Habitat Assessment & CVMSHCP Consistency Report
DHS Varner & West Project, APN 669-150-002
Updated April 2025
The one bird observed onsite included the common raven (Corvus corax). Other common bird species expected to occur onsite include, but are not limited to, house finch (Haemorhous mexicanus), Say’s phoebe (Sayornis saya), mourning dove (Zenaida macroura), and yellow-rumped warbler (Setophaga coronata).
It should be noted that relatively short-term biological studies of this nature are often limited by the seasonality of annual plants, the migratory habits of many birds, the fossorial and nocturnal habits of many mammals and reptiles, and the timing of field surveys. A complete inventory of the wildlife on the site would require extensive year-round surveys for birds, amphibians, and reptiles, and additional surveys, such as placement of scent stations or tracking stations, for the detection of nocturnal mammals. Knowledge of habitat associations, natural history, seasonality, and distribution is essential in the assessment of the potential for occurrence of the various special status plants and animals known to occur throughout the various areas of Riverside County. For these reasons, other common and special status species that were not observed on-site may also have the potential to occur based on their geographic distribution, habitat preferences, and the regional location of the site. Tables 1-6 below summarize information on special status species known to occur in the vicinity of the project site, including the status of each species on the project site based on the best available information and the collective expertise of WSP biologists.
5.6 Special Status Species
Plant or animal taxa may be considered "sensitive" or as having “special status” due to declining populations, vulnerability to habitat change, or because they have restricted ranges. Some are listed as threatened or endangered by the USFWS or by the CDFW and are protected by the federal and state Endangered Species acts and the California Native Plant Protection Act. Others have been identified as sensitive or as special status species by the USFWS, the BLM, the CDFW, or by private conservation organizations, including the CNPS. Unlisted sensitive species do not have formal state or federal status but may nevertheless be considered significant under the CEQA.
No special status species, flora, or fauna were detected onsite. The review of the CNDDB, CNPS Online Inventory of Rare Plants, other biological reports from the vicinity, and consultation with other experienced biologists/naturalists resulted in the identification of sixty-four (64) special status biological resources known to occur in the vicinity (within an approximate 5-mile radius) of the project site. These included thirty (30) plants, three (3) vegetation communities, six (6) invertebrates, five (5) reptiles, ten (10) birds and ten (10) mammals. Tables 1 through 6 provide a complete list of the special status biological resources, their associated legal status, and their respective onsite occurrence potentials.
Item Number: 1.
Habitat Assessment & CVMSHCP Consistency Report
DHS Varner & West Project, APN 669-150-002
Updated April 2025
The CVMSHCP provides conservation for twenty-seven (27) imperiled plant and animal species (five (5) plants, two (2) insects, one (1) amphibian, three (3) reptiles, eleven (11) birds, and five (5) mammals). These include federal and state-listed species, federal and California Species of Concern, and species on the CNPS California Rare Plant Ranking system. CVMSHCP covered species are designated on the tables below.
The site does appear to be within modeled habitats for two special status fauna species addressed by the CVMSHCP. This includes LeConte’s thrasher (Toxostoma lecontei), and Palm Springs pocket mouse (Parognathus longimembris bangsi). CVMSHCP modeled habitat is also present within the nearby designated conservation areas. These include but are not necessarily limited to: Coachella Valley milk-vetch (Astragalus lentiginosus var. coachellae), Little San Bernardino Mountains linanthus (Linanthus maculatus ssp. maculatus), Coachella Valley Jerusalem cricket (Stenopelmatus cahuilaensis), Coachella Valley fringe-toed lizard (Uma inornata), and flat-tailed horned lizard (Phrynosoma mcallii) (CVCC 2022).
No special status flora was detected on-site during the field assessment. The project site also does not appear to fall within designated critical habitat for any special status flora species (USFWS 2022). Limited potentially suitable habitat remains present onsite for a few special status flora species known from the vicinity. These include Coachella Valley milk-vetch, Little San Bernardino Mountains linanthus, and desert spike-moss (Selaginella Eremophila).
No special status wildlife species were observed or detected onsite during the assessment. Limited potentially suitable habitat remains present onsite for a variety of special status wildlife species known from the vicinity. These include red-diamond rattlesnake (Crotalus ruber), flat-tailed horned lizard, Coachella Valley fringe-toed lizard, burrowing owl, black-tailed gnatcatcher (Polioptila melanura), pallid San Diego pocket mouse (Chaetodipus fallax pallidus), Palm Springs pocket mouse and Coachella Valley (Palm Springs) round-tailed ground squirrel.
Tables 1 through 6 summarize information on all special status species that have been reported within the vicinity (5-mile radius) or are considered to have some potential to occur onsite based on known geographic distribution and the presence of potentially suitable habitat. These tables provide the names, legal or conservation status, general habitat associations, and the probability of occurrence for each of these species.
Item Number: 1.
Habitat Assessment & CVMSHCP Consistency Report
DHS Varner & West Project, APN 669-150-002
Updated April 2025
Table 1. Special Status Plants
Species Status Habitat Probability
Abronia villosa var. aurita
chaparral sand-verbena
CVMSHCP = No
F = None
C = S2
CNPS: CRPR 1B.1
Sandy areas in chaparral &
coastal sage scrub; 80-
1,600 meters (m) (260-
5,250 feet [ft]). Known only
from Riverside, Orange
(believed extirpated), and
San Diego Counties.
(Blooms (B): Jan-Aug.
Absent
Suitable habitat lacking.
Acmispon haydonii
pygmy lotus
CVMSHCP = No
F = None
C = S3
CNPS: CRPR 2B.3
Perennial herb found in
creosote bush scrub, rocky,
and pinyon-juniper
woodland habitats; 520-
1,200 m (1,700-3,950 ft). B:
Jan-Jun.
Absent
Habitat unsuitable, site
below known elevational
range.
Almutaster
pauciflorus
alkali marsh
aster
CVMSHCP = No
F = None
C = S1S2
CNPS: CRPR 2B.2
Meadow and seep; 280-
1010 m (920-3,315 ft). B:
Jun–Oct.
Absent
Suitable habitat lacking,
site below known
elevational range.
Ambrosia monogyra
singlewhorl burrobrush
CVMSHCP = No
F = None
C = S2
CNPS: CRPR 2B.2
Perennial shrub found in
sandy soils, Sonoran Desert
scrub & chaparral; 10-500
m (32-1,640 ft). B: Aug–
Nov.
Absent
Suitable habitat present,
however, nearest recorded
location historic (1919) and
outside of vicinity.
Astragalus hornii var. hornii
Horn's milk-vetch
CVMSHCP = No
F = None
C = S1
CNPS: CRPR 1B.1
Alkali playa, Meadow &
seep, Wetland; 60-850 m
(195-2,790 ft); B: May-Oct.
Absent
Suitable habitat lacking.
Astragalus lentiginosus var.
coachellae
Coachella Valley milk-vetch
CVMSHCP = Yes
F = END
C = S1
CNPS: CRPR 1B.2
Sonoran Desert scrub;
sandy flats, washes,
outwash fans, sometimes
on dunes; 40-665 m (131-
2,182 ft). B: Jan–Sept.
Moderate-High
Suitable habitat present,
species known from
immediate vicinity. Nearest
CNDDB records ~0.4 miles
west/northwest.
Astragalus tricarinatus
triple-ribbed milk-vetch
CVMSHCP = Yes
F = END
C = S2
CNPS: CRPR 1B.2
Joshua tree woodland &
Sonoran Desert scrub on
hot, rocky slopes in
canyons & along edge of
boulder-strewn desert
washes with
Larrea and Encelia; 455-
1525 m (1,492-5,000 ft). B:
Feb–May.
Absent
Suitable habitat lacking,
site below known
elevational range.
Item Number: 1.
Habitat Assessment & CVMSHCP Consistency Report
DHS Varner & West Project, APN 669-150-002
Updated April 2025
Table 1. Special Status Plants
Species Status Habitat Probability
Atriplex parishii
Parish's brittlescale
CVMSHCP = No
F = None
C = S1
CNPS: CRPR 1B.1
Alkali playa, Chenopod
scrub, Meadow & seep,
Vernal pool, Wetland; 0-
500 m (0-1,640 ft); B: JunOct.
Absent
Suitable habitat lacking,
nearest records from Palm
Springs.
Ayenia compacta
California ayenia
CVMSHCP = No
F = None
C = S3
CNPS: CRPR 2B.3
Rocky canyons & sandy or
gravelly washes; 150- 1,095
m (500-3,600 ft). In
California, known from
Providence Mountains,
Eagle Mountains & west
edge of Sonoran Desert. B:
Mar-Apr
Absent
Suitable habitat lacking.
Caulanthus simulans
Payson's jewelflower
CVMSHCP = No
F = None
C = S4
CNPS: CRPR 4.2
Chaparral & coastal scrub;
650-1900 m (2,135-6,235
ft); B: Mar-May
Absent
Suitable habitat lacking,
site below known
elevational range.
Chorizanthe parryi var. parryi
Parry’s spineflower
CVMSHCP = No
F = None
C = S3
CNPS: CRPR 1B.1
Dry sandy soils in chaparral
& coastal scrub; 40-1,750
m (100-5,700 ft). Known
only from Riverside and
San Bernardino Counties
and possibly extending
into Los Angeles County. B:
Apr-Jun.
Absent
Suitable habitat lacking,
nearest CNDDB records
from Palm Springs.
Chorizanthe xanti var. leucotheca
white-bracted spineflower
CVMSCHP = No
F = None
C = S3
CNPS: CRPR 1B.2
Mojavean desert scrub,
pinyon & juniper
woodland, sandy or
gravelly; 300-1200 m (980-
3,940 ft). B: Apr-Jun.
Absent
Suitable habitat lacking,
site below known
elevational range.
Dodecahema leptoceras
slender-horned spineflower
CVMSHCP = No
F = END
C = END, S1
CNPS: CRPR 1B.1
Chaparral, Cismontane
woodland, Coastal scrub;
350-2,290 m (1,150-7,515
ft); B: Apr-Jun
Absent
Suitable habitat lacking,
site below known
elevational range.
Eriastrum harwoodii
Harwood’s eriastrum
CVMSHCP = No
F = None
C = S2
CNPS: CRPR 1B.2
Desert dunes; 125-915 m
(410-3000 ft). B: Mar-Jun.
Absent
Suitable habitat lacking, no
records within vicinity.
Euphorbia arizonica
Arizona spurge
CVMSHCP = No
F = None
C = S3
CNPS: CRPR 2B.3
Sandy soils in Sonoran
Desert scrub; 50-300 m
(200-1000 ft). B: Mar-Apr.
Absent
Marginally suitable habitat,
however, no records within
vicinity.
Euphorbia misera
cliff spurge
CVMSHCP = No
F = None
C = S2
CNPS: CRPR 2B.2
Coastal bluff scrub, coastal
scrub & Mojavean Desert
scrub; 10-500 m (35-1640
ft). B: Oct-Aug (perennial
shrub).
Absent
Suitable habitat lacking,
nearest records from
Whitewater Canyon and
Palm Springs.
Item Number: 1.
Habitat Assessment & CVMSHCP Consistency Report
DHS Varner & West Project, APN 669-150-002
Updated April 2025
Table 1. Special Status Plants
Species Status Habitat Probability
Euphorbia platysperma
flat-seeded spurge
CVMSHCP = No
F = None
C = S1
CNPS: CRPR 1B.2
Desert dunes, Mojavean
desert scrub; 65-100 m
(215-330 ft); B: Feb-Sep
Absent
Suitable habitat lacking,
site above known
elevational range.
Heuchera hirsutissima
shaggy-haired alumroot
CVMSHCP = No
F = None
C = S3
CNPS: CRPR 1B.3
Subalpine coniferous
forest, Upper montane
coniferous forest; 1,610-
3,290 m (5,280-10,795 ft);
B: Jun-Jul
Absent
Suitable habitat lacking,
site below known
elevational range.
Imperata brevifolia
California satintail
CVMSHCP = No
F = None
C = S3
CNPS: CRPR 2B.1
Chaparral, Coastal scrub,
Meadow & seep, Mojavean
desert scrub, Riparian
scrub, Wetland; 110-2,280
m (360-7,480 ft); B: SepMay
Absent
Suitable habitat lacking.
Lilium parryi
lemon lily
CVMSHCP = No
F = None
C = S3
CNPS: CRPR 1B.2
Lower montane coniferous
forest, Meadow & seep,
Riparian forest, Upper
montane coniferous forest,
Wetland; 1,390-2,450 m
(4,560-8,040 ft); B: Jul-Aug
Absent
Suitable habitat lacking,
site below known
elevational range.
Linanthus jaegeri
San Jacinto linanthus
CVMSHCP = No
F = None
C = S2
CNPS: CRPR 1B.2
Subalpine coniferous
forest, Upper montane
coniferous forest; 2900-
3000 m (9,514-9,842 ft); B:
Jul-Sep
Absent
Suitable habitat lacking,
site below known
elevational range.
Linanthus maculatus maculatus
Little San Bernardino
Mountains linanthus (gilia)
CVMSHCP = Yes
F = None
C = S2
CNPS: CRPR 1B.2
Desert dunes, Sonoran &
Mojavean Desert scrub,
Joshua tree woodland;
most often on low benches
along washes or bajadas
where substrate shows
evidence of water flow;
195-2075 m (635-6,800 ft).
B: Mar–May.
Low
Potentially suitable habitat
present, nearest CNDDB
records ~2.25 miles east of
site.
Mentzelia tricuspis
spiny-hair blazing star
CVMSHCP = No
F = None
C = S2
CNPS: CRPR 1B.2
Mojavean Desert scrub &
creosote bush scrub.
Occurs in sandy, gravelly,
slopes, and washes; 150-
1280 m (490-4,200 ft). In
California known only from
Riverside, San Bernardino,
San Diego Counties. B:
Mar–May.
Absent
Potentially suitable habitat
present, however, nearest
CNDDB records from
Whitewater, outside of
vicinity.
Item Number: 1.
Habitat Assessment & CVMSHCP Consistency Report
DHS Varner & West Project, APN 669-150-002
Updated April 2025
Table 1. Special Status Plants
Species Status Habitat Probability
Nemacaulis denudata var.
gracilis
slender cottonheads
CVMSHCP = No
F = None
C = S2
CNPS: CRPR 2B.2
Sandy places in coastal
dunes, desert dunes &
Sonoran Desert scrub; 50-
400 m (164-1315 ft). B:
Mar– May.
Absent
Suitable habitat lacking,
nearest CNDDB record
from Palm Springs.
Pelazoneuron puberulum var.
sonorense
Sonoran maiden fern
CVMSHCP = No
F = None
C = S2
CNPS: CRPR 2B.2
Streams and seeps; San
Jacinto Mountains & San
Gabriel Mountains west in
Riverside, San Bernardino,
and Los Angeles Counties;
50-610 m (170- 2000 ft). B:
Jan-Sept.
Absent
Suitable habitat lacking.
Saltugilia latimeri
Latimer's woodland-gilia
CVMSHCP = No
F = None
C = S3
CNPS: CRPR 1B.2
Chaparral, Limestone,
Mojavean desert scrub,
Pinon & juniper
woodlands; 650-1,720 m
(2,135-5,645 ft); B: Mar-Jun
Absent
Suitable habitat lacking.
Selaginella eremophila
desert spike-moss
CVMSHCP = No
F = None
C = S2S3
CNPS: CRPR 2B.2
Chaparral, Sonoran Desert
scrub; shaded sites,
gravelly soils, crevices or
among rocks; 200-900 m
(656-2953 ft). B: May–Jul.
Low
Potentially suitable habitat
present, nearest CNDDB
records ~4 miles
southwest.
Stemodia durantifolia
purple stemodia
CVMSHCP = No
F = None
C = S2
CNPS: CRPR 2B.1
Wet sand or rocks, drying
riverbeds, Sonoran Desert
scrub; 180-300 m (600-
1000 ft). B: Apr-Dec.
Absent
Suitable habitat lacking.
Streptanthus campestris
southern jewel-flower
CVMSHCP = No
F = None
C = S3
CNPS: CRPR 1B.3
Open rocky areas in
chaparral, lower montane
coniferous forest &
pinyon-juniper; 900-2300
(2953-7546 ft). B: May-Jul.
Absent
Suitable habitat lacking,
site below known
elevational range.
Xylorhiza cognata
Mecca aster
CVMSHCP = Yes
F = None
C = S2
CNPS: CRPR 1B.2
Steep slopes of arid
canyons in sandstone &
clay in Sonoran Desert
scrub in Imperial and
Riverside Counties, known
mostly from the Indio and
Mecca hills of Riverside
County; 20-300 m (70-
1000 ft). B: Jan-Jun.
Absent
Suitable habitat lacking.
Table 2. Special Status Vegetation Communities
Community Status Habitat Probability
desert fan palm oasis
woodland
CVMSHCP = Yes
F=None
C= S3.2
Natural California fan palm
(Washingtonia filifera)
stands
Absent
No palms present.
Item Number: 1.
Habitat Assessment & CVMSHCP Consistency Report
DHS Varner & West Project, APN 669-150-002
Updated April 2025
Table 2. Special Status Vegetation Communities
mesquite bosque
CVMSHCP = Yes
F=None
C= S2.1
Stands of honey mesquite
(Prosopis glandulosa)
Absent
No mesquites present.
southern riparian forest
CVMSHP = Yes
F=None
C= S4
Tree species that are winter
deciduous.
Absent
No riparian present.
Table 3. Special Status Invertebrates
Community Status Habitat Probability
Bombus crotchii
Crotch's bumble bee
CVMSHCP = No
F = None
C = CAN END S2
inhabits grasslands,
shrublands and requires a
hotter and drier
environment than other
bumblebee species. food
source: milkweeds, dusty
maidens, lupines, medics,
phacelias, sages, clarkias,
poppies, and wild
buckwheats.
Absent
Suitable habitat lacking,
nearest CNDDB records
from Palm Springs.
Bombus pensylvanicus
American bumble bee
CVMSHCP = No
F = None
C = S2
Coastal prairie, Great Basin
grassland, Valley & foothill
grassland
Absent
Suitable habitat lacking.
Calileptoneta oasa
Andreas Canyon leptonetid
spider
CVMSHCP = No
F = None
C = S1
Mojavean desert scrub
Absent
Potentially suitable
habitat present, however,
no records within vicinity.
Dinacoma caseyi
Casey's June beetle
CVMSHCP = No
F = END
C = S1
Desert wash, Mojavean
desert scrub
Absent
Potentially suitable
habitat, however, known
populations occur within
Palm Springs only.
Macrobaenetes valgum
Coachella giant sand-treader
cricket
CVMSHCP = Yes
F=None
C= S2
Active sand dunes, sandy
washes
Absent
Suitable habitat marginal.
Site stabilized and
disturbed. No records
within vicinity.
Stenopelmatus cahuilaensis
Coachella Valley Jerusalem
cricket
CVMSHCP = Yes
F = None
C = S2
Sandy, moist soils in
Coachella Valley
Very Low-Absent
Suitable habitat marginal,
but disturbed. Nearest
CNDDB records ~2.5
miles southwest.
Item Number: 1.
Habitat Assessment & CVMSHCP Consistency Report
DHS Varner & West Project, APN 669-150-002
Updated April 2025
Table 4. Special Status Reptiles
Species Status Habitat Probability
Crotalus ruber
red-diamond rattlesnake
CVMSHCP = No
F = None
C = SSC, S3
Chaparral, woodland,
grassland, desert in rocky
areas & dense vegetation,
Needs burrows, rock
cracks, or surface cover
objects.
Very low
Marginally suitable
habitat present and site
adjacent to other suitable
open space. Nearest
CNDDB records ~3 miles
north/northeast.
Gopherus agassizi
desert tortoise
CVMSHCP = Yes
F: THR
C: THR, S2S3
Creosote bush scrub,
Joshua tree woodland,
saltbush scrub); washes,
arroyos, bajadas, rocky
hillsides, open flat desert.
Absent
Marginally suitable
habitat. Sign not
observed, No records
within vicinity.
Phrynosoma blainvillii
coast horned lizard
CVMSHCP = No
F: None
C: SSC, S4
Annual grassland, coastal
sage scrub, chaparral &
woodland communities.
Prefers sandy open areas,
washes & floodplains.
Requires open areas for
sunning, bushes for cover,
patches of loose soil for
burial & an abundant
supply of ants or other
insects. Occurs adjacent
foothills below 1200 m
(4,000 ft), in coastal areas
of central California & in
non-desert areas of
southern California below
1830 m (6000 ft).
Absent
Marginally suitable
habitat present, however,
site may be outside of
known distribution.
Phrynosoma mcallii
flat-tailed horned lizard
CVMSHCP = Yes
F = None
C = SSC, S3
Sandy and gravelly areas
in desert washes, edges of
dunes and desert flats;
requires vegetative cover,
ants & fine sand.
Moderate-High
Suitable habitat present,
CNDDB records from
immediate vicinity, ~0.35
miles southwest.
