in human-caused eutrophication. Under natural conditions, algae populations are limited by the available supply of nitrogen and/or phosphorous, both of which are essential for plant growth. When human activities cause an increase in lake, river, or estuary nutrient levels, aquatic plant growth accelerates and the resulting algal blooms can interfere with water uses, in addition to being potentially toxic. Under severe conditions, the bacterial decomposition of algae depletes water of its oxygen supply, leading to fish kills and “dead zones” within water bodies. Eutrophication in the Great Lakes in the 1960s attracted national attention and was a major factor in the passage of the Clean Water Act.
Manufactured fertilizers and synthetic laundry detergents were the chief source of excess nitrogen and phosphorous, respectively, and the production of both increased dramatically in the postwar decades. The United States government invested heavily in nitrogen production during World War II, building large nitrogen-synthesizing factories to manufacture high explosives for munitions; at war’s end, these plants shifted to producing fertilizer. The first all-purpose synthetic laundry detergent appeared near the same time, in 1948, and by 1953 the sale of synthetic detergents surpassed those of traditional soaps. The American public made enthusiastic use of these cheap and effective marvels of modern chemistry, but the excess nutrients readily found their way into streams and groundwater basins.
Conventional wastewater treatment removed only a portion of the dissolved nitrogen and phosphorous that entered a plant. Most of the forms taken by phosphorous are soluble and therefore plain sedimentation did not act upon them. In biological treatments, microorganisms absorbed some 20 to 30 percent of the phosphorous in support of their growth, but the remainder passed through to the effluent. Likewise, only about 25 percent of nitrogen was removable by sedimentation or biological uptake. These substances also caused problems within the treatment plants as operators blamed detergents for causing foaming within activated sludge basins and hindering sedimentation by emulsifying solid particles.
Engineers developed chemical methods for removing phosphorous and nitrogen from wastewater in the 1960s. Phosphorous removal was by chemical precipitation using metal salts or lime as a coagulant. Pickle liquor, a waste product of the steel industry, provided an inexpensive source of iron salt in industrial regions and was the most commonly used coagulant. The salts could be added at any stage of the treatment process. Some plants mixed it with raw influent before primary clarification, others added it to their activated sludge tanks as part of secondary treatment, and still
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others mixed it with the secondary effluent for a tertiary stage of treatment prior to final clarification. Lime was used in either primary or tertiary treatment. When used as tertiary treatment, the chemicals required mixing and sedimentation basins and the effluent was commonly filtered before discharge.
Nitrogen exists in a variety of forms including as ammonia, nitrate, nitrite, gaseous nitrogen, and bound to organic matter as in ammino acids and DNA. In wastewater, its principal forms were organic from fecal matter and kitchen or agricultural waste and as ammonia from urine. Biological decomposition as part of secondary treatment converted most of the organic nitrogen to ammonia.
Ammonia could then be air stripped from wastewater if the pH was first raised to around 11 (extremely alkaline) with a heavy addition of lime. The water was pumped into a stripping tower where it dripped downward while forced air blew around it. This converted liquid ammonia to a gas and released it to the atmosphere, reducing effluent ammonia levels by 90 to 95 percent. This process was fairly simple but involved additional pumping expenses and functioned poorly at low temperatures. Heavy chlorination (called breakpoint chlorination) could also reduce ammonia by converting it to nitrogen gas, nitrous oxide, and other forms. However, the process raised the total level of dissolved solids in the effluent and could leave excessive levels of chlorine, both of which required additional treatment steps before effluent discharge. An ion exchange process, similar to that used in water softening, also existed for nitrogen removal, though it remained a poorly understood and experimental technology.
Chemical treatments were successful and generally uncomplicated to manage, but they were also expensive as they needed continual large chemical inputs and produced copious volumes of sludge that required disposal. In the 1970s, James Barnard, a South African engineer, sought biological methods of nitrogen and phosphorus removal that would be better adapted to the requirements of his country. This required manipulating environmental conditions in biological treatment tanks to encourage the growth of microorganisms that could feed upon the nutrients. Biological treatment had developed with a narrow goal of reducing organic matter, but once the plants were in place, they provided the means for addressing other pollutant problems. Retaining and returning a greater volume of activated sludge to the aeration tanks allowed for slower-growing bacteria to develop.
This exposed pollutants to a larger variety of organisms with unique biochemical strategies for converting organic and inorganic matter into the energy and materials needed to sustain life and reproduce.
The digestion of nitrogen involved a two-part nitrification-denitrification process in which bacteria first oxidized ammonia to nitrate and then different groups of bacteria biologically reduced the nitrates to nitrogen gas. Nitrification occurred in presence of oxygen, while denitrification required anoxic conditions with very low oxygen levels. Phosphorous removal relied on microorganisms that stored phosphorous in excess of what they required for biological growth (known as phosphorous-accumulating organisms or PAOs). PAOs also had a two-phased growth cycle that required alternating anoxic and aerobic conditions. Generating the two-phase aerobic and anoxic environments required either modifying existing activated sludge aeration tanks to wall-off an anoxic chamber or constructing new anoxic tanks following the aeration chambers.
By 1974, Barnard had established pilot projects capable of removing nitrogen and phosphorous separately. After several additional years of experimentation, he found means of combining the
2. Environmental and Cultural Background
Coalinga Sanitary Sewer Collection System and WWTP Improvements Project 85 processes, allowing for the simultaneous removal of both nutrients through biological means. This process became known as Biological Nutrient Removal or BNR. Florida constructed the first combined phosphorous-nitrogen BNR plant in the nation in 1979. A half-dozen BNR plants operated across the county by the mid-1980s, testing and refining the processes. Ultimately, BNR proved to be less expensive to operate than chemical methods and was capable of purifying effluent to a higher standard. However, these biological methods required much more monitoring and adjusting of environmental conditions, necessitating a high level of technical skill among operational staff. The combination of chemical and biological methods was often the most cost effective, particularly where it allowed for existing equipment to be modified without requiring new construction. By 1994, some 300 BNR plants were in operation, including 16 in California.
Lake Tahoe, on the California-Nevada border, was one of the first bodies of water in the nation to benefit from advanced nutrient control. The clear blue waters of Lake Tahoe were a major tourist draw for the region and warranted a high level of protection. The Bureau of Sanitary Engineering had prohibited all direct sewage disposal to the lake since the 1920s, but effluent continued to be disposed of by spray irrigation to land within the Tahoe Basin and runoff from these sites contributed to eutrophication. In 1961, the South Tahoe Public Utility District began laboratory and pilot plant studies in Oregon to test the effectiveness of chemical coagulation, filtration, and carbon absorption on nutrients. The district constructed a small-scale plant in the Lake Tahoe Basin in 1965 and expanded it over the following years. The plant design mixed secondary effluent from activated sludge tanks with a lime coagulant and then passed it through filter beds and columns of activated carbon. The district added a nitrogen stripping tower in 1969. The plant served as a national testing ground for innovative technologies, both for the direct treatment process and for such secondary tasks as coagulant recovery and carbon regeneration. The recovery of lime saved little on chemical costs, but reduced the volume of sludge requiring incineration by about half.
Additional facilities added throughout the Tahoe Basin in later years included a 1974 biologicalchemical phosphorous removal plant to treat the waste returned from sludge digestion at the Truckee Meadows plant; tertiary chemical phosphorous removal and ion exchange ammonia removal facilities at Tahoe-Truckee in 1976; and a denitrifying trickling filter at Truckee Meadows in 1985. Cold winter conditions required that many of these processes be contained in covered tanks or sheltered in buildings. Biological processes later replaced most of the original chemical ones as technology continued to evolve.
Wastewater Reclamation
Californians have made planned reuse of municipal wastewater since at least 1888, when Pasadena established the first municipal sewage farm in the state. The State Board of Health crafted regulations governing the agricultural reuse of wastewater in 1918, and ultimately more than 100 cities or institutions disposed of their wastewater effluent to agricultural users at some point prior to World War II. For the most part, however, these users valued sewage farms as a convenient means of disposing of wastewater and treated the reuse of water as only a secondary, almost incidental benefit. San Francisco’s Golden Gate Park activated-sludge treatment plant, completed in 1932, was the first facility in the state specifically created to provide a source of recycled water.
The purified effluent irrigated the park landscaping, filled scenic ponds, and cascaded down manufactured waterfalls. In 1961, the Santee County Water District outside of San Diego used treated effluent to fill a series of artificial lakes that provided public access for boating, fishing,
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and swimming, making it the first planned use of reclaimed water for recreational purposes. The Santee Lakes did not include tertiary treatment methods, which were not yet economically viable, but instead discharged the activated-sludge treatment plant effluent into a spreading basin a mile from the lakes. The effluent combined with subsurface creek flow and percolated horizontally through the gravel bed to fill the lakes. Extensive testing demonstrated that the water was safe for bodily contact, but the facility struggled with high nutrient levels that caused algae blooms and necessitated expensive deodorizing and disinfecting agents. The introduction of viable tertiary treatment methods in the 1970s increased the diversity of uses for reclaimed water in California to include industrial applications, groundwater recharge, landscape and golf course irrigation, and environmental enhancement.
The term “recycled water” refers to wastewater that has been treated to a quality suitable for beneficial use in either potable (groundwater recharge) or nonpotable (irrigation, industrial) applications. In common practice, recycled water referred chiefly to purified wastewater originating from a municipal treatment plant, while “water reuse” applied to the repeated cycling of graywater at a single facility such as an industrial plant or golf course. Historically, the term did not specify a particular level or type of treatment, nor did it apply to highly treated water that discharged to natural waterbodies. All the processes used in nutrient removal were also employed in treating recycled water (and to a lesser degree vice-versa), so the two differed primarily in the handling of the final effluent by either discharge or reuse. However, because some applications of water reuse involved great probability of human contact, higher standards applied for the removal of organic matter, inorganic salts, heavy metals, and viruses. While recycled water could achieve high levels of purity, public perception remained an obstacle to greater use of the resource. Though some 300,000 visitors made annual use of Santee Lakes, the facility was still jokingly derided as “piss lake.” Only one comparable recreational project in Lancaster opened during the historic period and no domestic use was made of recycled water despite it exceeding drinking water standards.
The wastewater recycling process started with conventional treatment in an activated-sludge tank, perhaps with iron-salt coagulant enhancement for nutrient removal. Coagulation with lime commonly followed, using tertiary mixing and sedimentation basins. The lime precipitated heavy metals, suspended and dissolved organics, and phosphates, while the alkaline conditions at a pH above 11 killed bacteria and viruses. The alkaline solution could then be sent to a stripping tower for removal of ammonia and volatile organics. In cold climates, ionic exchange might substitute for air stripping. Recarbonization by injection of carbon dioxide returned pH levels to near neutral (7) to prevent the buildup of calcium carbonate scale in subsequent equipment and to recover some portion of the lime. Filtration beds or pressured tanks with activated carbon then removed fine matter and any remaining coagulant. Disinfection by chlorination, ozone, or ultraviolet (UV) exposure followed. Finally, reverse osmosis, a technology first developed for drinking water desalinization, removed inorganic salts, trace metals, and dissolved organics.
The Central Contra Costa Sanitary District, in conjunction with the Contra Costa County Water District, constructed one of the first modern wastewater recycling plants in the early 1970s in order to supply nearby industrial users along the southern shore of Suisun Bay. The sanitary district constructed a full-scale test facility at its existing wastewater treatment plant in Martinez in 1971.
The facility used preliminary lime treatment ahead of an activated sludge tank enhanced for
2. Environmental and Cultural Background
Coalinga Sanitary Sewer Collection System and WWTP Improvements Project 87 nitrification, followed by ammonia stripping. On a larger scale, Orange County Water District completed its Water Factory 21 in 1975. The plant, named for the belief that it would serve as a prototype for meeting twenty-first-century water needs, treated wastewater with chemical coagulation, air stripping, filtration, and reverse osmosis. The effluent was blended with deep well water and then injected into the groundwater basin through a series of wells to replenish local groundwater basins and buffer against saltwater intrusion.