Uma inornata
Coachella Valley fringe-toed
lizard
CVMSHCP = Yes
F = THR
C = END, S1
Requires fine, loose,
windblown sand (dunes)
interspersed with hardpan
& widely spaced desert
shrubs. Known only from
the Coachella Valley.
Moderate-High
On-site habitat marginal,
suitable sands likely too
little in presence for this
species. However, CNDDB
records occur within site
boundaries and
immediately surrounding
the site. May be found
onsite as a pass-through
occurrence from a nearby
property.
Item Number: 1.
Habitat Assessment & CVMSHCP Consistency Report
DHS Varner & West Project, APN 669-150-002
Updated April 2025
Table 5. Special Status Birds
Species Status Habitat Probability
Aimophila ruficeps canescens
southern California rufouscrowned sparrow
CVMSHCP = No
F = MBTA, BCC
C = S4, FGC, WL
Chaparral, Coastal scrub
Breeding: Absent
Suitable habitat lacking.
Foraging: Absent
No records within vicinity.
Aquila chrysaetos
golden eagle
CVMSHCP = No
F = MBTA, BCC
C = S3, FGC, WL
Broadleaved upland
forest, Cismontane
woodland, Coastal prairie,
Great Basin grassland,
Great Basin scrub, Lower
montane coniferous
forest, Pinon & juniper
woodlands, Upper
montane coniferous
forest, Valley & foothill
grassland
Breeding: Absent
Suitable habitat lacking.
Foraging: Low
May nest or winter nearby
& forage over site.
CNDDB records from
project quadrangle.
Athene cunicularia
burrowing owl
CVMSHCP = Yes*
F = MBTA, BCC
C = SSC (burrows), S2,
FGC
Open, dry annual or
perennial grassland,
deserts & scrublands
characterized by lowgrowing vegetation.
Burrow sites essential.
Breeding: Low
Site is disturbed. Limited
suitable habitat and no
suitable ground squirrel
burrows present. No sign
detected.
Foraging: Low –
Moderate
May nest on nearby lands
to north, south, east, west
and, if so, forage onsite.
CNDDB records within
vicinity.
Cypseloides niger
black swift
CVMSHCP = No
F = MBTA, BCC
C = SSC (nesting), S3,
FGC
Open sky over mountains,
coastal cliffs. Forages
widely over any kind of
terrain but is still very
local in its occurrence,
probably limited to
regions with suitable
nesting sites. Nests on
ledges or in crevices in
steep cliffs, either along
coast or near streams or
waterfalls in mountains.
Breeding: Absent
Suitable habitat lacking.
Foraging: Absent
No records within vicinity.
Item Number: 1.
Habitat Assessment & CVMSHCP Consistency Report
DHS Varner & West Project, APN 669-150-002
Updated April 2025
Table 5. Special Status Birds
Species Status Habitat Probability
Falco mexicanus
prairie falcon
CVMSHCP = No
F = MBTA, BCC
C = SSC (nesting), S4,
FGC, WL
Inhabits dry, open terrain,
either level or hilly.
Breeding sites located on
cliffs, but forages far
afield.
Breeding: Absent
Suitable habitat lacking.
Foraging: Low
May nest or winter nearby
& forage over site.
CNDDB records within
vicinity.
Polioptila californica californica
coastal California gnatcatcher
CVMSHCP = No
F = MBTA, BCC
C = SSC (nesting), S2,
FGC
Coastal bluff scrub,
Coastal scrub
Breeding: Absent
Suitable habitat lacking.
Foraging: Low
May nest or winter nearby
& forage over site.
CNDDB records within
vicinity.
Polioptila melanura
black-tailed gnatcatcher
CVMSHCP = No
F = MBTA, BCC
C = SSC (nesting),
S3S4, FGC, WL
Mojavean desert scrub,
Sonoran desert scrub
Breeding: Low
Potentially suitable
habitat present.
Foraging: Low
May nest or winter nearby
& forage over site.
CNDDB records within
vicinity.
Toxostoma Crissale
Crissal thrasher
CVMSHCP = Yes
F = MBTA, BCC
C = SSC (nesting), S2,
FGC
Riparian woodland
Breeding: Absent
Suitable habitat lacking.
Foraging: Low
May nest or winter nearby
& forage over site.
CNDDB records within
vicinity.
Toxostoma lecontei
Le-Conte’s thrasher
CVMSHCP = Yes*
F = MBTA, BCC
C = SSC (nesting), S3,
FGC
Desert resident; primarily
of open desert wash,
desert scrub, alkali desert
scrub, and desert
succulent scrub habitats.
Nest in dense, spiny shrub
or densely branched
cactus in desert wash
habitat, usually 2-8 feet
above ground.
Breeding: Absent
Suitable habitat lacking.
Foraging: Low
May nest or winter nearby
and/or forage over site.
CNDDB records within
vicinity.
Item Number: 1.
Habitat Assessment & CVMSHCP Consistency Report
DHS Varner & West Project, APN 669-150-002
Updated April 2025
Table 5. Special Status Birds
Species Status Habitat Probability
Vireo bellii pusillus
least Bell's vireo
CVMSHCP = Yes*
F = END, MBTA, BCC
C = END, SSC
(nesting), S3, FGC
Riparian forest, Riparian
scrub, Riparian woodland
Breeding: Absent
Suitable habitat lacking.
Foraging: Low
May nest or winter nearby
& forage over site.
CNDDB records within
vicinity.
* Species is to be conserved under the CVMSHCP, but is still protected by the MBTA Table 6. Special Status Mammals
Species Status Habitat Probability
Chaetodipus fallax pallidus
pallid San Diego pocket mouse
CVMSHCP = No
F = None
C = SSC, S3S4
Desert border areas in
desert wash, desert scrub,
desert succulent scrub,
pinon-juniper, etc. Sandy
herbaceous areas usually
in association with rocks
or coarse gravel.
Low
On-site habitat marginal,
nearest records ~3.5
miles southwest.
Corynorhinus townsendii
Townsend’s big-eared bat
CVMSHCP = No
F = CAN, THR
C = SSC, S2
WBWG: H
Known to occur
throughout California in a
wide variety of habitats.
Roosts in the open,
hanging from walls &
ceilings. Roosting sites
limiting. Extremely
sensitive to human
disturbances.
Roost Site: Absent
Suitable habitat lacking.
Foraging: Absent
Habitat marginal;
However, no CNDDB
records within vicinity of
project.
Lasiurus xanthinus
western (southern) yellow bat
CVMSHCP = Yes
F = None
C = SSC, S3
WBWG: H
Found in valley foothill
riparian, desert riparian,
desert wash, and palm
oasis. Roosts in trees,
particularly palms.
Forages over water and
among trees.
Roost Site: Absent
Suitable habitat lacking.
Foraging: Absent
Suitable foraging habitat
lacking.
Neotoma lepida intermedia
San Diego desert woodrat
CVMSHCP = No
F = None
C = SSC, S3S4
Coastal scrub of southern
California. Moderate to
dense canopies preferred.
Particularly abundant in
rock outcrops & rocky
cliffs & slopes.
Absent
Suitable habitat lacking.
Item Number: 1.
Habitat Assessment & CVMSHCP Consistency Report
DHS Varner & West Project, APN 669-150-002
Updated April 2025
Table 6. Special Status Mammals
Species Status Habitat Probability
Nyctinomops femorosaccus
pocketed free-tailed bat
CVMSHCP = No
F = None
C = SSC, S3
Joshua tree woodland,
Pinon & juniper
woodlands, Riparian
scrub, Sonoran desert
scrub
Roost Site: Absent
Suitable habitat lacking.
Foraging: Very lowAbsent
Habitat marginal; may
forage over site. Nearest
CNDDB records ~3.5
miles southwest.
Nyctinomops macrotis
big free-tailed bat
CVMSHCP = No
F = None
C = SSC, S3
Deserts and arid
landscapes with rugged
terrain, rocky outcrops,
canyons, or cliffs; Roosts
in rock crevices,
occasionally roosts in
buildings and tree
cavities.
Roost Site: Absent
Suitable habitat lacking.
Foraging: Very low -
Absent
Habitat marginal; may
forage over site. Nearest
CNDDB records ~3.5
miles southwest.
Ovis canadensis nelsoni
desert bighorn sheep
CVMSHCP = No
F = None
C = FP, S3
Open, rocky, steep areas
with available water and
herbaceous forage.
Absent
Suitable habitat lacking.
Known from Whitewater
Canyon, Morongo Valley
and Little San Bernardino
Mountains
Ovis canadensis nelsoni (pop. 2)
Peninsular bighorn sheep (DPS)
CVMSHCP = Yes
F = END
C = THR, FP
Mountainous terrain,
rocky hillsides and
outcrops, cliffs, steep
canyons.
Absent
Suitable habitat lacking.
Known from San Jacinto
and Santa Rosa
Mountains
Perognathus longimembris bangsi
Palm Springs pocket mouse
CVMSHCP = Yes
F = None
C = SSC, S1
Desert riparian, desert
scrub, desert wash &
sagebrush habitats. Most
common in creosotedominated desert scrub.
Low
Habitat suitable but
disturbed. Nearest
CNDDB record is
northwest, ~4.2 miles
away.
Xerospermophilus tereticaudus
chlorus
Coachella Valley (Palm Springs)
round-tailed ground squirrel
CVMSHCP = Yes
F = None
C = SSC, S2
Prefers open, flat, grassy
areas in fine-textured,
sandy soil in desert
succulent scrub, desert
wash, desert scrub, alkali
scrub, & levees.
Low
Habitat suitable but
disturbed. Nearest
CNDDB records ~3.5
miles southwest.
Definitions of status designations and occurrence probabilities for Tables 1-6 Definitions for Species
Italics – Scientific name (i.e., Genus species subspecies) Bold – Standard common name (if any)
Item Number: 1.
Habitat Assessment & CVMSHCP Consistency Report
DHS Varner & West Project, APN 669-150-002
Updated April 2025
[Genus] – Previous genus, relatively recent taxonomic revision var. – variety (plants only)
DPS – Distinct Population Segment (i.e., Peninsular bighorn sheep) Definitions of occurrence probability:
Occurs: Observed or detected on-site by WSP or recently reported by another reliable source.
High: Observed in similar habitat in region by qualified biologists, or habitat on-site is a type often utilized by the species and the site is within the known range of the species.
Moderate: Reported sightings in surrounding region, or site is within the known range of the species and habitat onsite is a type occasionally used by the species.
Low: Site is within the known range of the species but habitat on-site is rarely used by the species Very Low: Habitat is of marginal suitability and/or site is at the edge of species known range or distribution.
Absent:A focused study failed to detect the species, suitable habitat not present, or site is outside the geographic distribution of the species.
Unknown: No focused surveys have been performed in the region, & the species' distribution & habitat are poorly known.
CVMSHCP designations
Yes: Conserved by the CVMSHCP
No: Not Specifically Conserved by the CVMSHCP
Federal designations: (F = federal Endangered Species Act or USFWS designations) END: Federally listed, Endangered
THR: Federally listed, Threatened
CAN: Candidate for Federal listing
MBTA: Migratory Bird Treaty Act
BEPA: Bald Eagle Protection Act (also protects Golden Eagles) BCC: Birds of Conservation Concern
None: No designation
State designations: (C = California Endangered Species Act or CDFG designations) END: State listed, Endangered
THR: State listed, Threatened
CAN: Candidate for State listing
RARE: State listed, Rare
FP: Fully Protected Species
SSC: Species of Special Concern
FGC: Fish and Game Code
WL: Watch List Species
Item Number: 1.
Habitat Assessment & CVMSHCP Consistency Report
DHS Varner & West Project, APN 669-150-002
Updated April 2025
CDFW state rankings are a reflection of the overall condition of an element throughout its California range. The number after the decimal point represents a threat designation attached to the rank:
S1 = Critically Imperiled. Less than (<) 6 Element Occurrences (EOs) OR < 1,000 individuals OR < 2,000 acres S1.1 = very threatened
S1.2 = threatened
S1.3 = no current threats known
S2 = Imperiled. 6-20 EOs OR 1,000-3,000 individuals OR 2,000-10,000 acres S2.1 = very threatened
S2.2 = threatened
S2.3 = no current threats known
S3 = Vulnerable. 21-80 EOs OR 3,000-10,000 individuals OR 10,000-50,000 acres S3.1 = very threatened
S3.2 = threatened
S3.3 = no current threats known
S4 = Apparently Secure. Uncommon but not rare in the state; some cause for long-term concern.
S5 = Secure. Common, widespread, and abundant in the state.
SH = All known California sites are historical, not extant California Native Plant Society (CNPS) California Rare Plant Ranks (CRPR) designations:
Primary Categories
LIST 1A: Plants Presumed Extirpated in California and Either Rare or Extinct Elsewhere LIST 1B: Plants Rare, Threatened, or Endangered in California and Elsewhere LIST 2A: Plants Presumed Extirpated in California, But Common Elsewhere LIST 2B: Plants Rare, Threatened, or Endangered in California, But More Common Elsewhere LIST 3: Plants About Which More Information is Needed - A Review List LIST 4: Plants of Limited Distribution - A Watch List
Subdivisions within Categories
0.1: Seriously threatened in California
0.2: Moderately threatened in California
0.3: Not very threatened in California
Western Bat Working Group (WBWG) designations:
The Western Bat Working Group is comprised of agencies, organizations and individuals interested in bat research, management and conservation from the 13 western states and provinces. Its goals are (1) to facilitate communication among interested parties and reduce risks of species decline or extinction; (2) to provide a mechanism by which current information on bat ecology, distribution and research techniques can be readily accessed; and (3) to develop a forum to discuss conservation strategies, provide technical assistance and encourage education programs.
H: High: Species which are imperiled or are at high risk of imperilment based on available information on distribution, status, ecology and known threats.
M: Medium: Species which warrant a medium level of concern and need closer evaluation, more research, and conservation actions of both the species and possible threats. A lack of meaningful information is a major obstacle in adequately assessing these species' status and should be considered a threat.
L: Low: Species for which most of the existing data support stable populations, and for which the potential for major changes in status in the near future is considered unlikely. There may be localized concerns, but the overall status of the species is believed to be secure. Conservation actions would still apply for these bats, but limited resources are best used on High and Medium status species.
P: Periphery: This designation indicates a species on the edge of its range, for which no other designation has been determined.
Item Number: 1.
Habitat Assessment & CVMSHCP Consistency Report
DHS Varner & West Project, APN 669-150-002
Updated April 2025
6.0 DISCUSSION
Implementation of the proposed project would result in the loss of approximately 83-123 acres of undeveloped Sonoran mixed woody and succulent scrub and the biological resources, sensitive and otherwise, potentially occurring on-site.
The CVMSHCP was designed to streamline the permitting process and to mitigate potential impacts resulting from covered projects and the lawful activities of permittees through payment of the requisite development fee and participation in plan’s requirements. A few species, which are not covered by the CVMSHCP and/or are not yet adequately conserved by the CVMSHCP (e.g., nesting birds, burrowing owl) require additional consideration and/or action, which are detailed below.
6.1 Discussion of the Special-status Species Tables
A review of the CNDDB, CNPS, and the collective knowledge of WSP senior biologists resulted in a total of sixty-four (64) special status biological resources that are known from the vicinity of the project site (Tables 1-6). These include: thirty (30) plants, three (3) vegetation communities, six (6) invertebrates, five (5) reptiles, ten (10) birds and ten (10) mammals. Of these, fifty-two (53) are considered to be absent from the site due to a lack of suitable habitat or outside the range of the species. These include: Chaparral sand-verbena (Abronia villosa var. aurita), pygmy lotus (Acmispon haydonii), alkali marsh aster (Almutaster pauciflorus), single whorl burrobush (Ambrosia monogyra), Horn’s milk-vetch (Astragalus hornii var. hornii), triple-ribbed milkvetch (Astragalus tricarinatus), Parish’s brittlescale (Atriplex parishii), California ayenia (Ayenia compacta), Payson’s jewelflower (Caulanthus simulans), Parry’s spineflower (Chorizanthe parryi var. parryi), whitebracted spineflower (Chorizanthe xanti var. leucotheca), slender-horned spineflower (Dodecahema leptoceras), Harwood’s eriastrum (Eriastrum harwoodii), Arizona spurge (Euphorbia arizonica), cliff spurge (Euphorbia misera), flat-seeded spurge (Euphorbia platysperma), shaggy-haired alumroot (Heuchera hirsutissima), California satintail (Imperata brevifolia), lemon lily (Lilium parryi), San Jacinto linanthus (Linanthus jaegeri), spiny-hair blazing star (Mentzelia tricuspis), slender cottonheads (Nemacaulis denudate var. gracilis), Sonoran maiden fern (Pelazoneuron puberulum var. sonorense), Latimer’s woodland-gilia (Saltugilia latimeri), purple stemodia (Stemodia durantifolia), southern jewel-flower (Streptanthus campestris), Mecca aster (Xylorhiza cognata), desert fan palm oasis woodland, mesquite bosque, southern riparian forest, Crotch’s bumble bee (Bombus crotchii), American bumble bee (Bombus pensylvanicus), Andreas Canyon leptonetid spider (Calileptoneta oasa), Casey’s June beetle (Dinacoma caseyi), Coachella giant sand-treader cricket (Macrobaenetes valgum), Coachella Valley Jerusalem cricket (Stenopelmatus cahuilaensis), desert tortoise (Gopherus agassizi), coast horned lizard (Phrynosoma blainvillii), nesting southern California rufous-crowned sparrow (Aimophila ruficeps canescens), nesting golden eagle (Aquila chrysaetos), nesting black swift (Cypseloides niger), nesting prairie falcon (Falco mexicanus), nesting coastal California gnatcatcher (Polioptila californica californica), nesting Crissal thrasher Item Number: 1.
Habitat Assessment & CVMSHCP Consistency Report
DHS Varner & West Project, APN 669-150-002
Updated April 2025
(Toxostoma crissale), nesting LeConte’s thrasher, nesting least Bell’s vireo (Vireo bellii pusillus), roosting Townsend’s big-eared bat (Corynorhinus townsendii), roosting western (southern) yellow bat (Lasiurus xanthinus), San Diego desert woodrat (Neotoma lepida intermedia), roosting pocketed free-tailed bat (Nyctinomops femorosaccus), roosting big free-tailed bat (Nyctinomops macrotis), desert bighorn sheep (Ovis canadensis nelsoni) and Peninsular bighorn sheep (Ovis canadensis nelsoni [pop. 2]). These special status biological resources will not be discussed further.
Six (6) of the remaining twelve (12) species are fully covered and conserved under the CVMSHCP.
Participation in the CVMSHPS and payment of the requisite CVMSHCP development fee and participation in the plan is expected to fully mitigate project related impacts (if any) to these species. These include: Coachella Valley milk-vetch, Little San Bernardino Mountains linanthus, flat-tailed horned lizard, Coachella Valley fringe-toed lizard, Palm Springs pocket mouse and Coachella Valley (Palm Springs) round-tailed ground squirrel. Regardless of whether these species occur on the project site or not, participation in the CVMSHCP and payment of the development fee is designed and intended to provide full coverage of all potential project-related impacts.
These species will not be discussed further.
The remaining five (5) species, which are not covered, or not fully covered, under the CVMSHCP are discussed below.
6.1.1 Potentially Occurring Plant Species Not Fully Covered Under the CVMSHCP Desert spike moss (Selaginella eremophila) is considered to have a low potential for occurrence as it is associated with gravelly soils, crevices and is found among rocks. It is known to occur within the vicinity and potentially suitable habitat is present on the project site. This species was not detected during the field assessment as the assessment was conducted outside of this species blooming period (May-July). Desert spike moss is not listed as threatened or endangered but is designated as S2S3 by the CDFW and List 2B.2 by the CNPS meaning that it is considered to be “imperiled to vulnerable” by the CDFW and “rare, threated or endangered in California, but more common elsewhere” and “moderately threatened in California”. This species is not covered under the CVMSHCP therefore payment of development fees and participation in the plan offers no mitigation for impacts to this species. If a significant population were to be present, unmitigated impacts may be considered significant under the CEQA. The likelihood of a significant population occurring on the project site, however, is very low but the only way to know for certain would be to conduct a rare plant survey during its blooming period.
6.1.2 Potentially Occurring Reptile Species Not Fully Covered Under the CVMSHCP The red-diamond rattlesnake is not listed as threatened or endangered by the CDFW or USFWS but is designated as a California “Species of Special Concern” (SSC) by the CDFW. This species is associated with a variety of habitats and is not a CVMSHCP-covered species. In the Coachella Valley, San Gorgonia Pass, Morongo Valley and Yucca Valley areas, it is also known to occur in Item Number: 1.
Habitat Assessment & CVMSHCP Consistency Report
DHS Varner & West Project, APN 669-150-002
Updated April 2025
Mojavean and Sonoran Desert scrubs and has occurrence records within the vicinity of the project site. The site contains potentially suitable burrows, rocks and other surface cover debris. For these reasons, WSP considers there to be a very low potential for this species to occur on the project site. Although this species is declining, project-related impacts to this species (if any) would be incremental and localized. As a result, impacts (if any) to this species would not likely be considered significant under the CEQA.