Advanced Drinking Water Treatment
Drinking water treatment prior to World War II focused on the major public health impacts caused by pathogenic microorganisms. The heightened environmental consciousness of the 1960s and 1970s shifted attention to other pollutants, including synthetic organic compounds and such inorganic contaminants as arsenic, chromium, fluoride, lead, mercury, nitrates, and silver. These substances entered the water supply either as naturally occurring minerals or as industrial and agricultural waste byproducts. No single treatment method was effective for the removal of all contaminants, so different processes were developed to target particular problems. As relatively little was known about the effectiveness of removal technologies, the EPA conducted pioneering research at its Robert A. Taft Sanitary Engineering Center in Cincinnati, Ohio. The basic philosophy of treatment was to employ conventional techniques such as coagulation and lime-andsoda-ash softening first and to use more advanced techniques only as needed. These new technologies, discussed below, included ion exchange, reverse osmosis, the use of activated carbon, and disinfection by ultraviolet (UV) radiation. Electrodialysis and distillation were also experimented with, but these methods were expensive and were employed only in special cases, such as for industrial processes that required high levels of water purity. All these technologies were also used in wastewater treatment, with some minor modifications of procedures.
Ion Exchange
Ion exchange had been a common feature of water treatment since the early twentieth century when it was introduced for water softening. Subsequent developments expanded the range of materials that ion exchange could strip from the water beyond just the hardwater minerals of calcium and magnesium to include nitrate, tannin, fluoride, barium, arsenic, and uranium. The earliest progress was made by altering the chemical and physical properties of greensand, the rock used in water softening, to increase its effectiveness. Later work experimented with other natural materials that had intrinsic qualities favorable to ion exchange, as for example with bone char's ability to absorb fluoride. USPHS constructed a full-scale deflouridation plant in Britton, South Dakota, in 1953 that utilized ground and charred animal bone for ion exchange with a caustic soda used for regeneration. However, natural materials had limits that were difficult to overcome.
Because bone is soluble in acid, the South Dakota plant had to carefully regulate the pH levels of the raw water. This added expense that made the plant cost inefficient and it closed in 1971.
The introduction of synthetic resins allowed for far greater control over the ion exchange process.
English chemists manufactured the first synthetic resins in 1935. While greenstone worked only with positively-charged cations such as calcium, magnesium, and barium, the new synthetic material could be modified to attract negatively-charged anions such as nitrate, arsenic, and uranium. Extensive research conducted after World War II led to the discovery of organic polymers that produced a resin of superior strength and stability with less pH sensitivity. Having greater control over the molecular structure of the resin allowed for assembling materials with
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large surface-area-to-volume ratios, and the typical resins resembled beads with a porous whiffle ball structure. This permitted processing far greater quantities of water using the same sized tanks, and the tougher materials could withstand stronger salt brines so that regeneration occurred in a matter of minutes rather than hours. Customizable resins also allowed for engineering the ion exchange process to optimally target particular contaminants. By the late-1970s, dozens of different synthetic resins were commercially available to deal with a wide range of mineral removal needs.
Municipalities began to construct full-scale facilities using the new ion exchange processes in the mid-1970s. A 1974 plant constructed by the Garden City Park Water District on New York’s Long Island was indicative of these facilities. The plant design was based on a prototype facility operated by Oak Ridge National Laboratory in Tennessee beginning in 1970. Its innovative features included a process for continuous resin regeneration. A hydraulic pulse flow pushed the resin material through a closed loop that included treatment, regeneration, and rinse phases. Each phase lasted around 15 minutes, followed by a hydraulic pulse of a few seconds duration. The sodium chloride regeneration thus operated continuously, recharging a portion of the resin at a time, rather than requiring the ion exchange to halt while the full load of resin was recharged as in conventional batch operations. The continuous regeneration process became standard in desalination plants and was later expanded to other ion-exchange facilities.
The vessels used in the new ion exchange systems did not differ substantially from their watersoftening predecessors. The tanks continued to resemble pressure filters with components to regulate the in- and out-flow of treatment water, regeneration solution, and backwash water, along with sampling taps. As with most treatment equipment, the tanks commonly were paired to allow processing to continue while one tank was regenerated. Two nearby holding tanks, constructed with special lining to resist corrosion, contained the fresh and used regeneration solution. As the ion exchange process became increasingly specialized, plants sometimes added multiple pairs of tanks in serial, with each pair focused on removal of a particular contaminant.
Reverse Osmosis
Osmosis is the process by which a solvent liquid naturally moves from an area of low dissolved mineral concentration, through a membrane, to an area of high concentration until an equilibrium is reached with both sides having equal solvent to dissolved mineral ratios. In reverse osmosis, pressure is applied to the high concentration side of the membrane so that the flow of solvent is reversed. The semipermeable membrane was engineered to selectively allow water molecules to pass through but not larger mineral or biological molecules. This process could extract pure water from high-concentration inputs, such as salt water, or treat raw water to remove microbiological pathogens and essentially all dissolved organic or mineral contaminants. Reverse osmosis differed from ordinary water filtration in that it processed solutions at a molecular level and could remove dissolved chemicals, while filters could only screen suspended, not dissolved, matter. Filters also trapped the removed particles and thus required regular backwashing. Membranes acted as a barrier but did not physically capture the impurities, so they remained cleaner and required less maintenance. A chief disadvantage of reverse osmosis technology was its high energy inputs. The pressure required to purify water, using 1970s technology, was usually several orders of magnitude greater than the natural osmotic pressure, and ranged from 200 to 1,500 psi.
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Coalinga Sanitary Sewer Collection System and WWTP Improvements Project 89 Efforts to desalinate seawater drove innovation in reverse osmosis technology. Researchers at the University of California, Los Angeles (UCLA) and the University of Florida created the first workable membranes in the 1950s, though the practice remained impractical until improved membranes became available in the mid-1960s (see discussion of desalination below). Researchers recognized the potential for reverse osmosis to be of use in purifying drinking water, but technical challenges and energy costs prevented it from being widely adopted by public utility companies during the historic period. Instead, industrial manufactures were the leading adopters as they required high-purity water for making pharmaceuticals, semiconductors, and consumer food and beverage products.
A typical reverse osmosis treatment unit consisted of a high-pressure pump connected to a rack of filter cartridges (Figure 61). The cartridges commonly contained two flat sheets of membrane material separated by porous sheets through which the feed water and treated water flowed. The sheets were laid flat then spiral wound within the cartridges like rolls of giftwrap. Most units were automated to regulate flow rates and pump pressure.
Activated Carbon
Carbon’s ability to purify water of foul tastes and odors has long been recognized. For centuries, sailors charred the inside of their wooden water barrels to keep the water fresh. However, only in the twentieth century did activated carbon begin to be produced on an industrial scale. Carbon could be made from a variety of substances including wood, nutshells, peat, and petroleum products. Much of the activated carbon used in water treatment was manufactured from coal that was converted to carbon by heating it in the absence of oxygen to prevent burning. The material was then exposed to steam at high temperatures, fracturing the carbon and forming many interconnected pores of various sizes. This gave the activated carbon a very large surface area, so that one pound of activated carbon could have a total surface area of more than 150 acres. Organic compounds of various sizes would adhere to the surfaces and thus be filtered from the water.
Activated carbon came in two commercially available forms, powdered or granular, determined by the particle size. Powdered activated carbon (PAC) was the first form to be used for water treatment beginning in the late 1920s. Plants mixed the dry powder or a prepared slurry into raw water prior to the normal coagulation and sedimentation step. With adequate contact time, the carbon absorbed the organic compounds that caused undesired tastes, odors, and colors.
Sedimentation or filtration removed the PAC to prevent it entering the distribution system. The carbon could not be easily recovered, as it mixed with sedimentation sludge, so it was disposed of as a waste product. By 1943, about 1,200 American treatment plants made at least occasional use of PAC for odor and taste control.
The advantage of granular activated carbon (GAC) was that it could be reused, allowing for continual removal of organics. GAC was first mass produced during World War I for use in gas masks, and further manufacturing improvements were realized during the 1940s. A Hopewell, Virginia plant installed the first major GAC filter for odor and taste control in 1961. Where the total organic load of the water source was not exceptionally high, GAC was simply added to an existing rapid sand filter. A layer of GAC, approximately two feet deep, was either laid on top of the filter layers or replaced the existing media, in which case it acted as both an absorbent and a
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filter. The effective life of GAC varied between a few months and several years, depending on the quantity and type of organics being removed.
The early use of GAC focused on traditional issues of odor and taste, but by the late 1960s concern had shifted to the presence of synthetic organic compounds (SOCs) in the water supply. These included a wide variety of pesticides, industrial chemicals, and oils. By the late 1970s, the EPA had identified 253 SOCs in municipal water distribution systems, post treatment, that were suspected carcinogens. Reducing the concentration of these compounds to presumed safe levels required more intensive filtration. Carbon columns, also known as GAC contractors, resembled pressure filters, being cylindrical tanks with beds of media through which the water was forced under pressure. These columns were similar in design to those used in wastewater treatment plants, as with the South Tahoe facility. Carbon columns were generally included at the end of the drinking water treatment process, just ahead of final disinfection. Portable GAC contractors, mounted on trucks or skids, allowed for emergency decontamination of small systems, as when a rural well was found to have high pesticide levels. These portable systems were designed for temporary use while permanent solutions were arranged.
UV Disinfection
The use of UV radiation to disinfect drinking water and wastewater emerged from regulatory pressures in the late 1970s that discouraged an overreliance on chlorine. Scientists had known since the late nineteenth century that UV light could kill microorganisms, and UV radiation was used to disinfect drinking water as early as 1906. However, the introduction of chlorination two years later effectively ended experimentation with UV disinfection. Later, as environmental concerns grew, regulators sought to balance the need to control pathogens with the impact of chlorine residuals on the environment. In the late 1970s, the EPA began funding research into chlorination alternatives and making grant funds available for construction. Experiments were made with ozone, bromine chloride, and chlorine dioxide as disinfectants, but UV radiation emerged as the principal alternative to chlorine.
UV light offered several advantages as a disinfectant, chief of which was that it did not produce any toxic by-products during the treatment process. UV light operated with relatively simple equipment, principally mercury arc lamps, and because it killed viruses and bacteria almost instantly, it required shorter retention times and thus smaller contact chambers. UV light also dispensed with the need to handle and store dangerous chemicals and there was no chance of overapplication. However, because UV light left no residual disinfectant in the water, it was necessary to still add a low dose of chlorine to handle any microorganisms living in the distribution system.
Prompted by the EPA research and grant program, several small companies emerged to develop UV light systems that could handle the unique issues of drinking water and wastewater treatment.
Many first-generation systems were made operational in the late-1970s and early-1980s, but most suffered from basic design flaws that rendered the equipment inefficient and unreliable. A lack of scientific information and industry standards made it difficult for plant operators to determine the right size and configuration for their equipment, and repairing the rapidly evolving equipment was challenging. As a result, even at the end of the twentieth century, less than one percent of the nation’s drinking water supply was treated with UV radiation.
2. Environmental and Cultural Background
Coalinga Sanitary Sewer Collection System and WWTP Improvements Project 91 Fluoridation
The fluoridation of public water supplies proved to be the most controversial water treatment issue in the postwar decades. Fluoride occurs naturally in many groundwaters and is particularly prevalent in mountainous regions with volcanic geology. Where fluoride levels are exceptionally high, dental fluorosis can result, producing an aesthetically undesirable mottling of tooth enamel.
It was such cases of excessive fluoridation that first attracted scientific interest, with the earliest studies occurring in Colorado Springs in 1909. Investigations by USPHS linked the condition to water supplies in the 1920s and identified fluoride as the culprit in 1931. During their studies, researchers had noted that children with mottled teeth also had low incidences of tooth decay. This led the National Institute of Health (NIH) to try to determine if there was an ideal level of fluoride that would strengthen teeth without marring them. By the late 1930s, NIH had identified an upper limit of one part per million that would cause only minor fluorosis in a small portion of the population.
In 1945, Grand Rapids, Michigan, installed the world’s first municipal fluoridation facility, followed the same year by Newburgh, New York, and Evanston, Illinois. NIH and the US Surgeon General closely studied the pilot programs and found that the rate of tooth decay among children declined by as much as 60 percent. By the end of the decade, USPHS, the AMA, the American Dental Association, and the National Research Council all endorsed drinking water fluoridation as safe, effective, and inexpensive. A major public health breakthrough, fluoridation made tooth decay a preventable disease for the first time in history. Fluoridation of the domestic water supply expanded rapidly between 1950 and 1953. San Francisco and Antioch added fluoride to their water supplies in 1952, the first cities in California to do so.
Popular opposition to fluoridation gained traction in 1953. Some 60 cities nationwide reversed themselves over the next decade, halting fluoridation programs that they had earlier begun. In California, 36 communities held referendums on the matter, and in 25 cases voters rejected beginning or continuing fluoridation. Opponents voiced a variety of concerns. Some objected in principle to the idea of forced medication or challenged the addition of any chemical to a natural water supply, echoing earlier complaints about the use of chlorine in water treatment. Others noted that sodium fluoride in large doses functioned as a rat poison and worried about the potential of accidentally providing a toxic dose to humans. In the context of the Cold War, some feared that saboteurs might use fluoridation as cover for introducing harmful substances into the water supply, while figures on the fringe insisted that fluoridation was a communist plot to weaken Americans.
Nationally, the supporters of fluoridation prevailed in the long run, backed by the unwavering support of public health officials and the clear and measurable dental health improvements in towns that embraced fluoridation. The introduction of fluoridated toothpastes in the early 1970s lessened tensions around the issue and proponents benefited from the greater calm. By 1980, half of the national population consumed water enhanced with fluoride. California, however, lagged the national trend. In a much-watched campaign, Los Angeles voters strongly rejected fluoridation in 1974. As late as 1992, less than 16 percent of the state’s population received fluoridated water, the fourth lowest percentage in the nation. That figure has since increased as a result of legislation in 1995, but California still ranks below the national average.
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Water treatment plants inject fluoride as one of the final steps of treatment following filtration to avoid any loss that could occur in reaction with other chemicals. For groundwater systems, injection is either at individual well pumps or in a common line leading to a storage reservoir. No specific type of injection equipment is standard across all plants. Small systems commonly use a solution tank and metering pump with a line to the watermain. Larger plants may use dry or solution feeders, depending upon what commercial form of fluoride is most economical for their purposes. The fluoride feed system is frequently automated, with flow meters used to regulate and adjust the feed rate.
Political Organization
Prior to 1949, the California Department of Public Health had been the chief agency responsible for regulating water pollution and it issued permits for all new sewage disposal sites in the state based upon the recommendations of its Bureau of Sanitary Engineering. The permitting process had originated as a means of providing technical engineering review of proposed treatment plants, and it was thus fundamentally oriented towards regulating the means of pollution abatement rather than the end results. The department did not establish general guidelines for the quantity and quality of sewage discharge, but undertook a site-by-site review to ensure that plants operated as designed and did not endanger the public health or cause a nuisance. By the end of World War II, this system was widely understood to be inadequate and in need of replacement.
The California Legislature in 1949 passed the Dickey Water Pollution Act to overhaul the regulation of water quality. The act created a State Water Pollution Control Board and nine regional boards with authority over water pollution and nuisances. The State Board served as a review authority for appeals of regional board decisions, formulated state-wide policy, and directed a research and construction financing program, but it was to defer to the authority of the regional boards for prescribing and enforcing discharge requirements. The regional boards were established in the nine major drainages (hydrologic basins) of the state and each was composed of five individuals appointed by the governor. The boards were to represent the various regional water interests with the five board members drawn one each from the ranks of irrigated agriculture, industry, water supply organizations, municipal government, and country government. In theory, the conflicting interests of the board members would be so balanced as to prevent requirements from being overly stringent or lax.
The Dickey Act repealed the earlier permitting system through the Department of Public Health and replaced it with a method that set overall standards of water quality, but did not specify what means were to be used to meet those ends. Municipalities no longer had to submit their treatment plant designs for technical review by the state so long as they could met the water quality standards.
The act defined pollution as “an impairment of the quality of the waters of the State by sewage or industrial waste to a degree which does not create an actual hazard to public health but which does adversely and unreasonably affect such waters for domestic, industrial, agricultural, navigational, recreational, or other beneficial uses.” The pollution control boards thus had jurisdiction over the economic aspects of waste discharge. The definition excluded substances that created an actual hazard to public health through the spread of disease or introduction of a toxic poison, and these remained the jurisdiction of local and state health officials who could order an immediate abatement of such conditions.
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Coalinga Sanitary Sewer Collection System and WWTP Improvements Project 93 In 1969 the state legislature passed the Porter-Cologne Water Quality Control Act that substantially revised the Dickey Act. Described at the time as “the toughest water quality act in the nation,” Porter-Cologne added strong enforcement tools, created an enhanced role for public participation, and for the first time recognized aesthetic enjoyment as a legitimate value meriting protection.314The act retained the nine regional boards and the state board under a new name as the State Water Resources Control Board. The regional boards were expanded to nine members with additional representation from water quality experts and private associations concerned with recreation, fish, and wildlife. The act strengthened the state’s regulatory role by explicitly redefining the discharge of waste as a privilege that could be revoked, rather than as a right that might enjoy protection as a beneficial use. The definition of pollution was also rewritten so that it applied to any unreasonable impact to beneficial uses, without the requirement that it be an adverse effect, thus allowing for strict standards to protect future uses without having to show present harm. This broadened authority was necessary for protecting a body of water like Lake Tahoe, where the highest standards of treatment were needed to safeguard unique aesthetic values.
The federal government had been slow to engage with water quality issues, historically treating the matter as a concern for local or state government, but this began to change in the postwar era.
Through the first half of the twentieth century, Congress repeatedly debated establishing federal water quality standards, but none of the more than 100 introduced bills was ever passed and enacted into law. The US Public Health Service standards for water used in interstate travel, established in 1914, remained the only federal involvement in water quality issues. Then in 1948, Congress passed the Water Pollution Control Act, the first major federal involvement in water quality regulation. The act was limited in scope—it applied only to interstate waters and required consent of the participating states—but it established a precedent for a federal role in pollution disputes.
Debate over the proper federal role in water issues continued through the 1950s and 1960s, coinciding with the emergence of environmentalism as a major political concern. The 1948 act had been regarded as an experiment and it had a sunset provision following a five-year trial period.
After extensive negotiations, Congress extended the act in 1953 for another three-year period and then finally made it permanent in 1956, though with major amendments in 1961 and 1965. Federal involvement deepened every step along the way. Federal jurisdiction was extended from interstate waters to all navigable waters in 1961, encompassing every significant waterway in the country.
In 1965, a new bureaucracy, the Federal Water Pollution Control Administration (FWPCA), was created to coordinate the federal role. The administration was placed under the Department of Interior in 1966, highlighting the environmental role of water regulation and downgrading the former importance of USPHS. Federal financial assistance also increased regularly, reversing the slump in spending that had come with the end of the New Deal programs and curtailment of emergency wartime funding. Most grant assistance was doled out in modest sums to standalone projects, so that small cities, towns, and institutions were the primary beneficiaries, rather than more comprehensive, regional treatment programs.
In 1972, Congress radically amended the Federal Water Pollution Control Act, creating the modern environmental law commonly known as the Clean Water Act. The act established the federal government’s EPA as the leading actor in setting and enforcing water quality standards, with the states in a supporting role. Partially modeled on California’s Porter-Cologne Act, the Clean Water
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Act asserted a wide range of uses that merited protection including wildlife conservation and recreation, the so-called “fishable-swimmable” goal. The declared objective of the act was “to restore and maintain the chemical, physical, and biological integrity of the Nation’s waters.” This meant rendering the waters safe for wildlife and recreation by 1983 and fully eliminating toxic discharges by 1985. To accomplish this goal, the act focused on individual dischargers rather than establishing general water quality standards that were measured in-stream. Every municipal or industrial point-source emitter of waste was required to obtain a federal permit from the EPA that placed specific limits on the discharged effluent.
A distinctive characteristic of the Clean Water Act was its reliance on technology-based standards.
In what was termed “technology-forcing,” dischargers were obligated to adopt particular levels of technology regardless of their quantities of discharge or the existing levels of pollution in the absorbing body of water. For municipal treatment plants, this meant adopting secondary treatment methods prior to July 1977 (extendable to 1988). Higher levels of treatment could be required if the permitting agency (EPA or the state) determined secondary treatment to be inadequate.
Approximately 86% of municipal plants nationwide met the 1988 deadline and others were placed under court-ordered schedules requiring compliance as soon as possible. The federal law allowed plants that discharged to seawater to apply for waivers from secondary treatment if they could show that natural conditions allowed for waste dilution without unreasonable risk to fish, shellfish, wildlife, or recreational use. California, however, enacted stricter standards in 1974 that prohibited discharge to bays or estuaries unless enhancement of the receiving waters was proven.
Industrial dischargers were required to adopt “best practical technology” (BPT) by July 1977 and upgradable to the “best available technology” (BAT) that was economically available by 1989. In practice, BPT standards were used to control discharges of conventional pollutants that included biodegradable organic substances. BAT controls applied principally to toxic or persistent pollutants. The EPA had authority to define BPT and BAT standards and states had responsibility for enforcing the requirements. To aid compliance with the standards, federal grants were made available for up to 85 percent of construction costs for projects involving innovative technology, versus a maximum of 75 percent for more conventional treatments. These measures spurred innovation in the wastewater treatment industry and led to a fundamental redesign of many industrial processes to decrease the amount of water used, recapture waste byproducts for reuse, and reduce the effluent discharge.
The Clean Water Act addressed only surface waters and did not directly apply to groundwater that provided the drinking water supply for many communities. Investigative reporting in the early 1970s upended assumptions about the safety of municipal water supplies by exposing the existence of potential carcinogens in the tap water of New Orleans and Pittsburgh and lead contamination in Boston. In response, Congress passed the Safe Drinking Water Act of 1974 to coordinate local, state, and federal agencies in protecting drinking water supplies. The program built on the USPHS model of regulating contamination levels in drinking water, but it vastly expanded the scope of the law. While the USPHS regulations had applied to approximately 700 supply systems that provided water for interstate carriers, the Safe Drinking Water Act applied to approximately 40,000 community systems. Under direction of the EPA, the National Academy of Science conducted studies to determine the maximum contaminant levels (MCLs) that were fully protective of human health for biological, chemical, radiological, and physical contaminants. To protect groundwater
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Coalinga Sanitary Sewer Collection System and WWTP Improvements Project 95 aquifers, the act established a permit system regulating underground injections of wastewater, gases, brines, and other potential contaminates.
Under the terms of the Safe Drinking Water Act, states assumed primary responsibility for monitoring public drinking water supply systems and enforcing compliance. States could establish their own MCL standards, so long as they were at least as stringent as federal criteria. The California legislature passed the California Safe Drinking Water Act in 1976. California initially defined a public water system as one having five or more service connections, in comparison to the 15 or more specified in federal law, though the legislature later amended the state code to match the federal definition. The Sanitary Engineering Section of the Department of Health (successor to the Bureau of Sanitary Engineering) regulated an initial 1,084 large water systems, defined as those with 200 service connections or more. Local health departments retained responsibility for the 8,887 smaller systems in the state. The State Water Resources Control Board assumed primary responsibility for the regulation of drinking water in 1994 and has continued to expand and refine the list of substances regulated by MCL criteria through regular updates to the Safe Drinking Water Plan.
Technology
The wastewater treatment technologies developed in the early twentieth century—sedimentation basins, sludge digestors, trickling filters, activated sludge tanks, and the like—remain the primary tools in use today. A sanitary engineer transplanted from the 1930s would immediately recognize and comprehend the purpose and functioning of nearly every major piece of equipment found at a plant constructed in the twenty-first century, although there have been notable improvements to facilities, systems, and processes.
Automation
Automation came late to wastewater and drinking water treatment systems in comparison to such similar industrial processes as oil refining and chemical manufacturing. Basic mechanical automation had been a part of water and sewer systems since the nineteenth century in such forms as floats used for triggering well pumps or automatic flushing tanks used for clearing sewer laterals. Electrically powered systems were employed as early as the late 1920s when the Sanitary District of Chicago installed electric eye monitors in sedimentation tanks to regulate sludge levels.
However, treatment plants remained overwhelmingly under manual control into the postwar decades, with operators physically opening and closing valves and gates and taking laboratory measurements of turbidity and pH levels.
Tightening municipal budgets in the 1970s prompted increased adoption of automation to economize on labor, real estate, chemical, and energy costs. The design of prewar plants had followed generally conservative standards and intentionally built-in excess capacity to handle unexpectedly high flows. This added to land acquisition and construction costs and permitted a more loosely controlled operation. Automation promised to maximize efficiency by continually adjusting flow rates, temperatures, pH levels, and other variables to remain within set parameters.
This allowed adding treatment capacity to existing facilities, rather than building new plants, and offered savings on chemical, energy, and labor inputs. As an additional benefit, automation held the potential to increase the reliability of the treatment process, necessitating fewer shutdowns and enhancing the quality of the final effluent or water supply.
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Treatment plant instrumentation performed two chief tasks: monitoring conditions and automating processes. The first was much more widely practiced than the second. The principal sensors used in the 1970s measured hydraulic flow rates and levels. Of secondary importance were analytical instruments for measuring temperature, pressure, pH levels, turbidity, and chlorine concentrations.