6.1.3 Potentially Occurring Bird Species Not Fully Covered by the CVMSHCP Although the burrowing owl is a CVMSHCP covered species, if present, additional actions may be required to relocate individual owls where found. This species was not detected on the project site during the assessment but is known from the vicinity and has at least some potential to nest and forage on the project site. This species nests and roosts underground and is particularly sensitive to ground disturbing activities, loud noise created by operation of heavy equipment up to 500 feet away and may abandon nests or burrows if/when such activities occur. Therefore, in addition to on-site impacts, impacts to burrowing owls potentially occurring nearby off-site must also be considered. The burrowing owl is not listed as threatened or endangered by the USFWS or CDFW. Burrowing owl has been listed as a candidate species for listing by CDFW and if found onsite will be treated as an endangered species. The species is currently managed as a Bird of Conservation Concern (BCC) by the USFWS and designated as an SSC by the CDFW. It is also protected from take by the MBTA and California FGC. The burrowing owl is a covered species under the CVMSHCP, however the federal permit for the CVMSHCP does not allow take of this species under the MBTA. For these reasons, because the site is not within a conservation area, two pre-construction take avoidance surveys (the first within 14-30 days prior to ground disturbance and the second within 24 hours of ground disturbance) would be required to ensure that no direct take of burrowing owls occur. If a burrowing owl is found to occur on the project site, the CDFW should be contacted as soon as possible to determine the appropriate course of action required should burrowing owl(s) continue to occupy the site at the time of project implementation.
The black-tailed gnatcatcher (Polioptila melanura) is considered to have a low potential for occurrence as it is associated with Mojavean desert and Sonoran desert scrubs. This species is not listed as threatened or endangered but is managed as a Bird of Conservation Concern (BCC) by the USFWS and designated as an SSC by the CDFW. It is also protected from take by the MBTA and California FGC. For these reasons, because the site is not completely within a conservation area, a pre-construction nesting bird survey, as further discussed below, would be required to ensure that no direct take of black-tailed gnatcatchers occur.
Item Number: 1.
Habitat Assessment & CVMSHCP Consistency Report
DHS Varner & West Project, APN 669-150-002
Updated April 2025
6.1.4 Additional Bird Species Protected by the Migratory Bird Treaty Act Excluded from coverage under the CVMSHCP are a variety of common bird species that are protected by the MBTA. This includes virtually all native migratory and resident bird species, including birds already known to occur in the vicinity. Avoidance of impacts to these nesting migratory and resident birds is a requirement of the federal permit issued for the CVMSHCP. In order to avoid impacting nesting birds, either avoidance of project-related disturbance during the nesting season (generally from approximately 15 January through 31 August) or nesting bird surveys conducted by a qualified ornithologist or biologist immediately prior to on-site disturbance during the nesting season would be required.
If nesting birds are found, no work would be permitted near the nest until young have fledged.
There is no established protocol for nest avoidance, however, when consulted the CDFW generally recommends avoidance buffers of about 500 feet for listed species and birds-of-prey, and 100– 300 feet for unlisted songbirds.
6.1.5 Potentially Occurring Mammal Species Not Covered by the CVMSHCP The only potentially occurring mammal species that is not covered under the CVMSHCP is the pallid San Diego Pocket mouse. This species is not listed as threatened or endangered by the USFWS or CDFW. It is, however, designated as an SSC by the CDFW. Although the state has designated it an SSC, it is ranked S3S4 which means that it is “vulnerable to apparently secure”.
Although small mammal trapping would be the only way to determine this species status on-site, impacts, even if this species is present, would be not likely meet the threshold of significance under the CEQA, given its lower status of sensitivity. Therefore, trapping surveys for this species are not considered to be warranted.
7.0 CONCLUSION
In 2016 the city of Desert Hot Springs was accepted as a signatory to the CVMSHCP. Since then, payment of the required development fee for approved projects are designed to mitigate the impacts to covered species resulting from the loss/conversion of the approximately 123±-acres of natural open space. Covered species that are considered to have at least some potential to occur on-site and would potentially be affected by implantation of the proposed project include:
Coachella Valley milk-vetch, Little San Bernardino Mountains linanthus, flat-tailed horned lizard, Coachella Valley fringe-toed lizard, burrowing owl, Palm Springs pocket mouse, and Coachella Valley (Palm Springs) round-tailed ground squirrel. Impacts to these species (if present) and their habitat, with the exception of burrowing owl (and other bird species protected by the MBTA), would be fully covered and mitigated under the CVMSHCP with the payment of the requisite development fee and participation in the requirements of the plan.
Item Number: 1.
Habitat Assessment & CVMSHCP Consistency Report
DHS Varner & West Project, APN 669-150-002
Updated April 2025
Some rare plant species that are not covered under the CVMSHCP have at least some potential to occur and although impacts may not be considered significant, due to the size of the site and the remote likelihood of substantial populations occurring, the only way to conclusively determine if any of them are present is to conduct a focused survey for rare plant species during their respective blooming periods.
Impacts to burrowing owl and other bird species not fully covered under the CVMSHCP require avoidance. If project activities (i.e., site grading, vegetation removal/trimming, earthwork in undisturbed areas, etc.) are conducted during the nesting season (i.e., generally between 15 January and 31 August), a nesting bird clearance survey may be required to ensure impacts to nesting birds are avoided. If project activities are conducted outside of the nesting season, a nesting bird clearance survey would likely be avoided. If active bird nests are found, at any time, proposed project activities would need to be postponed until young have fledged the nest and impacts to nesting birds are entirely avoided.
Because the project site is not completely within a conservation area, two pre-construction take avoidance surveys are required to determine if burrowing owl presently occur on, or immediately adjacent to, the site to ensure that impacts to burrowing owl do not result from project implementation. Additionally, the CDFW should be contacted for guidance on any burrowing owl(s) found to be present as soon as possible. Relocation of any burrowing owl(s) on-site may be required and would require coordination with the CVAG and CDFW. A copy of a California Native Species Field Survey Form would also be sent to the CDFW, as required.
No creeks, rivers, washes, drainages, bodies of water, etc., were observed on recent historical photos. Areas in the southwest of the project site have evidence of flood flows from tropical storm Hilary and may be considered jurisdictional by CDFW and RWQCB. A jurisdictional delineation has been prepared and it will be determined by the agencies if permitting will be required.
With participation in and compliance with the requirements of the CVMSHCP and implementation of the recommendations above, impacts to special status species and their habitats are anticipated to be mitigated to a less than significant level.
Item Number: 1.
Habitat Assessment & CVMSHCP Consistency Report
DHS Varner & West Project, APN 669-150-002
Updated April 2025
8.0 LITERATURE CITED AND REFERENCES
California Bird Records Committee. 2024. Official California Checklist. Accessed online at:
http://californiabirds.org/ca_list.asp.
California Burrowing Owl Consortium. 1997. Burrowing Owl Survey Protocol and Mitigation Guidelines. Journal of Raptor Research Report, The Raptor Research Foundation, Inc.
California Department of Fish and Game (CDFG). 2012. Staff report on Burrowing Owl Mitigation. CDFG, Sacramento, CA.
California Department of Fish and Wildlife (CDFW). 2024a. California Natural Diversity Data Base, Rarefind 5. Report for the Desert Hot Springs and Seven Palms Valley, Calif. quadrangles. Accessed at: dfg.ca.gov/biogeodata/cnddb/mapsanddata.asp CDFW. 2024b. Special Animals List. July. Periodic publication. Sacramento, CA. Accessed online at: https://nrm.dfg.ca.gov/FileHandler.ashx?DocumentID=109406&inline=1 CDFW. 2016. Complete List of Amphibian, Reptile, Bird and Mammal Species in California.
Accessed online at: https://nrm.dfg.ca.gov/FileHandler.ashx?DocumentID=87155&inline CDFW. 2015a. Fish and Game Code of California. http://www.leginfo.ca.gov/calaw.html CDFW. 2015b. California Wildlife Habitat Relationships, Life History Accounts and Range Maps.
Accessed online at: http://www.dfg.ca.gov/biogeodata/cwhr/cawildlife.aspx CDFW. 2015c. Threatened and Endangered Species, Species Lists and Accounts, Species Accounts-Fish. Accessed online at:
https://www.dfg.ca.gov/wildlife/nongame/t_e_spp/
California Native Plant Society (CNPS). 2024a. Inventory of Rare, Threatened, and Endangered Plants of California. Report for the Desert Hot Springs, Palm Springs, Cathedral City and Seven Palms Valley, Calif. quadrangles. Accessed online at:
http://www.rareplants.cnps.org
CNPS. 2024b. The California Rare Plant Ranking System. Accessed online at:
https://www.cnps.org/cnps/rareplants/ranking.php
California Natural Resources Agency. 2014. CEQA Guidelines. Accessed online at:
http://resources.ca.gov/ceqa/guidelines/
City of Desert Hot Springs. 2020. City of Desert Hot Springs General Plan Land Use Map.
Accessed online at: cityofdhs.org
Item Number: 1.
Habitat Assessment & CVMSHCP Consistency Report
DHS Varner & West Project, APN 669-150-002
Updated April 2025
Coachella Valley Association of Governments (CVAG). 2016. Final Major Amendment to the Coachella Valley Multiple Species Habitat Conservation Plan/Natural Community Conservation Plan. Accessed online at:
https://www.cvmshcp.org/Plan%20Documents/10.%20CVAG%20MSHCP%20Plan%20S ection%203.0.pdf
CVAG. 2008. Coachella Valley Multiple Species Habitat Conservation Plan. Accessed online at:
cvmshcp.org
Coachella Valley Conservation Commission (CVCC) CVAG/CVCC All Species Habitat Models. 2022. CVMSHCP Open Data. Accessed online at: https://mshcpcvag.hub.arcgis.com/datasets/all-species-habitat-models/explore Jepson Flora Project (2nd ed.). 2024. Jepson eFlora. Accessed online at:
http://ucjeps.berkeley.edu/IJM.html
Riverside County Information Technology. 2024. Map My County. Accessed online at:
http://mmc.rivcoit.org/MMC_Public/Custom/disclaimer/Default.htm Sawyer, J.O., T. Keeler-Wolf, and J.M. Evens. 2009. A manual of California vegetation (2nd ed.).
California Native Plant Society, Sacramento, CA.
United States Department of Agriculture (USDA), Natural Resources Conservation Service (NRCS). 2024a. Web Soil Survey. Accessed online at:
http://websoilsurvey.nrcs.usda.gov/app/
USDA, NRCS. 2024b. The PLANTS Database. National Plant Data Team. Accessed online at:
plants.usda.gov
United States Fish and Wildlife Service (USFWS). 2016. Bird Laws and Treaties. Accessed online at:
http://www.fws.gov/migratorybirds/RegulationsandPolicies.html USFWS. 2022. Critical Habitat for Threatened & Endangered Species Map. Accessed online at: arcgis.com
https://fws.maps.arcgis.com/home/webmap/viewer.html?webmap=9d8de5e265a d4fe09893cf75b8dbfb77
USGS. 2016. US Topo and Historical Topographic Map Collection. Accessed online at:
http://geonames.usgs.gov/apex/f?p=262:1:0::NO:RP:
Item Number: 1.
APPENDIX A
FIGURES
Item Number: 1.
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Miles °
Service Layer Credits: World Street Map: Esri, HERE, Garmin, NGA, USGS, NPS World Topographic Map: UC Riverside, County of Riverside, California State Parks, Esri, TomTom, Garmin, SafeGraph, GeoTechnologies, Inc, METI/NASA, USGS, Bureau of Land FIGURE 1
Regional Location
CVMSHCP
DHS Varner & West Project
Riverside County, California
Project Site
1 inch =1 miles
Item Number: 1.
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Palm Springs
Seven Palms Valley
Cathedral City
0 2,500 5,000
Feet °
Service Layer Credits: USA Topo Maps: Copyright:© 2013 National Geographic Society, i-cubed FIGURE 2
USGS 7.5' Topo Quad: Desert Hot Springs
CVMSHCP
DHS Varner & West Project
Riverside County, California
Project Site
1 inch =5,000 feet
Item Number: 1.
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Feet °
Service Layer Credits: NAIP Imagery: Esri, USDA FSA
FIGURE 3
Relationship to CVMSHCP
CVMSHCP
DHS Varner & West Project
Riverside County, California
ProjectSite
Upper Mission Creek/Big Morongo Canyon
Willow Hole
Whitewater Floodplain
1 inch =3,000 feet
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Feet °
Service Layer Credits: NAIP Imagery: Esri, USDA FSA
FIGURE 4
Soils
CVMSHCP
DHS Varner & West Project
Riverside County, California
Project Site
1 inch =500 feet
Item Number: 1.
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Mihalyo Rd
West Dr
Micro Pl
0 250 500
Feet °
Service Layer Credits: NAIP Imagery: Esri, USDA FSA
World Imagery: Maxar
FIGURE 5
Vegetation
CVMSHCP
DHS Varner & West Project
Riverside County, California
ProjectSite
Vegetation
Bolder Pile
Creosote bush - white bursage scrub
Disturbed
1 inch =500 feet
Item Number: 1.
APPENDIX B
SPECIES LIST: VASCULAR PLANTS
Item Number: 1.
APPENDIX B
Species List: Vascular Plants
This list reports only plants observed on the site by this study. Other species may have been overlooked or undetectable due to their growing season. Unless noted otherwise, nomenclature and systematics follows Jepson Flora Project (2023) = non-native species, sp. = identified only to genus, cf= compares favorably with]. Common names not provided by Jepson Flora Project follows those provided by USDA, NRCS (2023b). [†= special status species, * = non-native species, sp. = identified only to genus, cf= compares favorably with] Asteraceae Sunflower family
Ambrosia dumosa white bursage
Ambrosia salsola cheesebush
Encelia farinosa brittlebush
Ericameria sp. unidentified goldenbush
Psathyrotes ramosissima Velvet turtleback
Boraginaceae Borage family
Cryptantha angustifolia narrow-leaved cryptantha
Brassicaceae Mustard family
Brassica tournefortii* Saharan mustard*
Cactaceae Cactus family
Cylindropuntia echinocarpa silver/golden cholla
Cleomaceae Spider flower family
Peritoma arborea bladderpod
Ephedraceae Jointfir family
Ephedra sp. unidentified jointfir
Euphorbiaceae Spurge family
Euphorbia setiloba Yuma sandmat
Fabaceae Pea family
Parkinsonia florida blue palo verde
Psorothamnus emoryi Emory’s indigobush
Krameriaceae Rhatany family
Krameria erecta littleleaf rhatany
Poaceae Grass family
Schismus barbatus* common Mediterranean grass*
Polygonaceae Buckwheat family
Eriogonum sp. unidentified wild buckwheat
Zygophyllaceace Caltrop family
Larrea tridentata creosote bush
Item Number: 1.
APPENDIX C
SPECIES LIST: VERTEBRATE ANIMALS
Item Number: 1.
APPENDIX C
Species List: Vertebrate Animals
This list reports only the vertebrate animals observed or detected by WSP during the field assessment. Other species may have been overlooked or undetectable due to their activity patterns or weather conditions. High winds made species detection difficult and especially low at the time of the field assessment. [†= special status species, * = non-native species, sp. = identified only to genus, cf = compares favorably with]
VERTEBRATES
REPTILIA REPTILES
Phrynosomatidae Spiny Lizards
Aspidoscelis tigris western whiptail
Uta stansburiana side-blotched lizard
MAMMALIA MAMMALS
Corvidae Oscine Passerine Birds
Corvus corax Common Raven
Leporidae Rabbits and Hares
Lepus californicus Black-tailed jackrabbit
Item Number: 1.
APPENDIX D
PHOTOGRAPHIC EXHIBITS
Item Number: 1.
Photo 1. View from the northeast corner of the project site on Varner Road, looking southwest Photo 2. View looking south from the northeast corner of the project site, along West Drive Item Number: 1.
Photo 3. View looking west onto Varner Road, from West Drive Photo 4. View looking south, showing a dumped trash/rubble pile on the project site Item Number: 1.
Photo 5. Exhibiting one of the rock piles on the project site Photo 6. View from southeast corner of the project site, looking north Item Number: 1.
Photo 7. View from the southeast corner of the project site, looking west Photo 8. Exhibiting various trash and debris along Varner Road on the northern side of the project site
Item Number: 1.
Photo 9. Exhibiting an area of trash on the northern side of the project site Photo 10. Exhibiting trash and debris on the southern side of the project site, near Mihalyo Road
Item Number: 1.
Photo 11. Exhibiting a sandier area towards the western side of the project site. Vegetation in this area mostly consists of invasive mustard.
Photo 12. Representative photo of site conditions on the western side of the project site.
Exhibiting dried mustard and creosote bushes in sandy substrate.
Item Number: 1.
Photo 13. View of dumped trash (tires) along Varner Road Photo 14. Representative site photo depicting an area of finer sands on the project site Item Number: 1.
Photo 15. Depicting more dumped trash along Varner Road Photo 16. Exhibiting a view of the square shaped disturbed area (visible in satellite images), along Varner Road
Item Number: 1.
Photo 17. Exhibiting the view, looking west, of the square shaped disturbed area (visible in satellite images), from the eastern side of the area
Photo 18. View looking north from the southwest corner of the project site, towards Varner Road
Item Number: 1.
Photo 19. View looking east from the northwest corner of the project site, along Varner Road Photo 20. View looking south onto the project site, from the northwest corner Item Number: 1.
D
Appendix D
Jurisdictional Delineation
Item Number: 1.
DHS VARNER AND WEST PROJECT
DELINEATION OF JURISDICTIONAL WATERS
DESERT HOT SPRINGS
RIVERSIDE COUNTY, CALIFORNIA
Submitted to:
Terra Nova Planning and Research
42635 Melanie Place, Suite 101
Palm Desert, CA 92211
Contact: Nicole Criste, Principal
(760) 341-4800
Submitted by:
WSP USA Environment & Infrastructure Inc.
11870 Pierce St, Suite 160
Riverside, CA 92505
Contact: Scott Crawford, Assistant Vice President
(714) 742-5316
Principal Investigator: Dale Hameister
Updated April 2025
Item Number: 1.
Jurisdictional Delineation Report
DHS Varner and West Project, APN 669-150-002
Updated April 2025
Page i
TABLE OF CONTENTS
PAGE
ACRONYMS AND ABBREVIATIONS................................................................................................................. III
1.0 INTRODUCTION...............................................................................................................1-1
1.1 Purpose................................................................................................................1-1
1.2 Project Description..............................................................................................1-1
1.3 Project Location ..................................................................................................1-1
2.0 REGULATORY FRAMEWORK ...........................................................................................2-2
2.1 U.S. Army Corps of Engineers.............................................................................2-2
2.2 Regional Water Quality Control Board ..............................................................2-7
2.3 California Department of Fish and Wildlife .......................................................2-9
3.0 METHODS ........................................................................................................................3-9
4.0 ENVIRONMENTAL SETTING..........................................................................................4-11
4.1 Existing Conditions ...........................................................................................4-11
4.2 Hydrology..........................................................................................................4-11
4.3 Vegetation .........................................................................................................4-11
4.4 National Wetlands Inventory............................................................................4-12
4.5 Soils....................................................................................................................4-12
5.0 RESULTS............................................................................................................................5-1
6.0 IMPACTS TO JURISDICTIONAL AREAS............................................................................6-1
6.1 Permitting Requirements....................................................................................6-1
6.1.1 U.S. Army Corps of Engineers................................................................6-1
6.1.2 Regional Water Quality Control Board..................................................6-1
6.1.3 California Department of Fish and Wildlife ..........................................6-1
7.0 REFERENCES.....................................................................................................................7-1 Item Number: 1.
Jurisdictional Delineation Report
DHS Varner and West Project, APN 669-150-002
Updated April 2025
Page ii
LIST OF TABLES
Table 1. Survey Site Information............................................................................................................ 5-2 Table 2. Summary of Jurisdictional Areas……………………………………………………………5-4
LIST OF APPENDICES
APPENDIX A JURISDICTIONAL DELINEATION MAPS
APPENDIX B SITE PHOTOGRAPHS
APPENDIX C JURISDICTIONAL DELINEATION FORMS
Item Number: 1.
Jurisdictional Delineation Report
DHS Varner and West Project, APN 669-150-002
Updated April 2025
Page iii
ACRONYMS AND ABBREVIATIONS
AMSL above mean sea level
BSA Biological Survey Area
CEQA California Environmental Quality Act
CDFW California Department of Fish and Wildlife
CWA Clean Water Act
EPA Environmental Protection Agency
FAC facultative
FACU facultative upland
FACW facultative wetland
ft. Feet
GIS Geographic Information System
HUC Hydrologic Cataloging Unit
I-10 Interstate 10
IP Individual Permit
M Meters
NL not listed
NOAA National Oceanic and Atmospheric Administration
NWI National Wetlands Inventory
NWP Nationwide Permit
OBL obligate
OHWM ordinary high-water mark
Rapanos Rapanos v. U.S. and Carabell v. U.S.
RPW relatively permanent waterway
RWQCB Regional Water Quality Control Board
SWANCC Solid Waste Agency of Northern Cook County v. USACE TNW traditionally navigable waterway
Item Number: 1.