These more advanced sensors were not always economical to use as the difficult conditions inherent in sewage treatment generated heavy wear and tear. Air, liquid, and sludge pumps were the principal controllers to be automated. Used in conjunction with autonomous sensors, these could adjust flowrates through the plant and maintain consistent processing rates. Chlorination injections and sludge digester temperature controls were also automated successfully and produced savings in chemical and energy inputs.
By the mid-1970s, every wastewater treatment plant other than the smallest systems had a centralized control room that displayed information gathered from remote sensors, showing the operational status of the plant at a glance (Figure 62). By allowing a single worker to monitor plant operations, control rooms produced labor savings and were the one form of automation almost universally justifiable on economic grounds. A standard control room had display panels and consoles with indicators, recorders, alarms, and automatic and manual controls. The graphic panels frequently were organized into a sequence that followed the plant layout, though as plants increased in complexity this became less feasible. Computers were common at most new plants constructed in the late 1970s, though these primarily served to display and record data, rather than to directly control the treatment process.
Still, automation proceeded more slowly than treatment plant operators and equipment manufacturers expected or desired. When the EPA sponsored a nationwide study of automation in 1976, they found few processes operating by automated control loops and a generally low level of technological adoption. Even where automated systems existed, operators had switched many off to allow for manual override. Experts initially thought that technological limits were the problem and that solutions would emerge as sensors improved, but the biological complexity of sewage treatment proved a larger obstacle. A plant never operated at complete equilibrium, but experienced constant variation as bacterial populations adjusted to diurnal and seasonal changes in inputs and ambient conditions. The underlying biology was only incompletely understood, and even sophisticated models were approximations at best. The objective of plant operations also changed with circumstance. What worked best during ordinary conditions was different from what was required during a storm or following an industrial chemical discharge. The challenge of integrating all these variables presented real limits for automated systems and left most plant operations under human control.
Desalination
Desalination is not a modern concept. Oceangoing vessels have supplemented their fresh water supplies by distilling seawater since at least the early seventeenth century, and humans have understood the principles of desalination for many centuries before then. Distillation methods continued to advance, with small seawater-purification machines becoming ubiquitous among naval ships by the Second World War, but large-scale land-based desalination remained in its infancy into the mid-twentieth century.
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Coalinga Sanitary Sewer Collection System and WWTP Improvements Project 97 In 1952, Congress passed the Saline Water Act, which Secretary of the Interior Oscar Chapman had promoted as a necessary response to an ongoing drought in the Southwest that had begun in 1949. The act initially allocated only $2 million over five years, but with the drought only worsening during that period, Congress increased funding fourfold and created the Office of Saline Water in 1958. They tasked the new office with constructing five demonstration desalination plants in different regions. Coastal regions would desalinate seawater while inland regions would desalinate brackish groundwater. Walter L. Badger Associates designed the first nation’s first desalination plant in Freeport, Texas, and construction was completed in 1961. The U.S.
Department of the Interior’s Office of Saline Water operated the plant, supplying half of its production to Dow Chemical and the other half to the City of Freeport. As a result of the Freeport plants success, support for desalination continued growing over the subsequent decade until the energy crisis of the 1970s made desalination appear less cost-effective.
California’s first desalination plant was constructed in Coalinga in 1965. Located in the San Joaquin Valley, the city’s water supply came mostly from groundwater, which was growing increasingly brackish. The Freeport plant had purified salt water through distillation, but subsequent research had shown reverse osmosis to be more efficient for treating brackish groundwater. The technology passed the water through semipermeable membranes whose openings were of such a size and shape to permit only water molecules through them, thereby holding back salt and other impurities. Coalinga became home to the first Office of Saline Water demonstration plant that used reverse osmosis in 1965. Though experiments with reverse osmosis had already occurred elsewhere in the United States, two UCLA graduate students developed a new membrane that produced freshwater from saltwater ten times faster than the existing membranes. The Coalinga plant functioned as a test site for the viability of the new membrane, and as such, it was small, supplying only 5,000 gallons per day. Their new membrane was successful, and though only a few additional plants were built in California, they all adopted reverse osmosis. Orange County Water District, for instance, integrated reverse osmosis into its Water Factory 21 completed in 1975. A Santa Barbara plant completed in 1991 had a capacity of
6.7 mgd and was the largest built to date in California. However, the plant was decommissioned after Santa Barbara received a connection to the State Water Project and could more easily import surface water than treat groundwater.
2.4.2 Coalinga Wastewater Treatment Plant Operations
The following is excerpted from the City of Coalinga’s Preliminary Engineering Report (AM Consulting Engineers 2023:6-7):
The City of Coalinga imports its water through the federal Central Valley Project (CVP) supervised by the U.S. Bureau of Reclamation (USBR). Due to the poor groundwater quality in the area, the City does not pump groundwater to supplement the water supply due to its poor quality and high concentrations of sulfates, total dissolved solids (TDS), and sodium. On October 28, 1968, the City entered a 40-year contract with the US Bureau of Reclamation for up to 10,000 acre-feet (ac-ft) of CVP water on an annual basis. This contract expired on December 31, 2008. On January 22, 2021, a long-term contract was signed between the City and the USBR (Contract No. 14-06-200-4173A-IR1-P) that established new rates and extended the City’s right to pump up to 10,000 AF of water per year.
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Raw water for the City flows from the Sacramento-San Joaquin Delta to the south into either the Delta-Mendota Canal or the CVP California Aqueduct, which discharges in the O’Neil Forebay. From the O’Neil Forebay, water continues to flow south into the California Aqueduct to the point of origination of the Coalinga Canal, approximately 15 miles northeast of the City where Highway 145 crosses over the California Aqueduct. After leaving the California Aqueduct, water is carried in the Coalinga Canal approximately 12 miles south to the City of Coalinga WTP intake. A raw water pump station then lifts the water from the Coalinga Canal to the City’s conventional surface WTP.
Surface water from the Coalinga Canal is treated at the City’s Water Treatment Plant, which is located approximately 7 miles outside of city limits. The City’s surface WTP originally came online in April 1972 with an average daily flow capacity of 8 million gallons per day (MGD) and maximum daily flow capacity of 12 MGD. In anticipation of the increased demands resulting from the construction of the Pleasant Valley State Prison, the capacity of the WTP was increased to receive an average daily flow of 12 MGD and a maximum daily flow of 16 MGD. The Plant provides conventional surface water treatment, with processes that include chemical pretreatment, chlorine disinfection, corrosion control, filtration, flocculation, and sedimentation. As a secondary disinfection, chlorination is used to maintain chlorine residual in the distribution system while reducing further production of disinfection byproducts.
Treated water is pumped by a filtered-water pump station into a 27-inch diameter pipeline in Palmer Avenue.
Treated water is pumped by a filtered-water pump station into a 27-inch diameter pipeline on Palmer Avenue. Approximately two miles west of the WTP, the flow tees at Calaveras Avenue.
Water flowing west continues for another mile and a half to the Palmer Avenue Reservoir.
Water going to the Pleasant Valley State Prison travels south in the 12-inch Calaveras Avenue pipeline to the Calaveras Avenue Reservoir. After flowing through the Calaveras Reservoir, it continues south along Calaveras Avenue another 3.5 miles to Jayne Avenue and then east to the prison. Water can potentially travel from the Calaveras Reservoir westerly into the City; however, this seldom occurs due to the hydraulic conditions. Water leaving the Palmer Reservoir flows through approximately eight miles of 24 and 27-inch transmission mains to the Derrick Avenue Reservoir. Water travels primarily from the Derrick Avenue Reservoir through 18, 24, and 30-inch transmission mains into the City’s water distribution system. The distribution system consists of a network of water mains ranging in size from 4 to 14 inches in diameter. The system can supply peak hour needs without excessive losses and can deliver fire flows to main lines.
The City’s existing storage reservoirs all consist of steel tanks resting on reinforced concrete ring wall foundations. The following is a description of each of the City’s treated water storage reservoirs:
• Palmer Avenue Reservoir – This reservoir is located on the south side of Palmer Avenue and has a capacity of 2.8 MG. This reservoir receives pumped treated water from the WTP.
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Coalinga Sanitary Sewer Collection System and WWTP Improvements Project 99 • Calaveras Avenue Reservoir – This reservoir is located on the east side of Calaveras Avenue and has a capacity of 5.0 MG. Water flows from the WTP to the Calaveras Reservoir and then to the Pleasant Valley State Prison. • Derrick Avenue Reservoir – This reservoir is located west of the City, on the east side of Derrick Avenue. This reservoir has a capacity of 7.6 MG. Water from the Palmer Reservoir flows to the Derrick Reservoir and then into the City. • Oil King Reservoir – This reservoir is located west of Highway 33/198, approximately three miles north of Palmer Avenue. The reservoir has a capacity of
0.5 MG and exclusively serves the City’s oil company customers. • Northwest Reservoir – This reservoir is located east of Derrick Avenue, approximately three miles north of Gale Avenue. This reservoir has a capacity of
0.2 MG. Like the Oil King Reservoir, this reservoir is also used exclusively for the City’s oil company customers.
Since the Oil King and Northwest reservoirs’ sole function is to provide water to oil companies, they are excluded from the evaluation of the City’s available storage. The existing combined storage capacity of the Palmer, Derrick and Calaveras reservoirs is 15.4 million gallons (MG).
2.4.3 Coalinga Wastewater Treatment Plant
The WWTP within the APE is part of a wastewater collection and treatment system for the urbanized areas of the City of Coalinga that includes more than 42 miles of sewer pipelines (6 in. to 24 in. in diameter). As of 2023, the WWTP within the APE serves 3,369 residences and 318 businesses. The WWTP “treats and discharges the municipal wastewater generated by residences and businesses within the City. The treatment process at the City’s WWTP consists of screening, primary clarification, and secondary treatment (aerated facultative lagoons followed by stabilization lagoons)” (AM Consulting Engineers 2023:16).
The first step in the treatment process is screening the wastewater that enters the system at the headworks, and the large debris is screened out. Then the wastewater continues through a Parshall flume with an ultrasonic-level transducer that measures and records plant flow data.
According to AM Consulting Engineers (2026):
Pretreated effluent from the headworks flows through a 24-inch gravity line into a clarifier center feed well. The purpose of the feed well baffle is to disperse the incoming wastewater without disturbing the settled sludge in the bottom of the clarifier. As wastewater flows through the clarifier, heavy solids settle to the bottom and are removed as primary sludge. The clarified effluent is collected by a peripheral overflow launder protected by a submerged baffle that retains floatable from entering the effluent channel. Floating material is removed by a surface skimmer that pushes the material into a scum beach. From there, the scum is pumped to the digester. Settled solids, primarily inorganic, and some large organic particles constitute the primary settled sludge. This sludge is scraped and pushed into the center sludge hopper by rotating rake arms. Scum is scraped by a rotating skimmer and deposited into a scum box.
Eight spray nozzles are mounted along the clarifier walkway to aid in scum removal. Two 6- inch lines carry sludge from the sludge hopper and scum from the scum box to the primary pump station. From the primary pump station, the sludge is pumped to an aerobic digester by
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two separate plunger pumps. Both pumps are actuated either manually or automatically from a local control panel at the pump station. The piping is arranged in a way that both pumps are capable of pumping sludge (AM Consulting Engineers 2023:17-18).
According to AM Consulting Engineers (2026):
Aerated facultative lagoons (AFLs) are the main treatment process responsible for the reduction of the soluble BOD. These lagoons, in conjunction with the downstream stabilization ponds, achieve high removal of organic materials, solids that are not removed in primary treatment, and pathogen bacteria.
The AFLs are equipped with surface aerators to supply the required oxygen for treatment and provide mixing of the surface zone. Eight aerators are installed, four in each lagoon. The aerators are driven by constant-speed electric motors. The aerators are controlled where they can be started and stopped to maintain a minimum dissolved oxygen concentration of 1 mg/L in the top layer of the lagoons.
The AFLs are designed to operate in parallel to better distribute the wastewater. The first aerator in each lagoon is a 20 HP unit while the remaining three are 10 HP. This design provides increased aeration in the zones of high oxygen demand at the beginning of the AFLs and inhibits uneven deposition or mounding of sludge (AM Consulting Engineers 2023:18).