Jurisdictional Delineation Report
DHS Varner and West Project, APN 669-150-002
Updated April 2025
Page iv
UPL upland
USACE U.S. Army Corps of Engineers
USDA United States Department of Agriculture, Natural Resources Conservation Service USFWS United States Fish and Wildlife Service
USGS U.S. Geological Survey
WSC Waters of the State of California
WUS Waters of the United States
Item Number: 1.
Jurisdictional Delineation Report
DHS Varner and West Project, APN 669-150-002
Updated April 2025
1.0 INTRODUCTION
At the request of Terra Nova Planning and Research (Client), WSP USA Environment and Infrastructure, Inc. (WSP) conducted a jurisdictional delineation and report for the proposed 123±-acre project site, located in Desert Hot Springs, Riverside County, California This report presents regulatory framework, methods, and results of a delineation of jurisdictional waters, wetlands, and associated riparian habitat potentially impacted by the proposed project. The project is located on Assessor’s Parcel Number (APN) 669-150-002.
1.1 Purpose
The purpose of the delineation is to determine the extent of state and federal jurisdiction within the project area potentially subject to regulation by the U.S. Army Corps of Engineers (USACE) under Section 404 of the Clean Water Act (CWA), Regional Water Quality Control Board (RWQCB) under Section 401 of the CWA and Porter Cologne Water Quality Control Act, and California Department of Fish and Wildlife (CDFW) under Section 1602 of the California Fish and Game Code.
1.2 Project Description
The purpose of the proposed project is the development of a 1,209,230 sq. ft. warehouse building on a 123± acre site. The building would include a 10,000 sq ft office space and be surrounded by parking lots that would consist of 1,619 parking stalls for both vehicle and trailer parking. The actual footprint of the project site only occupies approximately 83 acres of the site, leaving areas of “open space” to the north and northwest, in existing conservation areas. A drainage channel and basin are planned to be installed along the road on the north side of Varner Road. This drainage channel is designed to capture sheet flow from any large storm events that flood the existing drainage to the west. The drainage channel proposed to be installed would impact approximately 10 acres on the north side of Varner Road.
1.3 Project Location
The 123-acre project site is located northwest and southwest of the intersection of Varner Road and West Drive in the city of Desert Hot Springs, Riverside County, California. (Appendix A – Figure 1). Specifically, the project site is located in Section 24 of Township 3 South and Range 4 East, as shown on the United States Geological Survey (USGS) Desert Hot Springs, California, 7.5-minute topographic quadrangle (Appendix A – Figure 2). The geographic coordinates near the approximate center of the project area are 33.892678° north latitude and -116.514736° west longitude. The elevation of the project site ranges from approximately 186 to 202 meters (m) (613-662 feet [ft]) above mean sea level.
Item Number: 1.
Jurisdictional Delineation Report
DHS Varner and West Project, APN 669-150-002
Updated April 2025
2.0 REGULATORY FRAMEWORK
2.1 U.S. Army Corps of Engineers
The USACE regulates the discharge of dredged or fill material in waters of the United States (WUS) pursuant to Section 404 of the CWA.
Waters of the U.S.
Categories of Jurisdictional Waters
Under the final rule, the following waters are jurisdictional:
(1) Waters which are: (i) traditional navigable waters (TNWs), i.e., all waters 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; (ii) territorial seas; or (iii) interstate waters, including interstate wetlands. (2) Impoundments of waters otherwise defined as WOTUS under this definition, other than impoundments of waters identified under paragraph (5). (3) Tributaries of waters identified in (1) or (2) of this section that:
i. Are relatively permanent, standing or continuously flowing; or ii. Either alone or in combination with similarly situated waters in the region, significantly affect the chemical, physical, or biological integrity of waters identified in paragraph (1).
• Tributary is not defined in the regulatory text, but the preamble clarifies that this category includes rivers, streams, lakes, ponds, and impoundments, regardless of their flow regime, that flow directly or indirectly through another water or waters to a TNW, territorial sea, or interstate water. • Tributaries can be natural, modified, or constructed waters and thus, can include ditches and canals.
(4) Wetlands adjacent to:
i. Waters identified in (1); or Relatively permanent, standing, or continuously flowing bodies of water identified in (2) or (3)(i) and with a continuous surface connection to those waters;
ii. Waters identified in (2) or (3) when the wetlands either alone or in combination with similarly situated waters in the region, significantly affect the chemical, physical, or biological integrity of waters identified in paragraph (1).
• Adjacent is defined as “bordering, contiguous, or neighboring.” Wetlands separated from other WOTUS by man-made dikes or barriers, natural river Item Number: 1.
Jurisdictional Delineation Report
DHS Varner and West Project, APN 669-150-002
Updated April 2025
berms, beach dunes, and the like are adjacent wetlands. Shallow subsurface hydrologic connections can establish adjacency.
• The preamble says that in a substantial number of cases, adjacent wetlands abut other WOTUS and that, on the whole, nationwide, adjacent wetlands are within a few hundred feet from other WOTUS. In arid areas, adjacent wetlands are likely to be much closer than a few hundred feet, but in larger floodplains and riparian areas where rainfall is higher, wetlands can be a few hundred feet away and still be “adjacent.”
(5) Intrastate lakes and ponds, streams, or wetlands not identified in paragraphs (1) through (4) that:
i. Are relatively permanent, standing or continuously flowing bodies of water with a continuous surface connection to the waters identified in paragraph (1) or (3)(i) of this section; or
ii. That either alone or in combination with similarly situated waters in the region, significantly affect the chemical, physical, or biological integrity of waters identified in paragraph (1).
• This is the former (a)(3) “other waters” category. As in the proposed rule, the preamble to the final rule again acknowledges that the agencies have not asserted jurisdiction over (a)(3) waters since 2003. And because this category was not discussed in the 2008 Rapanos Guidance, the application of the relatively permanent and significant nexus tests to this category represents a clear expansion of the pre-2015 regulatory regime.
• The preamble commits both EPA and Corps headquarters to review all draft AJDs for waters assessed under (a)(5) based on the significant nexus standard.
Relatively permanent standard
• The final rule does not define or quantify what constitutes “relatively permanent” flow. The preamble merely says relatively permanent includes features that have flowing or standing water year-round or continuously during certain times of the year.
• The Agencies are no longer using the term “seasonal” and appear to be backing away from the “typically three months” language in the 2008 Rapnanos Guidance.
Moreover, the preamble could be interpreted to say that “relatively permanent” means flow for more than a short duration in direct response to precipitation, i.e., anything more than ephemeral flow. And the preamble suggests that multiple storm events in succession could be enough to create relatively permanent flow.
The Agencies interpret “continuous surface connection” to be a physical connection requirement, which does not require a continuous surface water connection. Even linear features (e.g., pipes, swales, ditches) can satisfy the physical connection Item Number: 1.
Jurisdictional Delineation Report
DHS Varner and West Project, APN 669-150-002
Updated April 2025
requirement regardless of how often they carry flow. The preamble does not make it clear whether jurisdiction is dependent on the length/distance of a linear physical connection between an adjacent wetland and a relatively permanent WOTUS.
Significantly affect (significant nexus) standard
• The final rule defines “significantly affect” to mean “a material influence on the chemical, physical, or biological integrity of waters identified in paragraph (a)(1) of this section. To determine whether waters, either alone or in combination with similarly situated waters in the region, have a material influence on the chemical, physical, or biological integrity of waters identified in paragraph (a)(1) of this section,” the Agencies will assess the following functions and factors:
o Functions
Contribution of flow
Trapping, transformation, filtering, and transport of materials (including nutrients, sediment, and other pollutants
Retention and attenuation of floodwaters and runoff
Modulation of temperature in waters identified in paragraph (a)(1) of this section
Provision of habitat and food resources for aquatic species located in waters identified in paragraph (a)(1) of this section
o Factors
The distance from a water identified in paragraph (a)(1) of this section Hydrologic factors, such as the frequency, duration, magnitude, timing, and rate of hydrologic connections, including shallow subsurface flow
The size, density, or number of waters that have been determined to be similarly situated
Landscape position and geomorphology
Climatological variables such as temperature, rainfall, and snowpack Exclusions
The final rule codifies many more exclusions than the proposed rule (and the 1986 regulations). Most of the exclusions resemble those in the 2015 Rule:
Item Number: 1.
Jurisdictional Delineation Report
DHS Varner and West Project, APN 669-150-002
Updated April 2025
• Waste treatment systems, including treatment ponds or lagoons, designed to meet the requirements of the Clean Water Act.
• The preamble clarifies that Wastewater Treatment Systems (WTS) constructed prior to the enactment of the CWA can still be excluded and that WTS are not limited to manmade bodies of water consistent with longstanding practice.
Prior converted cropland designated by USDA. The exclusion would cease upon a change of use, which means that the area is no longer available for the production of agricultural commodities. For CWA purposes, the final authority regarding CWA jurisdiction remains with EPA.
o The preamble implies, but does not clearly state, that lands remain excluded as PCC even if they change to a non-agricultural use so long as wetland characteristics do not return.
• Ditches (including roadside ditches) excavated wholly in and draining only dry land and that do not carry a relatively permanent flow of water. o Excluded ditches would not become jurisdictional solely by virtue of connecting to a downstream WOTUS or because wetland characteristics develop within the confines of the ditch.
• Artificially irrigated areas that would revert to dry land if the irrigation ceased. • Artificial lakes or ponds created by excavating or diking dry land to collect and retain water and which are used exclusively for such purposes as stock watering, irrigation, settling basins, or rice growing.
o The preamble says this exclusion applies only to lakes/ponds that satisfy the terms of the exclusion, so apparently other types of ponds (e.g., log cleaning ponds) would not qualify.
• Artificial reflecting or swimming pools or other small ornamental bodies of water created by excavating or diking dry land to retain water for primarily aesthetic reasons.
• Waterfilled depressions created in dry land incidental to construction activity and pits excavated in dry land for the purpose of obtaining fill, sand, or gravel unless and until the construction or excavation operation is abandoned and the resulting body of water meets the definition of waters of the United States. iii. Swales and erosional features (e.g., gullies, small washes) characterized by low volume, infrequent, or short duration flow
Item Number: 1.
Jurisdictional Delineation Report
DHS Varner and West Project, APN 669-150-002
Updated April 2025
Supreme Court Decisions
Solid Waste Agency of Northern Cook County
On January 9, 2001, the Supreme Court of the United States issued a decision on Solid Waste Agency of Northern Cook County v. United States Army Corps of Engineers, et al. with respect to whether the USACE could assert jurisdiction over isolated waters. The Solid Waste Agency of North Cook County (SWANCC) ruling stated that the USACE does not have jurisdiction over “non-navigable, isolated, intrastate” waters.
Rapanos/Carabell
In the Supreme Court cases of Rapanos v. United States and Carabell v. United States (herein referred to as Rapanos), the court attempted to clarify the extent of USACE jurisdiction under the CWA. The nine Supreme Court justices issued five separate opinions (one plurality opinion, two concurring opinions, and two dissenting opinions) with no single opinion commanding a majority of the Court. In light of the Rapanos decision, the USACE will assert jurisdiction over a traditional navigable waterway (TNW), wetlands adjacent to TNWs, non-navigable tributaries of TNWs that are a relatively permanent waterway (RPW) where the tributaries typically flow year-round or have continuous flow at least seasonally (e.g., typically three months) and wetlands that directly abut such tributaries. The USACE will decide jurisdiction over the following waters based on a fact-specific analysis to determine whether they have a significant nexus with a TNW: non-navigable tributaries that are not relatively permanent, wetlands adjacent to non-navigable tributaries that are not RPWs, and wetlands adjacent to but that do not directly abut a non-navigable RPW.
Flow characteristics and functions of the tributary itself and the functions performed by all wetlands adjacent to the tributary indicate whether they significantly affect the chemical, physical and biological integrity of downstream TNWs. Analysis of potentially jurisdictional streams includes consideration of hydrologic and ecologic factors. The consideration of hydrological factors includes volume, duration, and frequency of flow, proximity to traditional navigable waters, size of watershed, average annual rainfall, and average annual winter snowpack. The consideration of ecological factors also includes the ability for tributaries to carry pollutants and flood waters to a TNW, the ability of a tributary to provide aquatic habitat that supports a TNW, the ability of wetlands to trap and filter pollutants or store flood waters, and maintenance of water quality.
Sackett v. EPA Supreme Court
Sackett began backfilling an Idaho lot with dirt to build a home. The Environmental Protection Agency informed Sackett that the property contained wetlands and that the backfilling violated the Clean Water Act, which prohibits discharging pollutants into “the waters of the United States,” 33 U.S.C. 1362(7). The EPA ordered Sackett to restore the site, threatening penalties of over $40,000 per day. The EPA classified the Sacket wetlands as Item Number: 1.
Jurisdictional Delineation Report
DHS Varner and West Project, APN 669-150-002
Updated April 2025
“waters of the United States” because they were near a ditch that fed into a creek, which fed into Priest Lake, a navigable, intrastate lake. The Ninth Circuit affirmed summary judgment in favor of the EPA.
The Supreme Court reversed. CWA jurisdiction over an adjacent wetland requires that the adjacent body of water constitutes waters of the United States (a relatively permanent body of water connected to traditional interstate navigable waters) and a continuous surface connection between the wetland and that water, making it difficult to determine where the ‘water’ ends and the ‘wetland’ begins.”
The Court reviewed the history of judicial interpretation of “the waters of the United States” and enforcement by federal agencies, which argued that the significant-nexus test was sufficient to establish jurisdiction over “adjacent” wetlands. Under that test, nearly all waters and wetlands are potentially susceptible to regulation, “putting a staggering array of landowners at risk of criminal prosecution for such mundane activities as moving dirt.” The CWA’s use of “waters” encompasses only relatively permanent, standing, or continuously flowing bodies, ordinarily called streams, oceans, rivers, and lakes. Wetlands qualify as “waters of the United States” only if “indistinguishable from waters of the United States,” having a continuous surface connection to bodies that are waters of the United States in their own right, with no clear demarcation between waters and wetlands.
On August 29, 2023, the EPA and USACE announced a final rule amending the 2023 definition of “waters of the United States” to conform with the recent Supreme Court decision in Sackett v. EPA. The ruling removes the significant nexus test and confirms that only drainages with relatively permanent flows will fall under USACE jurisdiction.
2.2 Regional Water Quality Control Board
The RWQCB regulates activities pursuant to Section 401(a)(1) of the CWA. Section 401 of the CWA specifies that certification from the State is required for any applicant requesting a federal license or permit including a Section 404 permit. Through the Porter Cologne Water Quality Control Act, the RWQCB asserts jurisdiction over Waters of the State of California (WSC) which is generally the same as WUS but may also include waters not in federal jurisdiction.
The State Wetland Definition and Procedures for Discharges of Dredged or Fill Material to Waters of the State was adopted in April 2020 and put into effect statewide on May 28, 2020 (State Water Resources Control Board, 2020).
The Water Boards define an area as wetland as follows:
An area is wetland if, under normal circumstances, (1) the area has continuous or recurrent saturation of the upper substrate caused by groundwater, or shallow surface water, or both; (2) the duration of such saturation is sufficient to cause anaerobic conditions in the upper Item Number: 1.
Jurisdictional Delineation Report
DHS Varner and West Project, APN 669-150-002
Updated April 2025
substrate; and (3) the area’s vegetation is dominated by hydrophytes or the area lacks vegetation.
The Water Code defines WSC broadly to include “any surface water or groundwater, including saline waters, within the boundaries of the state.” WSC include all WUS but also includes waters not in federal jurisdiction.
The following wetlands are waters of the state:
1. Natural wetlands,
2. Wetlands created by modification of a surface water of the state, and
3. Artificial wetlands that meet any of the following criteria:
a. Approved by an agency as compensatory mitigation for impacts to other waters of the state, except where the approving agency explicitly identifies the mitigation as being of limited duration;
b. Specifically identified in a water quality control plan as a wetland or other water of the state;
c. Resulted from historic human activity, is not subject to ongoing operation and maintenance, and has become a relatively permanent part of the natural landscape; or
d. Greater than or equal to one acre in size, unless the artificial wetland was constructed, and is currently used and maintained, primarily for one or more of the following purposes (i.e., the following artificial wetlands are not waters of the state unless they also satisfy the criteria set forth in 2, 3a, or 3b):
i. Industrial or municipal wastewater treatment or disposal, ii. Settling of sediment,
iii. Detention, retention, infiltration, or treatment of stormwater runoff and other pollutants or runoff subject to regulation under a municipal, construction, or industrial stormwater permitting program,
iv. Treatment of surface waters,
v. Agricultural crop irrigation or stock watering,
vi. Fire suppression,
vii. Industrial processing or cooling,
viii. Active surface mining – even if the site is managed for interim wetlands functions and values,
ix. Log storage,
Item Number: 1.
Jurisdictional Delineation Report
DHS Varner and West Project, APN 669-150-002
Updated April 2025
x. Treatment, storage, or distribution of recycled water, or xi. Maximizing groundwater recharge (this does not include wetlands that have incidental groundwater recharge benefits); or xii. Fields flooded for rice growing.
All artificial wetlands that are less than an acre in size and do not satisfy the criteria set forth in 2, 3.a, 3.b, or 3.c are not WSC.
2.3 California Department of Fish and Wildlife
The CDFW regulates water resources under Section 1600-1616 of the California Fish and Game Code. Section 1602 states:
“An entity may not substantially divert or obstruct the natural flow of, or substantially change or use any material from the bed, channel, or bank of, any river, stream, or lake, or deposit or dispose of debris, waste, or other material containing crumbled, flaked, or ground pavement where it may pass into any river, stream, or lake (CDFW, 2015).” Evaluation of CDFW jurisdiction followed guidance in the Fish and Game Code and A Review of Stream Processes and Forms in Dryland Watersheds. In general, under 1602 of the Fish and Game Code, CDFW jurisdiction extends to the maximum extent or expression of a stream on the landscape (CDFW, 2010). It has been the practice of CDFW to define a stream as “a body of water that flows perennially or episodically and that is defined by the area in a channel which water currently flows or has flowed over a given course during the historic hydrologic course regime, and where the width of its course can reasonably be identified by physical or biological indicators” (Brady and Vyverberg, 2013). Thus, a channel is not defined by a specific flow event, nor by the path of surface water as this path might vary seasonally. Rather, it is CDFW's practice to define the channel based on the topography or elevations of land that confine the water to a definite course when the waters of a creek rise to their highest point.
3.0 METHODS
Prior to conducting delineation fieldwork, the following literature and materials were reviewed:
Aerial photographs of the survey area at a scale of 1:1800 to determine the potential locations of jurisdictional waters or wetlands; USGS topographic map (Appendix A - Figure 2) to determine the presence of any “blue line” drainages or other mapped water features.
USDA soil mapping data (Appendix A - Figure 5); and
USFWS National Wetlands Inventory map to identify areas mapped as wetland features (Appendix A - Figure 4 ).
Item Number: 1.
Jurisdictional Delineation Report
DHS Varner and West Project, APN 669-150-002
Updated April 2025
A field survey of the project site was conducted by WSP senior biologist Dale Hameister on 13 November, and 12 December 2024. The survey consisted of walking the entire survey area and identifying potentially jurisdictional water features. All accessible portions of the survey areas were walked to determine if any topographic low-spots meet the minimum criteria to be considered under the jurisdiction of USACE, RWQCB, and CDFW. Visual observations of vegetation types and changes in hydrology and soil texture, and culvert locations were used to locate areas for evaluation. Weather conditions during delineation fieldwork was conducive for surveying with clear skies.
USACE regulated WUS, including wetlands, and RWQCB WSC were delineated according to the methods outlined in A Field Guide to the Identification of the Ordinary High-Water Mark (OHWM) in the Arid West Region of the Western United States (USACE, 2008a). The extent of WUS was determined based on indicators of an OHWM. The OHWM width was measured at points wherever clear changes in width occurred.
Potential federally regulated wetlands were identified based on the Wetlands Delineation Manual (USACE, 1987) and Regional Supplement to the Corps of Engineers Wetland Delineation Manual: Arid West Region (USACE, 2008b). Additional data was recorded to determine if an area fulfilled the wetland criteria parameters. Three criteria must be fulfilled in order to classify an area as a wetland under the jurisdiction of the USACE: 1) a predominance of hydrophytic vegetation, 2) the presence of hydric soils, and 3) the presence of wetland hydrology.
CDFW jurisdiction is delineated by measuring the elevations of land that confine a stream to a definite course when its waters rise to their highest level and to the extent of associated riparian vegetation. WSC/CDFW jurisdictional areas were determined by the bankfull channel edge and RWQCB jurisdictional areas were determined by the edge of the OHWM. In some areas the eroded banks were vertical, so these areas shared the same jurisdictional boundary lines.
The drainage areas identified were the result of a large flooding event and the bed and bank areas were inconsistent. The majority of the drainage areas had a large amount of scour and contained hard packed sand. Therefore, no soil pits were dug, and no wetland data forms were used to collect information.
To determine jurisdictional boundaries, the surveyor walked the length of the drainage within the project area and recorded the centerline with a Trimble GeoXH global positioning system.