According to AM Consulting Engineers (2026):
Wastewater effluent from the AFLs flows into an effluent control box and then through three stabilization ponds (SPs) operated in series. The main purpose of these stabilization ponds is to provide secondary treatment or further removal of the remaining BOD and TSS not removed in primary treatment and aerated facultative lagoons. The stabilization ponds also act as seasonal storage facilities for the treated wastewater prior to effluent disposal. The water surface elevation in the first two stabilization ponds is controlled by a downstream weir at the end of the second pond. The water level at the third stabilization pond is controlled by the effluent pumping rate used at a given time to meet irrigation needs (AM Consulting Engineers 2023:18).
According to AM Consulting Engineers (2026):
Sludge collected at the primary clarifiers is regularly pumped into the aerobic digester. The aerobic digester provides an anoxic environment where the organic matter contained in the sludge is decomposed and transformed into stable material that can be air dried without causing objectionable odors. The aerobic digestion process decomposes the organic matter in water and C02, reducing the strength or volatile suspended solids (VSS) in the sludge collected by the primary clarifier. Aeration in the aerobic digester is provided by two positive displacement blowers that feed coarse bubble diffusers located near the bottom of the digester. The aerators are located at the side to impart turnover and mixing in the digester (AM Consulting Engineers 2023:18).
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Coalinga Sanitary Sewer Collection System and WWTP Improvements Project 101 According to AM Consulting Engineers (2026):
Digested sludge leaving the aerobic digesters is fed to one of two asphalt-bottom sludge drying beds. These beds provide enough air-sludge surface contact to enhance the evaporation of the water contained in the sludge. The sludge is first allowed to settle at the beds, after which the supernatant is decanted by telescopic valves and returned to the headworks. The remaining sludge is allowed to dry before it is scraped and stockpiled on-site. The sludge is then tested for regulated heavy metals before it is transported off-site by truck to a sludge composting facility for final disposal (AM Consulting Engineers 2023:19).
According to AM Consulting Engineers (2026):
Currently, the City’s wastewater effluent is transported to adjacent land and used for irrigation of non-food crops such as cotton, alfalfa, and feed grains. Technically, all of Coalinga's wastewater can be said to be recycled since it is used to irrigate crops and a portion of the irrigation water percolates beyond the crop root zone ultimately to become groundwater. However, since groundwater is not a source of drinking water supply, it cannot be considered as offsetting potable water demand (AM Consulting Engineers 2023:19).
According to AM Consulting Engineers (2026):
The City’s WWTP has undergone two major modifications and additions over the last 40 years.
According to WDR Order No. 76-180, the WWTP originally consisted of a primary clarifier followed by three oxidation ponds in series. The final disposal consisted of irrigating land controlled by the City and West Hills Community College for agricultural reclamation. At that time, the WWTP’s treatment capacity was 0.6 MGD.
In 1980 the City submitted a Report of Waste Discharge for the expansion of the existing treatment capacity from 0.6 MGD to 0.93 MGD. The modifications consisted of influent screening followed by two aerated facultative lagoons and three stabilization ponds. Final effluent disposal was consistent with previous practices on City-owned land and West Hills College grounds. These modifications and additions were implemented in 1982. WDR Order No. 80-064 was adopted on May 26, 1980.
In 1991, the City submitted a Report of Waste Discharge in support of a change in operation and an increase in quantity of discharge from its municipal WWTP. The treatment capacity was increased from 0.93 MGD to the current 1.34 MGD. The City completed the rehabilitation of the primary clarifier and aerobic digester, which were removed from service during the previous plant modification. Effluent is pumped from one of the stabilization ponds to 30 acres of farmland owned by the Discharger (leased and operated by West Hills Community College District) and 102 acres of farmland owned by West Hills Community College (User) for crop irrigation and percolation disposal. The User grows alfalfa, hay, cotton, pasture, and sugar beets (for research only) with reclaimed wastewater. The Discharger owns an additional 96.7 acres of land in the immediate area, which could be used for reclamation if needed (AM Consulting Engineers 2023:16).
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2.4.4 Site Specific History
WWTP APE
According to USGS topographic quadrangles, historical aerials, Google Earth imagery, and Nationwide Environmental Title Research, the WWTP APE has undergone significant development since at least the mid-twentieth century. During 1933–1937, land within the APE was largely undeveloped, with several linear features in its near vicinity including the Southern Pacific Railroad, Siskiyou Avenue, and a San Joaquin Light and Power Corporation transmission line (USGS 1933, 1937). An unnamed road runs through the southern portion of the WWTP APE along the same alignment of present-day Palmer Avenue.
Structures are first visible within the WWTP APE circa 1940-1941 (USGS 1944). 2 The structures
appear to be in the same general area as the extant structures associated with the WWTP and retain the label of “Sewage Disposal.” The WWTP remained in the same configuration by 19533 with a main building, a water tank, and an unnamed access road that reaches the buildings from Jayne Avenue to the south. Topographic maps drawn from aerial photographs confirm that minimal changes occurred within the WWTP APE between 1940 and 1956 (USGS 1956) (Figures 3–4).
The Coalinga Wastewater Treatment Plant site underwent its first major expansion beginning in 1963, with an official dedication in 1964. Constructed for $250,000 (approximately $2.7 million adjusted for inflation), the plant was expanded with federal and matching local funds on land purchased from Standard Oil Company and was constructed by the Charles S. McCandless & Company. The opening of the newly expanded plant was seen as a step forward for Coalinga, where it represented community progress as it would permit the city to double in size as well as allow for industry in the area (The Fresno Bee 1964:32). These changes are first apparent in the 1967 historic aerial photograph, where the plant site consisting of the operating building, the primary clarifier, and the digester are visible with some minor supporting structures (USDA 1967) (Figure 5).
The plant developed again between this time and 1979, when improvement plans were prepared by John Carollo Engineers. While the plant site remained unchanged, these plans revealed that the plant had expanded to the east with treatment lagoons and ponds that replaced a body of water likely associated with Coalinga WWTP and Los Gatos Creek. Then, between 1981 and 1994, historic aerial photographs confirm further development of the site with construction of several new buildings and a sludge-drying bed to the northeast. This is supported by the Wastewater Treatment Plant Primary Treatment Rehabilitation drawings created by James M. Montgomery Consulting Engineers, Inc. in 1990 and historic photographs from 1991 depicting the construction of the new buildings and machinery at the plant. Construction of new buildings and modifications completed between 1994 and 2024 continued to change the WWTP’s configuration, particularly in the large area to the northwest of the plant site, where between 2018 and 2020 three additional sludge beds were constructed (Figures 6–12).
2 The USGS 1944 topographic map was first surveyed between 1935 and 1936, and again in 1940 and 1941. 3 The USGS 1956 topographic map was drawn based on 1953 aerial photographs.
2. Environmental and Cultural Background
Coalinga Sanitary Sewer Collection System and WWTP Improvements Project 103 Figure 3. Portion of 1944 USGS Topographic Map Coalinga Quadrangle. Surveyed in 1935-1936 and 1940-1941.
2. Environmental and Cultural Background
104 ASM Affiliates
Figure 4. Portion of 1956 USGS Topographic Map Coalinga Quadrangle. Aerial Photographs taken 1953.
2. Environmental and Cultural Background
Coalinga Sanitary Sewer Collection System and WWTP Improvements Project 105 Figure 5. 1967 historic aerial photograph of the Coalinga WWTP. Source: USGS 1967.
2. Environmental and Cultural Background
Coalinga Sanitary Sewer Collection System and WWTP Improvements Project 107 Figure 6. The Coalinga WWTP as depicted in the 1979 drawings by John Carollo Engineers.
2. Environmental and Cultural Background
108 ASM Affiliates
Figure 7. Detail of the plant area of the WWTP as depicted in the 1979 drawings by John Carollo Engineers.
2. Environmental and Cultural Background
Coalinga Sanitary Sewer Collection System and WWTP Improvements Project 109 Figure 8. The Coalinga WWTP as depicted in the 1990 drawings by James Montgomery Consulting Engineers.
2. Environmental and Cultural Background
110 ASM Affiliates
Figure 9. Detail of the WWTP plant area as depicted in the 1990 drawings by James Montgomery Consulting Engineers.
2. Environmental and Cultural Background
Coalinga Sanitary Sewer Collection System and WWTP Improvements Project 111 Figure 10. Photograph of the construction occurring at the Coalinga WWTP, dated May 28, 1991. The clarifier is visible in the foreground, and the animal shelter building is visible in the background.
2. Environmental and Cultural Background
112 ASM Affiliates
Figure 11. Photograph of the construction occurring at the Coalinga WWTP, dated May 28, 1991. This photograph depicts the materials that were removed for the modernization and expansion of the facility.
2. Environmental and Cultural Background
Coalinga Sanitary Sewer Collection System and WWTP Improvements Project 113 Figure 12. Photograph of the construction occurring at the Coalinga WWTP, dated May 28, 1991. The clarifier structure is depicted, and the primary pump station is visible under construction.
2. Environmental and Cultural Background
114 ASM Affiliates
Pipeline APE
Historical topographical maps and aerial imagery that included the Pipeline APE were consulted to identify potential historic-era structures or resources.
According to historical topographic maps, the portions of the APE in the city of Huron and outside of the WWTP have had significant development since at least the mid-twentieth century. The Pipeline APE was largely undeveloped except for the Southern Pacific Railroad northeastsouthwest segment that bisected this portion of the APE and Lassen Road that extended northsouth through the eastern portion (USGS 1933, 1937). Population growth had spurred incorporation of the City of Coalinga (1951) and by 1956, multiple buildings are depicted adjacent to the Pipeline APE (USGS 1956). Between 1971 to 1981, the Pipeline APE changes very little with an airfield being constructed southeast of the APE along with the realignment of roads east and south of the APE and industrial development in the eastern portion of the city. From 1981 to 2024, aerials confirm that land within the Pipeline APE had not been further developed.
2.5 HISTORIC-ERA ARCHAEOLOGY: REFUSE
DEPOSITS
Refuse deposits are a commonly identified site type. Before municipal trash collection and disposal was provided, individual households were responsible for disposing of their own trash. In many rural areas municipal trash collection was never implemented, and individual households remain responsible for disposing of their own trash. In the years before people had automobiles at their disposal, trash was generally disposed of either on the householder’s property, preferably at some distance removed from the residence, or on an adjacent vacant piece of land. Often householders dug pits into which they deposited trash until it became too full. Periodically the trash was burned so that it would not attract rodents. The pit was eventually backfilled, and another pit was excavated. Old privy pits were frequently used to dispose of trash before they were backfilled.
Trash was also dumped close to the main residence initially before it was moved to a pit for burning or burying. In rural settings, trash pits and trash surface scatters tend to cluster on the edge of the main residential/activity area, at some remove from the house.
Before the automobile, trash was transported in horse-drawn carts to municipal dumps. Farmers could also use carts to remove trash from their property to dump in an adjacent, vacant property, but as the road system was poor and moving trash by horse-drawn cart was a laborious process, rural dwellers did not tend to travel far to dispose of their trash. With the advent of the automobile, however, people experienced greater mobility and disposal of household trash became easier.
People could now travel out of town to dump trash on vacant parcels on the outskirts of town, and farmers could also transport their trash more easily to dump outside their property. Improved roads also facilitated trash disposal. Transporting trash for dumping elsewhere required considerably less labor than excavating a pit, transporting the trash to the pit, burning it, and then backfilling it.
Types of Historic Refuse Deposits
Guerrero and Bupp (1996) identify three principal types of trash dumps in the archaeological record: trash dumps associated with a residence; trash dumps associated with an on-site activity, but not a residence; and isolated trash dumps that are not associated with either a residence or on-
2. Environmental and Cultural Background
Coalinga Sanitary Sewer Collection System and WWTP Improvements Project 115 site activity. Historic archaeological sites are generally evaluated for their potential to address important regional research issues. Trash deposits associated with a known household have the greatest research potential. Where no historical context can be established for a trash deposit and there is no known association with any household, ethnic group, community or labor group, the lack of a definitive association diminishes its research potential.
Research Questions
These research questions address three main research domains: chronology, subsistence and economy, and structure and integrity of the cultural deposits.
2. Environmental and Cultural Background
116 ASM Affiliates
Chronology
• Can the chronological placement of the trash deposit be determined? • What kinds of chronometric data are available? How well do the different kinds of chronometric data correlate?