The width of the drainage was determined by the OHWM and bankfull width measurements at locations where transitions were apparent. Other data recorded included bank height and morphology, substrate type, and all vegetation within the streambed and riparian vegetation adjacent to the streambed. Areas that lacked evidence of hydrophytic vegetation, lacked evidence of wetland hydrology, and had no recent disturbance, did not require a soil pit since Item Number: 1.
Jurisdictional Delineation Report
DHS Varner and West Project, APN 669-150-002
Updated April 2025
the other wetland indicators were not present. Upon completion of fieldwork, all data collected in the field were incorporated into a Geographic Information System (GIS) along with basemap data. The GIS was then used to quantify the extent of jurisdictional waters and prepare graphical representations of that data.
4.0 ENVIRONMENTAL SETTING
4.1 Existing Conditions
The project area generally consists of gently sloping creosote and white bursage scrub with some disturbed areas. Surrounding areas include I-10, open space, and a single family residence.
4.2 Hydrology
The project is located within the Whitewater Watershed. Mission Creek, an ephemeral, dry wash is located approximately 0.1 miles (160 m) west of the project site and Morongo Wash is approximately 0.6 miles (965 m) to the east. These drainages connect downstream to the Whitewater River and eventually to the Salton Sea. No washes, drainages or any other evidence of water flow or pooling were observed during analysis of aerial photographs from recent years.
There was evidence of flow observed in the southwest area of the project site which was the result of flooding from tropical storm Hilary in August 2023. The flood flows scoured areas in the southwest corner of the project site and created new drainage channels in previous upland areas. The drainage features are not contiguous but there is evidence where the flows consolidated into a single channel and flowed off-site to the south and into a large roadside ditch adjacent to 1-10.
4.3 Vegetation
The on-site vegetation community is Sonoran mixed woody and succulent scrub (CVAG 2009). The CVMSHCP refers to this community as Sonoran creosote bush scrub. Sawyer et. al. (2009) also refers to this community as “Larrea tridentata-Ambrosia dumosa shrubland alliance (creosote bush-white bursage scrub)” (Figure 5). Dominant perennial plant species observed included creosote bush (Larrea tridentata) and white bursage (Ambrosia dumosa).
The dominant annual species, identified entirely through the presence of dead remnants was Saharan mustard (Brassica tournefortii). Other representative, but less abundant, plant species observed included cheesebush (Ambrosia salsola), brittlebush (Encelia farinosa), velvet turtleback (Psathyrotes ramosissima), goldenbush species (Ericameria sp.), narrow-leaved cryptantha (Cryptantha angustifolia), silver cholla (Cylindropuntia echinocarpa), bladderpod (Peritoma arborea), blue palo verde (Parkinsonia florida), Emory’s indigo bush (Psorothamnus emoryi), joint-fir species (Ephedra sp.), Yuma sandmat (Euphorbia setiloba), littleleaf ratany (Krameria erecta), common Mediterranean grass (Schismus barbatus), and a wild buckwheat Item Number: 1.
Jurisdictional Delineation Report
DHS Varner and West Project, APN 669-150-002
Updated April 2025
species (Eriogonum sp.). Sonoran mixed woody and succulent scrub is the predominant vegetation community occurring below 762 m (2500 ft) in the Colorado Desert from the Little San Bernardino Mountains south and eastward into Arizona and Mexico (Holland 1986). No wetland, riparian or otherwise special status vegetation communities were observed on the project site. A list of the plant species observed during the assessment, including common and scientific names, is appended to this report (Appendix B). Areas mapped as disturbed contained very little vegetation and include areas disturbed by human activities including dumping and clearing vegetation, as well as areas that were scoured by sheet flow and floodwaters.
4.4 National Wetlands Inventory
The United States Fish and Wildlife Service (USFWS) is the principal Federal agency that provides information to the public on the extent and status of the Nation’s wetlands. The USFWS has developed a series of maps, known as the National Wetlands Inventory (NWI) to show wetlands and deep-water habitat. This geospatial information is used by federal, state, and local agencies, academic institutions, and private industry for management, research, policy development, education, and planning activities. The NWI program was neither designed nor intended to produce legal or regulatory products; therefore, wetlands identified by the NWI program are not the same as wetlands defined by the USACE.
The NWI Mapper (USFWS, 2024) was accessed on-line to review mapped wetlands within the project study area. The NWI mapper (Figure 4, Appendix A) shows no drainages within the survey area. One drainage, Mission Creek is adjacent to the western edge of the project area was mapped as Riverine, Intermittent, Streambed, Intermittently Flooded (R4SBJ) (Cowardin, et. al., 1979).
4.5 Soils
The project site is sandy and relatively flat with small hills and an area of piled rocks on the eastern edge of the project site. Carsitas cobbly sand, and Carsitas gravelly sand has been mapped on the project site. (USDA, NRCS. 2024) (Appendix A - Figure 3).
The Carsitas series consists of very deep, somewhat excessively drained soils that formed in alluvium from granitoid and/or gneissic rocks. The Carsitas soils are on alluvial fans, fan aprons, valley fills, dissected remnants of alluvial fans and in drainageways. Slopes range from 0 to 30 percent. The mean annual precipitation is about 75 millimeters (3 inches) and the mean annual air temperature is about 25 degrees C (77 degrees F).
The site does not contain active sand dunes or clay lenses. No wetland soils were observed on-site.
Item Number: 1.
Jurisdictional Delineation Report
DHS Varner and West Project, APN 669-150-002
Updated April 2025
5.0 RESULTS
Analysis of historical aerial photographs and NWI mapping show that there were no established drainages within the project area in past 10 years. Areas that could appear to be washes in the easter portion of the project site contained wind-blown sands and did not contain any evidence of flow or OHWM.
The southwestern portion of the project was impacted by flooding during tropical storm Hillary in August 2023. The flooding scoured a large area and created channelized areas along the dirt road that runs parallel to I-10. The bed and bank of the new channelized areas were not fully contiguous and some areas there was evidence of scour and sheet flow with no bed and bank. The flows consolidated and turned south off the project site into the large roadside ditch adjacent to I-10. There is generally no vegetation within the scoured areas due to the flooding removing all loose sand and existing vegetation and also deposited debris and driftwood. The bottom of the scoured channel consists of hard compacted sandy material.
The soils within the flooded areas are sandy with no signs of redox or any other wetland soil indicator.
Due to the absence of hydric vegetation and total lack of hydric soils observed within the drainage area it is considered ephemeral and only convey flowing water during and immediately following large storm events. Due to the drainages not having permanent flows, the drainage area would not be considered USACE under the updated WUS and EPA vs Sackett ruling. The drainage area could be considered RWQCB and CDFW jurisdictional based on clear evidence of flows. The RWQCB and CDFW acreage is the same due to the vertical banks within the drainage and a lack of adjacent riparian habitat.
The USACE, in combination with the EPA, when necessary, reserves the ultimate authority in making the final jurisdictional determination of WUS and the RWQCB reserves the ultimate authority in making the final jurisdictional determination of WSC. Additionally, CDFW has ultimate discretion in the determination of their jurisdiction. Based on our delineation, the drainage area features identified could potentially meet the requirements for CDFW and RWQCB jurisdiction. Under the Sackett vs EPA decision, the significant nexus standard was removed from the tributaries provision and therefore, all drainages without a direct connection to flowing water are considered ephemeral and no longer under USACE jurisdiction.
Item Number: 1.
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DHS Varner and West Project, APN 669-150-002
Updated April 2025
Table 1. Survey Site Information
Drainage Latitude Longitude Quad Township Range Section 1 (western drainage from
floodwaters) 33.891757 -116.409002
Desert Hot
Springs 3S 4E 24
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DHS Varner and West Project, APN 669-150-002
Updated April 2025
Table 3. Summary of Jurisdictional Areas
R4SBC – Riverine, Intermittent, Streambed, Seasonally Flooded based on Classification of Wetlands and Deepwater Habitats of the United States (Cowardin, et. al., 1979).
Drainage ID
/Survey Area Watershed
Waters of the
US Length
(feet)
Waters of
the US
(acre)
RWQCB
Length (Feet)
RWQCB
(acre)
CDFW
Length
(Feet)
CDFW
(acre)
Latitude Longitude Cowardin
Class Class of Aquatic Resource
1 ( western
drainage from
floodwaters )
Whitewater
0 0 1,480 1.19 1,480 1.19
33.891757 -116.409002 R4SBJ
non-section10-non wetland
Item Number: 1.
Jurisdictional Delineation Report
DHS Varner and West Project, APN 669-150-002
Updated April 2025
6.0 IMPACTS TO JURISDICTIONAL AREAS
The proposed project would impact a total of 1.19 acres of potential RWQCB and CDFW jurisdictional area.
6.1 Permitting Requirements
The proposed project requires permanent impacts to jurisdictional drainages and therefore, authorizations from the RWQCB and CDFW are required as described below.
6.1.1 U.S. Army Corps of Engineers
The drainages on-site do not contain permanent flows and in accordance with the EPS vs Sackett ruling are not considered to be USACE jurisdictional.
6.1.2 Regional Water Quality Control Board
The project areas occur in the Colorado RWQCB (Region 7). Under Section 401 of the CWA, the RWQCB must certify that the discharge of dredged or fill material into WUS does not violate state water quality standards.
The RWQCB also regulates impacts to WSC under the Porter Cologne Water Quality Control Act through issuance of a Construction General Permit, State General Waste Discharge Order, or Waste Discharge Requirements, depending upon the level of impact and the properties of the waterway.
Where the project has the potential to impacts WUS or WSC, the project proponent would need to obtain a Water Quality Certification. In addition to the formal application materials and fee (based on area of impact), a copy of the appropriate California Environmental Quality Act (CEQA) documentation must be included with the application.
Mitigation measures typically include replacement of, or mitigation for temporary or permanent impacts. Mitigation can be implemented through on-site restoration, the purchase of mitigation credits through an approved in-lieu fee program or similar mitigation bank. Other options can include the purchase of off-site habitat and placed into a conservation easement. It should be noted that mitigation ratios are based on in-kind habitat replacement/restoration, and ratios may be reduced if higher quality habitat is secured or created.
6.1.3 California Department of Fish and Wildlife
A 1602 Streambed Alteration Agreement is required for all activities that alter streams and lakes and their associated riparian habitat, regardless of the extent of impacts. In addition to Item Number: 1.
Jurisdictional Delineation Report
DHS Varner and West Project, APN 669-150-002
Updated April 2025
the formal application materials and fee (based on cost of the project), a copy of the appropriate CEQA documentation must be included with the application.
Item Number: 1.
Jurisdictional Delineation Report
DHS Varner and West Project, APN 669-150-002
Updated April 2025
7.0 REFERENCES
Baldwin, B.G., D.H. Goldman, D.J. Keil, R. Patterson, T.J. Rosatti, and D.H. Wilken, editors. 2012.
The Jepson manual: vascular plants of California, second edition. University of California Press, Berkeley.
Brady, Roland H. III, Kris Vyverberg. 2013. Methods to Describe and Delineate Episodic Stream Processes on Arid Landscapes for Permitting Utility-Scale Solar Power Plants. California Energy Commission. Publication Number: CEC-500-2014-013.
California Department of Fish and Wildlife (CDFW). 2010. A Review of Stream Processes and Forms in Dryland Watersheds. Prepared by Kris Vyverberg, Conservation Engineering. 32 p.
CDFW. 2018. Fish and Game Code of California. http://www.leginfo.ca.gov/calaw.html.
Cowardin, L.M., V. Carter, F.C. Golet, and E.T. LaRoe. 1979. Classification of Wetlands and Deepwater Habitats of the United States. U.S. Department of the Interior.
Federal Register / Vol. 85, No. 77 / Tuesday, April 21, 2020 / Rules and Regulations (22250) Gretag/Macbeth. 2000. Munsell color. New Windsor, NY.
Lichvar, R.W., M. Butterwick, N.C. Melvin, and W.N. Kirchner. 2014.
The National Wetland Plant List: 2014 Update of Wetland Ratings.
Phytoneuron 2014-41: 1-42.
Soil Survey Staff, Natural Resources Conservation Service, United States Department of Agriculture. Web Soil Survey. Available online at http://websoilsurvey.nrcs.usda.gov/.
Accessed March 2020.
U.S. Army Corps of Engineers (USACE). 1987. Wetlands Delineation Manual, Technical Report Y-8. U.S. Army Engineer Waterways Experiment Station, Vicksburg, Mississippi. 100 pp. + append.
USACE. 2008a. A Field Guide to the Identification of the Ordinary High-Water Mark (OHWM) in the Arid West Region of the Western United States. A Delineation Manual. Lichvar and McColley. August.
USACE. 2008b. Regional Supplement to the Corps of Engineers Wetland Delineation Manual:
Arid West Region. September.
United States Department of Agriculture, Natural Resources Conservation Service (USDA). 2019a. The PLANTS Database. (http://plants.usda.gov, 15 June 2019). National Plant Data Team, Greensboro, NC 27401-4901 USA.
Item Number: 1.
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DHS Varner and West Project, APN 669-150-002
Updated April 2025
USDA. 2024. List of Hydric Soils. Available online at:
http://www.nrcs.usda.gov/wps/PA_NRCSConsumption/download?cid=stelprdb124859 6&ext=xlsx
U.S. Fish and Wildlife Service. 2024. National Wetlands Inventory Mapper. Available online at:
http://www.fws.gov/wetlands/Data/Mapper.html. Accessed March 2020.
United States Geological Survey (USGS). 1996. 7.5-Minute Series, Desert Hot Springs, California, Topographic Quadrangle. Reston, VA.
Item Number: 1.
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DHS Varner and West Project, APN 669-150-002
Updated April 2025
JURISDICTIONAL MAPS
Item Number: 1.
Path: \\corp.pbwan.net\glb-e&i\US\USSAN600-SDG2\GIS\3554_NaturalResources\TerraNova_DesertHotSprings_VarnerWestProject_US_EI_P585_1.4391\ArcPro\TerraNova DHS Varner West Project\TerraNova DHS Varner West Project.aprx; USMT738346; JD Fig 1 Regional 12/17/2024 0 0.5 1
Miles °
Service Layer Credits: World Street Map: Esri, HERE, Garmin, NGA, USGS, NPS World Topographic Map: UC Riverside, County of Riverside, California State Parks, Esri, TomTom, Garmin, SafeGraph, GeoTechnologies, Inc, METI/NASA, USGS, Bureau of Land FIGURE 1
Regional Location
JD
DHS Varner & West Project
Riverside County, California
Project Site
1 inch =1 miles
Item Number: 1.
Path: \\corp.pbwan.net\glb-e&i\US\USSAN600-SDG2\GIS\3554_NaturalResources\TerraNova_DesertHotSprings_VarnerWestProject_US_EI_P585_1.4391\ArcPro\TerraNova DHS Varner West Project\TerraNova DHS Varner West Project.aprx; USMT738346; JD Fig 2 USGS 12/17/2024 Desert Hot Springs
Palm Springs
Seven Palms Valley
Cathedral City
0 2,500 5,000
Feet °
Service Layer Credits: USA Topo Maps: Copyright:© 2013 National Geographic Society, i-cubed FIGURE 2
USGS 7.5' Topo Quad: Desert Hot Springs
JD
DHS Varner & West Project
Riverside County, California
Project Site
1 inch =5,000 feet
Item Number: 1.
Path: \\corp.pbwan.net\glb-e&i\US\USSAN600-SDG2\GIS\3554_NaturalResources\TerraNova_DesertHotSprings_VarnerWestProject_US_EI_P585_1.4391\ArcPro\TerraNova DHS Varner West Project\TerraNova DHS Varner West Project.aprx; USMT738346; JD Fig 3 Hydrology 12/17/2024 Southern
Mojave
Watershed
Santa Ana
Watershed
Salton Sea
Watershed
San Jacinto
Watershed
0 2 4
Miles °
Service Layer Credits: NAIP Imagery: Esri, USDA FSA
Project Site
Regional Watersheds
LakePond
Reservoir
SwampMarsh
CanalDitch
Pipeline
StreamRiver
ArtificialPath
1 inch =4 miles
FIGURE 3
Hydrology
JD
DHS Varner & West Project
Riverside County, California
Item Number: 1.
Path: \\corp.pbwan.net\glb-e&i\US\USSAN600-SDG2\GIS\3554_NaturalResources\TerraNova_DesertHotSprings_VarnerWestProject_US_EI_P585_1.4391\ArcPro\TerraNova DHS Varner West Project\TerraNova DHS Varner West Project.aprx; USMT738346; JD Fig 4 NWI 12/17/2024 0 2,500 5,000
Feet °
Service Layer Credits: NAIP Imagery: Esri, USDA FSA
Project Site
Freshwater Emergent Wetland
Freshwater Pond
Lake
Riverine
1 inch =5,000 feet
FIGURE 4
National Wetland Inventory
JD
DHS Varner & West Project
Riverside County, California
Item Number: 1.
Path: \\corp.pbwan.net\glb-e&i\US\USSAN600-SDG2\GIS\3554_NaturalResources\TerraNova_DesertHotSprings_VarnerWestProject_US_EI_P585_1.4391\ArcPro\TerraNova DHS Varner West Project\TerraNova DHS Varner West Project.aprx; USMT738346; JD Fig 5 Soils 12/17/2024 0 250 500
Feet °
Service Layer Credits: NAIP Imagery: Esri, USDA FSA
FIGURE 5
Soils
JD
DHS Varner & West Project
Riverside County, California
Project Site
1 inch =500 feet
Item Number: 1.
Path: \\corp.pbwan.net\glb-e&i\US\USSAN600-SDG2\GIS\3554_NaturalResources\TerraNova_DesertHotSprings_VarnerWestProject_US_EI_P585_1.4391\ArcPro\TerraNova DHS Varner West Project\TerraNova DHS Varner West Project.aprx; USAJ716460; JD Fig 6 12/17/2024 0 250 500
Feet °
Service Layer Credits: NAIP Imagery: Esri, USDA FSA
FIGURE 6
Jurisdictional Drainages
JD
DHS Varner & West Project
Riverside County, California
Project Site
CDFW/RWQCB Jurisdiction
1 inch =500 feet
Item Number: 1.
Jurisdictional Delineation Report
DHS Varner and West Project, APN 669-150-002
Updated April 2025
SITE PHOTOGRAPHS
Item Number: 1.
Photo 1: Looking west at Mission Creek west of the project site.
Photo 2: Looking northwest showing scour from floodwaters.
Item Number: 1.
Photo 3: Looking north showing partial bed and bank created by flood waters.
Photo 4: Looking south showing partial bend and bank where waters exited the project site adjacent to I-10.
Item Number: 1.
Jurisdictional Delineation Report
DHS Varner and West Project, APN 669-150-002
Updated April 2025
APPENDIX C
JURISDICTIONAL DELINEATION FORMS
Item Number: 1.
ENG FORM 6250, SEP 2024 PREVIOUS EDITIONS ARE OBSOLETE. Page of U.S. Army Corps of Engineers (USACE)
RAPID ORDINARY HIGH WATER MARK
(OHWM) FIELD IDENTIFICATION DATA SHEET
The proponent agency is Headquarters USACE CECW-COR.
Form Approved -
OMB No. 0710-0024
Expires: 2027-09-30
Project ID #: Site Name: Date and Time:
Location (lat/long): Investigator(s):
Step 1 Site overview from remote and online resources.
Check boxes for online resources used to evaluate site:
gage data LiDAR geologic maps
climatic data satellite imagery land use maps
aerial photos topographic maps Other:
Describe land use and flow conditions from online resources.
Were there any recent extreme events (floods or drought)? Step 2 Site conditions during field assessment. First look for changes in channel shape, depositional and erosional features, and changes in vegetation and sediment type, size, density, and distribution. Make note of natural or human-made disturbances that would affect flow and channel form, such as bridges, riprap, landslides, rockfalls, etc.
Step 3 Mark the boxes next to the indicators used to help identify the location of the OHWM.
OHWM is at a transition point, therefore some indicators used to identify the location of the OHWM may be just below or above the OHWM.
Make a slash in boxes next to indicators that are helpful in identifying the OHWM. After the initial assessment, those indicators identified at the OHWM elevation should be changed from slashes to x's. Note, it is not necessary to mark indicators that are present but do not help inform identification of the OHWM.
Go to page 2 to describe overall rationale for location of OHWM, write any additional observations, and attach a photo log.
Geomorphic indicators
Break in slope
on the bank
undercut bank
valley bottom
Other:
Shelving
shelf at top of bank
natural levee
human-made berms or levees
other berms:
Channel bar
shelving (berms) on bar
unvegetated
vegetation transition (go to veg.
indicators)
sediment transition (go to sed.
indicators)
upper limit of deposition on bar
lnstream bedforms and other
bedload transport evidence
deposition bedload indicators (e.g.,
imbricated clasts, gravel sheets, etc.)
bedforms (e.g., pools, riffles, steps,
etc.)
erosional bedload indicators (e.g.,
Secondary channels obstacle marks, scour, smoothing, etc.) Other physical indicators
Wracking/presence of organic litter
Sediment deposited on vegetation or
structures
Presence of large wood
Leaf litter disturbed or washed away
Water staining
Weathered clasts or bedrock
Sediment indicators
Soil development
Changes in character of soil
Mudcracks
Changes in particle-sized distribution
transition from to
upper limit of sand-sized particles
silt deposits
Vegetation indicators (Consider the vegetation transition looking from the middle of the channel, up the banks, and into the floodplain)
Exposed roots below intact soil layer Vegetation matted down and/or bent Change in density of vegetation
The Agency Disclosure Notice (ADN)
The Public reporting burden for this collection of information, 0710-0024, is estimated to average 30 minutes per response, including time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information.