• Are there data indicating the presence of multiple dumping episodes at project sites? Date ranges for individual historic deposits are derived from glass maker’s marks, maker’s marks on ceramics, technological features of both tin cans and bottles, and chronological markers such as glass color (Clark 1977; Fike 1987, 2002; Fontana and Greenleaf 1962; IMACS 1990; Jones and Sullivan 1985; Kendall 1978, 1979; Kovel and Kovel 1986; Lockhart 2000; Munsey 1972; Rock 1980a-b; Sharley 2002; Simonis 1987; Toulouse 2001). These various kinds of chronological data generally provide a fairly narrow date range for the manufacture of the artifact. To provide a date range for deposition, all of the chronological data from individual artifacts are correlated. The date of deposition is assumed to be sometime after the latest date of manufacture. The time lag between manufacture and discard varies depending on the function of the artifact. For example, an expensive porcelain teapot may be a family heirloom that would remain in the family for decades, while a tin can or milk bottle was likely discarded immediately after use. A date range for the deposit is estimated based on the latest manufacture date and the expected time lag before discard.
Where multiple dumping episodes were suspected based on the range of dates of manufacture, an effort is made to differentiate individual dumping episodes and provide an estimated date range for each.
Technology, Subsistence and Settlement Organization
• What is the nature of refuse at historic sites? Is it possible to determine the original activities that resulted in the historic deposit? For trash deposits is it possible to determine the origin of the deposits?
Trash deposits associated with homestead sites tend to be directly associated with the homestead household and therefore can be analyzed for data regarding the date of occupation and abandonment of the homestead, activities that took place within the homestead, household composition and gender, and consumer behavior of the residents. It should be remembered, however, that not all trash present on homestead sites relates to the original homestead occupation.
Once sites were abandoned, they were considered vacant, and roadside and opportunistic dumping could take place. It is important that every effort be made to identify post-abandonment trash deposits so that they can be eliminated from analysis of homestead-related activity.
For trash deposits, it is more difficult to make an association with a single household or even group of households. Typically, isolated trash deposits are found on what were vacant lots at the time of deposition. While the trash may have been deposited from a nearby household, this is extremely difficult to establish. Cross-matching of artifacts from adjacent home sites is one method that can be used to associate an isolated trash deposit with a home site. If a portion of an artifact is found on a homesite and another portion found in a nearby dump, this would help to establish the origin of the trash deposit. The association of other trash dumps are difficult to identify and therefore their research potential is poor.
2. Environmental and Cultural Background
Coalinga Sanitary Sewer Collection System and WWTP Improvements Project 117 • Is a sufficient range of materials present in the historic deposits to provide data on the consumption patterns of homesteaders and other historic-period residents in the area? Homesteaders and other settlers in the rural areas of Central Valley in the early decades of the twentieth century faced an uphill struggle in attempting to make a living. These settlers came from a wide catchment area, and surviving in this new environment necessitated adaptation and more than likely frugal living for a number of years.
One important research issue concerns how successful rural farm families defined wealth and spent money compared to middle- and upper-middle-class urban dwellers. Research has indicated that after achieving a basic standard of living that included inexpensive ceramics and a few luxury items, farm families invested in equipment, land, livestock, and outbuildings rather than in status symbols favored by urban dwellers such as fine furniture, table settings and clothes. The difference in household values between successful farm families and middle- and upper-middle-class urban residents is manifested through cross-site comparisons of functional profile and economic indexing data. Profiles of rural assemblages show higher frequencies of hardware, livery items, and equipment and machinery parts than those representing urban sites (Phillips and Van Wormer 1991; Van Wormer 1991; Van Wormer and Schaefer 1991; Van Wormer 1996). In addition, rural site assemblages tend to exhibit reduced ceramic index values (i.e., cheaper ceramic wares), that remain unaffected by fluctuating economic trends, as well as excessive ceramic and bottle manufacture-deposition lag time when compared to urban assemblages from the same period.
These patterns indicate that rural households exhibited a different style of consumption from urban residents by spending less money on ceramic tableware and being more conservative about disposing of items only a few years old. Trash deposits from ranch and farmstead sites provide an excellent opportunity to test hypotheses relating to consumption patterns of rural versus urban dwellers. Remote rural dwellers survived in very difficult conditions and the rural consumer pattern may be further accentuated at these sites.
Data requirements for an analysis of consumer patterns include a range of food and drink containers including glass jars, bottles and cans, and a range of domestic tableware, and furnishings. The range of cultural materials can vary from site to site, depending both on the nature of the deposits and the recovery methodology. While controlled collection from a surface scrape provides a representative sample of what is contained in a surface scatter, it can result in large quantities of highly fragmented glass and metal that contributes little to the data analysis. To obtain a representative sample of a wider range of artifact types it is preferable to excavate smaller samples from a number of deposits and to augment those with a larger surface collection.
Structure and Integrity of Cultural Deposits
• Do inclusive chronometric data from the sites permit the identification and definition of temporally and/or spatially discrete historic dumps?
• Are the definitions of discrete components supported by multiple, independent chronological controls and, if so, how similar are their age estimates? • Is there substantial evidence of occupational “overprinting?” How has this affected the temporal integrity of the refuse deposits?
2. Environmental and Cultural Background
118 ASM Affiliates
Later dumping episodes can result in a mixing of historic, submodern, and modern deposits in such a way that differentiation of dumping episodes can be difficult, if not impossible. Since historic trash deposits tend to be largely surface scatters, the sites lack vertical stratigraphy which would help in distinguishing between historic and later deposits. In some cases, the dumping episodes have taken place in different areas of the sites, and it is possible to distinguish between historic and later deposits. However, at many of the sites historic deposits are mixed with submodern and modern dumping. Consequently, chronological control is lacking, and the research potential of the historic deposits is reduced.
3. Records and Sacred Lands File Searches
Coalinga Sanitary Sewer Collection System and WWTP Improvements Project 119
3. RECORDS AND SACRED LANDS FILE
SEARCHES
3.1 RECORDS SEARCH
To determine whether the Project APE had been previously surveyed for cultural resources, and/or whether any such resources were known to exist within or near to it, staff of the Southern San Joaquin Valley Information Center (SSJVIC) conducted an archival records search on May 29, 2024. The records search was completed to determine: (i) if pre-contact or historic-era cultural resources had previously been recorded within the Project APE; (ii) if the Project APE had been systematically surveyed by archaeologists prior to the initiation of this fieldwork; and/or (iii) whether the area surrounding the proposed Project was known to contain archaeological sites or built environment resources and to thereby be culturally sensitive. Records examined included archaeological site files and maps, the NRHP, Historic Property Data File, California Inventory of Historic Resources, and the California Points of Historic Interest. The records search included the Project APE and a 0.5-mi. buffer.
According to the SSJVIC, six previous studies have been conducted within the Project APE, and 31 previous studies were identified within the 0.5-mi. buffer (Table 4). Based on SSJVIC data, approximately 30 percent of the Project APE has been previously surveyed. Dates for previous studies in the APE range from 1974 to 2021.
The SSJVIC results identified a single previously recorded cultural resource (P-10-003930) within the APE (Table 5). An additional 17 resources were identified within the 0.5-mi. buffer. The results of the SSJVIC records search are available in Confidential Appendix A.
Table 4. Previous Reports within 0.5 mi. of the APE
Report # Year Author/Affiliation Title
APE
Relationship
FR-00008 1996
Kus, James S. and
Mader, Claudia A.
Negative Archaeological Survey Repot for
Proposed Subdivision in Fresno County,
California Outside
FR-00175 1988 Brady, Jon L.
Archaeological Survey Report for Widening of
06-FRE-198 P.M. 16.0/22.4 06253-343310 Outside
FR-00197 1998
Binning, Jeanne Day
and Laylander, Don
Road Widening of State Route 33, north of the
town of Coalinga Outside
FR-00198 1996 Nissen, Karen
Negative Archaeological Survey Report for the
Warthan Creek Bridge in Coalinga, Fresno
County Outside
FR-00198A 1997 Scott, Gloria
Historical Architectural Survey Report for
Warthan Creek Bridge Replacement Project,
Fresno County, California Outside
FR-00198B 1998 Fredericks, Tom
Historical Property Survey Report for Caltrans
Proposal to Replace the Warthan Creek Bridge
(# 42-0119) Outside
FR-00251 1998
Binning, Jeanne Day
and Laylander, Don
Negative Archaeological Survey Report for the
Los Gatos Creek Overflow Bridge Replacement Outside
3. Records and Sacred Lands File Searches
120 ASM Affiliates
Report # Year Author/Affiliation Title
APE
Relationship
Bridge Number 42-0006 and Access
Improvement for State Route 33, Coalinga,
Fresno County, California
FR-00251A 1999 Lortie, Frank
Historic Property Survey Report for the Los
Gatos Creek Overflow Bridge Replacement
Bridge Number 42-0006 and Access
Improvement for State Route 33 Coalinga Outside
FR-00251B 1999 Lortie, Frank
Historic Architectural Survey Report for the Los
Gatos Creek Overflow Bridge Replacement
Bridge Number 42-0006 and Access
Improvement for State Route 33 Coalinga Outside
FR-00673 1974 Ritchie, Carl W.
An Archaeological Survey of Los Gatos and
Warthan Creeks Near Coalinga, California Within
FR-00779 1994 Varner, Dudley M.
An Archaeological Study of Property in the City
of Coalinga, In Fresno County, California Outside
FR-01610 1999
Binning, Jeanne Day
and Marine, Mandy
First Supplemental Archaeological Survey
Report for the Los Gatos Creek Overflow
Bridge Replacement, State Route 33, Coalinga,
Fresno County, California Outside
FR-01869 2001 Nadolski, John A.
Archaeological Investigations for Tower
modifications at 34 Cell Tower Sites Outside
FR-01957 2003 Losee, Carolyn
Cultural Resources Analysis for Cingular
Wireless Site No. CC-514-01 "Downtown
Coalinga" Outside
FR-02028 2004 Varner, Dudley M.
A Cultural Resource Study of the Los Gatos
Creek Property, Fresno County, California Outside
FR-02041 2004 Billat, Lorna
Proposed Wireless Telecommunication Service
Facility Projects in California (Coalinga/CA1363A) Outside FR-02163 2004 Roper, C. Kristina
A Cultural Resources Survey for the Proposed
Warthan Creek Housing Development,
Coalinga, Fresno County, California Outside
FR-02264 2005 Roper, C. Kristina
A Cultural Resources Survey for the 280-Acre
Coalinga Parcels, Coalinga, Fresno County,
California Outside
FR-02265 2005 Roper, C. Kristina
A Cultural Resources Survey for the 2,248-Acre
Coalinga Parcels, Coalinga, Fresno County,
California Within
FR-02267 2005 Roper, C. Kristina
A Cultural Resources Survey of the 296-Acre
Old School Farm, Coalinga, Fresno County,
California Within
FR-02365 2007
Baloian, Randy and
Dalu,
Chris
Cultural Resources Inventory for APN 070060-
76, 070-060-83, and 070-060-86, North of
Coalinga in Fresno County, California Outside
FR-02374 2007
Nettles, Wendy M.
and Baloian, Randy
Cultural Resources Inventory of a 320-acre
Parcel Northwest of Coalinga, Fresno County,
California Outside
FR-02400 2010 Brunzell, David
Cultural Resources Assessment and National
Register of Historic Places Eligibility Evaluation,
Coalinga Library Building, Coalinga, Fresno
County, California Within
FR-02652 2014 Greenberg, Gregory
Cultural Resources Survey East Coalinga /
CVU4251 1188 Gregory Way Coalinga,
Fresno County, California 93210 Outside
3. Records and Sacred Lands File Searches
Coalinga Sanitary Sewer Collection System and WWTP Improvements Project 121 Report # Year Author/Affiliation Title
APE
Relationship
FR-02671 2014
Dietler, Sara, Gibson,
Heather, and Hall,
Lee
Cultural and Paleontological Resources
Constraints Study for the Coalinga 1 and 2
Reconductoring Project, Fresno County,
California Outside
FR-02720 2015 Peak, Melinda A.