Send comments regarding the burden estimate or burden reduction suggestions to the Department of Defense, Washington Headquarters Services, at [email protected]. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number.
Change in vegetation type from
Other vegetation observations
to
Other observed indicators? Describe:
1 4
VARNER AND WEST PROJECT 9:45 Nov 13, 2024
33.891757, -116.409002 Dale Hameister
There was a large flood event (Tropical Storm Hilary) in August 2023. There is evidence of large amount of scour and flows in the southwest portion of the project site.
X
X
X
X
X
Extensive scour, including hard pan ares with no smaller sediment, with inconsistent bed and bank. Much of the bed and bank and OHWM area had vertical banks indicating newly cut from a large flow event.
Item Number: 1.
ENG FORM 6250, SEP 2024 Page of
Project ID #:
Step 4 Was additional information used to support identification of the OHWM? If yes, describe and attach information to data sheet:
Yes No
Step 5 Is an OHWM present at this site?
Describe rationale for location of OHWM or lack thereof by describing any observed indicators (at, above, and/or below the OHWM location).
Yes No
Additional observations or notes
Attach an imagery log of the site.
Imagery log attached? Yes No If no, explain why not:
List photographs, or other imagery/sketches, and include descriptions in the table below.
Number photographs in the order that they are taken. Attach imagery and include annotations of features.
Imagery
Number Imagery description
2 4
Evidence of bed and bank and channelization. This included new channels not evident on aerial photos from the previous years.
Photos included with attached JD report
Item Number: 1.
ENG FORM 6250, SEP 2024 Page of
OHWM Field Identification Data Sheet Instructions and Field Procedure Step 1 Site overview from remote and online resources (Chapter 5) Complete Step 1 prior to site visit.
Online Resources: Identify what information is available for the site. Check boxes on data sheet next to the resources used to assess this site.
a. gage data e. topographic maps
b. aerial photos f. geologic maps
c. satellite imagery g. land use maps
d. LiDAR h. climatic data (precipitation and temperature) Landscape context: Use the online resources to put the site in the context of the surrounding landscape. (Chapter 4) a. Note on the data sheet under Step 1:
i. Overall land use and change if known
ii. Recent extreme events if known (e.g., flood, drought, landslides, debris flows, wildfires) iii. Erosional and depositional environments
b. Consider the following to inform weighting of evidence observed during field visit. i. What physical characteristics are likely to be observed in specific environments? ii. Was there a recent flood or drought? Are you expecting to see recently formed or obscured indicators? iii. How will land use affect specific stream characteristics? How natural is the hydrologic regime? How stable has the landscape been over the last year, decade, century?
Step 2 Site conditions during the field assessment (assemble evidence) (Chapter 1 and 3) a. Identify the assessment area.
b. Walk up and down the assessment area noting all
the potential OHWM indicators.
c. Note broad trends in channel shape, vegetation,
and sediment characteristics.
i. Is this a single thread or multi-thread system?
Is this a stream-wetland complex?
ii. Are there any secondary and/or floodplain channels? iii. Are there obvious human-made alterations to the system? iv. Are there man-made (e.g., bridges, dams, culverts) or natural structures (e.g., bedrock outcrops, Large Wood
jams) that will influence or control flow?
d. Look for signs of recurring fluvial action.
i. Where does the flow converge on the landscape?
ii. Are there signs of fluvial action (sediment sorting, bedforms, etc.) at the convergence zone?
e. Look for indicators on both banks. If the opposite bank is not accessible, then look across the channel at the bank.
f. In Step 2 of the data sheet, describe any adjacent land use or flow conditions that may influence interpretation of each line of evidence.
i. What land use and flow conditions may be affecting your ability to observe indicators at the site?
ii. What recent extreme events may have caused changes to the site and affected your ability to observe indicators?
Step 3a List evidence (Chapter 2 and 3)
Assemble evidence by marking each box with a slash next to each line of evidence.
If using fillable form, then follow the instructions
for filling in the fillable form.
Questions to consider while making observations and listing evidence at a site:
Context is important when assembling evidence. For instance, pool development may be an indicator of interest on the bed of a dry stream, but may not be a useful indicator to take note of in a flowing stream. On the other hand, if the pool is found in a secondary channel adjacent to the main channel, it could provide a line of evidence for a minimum elevation of high flows. Therefore, consider the site context when deciding which indicators provide evidence for identifying the OHWM. Explain reasoning in Step 5.
Geomorphic indicators
Where are the breaks in slope?
Are there identifiable banks?
Is there an easily identifiable
top of bank?
Are the banks actively eroding?
Are the banks undercut?
Are the banks armored?
Is the channel confined by
the surrounding hillslopes?
Are there natural or man-made
berms and levees?
Are there fluvial terraces?
Are there channel bars?
Sediment and soil indicators
Where does evidence of
soil formation appear?
Are there mudcracks present?
Is there evidence of sediment
sorting by grain size?
Vegetation indicators
Where are the significant transitions in
vegetation species, density, and age?
Is there vegetation growing on the channel bed?
If no, how long does it take for the non-tolerant
vegetation to establish relative to how often flows
occur in the channel?
Where are the significant transitions in
vegetation?
Is the vegetation tolerant of flowing water?
Has any vegetation been flattened by flowing
water?
Other physical
indicators
Is there organic litter
present?
Is there any leaf litter
disturbed or washed
away?
Is there large wood
deposition?
Is there evidence of
water staining?
Are the following features of fluvial transport present? Evidence of erosion: obstacle marks, scour, armoring
Bedforms; riffles, pools, steps, knickpoints/headcuts
Evidence of deposition: imbricated clasts, gravel sheets, etc.
In some cases, it may be helpful to explain why an indicator was NOT at the OHWM elevation, but found above or below. It can also be useful to note if specific indicators (e.g., vegetation) are NOT present. For instance, note if the site has no clear vegetation zonation.
3 4 Item Number: 1.
ENG FORM 6250, SEP 2024 Page of
OHWM Field Identification Data Sheet Instructions and Field Procedure Step 3b Weight each line of evidence (Chapter 1 and 3)
Consider importance of each indicator by assessing the following:
a. Relevance:
i. Is this indicator left by low, high, or extreme flows? Did recent extreme events and/or land use affect this indicator?
ii. Consider the elevation of the indicator relative to the channel bed.
What is the current flow level based on season or nearby gages? iii. Consider the elevation of the indicator relative to the current flow.
If the stream is currently at baseflow and indicator is adjacent to that, then it is likely a low-flow indicator. The difference between high-and extreme-flow indicators can sometimes be difficult to determine. iv. Recent floods may have left many extreme-flow indicators, or temporarily altered channel form.
Other resources will likely be needed to support any OHWM identification at this site. Field evidence of the OHWM may have to wait for the site to recover from the recent flood. v. Droughts may cause field evidence of OHWM to be obscured because there has been an extended time since the last high-flow event. There can be overgrowth of vegetation or deposition of material from surrounding landscape that can obscure indicators. vi. Both human-made (e.g., dams, construction, mining activities, urbanization, agriculture, grazing) and natural (e.g., fires, floods, debris flows, beaver dams) disturbances can alter how indicators are expected to appear at a site. Chapter 6 and Chapter 7 of the OHWM field manual provide specific case-studies that can help in interpreting evidence at these sites. b. Strength:
i. Is this indicator persistent across the landscape?
1. Look up and downstream and across the channel to see if you see the same indicator at multiple locations.
2. Does the indicator occur at the same elevation as other indicators? c. Reliability:
i. Is this indicator persistent on the landscape over time? Will this indicator still persist across seasons?
1. This can be difficult to determine for some indicators and may be specific to climatic region (in terms of persistence of vegetation) and history of land use or other natural disturbances.
2. Chapter 2, Chapter 6, and Chapter 7 of the OHWM field manual describe each indicator in detail and provide examples of areas where indicators are difficult to interpret.
Step 4 Was additional information used to support identification of the OHWM? Are other resources used to support the lines of evidence observed in the field?
a. If additional resources are needed, then repeat steps 3a and 3b for the resources selected in Step 1 of assembling and weighting evidence collected from online resources. Chapter 5 of the OHWM field manual provides information on using online resources. b. Any data collected from online tools have strengths and weaknesses. Make sure these are clear when determining relevance, strength, and reliability of the remotely collected data. Clearly describe why other resources were used to support the lines of evidence observed in the field, as well as the relevance, strength, and reliability of the supporting data and/or resources. c. Attach any remote data and data analysis to the data sheet.
Step 5 Describe rationale for location of OHWM: (Chapter 1 and Chapter 3) a. Weigh body of evidence:
Combine information from Step 3b: Why do the combination of indicators represent the OHWM? i. Integrate the lines of evidence (relevance, strength, and reliability) of each indicator. ii. Consider which indicators are high value indicators that co-occur along the stream reach. Which indicators are most relevant to identifying high flow elevations, which are most persistent across the landscape, and which are most persistent over time? iii. Which indicators that are found above and below the location of the OHWM were helpful in identifying the elevation of the OHWM? b. If there is more than one possible location, explain why, Include any relevant discussion on why specific indicators were not included in the final decision.
c. If needed, add additional site notes on page 2 of the data sheet under Step 5 or attach additional sketches and field observations to the data sheet.
d. Take photographs of indicators and attach an imagery log using page 2 of data sheet or another method of logging images. i. Annotate images with descriptions of indicators.
*Landscape context from Step 1 (Chapter 4) can help
determine the relevance, strength, and reliability
of the indicators observed in the field.
*In Chapter 2 of the OHWM field manual provides
information on specific indicators that can assist in
putting these in context and determining relevance,
strength, and reliability.
4 4 Item Number: 1.
E
Appendix E
Preliminary Off-Site Drainage Analysis
Item Number: 1.
DATE February 7, 2025
TO Robert Glessner
Hunsaker & Associates Irvine, Inc.
FROM Hwee Hwang, Ph.D., P.E.
Richard Waskowsky, P.E
JE Fuller Hydrology and Geomorphology Inc.
RE DHS Varner Road Preliminary Off-Site Drainage Analysis Introduction
The Desert Hot Springs (DHS) Varner Road site (Varner Site) is a planned industrial development located in DHS, CA, near the intersection of Varner Road and West Drive (see Figure 1). The proposed development encompasses an industrial building with loading docks, drive-through facilities, parking areas, landscaping, and ancillary features designed to support the area’s growing industrial needs. The southern boundary of the property is bordered by a channel in CalTrans right-of-way (ROW), an important regional drainage feature.
Notably, the site is situated within an effective FEMA floodplain (Zone A), which necessitates careful consideration of potential off-site flows and flood hazards.
The surrounding areas can experience storm events that generate significant runoff, making floodplain management and hydraulic analyses essential. The Varner Site’s topographic characteristics and proximity to major drainage channels underscore the importance of evaluating how proposed site modifications might influence existing flow patterns. Local regulatory agencies and floodplain management guidelines typically require projects within flood-prone zones to demonstrate a “no-adverse-impact” (NAI) outcome, ensuring that upstream and downstream properties remain protected. To meet this requirement, a two-dimensional hydrodynamic analysis was conducted using HEC-RAS 2D (RAS2D) version 6.6 (a model developed by the USACE and accepted by FEMA), focusing on identifying changes in water surface elevation (WSE) and flow discharges under a 100-year storm event scenario.
The purpose of this technical memorandum is to (1) document the existing hydrologic and hydraulic conditions affecting the Varner Site, (2) determine how these off-site flows interact with the preliminary site plan, and (3) assess whether the proposed development might adversely impact adjacent or downstream properties.
On-site drainage design is being analyzed by the site civil engineer, Hunsaker & Associates (H&A), and is not considered in this memorandum. This NAI analysis focuses on identifying changes in WSE and flow characteristics under a 100-year storm event scenario and comparing them to pre-development conditions to demonstrate that the project has no adverse impacts.
EXP 09/30/2026
Item Number: 1.
Figure 1. Vicinity Map
Hydrology and Hydraulics
2.1 Background and Inflows
The most recent offsite hydrology for the Varner Road area is based on the Desert Land Ventures (DLV) Flood Hazard Assessment (FHA) study1. The DLV FHA was approved by DHS in April 2018. The hydrographs from the DLV FHA study were used as input to the detailed two-dimensional model for the Varner Site.
The DLV FHA study flowpath uncertainty analysis included multiple scenarios simulating potential alluvial fan landform avulsions in the upper watersheds that eventually drain to the Varner Site. A series of FLO-2D floodplain cross-sections (FPXSECs) were established in the DLV FHA study to measure the peak discharge from each flowpath uncertainty scenario. The Base scenario resulted in the highest peak discharge immediately am of the Varner Site. The Base scenario FLO-2D model from the DLV FHA study was updated with new FPXSECs for the purpose of developing outflow hydrographs to be used as inflow hydrographs for the current study. 1 JE Fuller, Inc., 2017, Desert Land Ventures and Desert Dunes Geomorphic and Flood Hazard Assessment Riverside County, California. Prepared for Desert Land Ventured III.
Item Number: 1.
Twelve hydrographs were extracted at these FPXSECs and used as inflow boundaries for the current RAS2D model. These inflows represent the 100-year storm event. Figure 2 provides the locations of these inflow points, while Table 1 summarizes the corresponding 100-year peak discharge values.
Figure 2. Inflow Locations for the Varner Site study
Item Number: 1.
Table 1. Varner Study Detailed HEC-RAS 2D Model Inflow Hydrograph Peak Discharges
2.2 Existing Conditions
A RAS2D model was developed to assess both existing and proposed hydraulic conditions within the project site and in its upstream and downstream reaches. Recent existing topographic data near the project site was provided by H&A, the extent of which is shown in Figure 3. This existing data was merged with the USGS 3DEP LiDAR to create the terrain surface for the existing conditions modeling.
The RAS2D model was initially constructed with a 20-foot grid resolution and refined using breaklines around high points, including roadway curbs, channel banks, and other key topographic features. To more accurately represent flow conditions in and around the project area, a 10-foot grid refinement region was applied within the 2D flow area. A uniform Manning’s n value of 0.05 was used throughout the 2D flow domain. This value represents a reasonable value for washes and overland flow in the general desert.
Three hydraulic structures (bridges and culverts) are located within the model (see Figure 3):
• Structure ID 1: I-10 bridge over Mission Creek
• Structure ID 2: I-10 bridge over Unnamed Wash
• Structure ID 3: 7-foot diameter circular culvert under Palm Drive During an earlier study, field surveys were conducted to verify the dimensions and locations of these structures.
In August 2024, the structures were revisited, and no significant changes that would affect hydraulic performance were identified. Therefore, the bridge and culvert geometries adopted for this study are consistent with those established in the DLV study.
FPXSEC ID 100-Year Inflow Peak Discharge (cfs)
14 3
15 546
16 105
17 258
18 34
19 7,164
20 5,103
21 31
22 115
23 69
24 4,769
25 50
Item Number: 1.
Figure 3. Map of the RAS2D Model and Existing Topography Data Boundary Item Number: 1.
2.3 Proposed Conditions
A proposed conditions terrain was developed by adding the proposed grading into the existing conditions terrain. This proposed conditions terrain formed the basis of the new ground elevations in the RAS2D model.
The proposed conditions RAS2D model contains several basins and box culverts as shown in Figure 4.
Figure 4. Proposed Conditions Terrain
Item Number: 1.
Results
The 100-year flow depth and peak discharges of the existing conditions RAS2D model are shown in Figure 5, while the proposed conditions model results are shown in Figure 6. The NAI analysis was performed by creating the WSE difference rasters, which were generated by subtracting the existing WSE from the proposed WSE and shown in Figure 7. If the proposed conditions lead to an increase in WSE of more than 0.2 foot, it is considered an adverse impact. The 0.2-foot threshold was chosen because it represents reasonable tolerance given accuracy limitations inherent within numerical modeling and with topographic data sets.
Conclusions
The proposed development for the DHS Varner Road site demonstrates no significant adverse impacts on adjacent properties under 100-year storm conditions, based on the preliminary modeling results. The industrial building is appropriately elevated above the maximum projected water surface elevations, and the downstream discharge remains essentially unchanged compared to existing conditions.
An increase in WSEs greater than 0.2 foot is observed near the southwestern and southeastern corners of the property as highlighted in Figure 7. This increase will be reduced to less than 0.2 foot during the final design process. Overall, the proposed grading, drainage improvements, and site layout are not expected to cause any detrimental off-site flood impacts, thereby meeting the requirements of the NAI analysis.
Item Number: 1.
Figure 5. Existing Conditions RAS2D Model Results
Item Number: 1.
Figure 6. Proposed Conditions RAS2D Model Results
Item Number: 1.
Figure 7. Map of Water Surface Elevation Increase for Areas Outside the Property Boundary Item Number: 1.
ATTACHMENTS
• Exhibit 1 – Existing 100-Year Maximum Depths
• Exhibit 2 – Proposed 100-Year Maximum Depth
• Excerpt from Desert Land Ventures (DLV) Flood Hazard Assessment Item Number: 1.
Item Number: 1.
Item Number: 1.
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Item Number: 1.
F
Appendix F
On-Site Hydrology Study
Item Number: 1.
HYDROLOGY ANALYSIS
FOR
TENTATIVE PARCEL MAP NO. 39143
City of Desert Hot Springs
County of Riverside
February 17, 2025
Prepared for:
NEWLAND CAPITAL GROUP
200 Spectrum Center Drive, Suite 200
Irvine, CA 92618
(949) 214-4779
Prepared by:
Hunsaker & Associate Irvine, Inc.
157 Technology Drive
Irvine, CA 92618
(949)583-1010
Item Number: 1.
HYDROLOGY ANALYSIS
FOR
TENTATIVE PARCEL
MAP No. 39143
CITY OF DESERT HOT SPRINGS
COUNTY OF RIVERSIDE
Prepared Date: 02/17/2025
PREPARED UNDER THE SUPERVISION OF:
02/17/2025
Jianhua “Gary” Guan, R.C.E. 64519, Exp. 06/30/25 Date:
Item Number: 1.
TABLE OF CONTENTS
SECTION TITLE
1 INTRODUCTION
2 EXHIBITS
· EXHIBIT 1 - FEMA MAP
· EXHIBIT 2 – EXISTING CONDITION HYDROLOGY MAP
· EXHIBIT 3 – PROPOSED CONDITION HYDROLOGY MAP
· EXHIBIT 4 – INFILTRATION BASIN EXHIBIT
3 EXISTING CONDITION HYDROLOGY CALCULATIONS
A. 10-YEAR STORM
B. 100-YEAR STORM
4 PROPOSED CONDITION HYDROLOGY CALCULATIONS
A. 10-YEAR STORM
B. 100-YEAR STORM
5 UNIT HYDROGRAPH CALCUALTIONS
6 INFILTRATION BASIN SIZING CALCULATIONS
7 OFF-SITE DRAINAGE ANALYSIS PREPARED BY JE
FULLER
Item Number: 1.
SECTION 1
INTRODUCTION
Item Number: 1.
1 A. INTRODUCTION
The project site is Tentative Parcel Map (TPM) No. 39143 in the City of Desert Hot Springs, County of Riverside. The site consists of approximately 123.4 acres of undeveloped site in the southern end of the City of Desert Hot Springs, generally located north of Interstate 10 (I-10) and west of the intersection of Palm Drive and Varner Road. The general location of the project site can be found from the Vicinity Map below.
B. STUDY PURPOSE
The purpose of this study is to provide a hydrology analysis for the flow rates produced from existing and proposed site conditions for comparison purposes. It also serves as the basis for analyzing and designing proposed and required infiltration basins. The infiltration basins are designed to contain 100% of 100- year 24-hour storm event runoffs per City Ordinance #1997-03 Section
13.08.100. In addition, the infiltration basins also serve as the water quality treatment measures to ensure the developed flows are treated prior to releasing to downstream water courses. This hydrology study is mainly focused on the onItem Number: 1.
2 site development areas and the off-site runoff studies which were prepared by JE Fuller can be found in Section 7.
C. EXISTING CONDITION
The entire project site consists of desert land, with shrubs, boulders and rocks scattered throughout the area. Onsite vegetation consists mainly of Sonoran Creosote Brush Scrub in areas not disturbed by existing roads that traverse the project site. Topographically, the site is generally flat and slopes downward to the southeast.
There are no existing storm drain systems available off-site and on-site. Natural drainage channels convey the storm runoff into the project area on the north side and continue through the project area toward the south side of the site with storm runoff generally characterized as sheet flow to the existing drainage swale along I-10 and continue southeastern direction.
The portion north of Varner Road is completely within the Willow Hole Conservation Area. Currently, Varner Road is an unmarked, partially paved road from Palm Drive on the east to its existing terminus near Mission Creek. Mihalyo Road, which is an unpaved dirt road, terminates near the northwestern portion of the site. Mihalyo road will not be developed as a street. It is being removed as part of TPM. Additionally, two existing underground 30-inch diameter gas transmission lines traverse the area in a northwest-southeast alignment within a 40-ft wide utility easement.
Currently, flooding and drainage conditions and issues associated with Mission Creek and the Big Morongo Wash constrain the project developments and its surroundings. The entire project site is located within the 100-year flood plain with no base flood elevations determined (Zone A) per Flood Insurance Rate Map (FIRM) Map No. 06065C0895G dated August 28, 2008, receiving flows from the Mission Creek and Big Morongo Wash watersheds, the FIRM map with the project site can be found in Exhibit 1.
In response to these conditions and to comply with the National Flood Insurance Program (NFIP) requirements, a revision to the effective Flood Insurance Rate Map (FIRM) is required to remove the project site from the 100-year floodplain.
To comply with the NFIP requirements, a Letter Of Map Revision (LOMR) will be applied via FEMA after the improvements are completed.
D. PROPOSED CONDITION
The proposed development encompasses an industrial building with loading docks, drive-through facilities, parking areas, landscaping, and ancillary features designed to support the area’s growing industrial needs.
Item Number: 1.
3 development provides solutions to ensure that the drainage flows of the area are maintained and to ensure that flooding is not an issue for the development areas. Solutions include raising the development pads above the areas flood zone level/line and incorporating wide drainage channels and infiltration basins that function as an engineering solution to the area’s drainage and flooding issues. The infiltration basins will be designed and constructed not only for the retention of 100-year 24-hour storm runoffs in accordance with the City’s requirements, but also for water quality purposes. The infiltration basins will serve as water quality treatment measures to ensure the developed onsite flows are treated prior to releasing downstream water courses.
E. HYDROLOGY METHODOLOGY
The rational method was used to calculate the design discharge for the local drainage areas since the watershed area to the proposed storm drain systems is less than one square mile.
Hydrologic calculations to determine the 10-year and 100-year discharges at critical locations were performed using the Riverside County Rational Method. A technical description of the rational method is provided in the Riverside County Flood Control and Water Conservation District Hydrology Manual dated April, 1978.
The hydrology calculations are based on the Riverside County Hydrology Program, as incorporated by CIVILCADD/CIVILDESIGN Engineering Software for determining peak runoff. The equations, charts, soils maps and rainfall intensity curves maps used are from the Hydrology Manual. The precipitation data was from the latest NOAA atlas rainfall. The rational method was used to calculate the 10-year and 100-year storm frequency peak flow rates for a 1-hour storm event.
Synthetic Unit Hydrograph Method was used to calculate the storm runoff volumes. It was discovered that the peak flow rates generated by the synthetic unit hydrographs were quite different than those generated by the rational method. The Riverside County Flood Control & Water Conservation District informed us that the way they solve the same problem is by adjusting the Manning “n” value used to develop the Synthetic Unit Hydrograph. The manning “n” may be adjusted until the peak flow rate given from the Synthetic Unit Hydrograph matches that of the rational method peak flow rate.
This method was then implemented. Using “UNRIV”, it was possible to match the peak flow rate of U.H. to that of the rational run, by refining the “n” value repeatedly. Once the peak flow rates matched for the 1-hour storm, the same Manning “n” was applied to 24-hour period. All pertinent information is included on the hydrology maps contained in this report.
Item Number: 1.
4 The project site lies within the soil boundary of Riverside County Flood Control District Hydrology Manual; Soil Type A was selected in the hydrology analysis per the Hydrology Manual. Hydrologic soils ratings are based on a scale of A through D, where A is the most pervious, providing the least runoff.
F. HYDROLOGY CALCULATION RESULTS
The hydrology calculations were performed for the on-site development areas only. The off-site flows and conveyance studies prepared by JE Fuller can be found in Section 7 as references.
Existing Condition
There is only one drainage area in the existing condition. The studied Drainage Area contains an approximate area of 93.0 acres of on-site development areas and produces a 100-year storm peak flow rate of 212.1 cfs. Detailed hydrology calculations can be found in Section 3 and the existing condition hydrology map (Exhibit 2) can be found in Section 2.
Proposed Condition
In the proposed condition, the same drainage area was studied and analyzed.
Detailed hydrology calculations can be found in Section 4 and the proposed condition hydrology map (Exhibit 3) can be found in Section 2.
There will have three on-site infiltration basins to contain and infiltrate the development area 100-year 24-hour storm volumes. The tributary areas, required 100-year 24-hour storm volumes and provided basin volumes are illustrated in Exhibit 4. Overall, the drainage path is similar to the existing condition with all the project flows sheet flow to the existing drainage swale along I-10.
The hydrology summary with the comparison with existing conditions is illustrated in Table 1.
Item Number: 1.
5 TABLE 1 SUMMARY OF HYDROLOGY ANALYSIS
TPM 39143 in City of Desert Hot Springs, Riverside County Existing (1) Proposed (2) Difference (3) = (2) - (1)
Drainage
Area
Area 10-year 100-year Drainage
Area
Area 10-year 100-year Area 10-year 100-year
(ac) (cfs) (cfs) (ac) (cfs) (cfs) (ac) (cfs) (cfs)
A 93.0 100.1 212.1 A 93.0 146.5 280.4 0.0 46.4 68.3
Total 93.0 100.1 212.1 Total 93.0 146.5 280.4 0.0 46.4 68.3 Note:
The proposed onsite basins will be proposed to collect and infiltrate the 100-year 24-hour storm volumes Unit Hydrograph Analysis
Synthetic Unit Hydrograph Method was used to calculate the storm runoff volumes. Only the proposed condition unit hydrograph calculations were performed. The 100-year storm with 1-hour and 24-hour storm period was analyzed for sizing the required infiltration basins.
The Project would provide three (3) on-site stormwater infiltration basins that during the life of the project will comply with the Stormwater Management and Discharge Controls stipulated in Chapter 13.08 of the Desert Hot Springs Municipal Code (Ordinance #1997-03). The provided basin capacities are sized to contain the 100-year, 24-hour duration storm event and therefore meet the City’s requirements on Stormwater Management and Discharge Controls and minimize the discharge and transport of pollutants associated with the new developments.
The volumes for the proposed condition 100-year 24-hour storm events are used in the infiltration basin volume design to meet the City’s requirements for the low impact developments (LID) and water quality treatments due to the project developments. Detailed unit hydrograph calculations can be found in Section 5.
Infiltration Basins
There are 3 infiltration basins proposed for the project site – Basin B, Basin C and Basin D. Basin B and Basin D interconnected together with a concrete spillway in between. The concrete spillway was provided for the protection of the existing gas lines and was used to bypass the off-site storm runoffs. The volumes below the spillways were used for on-site storm runoff infiltration. The basins are proposed for LID and water quality treatment purposes. As shown from the basin sizing calculations in Section 6, the infiltration basins are all sized Item Number: 1.
6 larger than the 100-year 24-hour storm runoff volumes as required by City of Desert Hot Springs.
The detailed basin sizing calculations can be found in Section 6 and the summary of unit hydrograph and basin sizing calculations can be found in Table 2.
TABLE 2 SUMMARY OF UNIT HYDROGRAPH ANALYSIS AND INFILTRATION BASINS
TPM 39143 in City of Desert Hot Springs, Riverside County Infiltration
Basin
Area 1-HR Unit
Hydrograph
24-HR Unit
Hydrograph
Basin Volume
provided
(ac) (ac-ft) (ac-ft) (ac-ft)
B & C 76.3 9.3813 23.5849 40.37
D 12.6 1.4373 2.8105 3.16
Item Number: 1.
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SECTION 2
EXHIBITS
Item Number: 1.
Item Number: 1.
200 SPECTRUM CENTER DRIVE, SUITE 200
IRVINE, CA 92618
PH: (949) 214-4779
Item Number: 1.
200 SPECTRUM CENTER DRIVE, SUITE 200
IRVINE, CA 92618
PH: (949) 214-4779
Item Number: 1.
200 SPECTRUM CENTER DRIVE, SUITE 200
IRVINE, CA 92618
PH: (949) 214-4779
Item Number: 1.
200 SPECTRUM CENTER DRIVE, SUITE 200
IRVINE, CA 92618
PH: (949) 214-4779
Item Number: 1.
SECTION 3
EXISTING CONDITION HYDROLOGY
CALCULATIONS
Item Number: 1.
A. 10-YEAR STORM
Item Number: 1.
1 Riverside County Rational Hydrology Program
CIVILCADD/CIVILDESIGN Engineering Software,(c) 1989 - 2014 Version 9.0 Rational Hydrology Study Date: 02/07/25 File:39143exist.out ------------------------------------------------------------------------ Hydrology Study for TPM 39143
In the City of Desert Hot Springs
Existing Condition Onsite Areas
10-year Storm
------------------------------------------------------------------------ ********* Hydrology Study Control Information ********** English (in-lb) Units used in input data file
------------------------------------------------------------------------ Program License Serial Number 6406
------------------------------------------------------------------------ Rational Method Hydrology Program based on
Riverside County Flood Control & Water Conservation District 1978 hydrology manual
Storm event (year) = 10.00 Antecedent Moisture Condition = 2 2 year, 1 hour precipitation = 0.454(In.)
100 year, 1 hour precipitation = 1.690(In.)
Storm event year = 10.0
Calculated rainfall intensity data:
1 hour intensity = 0.963(In/Hr)
Slope of intensity duration curve = 0.5800
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 10.000 to Point/Station 11.000 **** INITIAL AREA EVALUATION ****
______________________________________________________________________ Initial area flow distance = 280.000(Ft.)
Top (of initial area) elevation = 660.900(Ft.)
Bottom (of initial area) elevation = 657.000(Ft.)
Difference in elevation = 3.900(Ft.)
Slope = 0.01393 s(percent)= 1.39
TC = k(0.530)*[(length^3)/(elevation change)]^0.2
Initial area time of concentration = 11.867 min.
Rainfall intensity = 2.464(In/Hr) for a 10.0 year storm UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.711
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 67.00
Pervious area fraction = 1.000; Impervious fraction = 0.000 Initial subarea runoff = 1.050(CFS)
Total initial stream area = 0.600(Ac.)
Pervious area fraction = 1.000
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 11.000 to Point/Station 12.000 **** NATURAL CHANNEL TIME + SUBAREA FLOW ADDITION ****
______________________________________________________________________ Top of natural channel elevation = 657.000(Ft.)
End of natural channel elevation = 653.000(Ft.)
Length of natural channel = 260.000(Ft.)
Item Number: 1.
2 Estimated mean flow rate at midpoint of channel = 3.151(CFS) Natural valley channel type used
L.A. County flood control district formula for channel velocity:
Velocity(ft/s) = (7 + 8(q(English Units)^.352)(slope^0.5) Velocity using mean channel flow = 2.35(Ft/s)
Correction to map slope used on extremely rugged channels with drops and waterfalls (Plate D-6.2)
Normal channel slope = 0.0154
Corrected/adjusted channel slope = 0.0154
Travel time = 1.84 min. TC = 13.71 min.
Adding area flow to channel
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.698
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 67.00
Pervious area fraction = 1.000; Impervious fraction = 0.000 Rainfall intensity = 2.266(In/Hr) for a 10.0 year storm Subarea runoff = 3.795(CFS) for 2.400(Ac.)
Total runoff = 4.846(CFS) Total area = 3.000(Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 12.000 to Point/Station 13.000 **** NATURAL CHANNEL TIME + SUBAREA FLOW ADDITION ****
______________________________________________________________________ Top of natural channel elevation = 653.000(Ft.)
End of natural channel elevation = 646.000(Ft.)
Length of natural channel = 530.000(Ft.)
Estimated mean flow rate at midpoint of channel = 9.691(CFS) Natural valley channel type used
L.A. County flood control district formula for channel velocity:
Velocity(ft/s) = (7 + 8(q(English Units)^.352)(slope^0.5) Velocity using mean channel flow = 2.85(Ft/s)
Correction to map slope used on extremely rugged channels with drops and waterfalls (Plate D-6.2)
Normal channel slope = 0.0132
Corrected/adjusted channel slope = 0.0132
Travel time = 3.10 min. TC = 16.81 min.
Adding area flow to channel
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.679
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 67.00
Pervious area fraction = 1.000; Impervious fraction = 0.000 Rainfall intensity = 2.013(In/Hr) for a 10.0 year storm Subarea runoff = 8.198(CFS) for 6.000(Ac.)
Total runoff = 13.044(CFS) Total area = 9.000(Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 13.000 to Point/Station 14.000 **** NATURAL CHANNEL TIME + SUBAREA FLOW ADDITION ****
______________________________________________________________________ Top of natural channel elevation = 646.000(Ft.)
End of natural channel elevation = 638.500(Ft.)
Length of natural channel = 750.000(Ft.)
Estimated mean flow rate at midpoint of channel = 23.044(CFS) Item Number: 1.
3 Natural valley channel type used
L.A. County flood control district formula for channel velocity:
Velocity(ft/s) = (7 + 8(q(English Units)^.352)(slope^0.5) Velocity using mean channel flow = 3.11(Ft/s)
Correction to map slope used on extremely rugged channels with drops and waterfalls (Plate D-6.2)
Normal channel slope = 0.0100
Corrected/adjusted channel slope = 0.0100
Travel time = 4.01 min. TC = 20.82 min.
Adding area flow to channel
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.657
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 67.00
Pervious area fraction = 1.000; Impervious fraction = 0.000 Rainfall intensity = 1.778(In/Hr) for a 10.0 year storm Subarea runoff = 16.129(CFS) for 13.800(Ac.)
Total runoff = 29.173(CFS) Total area = 22.800(Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 14.000 to Point/Station 15.000 **** NATURAL CHANNEL TIME + SUBAREA FLOW ADDITION ****
______________________________________________________________________ Top of natural channel elevation = 638.500(Ft.)
End of natural channel elevation = 630.000(Ft.)
Length of natural channel = 630.000(Ft.)
Estimated mean flow rate at midpoint of channel = 39.409(CFS) Natural valley channel type used
L.A. County flood control district formula for channel velocity:
Velocity(ft/s) = (7 + 8(q(English Units)^.352)(slope^0.5) Velocity using mean channel flow = 4.20(Ft/s)
Correction to map slope used on extremely rugged channels with drops and waterfalls (Plate D-6.2)
Normal channel slope = 0.0135
Corrected/adjusted channel slope = 0.0135
Travel time = 2.50 min. TC = 23.32 min.
Adding area flow to channel
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.645
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 67.00
Pervious area fraction = 1.000; Impervious fraction = 0.000 Rainfall intensity = 1.665(In/Hr) for a 10.0 year storm Subarea runoff = 17.195(CFS) for 16.000(Ac.)
Total runoff = 46.367(CFS) Total area = 38.800(Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 15.000 to Point/Station 16.000 **** NATURAL CHANNEL TIME + SUBAREA FLOW ADDITION ****
______________________________________________________________________ Top of natural channel elevation = 630.000(Ft.)
End of natural channel elevation = 625.500(Ft.)
Length of natural channel = 460.000(Ft.)
Estimated mean flow rate at midpoint of channel = 57.242(CFS) Item Number: 1.
4 Natural valley channel type used
L.A. County flood control district formula for channel velocity:
Velocity(ft/s) = (7 + 8(q(English Units)^.352)(slope^0.5) Velocity using mean channel flow = 3.98(Ft/s)
Correction to map slope used on extremely rugged channels with drops and waterfalls (Plate D-6.2)
Normal channel slope = 0.0098
Corrected/adjusted channel slope = 0.0098
Travel time = 1.93 min. TC = 25.25 min.
Adding area flow to channel
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.637
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 67.00
Pervious area fraction = 1.000; Impervious fraction = 0.000 Rainfall intensity = 1.590(In/Hr) for a 10.0 year storm Subarea runoff = 18.434(CFS) for 18.200(Ac.)
Total runoff = 64.801(CFS) Total area = 57.000(Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 16.000 to Point/Station 17.000 **** NATURAL CHANNEL TIME + SUBAREA FLOW ADDITION ****
______________________________________________________________________ Top of natural channel elevation = 625.500(Ft.)
End of natural channel elevation = 622.000(Ft.)
Length of natural channel = 310.000(Ft.)
Estimated mean flow rate at midpoint of channel = 85.264(CFS) Natural valley channel type used
L.A. County flood control district formula for channel velocity:
Velocity(ft/s) = (7 + 8(q(English Units)^.352)(slope^0.5) Velocity using mean channel flow = 4.81(Ft/s)
Correction to map slope used on extremely rugged channels with drops and waterfalls (Plate D-6.2)
Normal channel slope = 0.0113
Corrected/adjusted channel slope = 0.0113
Travel time = 1.07 min. TC = 26.32 min.
Adding area flow to channel
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.632
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 67.00
Pervious area fraction = 1.000; Impervious fraction = 0.000 Rainfall intensity = 1.552(In/Hr) for a 10.0 year storm Subarea runoff = 35.339(CFS) for 36.000(Ac.)
Total runoff = 100.140(CFS) Total area = 93.000(Ac.)
End of computations, total study area = 93.00 (Ac.)
The following figures may
be used for a unit hydrograph study of the same area.
Area averaged pervious area fraction(Ap) = 1.000
Area averaged RI index number = 67.0
Item Number: 1.
Item Number: 1.
B. 100-YEAR STORM
Item Number: 1.
1 Riverside County Rational Hydrology Program
CIVILCADD/CIVILDESIGN Engineering Software,(c) 1989 - 2014 Version 9.0 Rational Hydrology Study Date: 02/07/25 File:39143exist.out ------------------------------------------------------------------------ Hydrology Study for TPM 39143
In the City of Desert Hot Springs
Existing Condition Onsite Areas
100-year Storm
------------------------------------------------------------------------ ********* Hydrology Study Control Information ********** English (in-lb) Units used in input data file
------------------------------------------------------------------------ Program License Serial Number 6406
------------------------------------------------------------------------ Rational Method Hydrology Program based on
Riverside County Flood Control & Water Conservation District 1978 hydrology manual
Storm event (year) = 100.00 Antecedent Moisture Condition = 2 2 year, 1 hour precipitation = 0.454(In.)
100 year, 1 hour precipitation = 1.690(In.)
Storm event year = 100.0
Calculated rainfall intensity data:
1 hour intensity = 1.690(In/Hr)
Slope of intensity duration curve = 0.5800
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 10.000 to Point/Station 11.000 **** INITIAL AREA EVALUATION ****
______________________________________________________________________ Initial area flow distance = 280.000(Ft.)
Top (of initial area) elevation = 660.900(Ft.)
Bottom (of initial area) elevation = 657.000(Ft.)
Difference in elevation = 3.900(Ft.)
Slope = 0.01393 s(percent)= 1.39
TC = k(0.530)*[(length^3)/(elevation change)]^0.2
Initial area time of concentration = 11.867 min.
Rainfall intensity = 4.326(In/Hr) for a 100.0 year storm UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.781
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 67.00
Pervious area fraction = 1.000; Impervious fraction = 0.000 Initial subarea runoff = 2.028(CFS)
Total initial stream area = 0.600(Ac.)
Pervious area fraction = 1.000
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 11.000 to Point/Station 12.000 **** NATURAL CHANNEL TIME + SUBAREA FLOW ADDITION ****
______________________________________________________________________ Top of natural channel elevation = 657.000(Ft.)
End of natural channel elevation = 653.000(Ft.)
Length of natural channel = 260.000(Ft.)
Item Number: 1.
2 Estimated mean flow rate at midpoint of channel = 6.084(CFS) Natural valley channel type used
L.A. County flood control district formula for channel velocity:
Velocity(ft/s) = (7 + 8(q(English Units)^.352)(slope^0.5) Velocity using mean channel flow = 2.74(Ft/s)
Correction to map slope used on extremely rugged channels with drops and waterfalls (Plate D-6.2)
Normal channel slope = 0.0154
Corrected/adjusted channel slope = 0.0154
Travel time = 1.58 min. TC = 13.45 min.
Adding area flow to channel
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.774
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 67.00
Pervious area fraction = 1.000; Impervious fraction = 0.000 Rainfall intensity = 4.023(In/Hr) for a 100.0 year storm Subarea runoff = 7.471(CFS) for 2.400(Ac.)
Total runoff = 9.499(CFS) Total area = 3.000(Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 12.000 to Point/Station 13.000 **** NATURAL CHANNEL TIME + SUBAREA FLOW ADDITION ****
______________________________________________________________________ Top of natural channel elevation = 653.000(Ft.)
End of natural channel elevation = 646.000(Ft.)
Length of natural channel = 530.000(Ft.)
Estimated mean flow rate at midpoint of channel = 18.999(CFS) Natural valley channel type used
L.A. County flood control district formula for channel velocity:
Velocity(ft/s) = (7 + 8(q(English Units)^.352)(slope^0.5) Velocity using mean channel flow = 3.40(Ft/s)
Correction to map slope used on extremely rugged channels with drops and waterfalls (Plate D-6.2)
Normal channel slope = 0.0132
Corrected/adjusted channel slope = 0.0132
Travel time = 2.60 min. TC = 16.05 min.