Determination of Eligibility and Effect for the
Coalinga Senior Apartments Project, City of
Coalinga, Fresno County, California Outside
FR-02907 2017
Belcourt, Tria Marie,
Kelly, Jennifer, and
Sifuentes, Sonia
Cultural and Paleontological Assessment:
Anderson - Coalinga 1 - 1109 Solar Project
CA 17 - 0106 in Ora, Unincorporated Fresno
County, California Outside
FR-03096 2021 Valentin, Sylvere
Archaeological Survey Report for the
Coalinga SR 33 2R Rehabilitation Project,
Fresno County, California Within
FR-03103 2021 Carr, Paula Juelke
Historic Property Survey Report City of
Coalinga Trails Master Plan (TMP) Within
FR-03103A 2021
Laurie, Leroy and
Stevens, Nathan
Archaeological Survey Report for the City of
Coalinga Trails Master Plan, Segments 3, 4, and
9, City of Coalinga, Fresno County, California Outside
FR-02652 2014 Greenberg, Gregory
Cultural Resources Survey East Coalinga /
CVU4251 1188 Gregory Way Coalinga,
Fresno County, California 93210 Outside
Table 5. Previously Recorded Resources
Primary # Type Description NRHP Eligibility Status APE Relationship P-10-003930 Historic-era structure Southern Pacific Railroad Determined not eligible
for NRHP by consensus
through Section 106
process. Not evaluated for
CRHR or Local Listing Within
P-10-004725 Historic-era building
Wooden Walking Beam
Pumping Unit
Determined eligible for
NRHP by a consensus
through Section 106
process. Listed in the
CRHR. Outside
P-10-004726 Historic-era structure Coalinga Airport
Determined not eligible
for NRHP by consensus
through Section 106
process. Not evaluated for
CRHR or Local Listing Outside
P-10-004784 Historic-era building 740 East Polk Street
Determined not eligible
for NRHP by consensus
through Section 106
process. Not evaluated for
CRHR or Local Listing Outside
P-10-004785 Historic-era building 730 East Polk Street
Determined not eligible
for NRHP by consensus
through Section 106
process. Not evaluated for
CRHR or Local Listing Outside
P-10-004786 Historic-era building
Southeast Corner East
Polk/Thompson Streets
Determined not eligible
for NRHP by consensus
through Section 106 Outside
3. Records and Sacred Lands File Searches
122 ASM Affiliates
Primary # Type Description NRHP Eligibility Status APE Relationship process. Not evaluated for
CRHR or Local Listing
P-10-004787 Historic-era building 712 East Polk Street
Determined not eligible
for NRHP by consensus
through Section 106
process. Not evaluated for
CRHR or Local Listing Outside
P-10-004788 Historic-era building
Coalinga 4th District
Maintenance Yard
Bungalow
Determined eligible for
NRHP by a consensus
through Section 106
process. Listed in the
CRHR. Outside
P-10-004789 Historic-era structure
Coalinga 4th District
Maintenance Yard
Gateway Arch
Determined eligible for
NRHP by a consensus
through Section 106
process. Listed in the
CRHR. Outside
P-10-005019 Historic-era building 720 East Polk Street Outside P-10-005403 Historic-era building
Coalinga Polk Street
School
Determined not eligible
for NRHP by consensus
through Section 106
process. Not evaluated for
CRHR or Local Listing Outside
P-10-005595 Historic-era building
Old CDF Coalinga Fire
Station
Individual property listed
in NRHP by the Keeper.
Listed in the CRHR Outside
P-10-005769 Historic-era isolate Historic-era refuse Categorically not eligible Outside P-10-005771 Historic-era isolate Historic-era refuse Categorically not eligible Outside P-10-005772 Historic-era isolate Historic-era refuse Categorically not eligible Outside P-10-005830 Historic-era building Coalinga Library Building Recommended not
eligible Outside
P-10-005834 Historic-era site Refuse scatter Unknown Outside P-10-007414 Historic-era building 779 East Polk Street
Recommended not
eligible Outside
3.2 TRIBAL OUTREACH
As part of the CEQA process, a search of the Native American Heritage Commission (NAHC) Sacred Lands File was completed on May 9, 2024. Based on the NAHC records, the APE is negative for sacred sites or traditional cultural places. Outreach letters were sent on July 23, 2024, to tribal organizations on the NAHC contact list. Follow-up emails were sent on August 30, 2024.
On August 12, 2024, Table Mountain Rancheria responded stating the Project was out of their area of interest. No other responses were received as a result of this outreach. NAHC requests, NAHC results, Tribal outreach letters, and Tribal responses can be found in Confidential Appendix B.
4. Methods and Results
Coalinga Sanitary Sewer Collection System and WWTP Improvements Project 123
4. METHODS AND RESULTS
4.1 FIELD METHODS
The Class III inventory/Phase I survey of the Project APE was conducted from August to September 2024. ASM Associate Archaeologist Robert Azpitarte, BA, conducted the survey with assistance from Assistant Archaeologist Margarita Medina Lemus, BA. Parallel survey transects spaced at maximum intervals of 15 meters (m) apart were employed for pedestrian survey. The Class III inventory/Phase I survey included a review of the Project APE for the presence of built environment features. The field methods employed also included intensive pedestrian examination of the ground surface for evidence of archaeological sites in the form of artifacts, surface features (such as bedrock mortars or historical mining equipment), and archaeological indicators (e.g., organically enriched midden soil or burnt animal bone); the identification and location of any discovered sites, should they be present; tabulation and recording of surface diagnostic artifacts; site sketch mapping; preliminary evaluation of site integrity; and site recording, following the California Office of Historic Preservation (OHP) Instructions for Recording Historic Resources using California Department of Parks and Recreation (DPR) 523 forms. Parallel survey transects spaced at maximum intervals of 15 m. apart were employed for pedestrian survey of the 174.7 ac.
Project APE.
4.2 SURVEY RESULTS
4.2.1 Archaeological Results
The proposed Project APE consists of improvements to The Coalinga Wastewater Treatment Plant (WWTP APE), constructed in 1963, and its associated pipelines throughout the city of Coalinga (Pipelines APE). The Project APE outside of the water WWTP consists largely of paved roads (Figure 13 and Figure 14). As such, the vast majority of the APE has been hardscaped over. Within the water treatment facility, the majority of the APE was developed over (Figure 15 and Figure 16). Visibility within the WWTP outside of developed areas was excellent (over 95 percent) due to recent disturbance of the soil (Figure 18). Non-native vegetation inhibited visibility in undeveloped areas. A diffuse refuse scatter (WWTP-SITE-1) was observed on the northwestern edge of the existing aerator ponds in the WWTP APE. This resource is described below. No other archaeological resources were observed within the Project APE.
4. Methods and Results
124 ASM Affiliates
Figure 13. Project APE overview along Van Ness Street, facing east.
Figure 14. Project APE overview along Cherry Lane, facing west.
4. Methods and Results
Coalinga Sanitary Sewer Collection System and WWTP Improvements Project 125 Figure 15. WWTP APE infrastructure overview, facing east.
Figure 16. WWTP APE infrastructure overview, facing northwest.
4. Methods and Results
126 ASM Affiliates
Figure 17. Northwestern WWTP APE overview, facing southwest.
WWTP-SITE-1
The refuse concentration consists of a glass and ceramic scatter located along the northwestern edges of the existing aerator ponds. The scatter measures 1,016 ft. in length and 20 ft. in width and is entirely contained within the sloped pond embankment. Refuse was not identified in other areas of the WWTP. At least 3,000 highly fragmented pieces of assorted glass, including solarized amethyst glass, and dishware fragments were observed. Identified makers marks include Maywood glass (MARK) and Owens-Illinois (MARK)
Evaluation
The AIMS-R evaluation matrix defined in Section 2.5.3 serves as a useful rubric for evaluating historic-era archaeological sites.
Using the AIMS-R evaluation matrix for historic-era sites, the sites can be assessed for NRHP and CRHR eligibility as follows:
1. Association – WWTP-SITE-1 is ubiquitous throughout the region and lacks any clear social association. While it may be possible to associate a refuse scatter with an activity type, they lack clear association to any specific individual, and it is often unclear whether they are associated with domestic use or instead resulted from illicit dumping by residents of nearby towns. The only WWTP-SITE-1 is with the structural
4. Methods and Results
Coalinga Sanitary Sewer Collection System and WWTP Improvements Project 127 WWTP features they are found near. These features themselves have no distinguishable association with any specific individual or group. WWTP-SITE-1 therefore does not have research potential as an individual site due to the lack of a social or functional associative context.
2. Integrity – WWTP-SITE-1 includes materials of mixed ages from the early to midtwentieth century, without an associative context. Although identifiable materials such as bottle bases and ceramic sherds were recorded, many of the artifacts present are very fragmentary and thus lacking in integrity of design, workmanship, or setting.
3. Materials – WWTP-SITE-1 has a range in the variety of materials present, but overall the assemblage displays a limited diversity of artifact types that are ubiquitous throughout the region, most of which are mass-produced consumer goods.
4. Stratigraphy – Though stratigraphy is possible in historic-era refuse scatters, specifically when a privy is present, WWTP-SITE-1 is a surficial scatter which precludes stratigraphic development.
5. Rarity – No rare or unusual features/feature types were identified.
Based on the information above, WWTP-SITE-1 lacks association with important known historical events (Criterion A/CRHR Criterion 1) or individuals (Criterion B/CRHR Criterion 2) and does not represent a distinctive example of structural types or works of master craftsmen (Criterion C/CRHR Criterion 3). In addition, WWTP-SITE-1 lacks research potential beyond its recordation here (NRHP Criterion D/CRHR Criterion 4). Therefore, WWTP-SITE-1 is recommended as not NRHP/CRHR eligible.
Southern Pacific Railroad (P-10-003930)
Research revealed that a segment of the Southern Pacific Railroad (P-10-003930) is located within the Pipeline APE. The Southern Pacific Railroad extended northeast-southwest through the City of Coalinga (reference Confidential Appendix A), between the present streets of Glenn Avenue and Forest Avenue.
Segments of the Southern Pacific Railroad (P-10-003930) have previously been evaluated, and the resource has previously been recommended not eligible for listing in the NRHP or CRHR (Asselin and Baloian 2016; Jones et al. 2018; Schultz and Vanderslice 2007). In addition, the segment of the Southern Pacific Railroad (P-10-003930) that extends through the Pipeline APE has been determined not eligible by consensus through Section 106 process.
An October 2026 survey of the APE revealed no extant features of this resource, and all potentially associated features have been destroyed. The resource is a ruin whereby all the materials of the resource have been removed or deteriorated to the point that it cannot convey physical associations to any identified themes. As such, ASM agrees with the previous evaluations of the resource and no DPR update was completed for this resource.
4. Methods and Results
128 ASM Affiliates
Figure 18. WWTP-SITE-1 overview, facing north.
Figure 19. WWTP-SITE-1 refuse scatter.
4. Methods and Results
Coalinga Sanitary Sewer Collection System and WWTP Improvements Project 129
4.2.2 Built Environment Results
Coalinga Wastewater Treatment Plant
Coalinga WWTP is located immediately adjacent to Los Gatos Creek on the north and Warthan Creek on the west and measures 3,100 ft. (east-west) by 920 ft. (north-south).
The WWTP currently consists of four buildings and two primary structures: an operations building, an animal shelter building, a primary pump station building, a shed building, a digester structure, and a primary clarifier structure. It also retains additional secondary resources related to the process of waste treatment, including two aerated lagoons and three stabilization ponds to the east, a sludge bed to the immediate northeast of the plant site, and three sludge beds on the west.
Two modern shipping containers, placed in the 2010s, are also within the WWTP APE.
Coalinga Wastewater Treatment Plant Historic District
ASM investigated the potential for a historic district associated with the operations of the Coalinga WWTP. The Coalinga WWTP first appears in a 1944 topographic map of the area labeled as a sewage plant, and 1940 historic aerial photographs show a structure and water basin in the area.
By 1951, population growth spurred the incorporation of the City of Coalinga and prompted infrastructure improvements for higher capacity that led to a complete modernization and expansion of what is now the Coalinga WWTP in 1963. This first plant expansion included the Operations Building (Building 1), the Digester and Clarifier tanks (Structures 1 and 2 respectively), and the addition of a large body of water to the east of the plant site that conformed to pre-existing natural topographic configurations from Los Gatos Creek. These buildings and structures were modernized and improved in 1979, when the site was expanded again. This second expansion led to the reconfiguration of the large body of water to the east of the plant site, where three stabilization ponds and two aerated lagoons were added, likely to meet environmental standards. There were few improvements or additions until 1991, when a new primary pump station was constructed (Building 3) and the other buildings and structures were modernized as part of a third expansion, which also included the addition of a sludge-drying bed to the northeast of the plant site.
4 Based on the statewide historic context of WWTP prepared by JRP (2023) and the local historic context, ASM identified the period of significance (POS) for a potential Coalinga WWTP historic district. Although the presence of the sewage plant was recorded in the area as early as 1940, the contemporary configuration of the site was first constructed in 1963. Research did not reveal any buildings or structures within the plant older than 1963. The second recorded improvements to the site occurred in circa 1979, when some of the buildings and structures within the plant site were modernized to reflect environmental standards, and the area to the east of the plant site was expanded with the construction of additional resources of ponds and lagoons. The third expansion continued modernization of the plant with construction of new buildings and structures in 1991.
As such, the potential period of significance of the site as an example of a mid-century wastewater 4 First plant expansion: 1963; Second plant expansion: 1979; and third plant expansion: 1991.
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treatment plant in California begins in 1963, with the construction of the initial buildings and structures that support the incorporated City of Coalinga, and ends in 1979, when it was confirmed via drawings that lagoons and ponds were reconfigured from the existing body of water to the east and expanded the plant’s capacity.
According to the JRP (2023) report, wastewater treatment plants are an identified property type.
This resource notes that while modern plants “include secondary treatment with trickling filters or activated sludge tanks,” older plants “offer only primary treatment, using clarifiers to decrease the quantity of the suspended matter” (JRP 2023: 223). Coalinga WWTP operated under standard conditions and then was modernized to meet contemporary standards during the POS.
ASM then considered the boundary of the potential Coalinga WWTP historic district. To determine the boundary, ASM referenced the 1967 and 1971 historic aerial photographs of the plant site and the contemporary placement of fencing surrounding the plant site. The original plant site from the POS retained a sludge-drying bed directly to the north of the plant site that was removed in the 1991 expansion of the plant. Additionally, during the POS, a lagoon or body of water was extant to the east of the plant site and was likely related to the operations of the Coalinga WWTP. However, this body of water was modified in the c.1979 expansion of the plant. Therefore, the boundaries of the potential historic district that best reflect the extant resources from the POS are the historic boundaries of the plant site (Figures 20 and 21).
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Coalinga Sanitary Sewer Collection System and WWTP Improvements Project 131 Figure 20. Location Map of Coalinga WWTP APE and potential WWTP historic district boundary
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Coalinga Sanitary Sewer Collection System and WWTP Improvements Project 133 Figure 21. Aerial map that identifies the components of the Coalinga WWTP and the potential WWTP historic district boundary.
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Coalinga Sanitary Sewer Collection System and WWTP Improvements Project 135 Within the boundaries of the potential Coalinga WWTP historic district are several potential contributors. The buildings and structures that could potentially contribute to the potential Coalinga WWTP historic district are the Operations Building (Building 1), the Digester (Structure 1), and the primary clarifier (Structure 2). These buildings and structures were identified as potential contributors as they were constructed within the period of significance and directly contribute to the operations of the Coalinga WWTP.
One other building, the Animal Shelter Building (Building 2), was constructed during the period of significance within the boundary of the potential Coalinga WWTP historic district. However, this building is not a potential contributor as research did not reveal that it directly contributed to the operations of the Coalinga WWTP, and it likely only played a secondary or supporting role to the function of the plant. One other building, the Primary Pump Station (Building 3), was constructed within the boundary of the potential Coalinga WWTP historic district but is not a contributing resource as it was constructed outside of the POS. The various machinery and equipment present within the potential district boundaries, particularly the equipment related to the raw sewage influent located to the southwest of the clarifier, were installed outside of the POS and are therefore non-contributors. An additional building that was likely associated with the Coalinga WWTP was identified, the Shed Building (Building 4), but it is located outside of the potential district boundaries and was constructed outside of the POS and is therefore not considered a contributor. The two aerated lagoons and two stabilization ponds to the east of the plant site, the sludge-drying bed to the northeast of the plant site, and three sludge drying beds to the west of the plant site were all constructed after the POS, and therefore none are considered contributors.
ASM then considered whether the potential Coalinga WWTP historic district is eligible under any NRHP or CRHR considerations. Because wastewater treatment plants are an identified property type as defined by JRP (2023), ASM referenced and followed the evaluation procedures in that report to determine whether the potential historic district retained any historic significance.
ASM first considered whether the potential Coalinga WWTP historic district is eligible under NRHP/CRHR Criterion A/1. The JRP (2023) report notes that a district may be eligible under this criterion if it had “historic importance above and beyond fulfilling its ordinary role,” if it “introduced or proved the efficiency of an important new technology…public health measure, environmental treatment standard,” if it was “closely associated with the creation of a type of political organization,” or finally if it was “the clearly identified focus of important social or political conflicts” (JRP 2023:253). ASM referenced local newspapers and other primary and secondary sources for information regarding the reception of the 1963 modernization and expansion of the Coalinga WWTP. The expansion was popular amid the City of Coalinga and within Fresno County because the improved infrastructure could support greater development within the city and support agricultural growth at a time when the population of the city and county were expanding. Because the impetus of the 1963 modernization was to accommodate for growth, and because the modernization that occurred appears to be standard across California wastewater treatment plants, it does not appear to have retained historic importance beyond its ordinary role and did not introduce any new technology. While the plant was updated in later years to meet environmental standards, these updates appear to be standard, and research did not reveal that the Coalinga WWTP was an important site for the testing or implementation of any new technology.
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ASM did not find any reference to political or social conflicts associated with the plant. As such, the Coalinga WWTP appears to be the result of standard mid-century modernization of wastewater treatment plants in California. Therefore, ASM recommends that the potential Coalinga WWTP historic district is not eligible for listing in the NRHP/CRHR under Criterion A/1.
ASM then considered whether the potential Coalinga WWTP historic district is eligible for listing in the NRHP/CRHR under Criterion B/2. Research did not reveal that an individual of historic importance was associated with the Coalinga WWTP. The JRP (2023) report notes that “wastewater systems do not commonly have strong, direct association with single individuals” (JRP 2023:256). This statement applies to the Coalinga WWTP as no specific individual was identified in any announcements related to the plant, nor did research reveal that a specific individual important to the history of the state or nation was directly associated with the Coalinga WWTP. As such, ASM recommends that the potential Coalinga WWTP historic district is not eligible for listing in the NRHP/CRHR under Criterion B/2.
ASM then considered whether the Coalinga WWTP historic district is eligible for listing in the NRHP/CRHR under Criterion C/3. The JRP (2023) report notes that a wastewater treatment plant may be historically significant if it is the “earliest, best preserved, or a rare surviving example of its type,” if it “introduced a design innovation,” or finally if it “represents a transition between different expressions of the property type” (JRP 2023:256). Because the Coalinga WWTP was completely re-constructed, reconfigured, and modernized in 1963, performs standard operations associated with waste management, and replaced an earlier sewage plant, it is not the earliest, best preserved, nor a rare surviving example of its type. Research did not reveal that the Coalinga WWTP introduced any new design innovations. It appears to have undergone standard midcentury modernization with no reference to unique or new design innovations in relation to the operations and practices of the plant. Based on the historic context of wastewater management in California (JRP 2023), the Coalinga WWTP reflects period appropriate wastewater management practices and does not appear to represent a transition period. The buildings and structures that were constructed within the POS (the operations building, the digester, and the clarifier) represent standard operating practices for the mid-century, and the previous buildings and structures from the earlier decades of the twentieth century that the Coalinga WWTP replaced were removed entirely. Therefore, ASM recommends that the potential Coalinga WWTP historic district is not eligible for listing in the NRHP/CRHR under Criterion C/3.
Finally, the potential Coalinga WWTP historic district includes several buildings and structures that reflect common designs and whose function, use, design, and construction are readily apparent and therefore do not have the potential to provide information about history or prehistory that is not available through historic research. Therefore, ASM recommends that the potential Coalinga WWTP historic district is not eligible for listing in the NRHP/CRHR under Criterion D/4.
In conclusion, the potential Coalinga WWTP historic district does not meet any of the NRHP/CRHR eligibility criteria; therefore, ASM recommends that the potential Coalinga WWTP historic district is not eligible as a historic district associated with the Coalinga WWTP.
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Coalinga Sanitary Sewer Collection System and WWTP Improvements Project 137 Operations Building (Building 1)
The Operations Building was constructed in 1963, which was represented on the USGS (1963) topographic map, and confirmed on the 1967 historic aerial photograph of the area. The 1979 plans labeled the building as both an existing pumphouse and existing utility building and discussed proposed modifications for the building as part of the site expansion. By 1990, this building became known as an operations building.
Before the site expansions that occurred in 1991, this building served as the primary operations building for the site. This is reflected in the plaque that was placed on the building in 1964 when the Coalinga Sewer Plant was dedicated to the City of Coalinga after construction in 1963. This building likely replaced a smaller pump house that once supported the smaller sewer plant before the 1963 expansion. This building continued to provide sole support as the primary building associated with the sewer plant until the plant expanded again in 1991 and more support buildings were constructed. The JRP (2023) report identifies the Operations Building as most closely resembling the Control Building property type element. This building type is described as retaining a “control console that automates plant monitoring and operations,” and may include additional support structures such as “vehicle garages, workshops, and storage warehouses” (JRP 2023:230).
An October 2024 survey of the site revealed that the building is one-story and square, features a flat roof, and corrugated metal siding on all façades. The primary façade faces east, and features a covered porch, an entry area composed of two flat, metal doors, and a plaque commemorating the dedication of the building. The extending roof that creates the covered entry area is supported by three equidistant metal beams. The primary entrance doors are on the southern side of the wall, and a row of windows between the top of the entry doors and the roofline provide both light and ventilation into the interior space. Metal screens that appear to have since been added to the windows obscure the materials of the windows in this area. The area under the covered entry area is composed of poured concrete.
The side façade facing north retains the corrugated metal siding and provides additional entrance points into the interior of the building. One entrance point is slightly recessed and features a single flat, metal door. The other entrance point is not recessed; however, it features an extended porch roof covering that provides shade, and double flat, metal doors that appear to have ventilation paneling in the lower half of the door. The side façade facing south also retains the corrugated metal siding but no further architectural details or features beyond the presence of an outdoor lighting fixture and a generator. The rear façade similarly features no architectural details or fixtures beyond the continued use of corrugated metal siding and a utility box that appears to be associated with the nearby equipment (Figures 22–26).
ASM considered whether the Operations Building is individually eligible under any NRHP/CRHR criteria. Because the Operations Building is an identified property type element associated with Waste Treatment Plants as defined by JRP in their 2023 report, ASM referenced and followed the evaluation procedures stipulated in that report in order to determine the historic significance of the building.
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Figure 22. Building One, the Operations Building. Primary façade, view toward east.
Figure 23. Building One, the Operations Building. Side and primary façade, view toward southwest.
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Coalinga Sanitary Sewer Collection System and WWTP Improvements Project 139 Figure 24. Building One, the Operations Building. Rear façade, view toward west.
Figure 25. Building One, the Operations Building. Side and primary façade, view toward northeast.
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Figure 26. Detail of the plaque on the primary façade of Building One, the Operations Building.
ASM first considered whether the Operations Building is eligible for listing in the NRHP/CRHR under Criterion A/1. The JRP (2023) historic context notes that an individual feature may be eligible under this criterion if it had “historic importance above and beyond fulfilling its ordinary role,” if it “introduced or proved the efficiency of an important new technology…public health measure, environmental treatment standard,” if it was “closely associated with the creation of a type of political organization” or finally if it was “the clearly identified focus of important social or political conflicts” (JRP 2023:253). Research did not reveal that the Operations Building and its associated role in the wastewater management of the City of Coalinga was associated with the introduction of any new technology, public health measure, or environmental standard. Research additionally did not reveal that the construction and the use of the Operations Building and its associated role in wastewater management was associated with any political organization, nor was it ever a focus of important social or political conflicts. Because eligibility under this Criterion requires that the building must be an important example of a specific trend or theme related to the above described qualifications, the Operations Building does not qualify as historically significant under this criterion. Furthermore, although the building was modernized and was associated with the expansion of the plant, the expansion and modernization did not introduce any new services nor fundamentally change the nature of the municipal water system. Although the Operations Building was constructed as a result of modernization and expansion, the JRP (2023) report notes that “the construction of new, modern infrastructure is a routine function of municipal public
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Coalinga Sanitary Sewer Collection System and WWTP Improvements Project 141 service departments to account for population growth” (JRP 2023:254). This seems to be the case with the construction of the Operations Building in 1963, which replaced an older pump house building. Therefore, ASM does not recommend the Operations Building individually eligible for listing in the NRHP/CRHR under Criterion A/1.
ASM then considered whether the Operations Building is individually significant under NRHP/CRHR Criterion B/2. Research did not reveal that an individual of historic importance was associated with the Operations Building. The JRP (2023) historic context notes that “wastewater systems do not commonly have strong, direct association with single individuals” (JRP 2023:255).