Adding area flow to channel
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.762
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 67.00
Pervious area fraction = 1.000; Impervious fraction = 0.000 Rainfall intensity = 3.631(In/Hr) for a 100.0 year storm Subarea runoff = 16.606(CFS) for 6.000(Ac.)
Total runoff = 26.105(CFS) Total area = 9.000(Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 13.000 to Point/Station 14.000 **** NATURAL CHANNEL TIME + SUBAREA FLOW ADDITION ****
______________________________________________________________________ Top of natural channel elevation = 646.000(Ft.)
End of natural channel elevation = 638.500(Ft.)
Length of natural channel = 750.000(Ft.)
Estimated mean flow rate at midpoint of channel = 46.119(CFS) Item Number: 1.
3 Natural valley channel type used
L.A. County flood control district formula for channel velocity:
Velocity(ft/s) = (7 + 8(q(English Units)^.352)(slope^0.5) Velocity using mean channel flow = 3.78(Ft/s)
Correction to map slope used on extremely rugged channels with drops and waterfalls (Plate D-6.2)
Normal channel slope = 0.0100
Corrected/adjusted channel slope = 0.0100
Travel time = 3.31 min. TC = 19.35 min.
Adding area flow to channel
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.749
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 67.00
Pervious area fraction = 1.000; Impervious fraction = 0.000 Rainfall intensity = 3.257(In/Hr) for a 100.0 year storm Subarea runoff = 33.670(CFS) for 13.800(Ac.)
Total runoff = 59.775(CFS) Total area = 22.800(Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 14.000 to Point/Station 15.000 **** NATURAL CHANNEL TIME + SUBAREA FLOW ADDITION ****
______________________________________________________________________ Top of natural channel elevation = 638.500(Ft.)
End of natural channel elevation = 630.000(Ft.)
Length of natural channel = 630.000(Ft.)
Estimated mean flow rate at midpoint of channel = 80.749(CFS) Natural valley channel type used
L.A. County flood control district formula for channel velocity:
Velocity(ft/s) = (7 + 8(q(English Units)^.352)(slope^0.5) Velocity using mean channel flow = 5.17(Ft/s)
Correction to map slope used on extremely rugged channels with drops and waterfalls (Plate D-6.2)
Normal channel slope = 0.0135
Corrected/adjusted channel slope = 0.0135
Travel time = 2.03 min. TC = 21.38 min.
Adding area flow to channel
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.742
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 67.00
Pervious area fraction = 1.000; Impervious fraction = 0.000 Rainfall intensity = 3.074(In/Hr) for a 100.0 year storm Subarea runoff = 36.479(CFS) for 16.000(Ac.)
Total runoff = 96.254(CFS) Total area = 38.800(Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 15.000 to Point/Station 16.000 **** NATURAL CHANNEL TIME + SUBAREA FLOW ADDITION ****
______________________________________________________________________ Top of natural channel elevation = 630.000(Ft.)
End of natural channel elevation = 625.500(Ft.)
Length of natural channel = 460.000(Ft.)
Estimated mean flow rate at midpoint of channel = 118.829(CFS) Item Number: 1.
4 Natural valley channel type used
L.A. County flood control district formula for channel velocity:
Velocity(ft/s) = (7 + 8(q(English Units)^.352)(slope^0.5) Velocity using mean channel flow = 4.95(Ft/s)
Correction to map slope used on extremely rugged channels with drops and waterfalls (Plate D-6.2)
Normal channel slope = 0.0098
Corrected/adjusted channel slope = 0.0098
Travel time = 1.55 min. TC = 22.93 min.
Adding area flow to channel
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.736
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 67.00
Pervious area fraction = 1.000; Impervious fraction = 0.000 Rainfall intensity = 2.952(In/Hr) for a 100.0 year storm Subarea runoff = 39.556(CFS) for 18.200(Ac.)
Total runoff = 135.810(CFS) Total area = 57.000(Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 16.000 to Point/Station 17.000 **** NATURAL CHANNEL TIME + SUBAREA FLOW ADDITION ****
______________________________________________________________________ Top of natural channel elevation = 625.500(Ft.)
End of natural channel elevation = 622.000(Ft.)
Length of natural channel = 310.000(Ft.)
Estimated mean flow rate at midpoint of channel = 178.698(CFS) Natural valley channel type used
L.A. County flood control district formula for channel velocity:
Velocity(ft/s) = (7 + 8(q(English Units)^.352)(slope^0.5) Velocity using mean channel flow = 6.02(Ft/s)
Correction to map slope used on extremely rugged channels with drops and waterfalls (Plate D-6.2)
Normal channel slope = 0.0113
Corrected/adjusted channel slope = 0.0113
Travel time = 0.86 min. TC = 23.79 min.
Adding area flow to channel
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.733
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 67.00
Pervious area fraction = 1.000; Impervious fraction = 0.000 Rainfall intensity = 2.890(In/Hr) for a 100.0 year storm Subarea runoff = 76.293(CFS) for 36.000(Ac.)
Total runoff = 212.104(CFS) Total area = 93.000(Ac.)
End of computations, total study area = 93.00 (Ac.)
The following figures may
be used for a unit hydrograph study of the same area.
Area averaged pervious area fraction(Ap) = 1.000
Area averaged RI index number = 67.0
Item Number: 1.
SECTION 4
PROPOSED CONDITION
HYDROLOGY CALCULATIONS
Item Number: 1.
A. 10-YEAR STORM
Item Number: 1.
1 Riverside County Rational Hydrology Program
CIVILCADD/CIVILDESIGN Engineering Software,(c) 1989 - 2014 Version 9.0 Rational Hydrology Study Date: 02/10/25 File:39143prop.out ------------------------------------------------------------------------ Hydrology Study for TPM 39143
In the City of Desert Hot Springs
Proposed Condition Onsite Areas
10-year Storm
------------------------------------------------------------------------ ********* Hydrology Study Control Information ********** English (in-lb) Units used in input data file
------------------------------------------------------------------------ Program License Serial Number 6406
------------------------------------------------------------------------ Rational Method Hydrology Program based on
Riverside County Flood Control & Water Conservation District 1978 hydrology manual
Storm event (year) = 10.00 Antecedent Moisture Condition = 2 2 year, 1 hour precipitation = 0.454(In.)
100 year, 1 hour precipitation = 1.690(In.)
Storm event year = 10.0
Calculated rainfall intensity data:
1 hour intensity = 0.963(In/Hr)
Slope of intensity duration curve = 0.5800
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 10.000 to Point/Station 11.000 **** INITIAL AREA EVALUATION ****
______________________________________________________________________ Initial area flow distance = 280.000(Ft.)
Top (of initial area) elevation = 660.900(Ft.)
Bottom (of initial area) elevation = 657.000(Ft.)
Difference in elevation = 3.900(Ft.)
Slope = 0.01393 s(percent)= 1.39
TC = k(0.530)*[(length^3)/(elevation change)]^0.2
Initial area time of concentration = 11.867 min.
Rainfall intensity = 2.464(In/Hr) for a 10.0 year storm UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.711
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 67.00
Pervious area fraction = 1.000; Impervious fraction = 0.000 Initial subarea runoff = 1.050(CFS)
Total initial stream area = 0.600(Ac.)
Pervious area fraction = 1.000
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 11.000 to Point/Station 30.000 **** NATURAL CHANNEL TIME + SUBAREA FLOW ADDITION ****
______________________________________________________________________ Top of natural channel elevation = 657.000(Ft.)
End of natural channel elevation = 645.000(Ft.)
Length of natural channel = 430.000(Ft.)
Item Number: 1.
2 Estimated mean flow rate at midpoint of channel = 5.165(CFS) Natural valley channel type used
L.A. County flood control district formula for channel velocity:
Velocity(ft/s) = (7 + 8(q(English Units)^.352)(slope^0.5) Velocity using mean channel flow = 3.55(Ft/s)
Correction to map slope used on extremely rugged channels with drops and waterfalls (Plate D-6.2)
Normal channel slope = 0.0279
Corrected/adjusted channel slope = 0.0279
Travel time = 2.02 min. TC = 13.89 min.
Adding area flow to channel
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.697
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 67.00
Pervious area fraction = 1.000; Impervious fraction = 0.000 Rainfall intensity = 2.249(In/Hr) for a 10.0 year storm Subarea runoff = 7.364(CFS) for 4.700(Ac.)
Total runoff = 8.415(CFS) Total area = 5.300(Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 30.000 to Point/Station 30.000 **** CONFLUENCE OF MINOR STREAMS ****
______________________________________________________________________ Along Main Stream number: 1 in normal stream number 1
Stream flow area = 5.300(Ac.)
Runoff from this stream = 8.415(CFS)
Time of concentration = 13.89 min.
Rainfall intensity = 2.249(In/Hr)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 15.000 to Point/Station 16.000 **** INITIAL AREA EVALUATION ****
______________________________________________________________________ Initial area flow distance = 150.000(Ft.)
Top (of initial area) elevation = 656.500(Ft.)
Bottom (of initial area) elevation = 655.300(Ft.)
Difference in elevation = 1.200(Ft.)
Slope = 0.00800 s(percent)= 0.80
TC = k(0.300)*[(length^3)/(elevation change)]^0.2
Initial area time of concentration = 5.847 min.
Rainfall intensity = 3.715(In/Hr) for a 10.0 year storm COMMERCIAL subarea type
Runoff Coefficient = 0.861
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 32.00
Pervious area fraction = 0.100; Impervious fraction = 0.900 Initial subarea runoff = 1.279(CFS)
Total initial stream area = 0.400(Ac.)
Pervious area fraction = 0.100
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 16.000 to Point/Station 17.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 655.300(Ft.)
Downstream point/station elevation = 655.000(Ft.)
Pipe length = 45.00(Ft.) Manning's N = 0.013
Item Number: 1.
3 No. of pipes = 1 Required pipe flow = 1.279(CFS)
Nearest computed pipe diameter = 9.00(In.)
Calculated individual pipe flow = 1.279(CFS)
Normal flow depth in pipe = 6.98(In.)
Flow top width inside pipe = 7.50(In.)
Critical Depth = 6.25(In.)
Pipe flow velocity = 3.48(Ft/s)
Travel time through pipe = 0.22 min.
Time of concentration (TC) = 6.06 min.
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 17.000 to Point/Station 17.000 **** SUBAREA FLOW ADDITION ****
______________________________________________________________________ COMMERCIAL subarea type
Runoff Coefficient = 0.861
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 32.00
Pervious area fraction = 0.100; Impervious fraction = 0.900 Time of concentration = 6.06 min.
Rainfall intensity = 3.637(In/Hr) for a 10.0 year storm Subarea runoff = 1.252(CFS) for 0.400(Ac.)
Total runoff = 2.531(CFS) Total area = 0.800(Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 17.000 to Point/Station 18.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 655.000(Ft.)
Downstream point/station elevation = 654.900(Ft.)
Pipe length = 360.00(Ft.) Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 2.531(CFS)
Nearest computed pipe diameter = 21.00(In.)
Calculated individual pipe flow = 2.531(CFS)
Normal flow depth in pipe = 16.48(In.)
Flow top width inside pipe = 17.27(In.)
Critical Depth = 6.91(In.)
Pipe flow velocity = 1.25(Ft/s)
Travel time through pipe = 4.80 min.
Time of concentration (TC) = 10.86 min.
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 18.000 to Point/Station 18.000 **** SUBAREA FLOW ADDITION ****
______________________________________________________________________ COMMERCIAL subarea type
Runoff Coefficient = 0.853
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 32.00
Pervious area fraction = 0.100; Impervious fraction = 0.900 Time of concentration = 10.86 min.
Rainfall intensity = 2.594(In/Hr) for a 10.0 year storm Subarea runoff = 1.327(CFS) for 0.600(Ac.)
Total runoff = 3.859(CFS) Total area = 1.400(Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 18.000 to Point/Station 18.000 **** SUBAREA FLOW ADDITION ****
______________________________________________________________________ COMMERCIAL subarea type
Runoff Coefficient = 0.853
Item Number: 1.
4 Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 32.00
Pervious area fraction = 0.100; Impervious fraction = 0.900 Time of concentration = 10.86 min.
Rainfall intensity = 2.594(In/Hr) for a 10.0 year storm Subarea runoff = 1.549(CFS) for 0.700(Ac.)
Total runoff = 5.408(CFS) Total area = 2.100(Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 18.000 to Point/Station 19.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 654.900(Ft.)
Downstream point/station elevation = 654.000(Ft.)
Pipe length = 495.00(Ft.) Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 5.408(CFS)
Nearest computed pipe diameter = 21.00(In.)
Calculated individual pipe flow = 5.408(CFS)
Normal flow depth in pipe = 14.20(In.)
Flow top width inside pipe = 19.65(In.)
Critical Depth = 10.25(In.)
Pipe flow velocity = 3.12(Ft/s)
Travel time through pipe = 2.64 min.
Time of concentration (TC) = 13.51 min.
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 19.000 to Point/Station 19.000 **** SUBAREA FLOW ADDITION ****
______________________________________________________________________ COMMERCIAL subarea type
Runoff Coefficient = 0.850
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 32.00
Pervious area fraction = 0.100; Impervious fraction = 0.900 Time of concentration = 13.51 min.
Rainfall intensity = 2.286(In/Hr) for a 10.0 year storm Subarea runoff = 0.972(CFS) for 0.500(Ac.)
Total runoff = 6.379(CFS) Total area = 2.600(Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 19.000 to Point/Station 19.000 **** SUBAREA FLOW ADDITION ****
______________________________________________________________________ COMMERCIAL subarea type
Runoff Coefficient = 0.850
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 32.00
Pervious area fraction = 0.100; Impervious fraction = 0.900 Time of concentration = 13.51 min.
Rainfall intensity = 2.286(In/Hr) for a 10.0 year storm Subarea runoff = 0.389(CFS) for 0.200(Ac.)
Total runoff = 6.768(CFS) Total area = 2.800(Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 19.000 to Point/Station 20.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 654.000(Ft.)
Item Number: 1.
5 Downstream point/station elevation = 653.500(Ft.)
Pipe length = 125.00(Ft.) Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 6.768(CFS)
Nearest computed pipe diameter = 21.00(In.)
Calculated individual pipe flow = 6.768(CFS)
Normal flow depth in pipe = 12.64(In.)
Flow top width inside pipe = 20.56(In.)
Critical Depth = 11.53(In.)
Pipe flow velocity = 4.47(Ft/s)
Travel time through pipe = 0.47 min.
Time of concentration (TC) = 13.97 min.
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 20.000 to Point/Station 20.000 **** SUBAREA FLOW ADDITION ****
______________________________________________________________________ COMMERCIAL subarea type
Runoff Coefficient = 0.850
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 32.00
Pervious area fraction = 0.100; Impervious fraction = 0.900 Time of concentration = 13.97 min.
Rainfall intensity = 2.241(In/Hr) for a 10.0 year storm Subarea runoff = 0.381(CFS) for 0.200(Ac.)
Total runoff = 7.149(CFS) Total area = 3.000(Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 20.000 to Point/Station 21.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 653.500(Ft.)
Downstream point/station elevation = 646.500(Ft.)
Pipe length = 90.00(Ft.) Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 7.149(CFS)
Nearest computed pipe diameter = 12.00(In.)
Calculated individual pipe flow = 7.149(CFS)
Normal flow depth in pipe = 7.54(In.)
Flow top width inside pipe = 11.60(In.)
Critical depth could not be calculated.
Pipe flow velocity = 13.77(Ft/s)
Travel time through pipe = 0.11 min.
Time of concentration (TC) = 14.08 min.
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 21.000 to Point/Station 30.000 **** IMPROVED CHANNEL TRAVEL TIME ****
______________________________________________________________________ Upstream point elevation = 646.500(Ft.)
Downstream point elevation = 645.500(Ft.)
Channel length thru subarea = 400.000(Ft.)
Channel base width = 50.000(Ft.)
Slope or 'Z' of left channel bank = 4.000
Slope or 'Z' of right channel bank = 4.000
Manning's 'N' = 0.030
Maximum depth of channel = 5.000(Ft.)
Flow(q) thru subarea = 7.149(CFS)
Depth of flow = 0.180(Ft.), Average velocity = 0.782(Ft/s) Channel flow top width = 51.441(Ft.)
Flow Velocity = 0.78(Ft/s)
Travel time = 8.52 min.
Time of concentration = 22.60 min.
Sub-Channel No. 1 Critical depth = 0.086(Ft.)
' ' ' Critical flow top width = 50.688(Ft.)
' ' ' Critical flow velocity= 1.652(Ft/s)
Item Number: 1.
6 ' ' ' Critical flow area = 4.326(Sq.Ft)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 30.000 to Point/Station 30.000 **** CONFLUENCE OF MINOR STREAMS ****
______________________________________________________________________ Along Main Stream number: 1 in normal stream number 2
Stream flow area = 3.000(Ac.)
Runoff from this stream = 7.149(CFS)
Time of concentration = 22.60 min.
Rainfall intensity = 1.696(In/Hr)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 25.000 to Point/Station 26.000 **** INITIAL AREA EVALUATION ****
______________________________________________________________________ Initial area flow distance = 460.000(Ft.)
Top (of initial area) elevation = 655.500(Ft.)
Bottom (of initial area) elevation = 651.000(Ft.)
Difference in elevation = 4.500(Ft.)
Slope = 0.00978 s(percent)= 0.98
TC = k(0.300)*[(length^3)/(elevation change)]^0.2
Initial area time of concentration = 8.793 min.
Rainfall intensity = 2.932(In/Hr) for a 10.0 year storm COMMERCIAL subarea type
Runoff Coefficient = 0.856
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 32.00
Pervious area fraction = 0.100; Impervious fraction = 0.900 Initial subarea runoff = 8.279(CFS)
Total initial stream area = 3.300(Ac.)
Pervious area fraction = 0.100
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 26.000 to Point/Station 27.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 651.000(Ft.)
Downstream point/station elevation = 650.500(Ft.)
Pipe length = 80.00(Ft.) Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 8.279(CFS)
Nearest computed pipe diameter = 18.00(In.)
Calculated individual pipe flow = 8.279(CFS)
Normal flow depth in pipe = 14.72(In.)
Flow top width inside pipe = 13.90(In.)
Critical Depth = 13.37(In.)
Pipe flow velocity = 5.36(Ft/s)
Travel time through pipe = 0.25 min.
Time of concentration (TC) = 9.04 min.
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 27.000 to Point/Station 27.000 **** SUBAREA FLOW ADDITION ****
______________________________________________________________________ COMMERCIAL subarea type
Runoff Coefficient = 0.855
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 32.00
Pervious area fraction = 0.100; Impervious fraction = 0.900 Time of concentration = 9.04 min.
Item Number: 1.
7 Rainfall intensity = 2.885(In/Hr) for a 10.0 year storm Subarea runoff = 2.468(CFS) for 1.000(Ac.)
Total runoff = 10.747(CFS) Total area = 4.300(Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 27.000 to Point/Station 28.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 650.500(Ft.)
Downstream point/station elevation = 645.800(Ft.)
Pipe length = 220.00(Ft.) Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 10.747(CFS)
Nearest computed pipe diameter = 18.00(In.)
Calculated individual pipe flow = 10.747(CFS)
Normal flow depth in pipe = 11.10(In.)
Flow top width inside pipe = 17.50(In.)
Critical Depth = 15.09(In.)
Pipe flow velocity = 9.40(Ft/s)
Travel time through pipe = 0.39 min.
Time of concentration (TC) = 9.43 min.
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 28.000 to Point/Station 30.000 **** IMPROVED CHANNEL TRAVEL TIME ****
______________________________________________________________________ Upstream point elevation = 645.800(Ft.)
Downstream point elevation = 645.500(Ft.)
Channel length thru subarea = 100.000(Ft.)
Channel base width = 50.000(Ft.)
Slope or 'Z' of left channel bank = 4.000
Slope or 'Z' of right channel bank = 4.000
Manning's 'N' = 0.030
Maximum depth of channel = 5.000(Ft.)
Flow(q) thru subarea = 10.747(CFS)
Depth of flow = 0.218(Ft.), Average velocity = 0.970(Ft/s) Channel flow top width = 51.742(Ft.)
Flow Velocity = 0.97(Ft/s)
Travel time = 1.72 min.
Time of concentration = 11.15 min.
Sub-Channel No. 1 Critical depth = 0.112(Ft.)
' ' ' Critical flow top width = 50.898(Ft.)
' ' ' Critical flow velocity= 1.897(Ft/s)
' ' ' Critical flow area = 5.666(Sq.Ft)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 30.000 to Point/Station 30.000 **** CONFLUENCE OF MINOR STREAMS ****
______________________________________________________________________ Along Main Stream number: 1 in normal stream number 3
Stream flow area = 4.300(Ac.)
Runoff from this stream = 10.747(CFS)
Time of concentration = 11.15 min.
Rainfall intensity = 2.555(In/Hr)
Summary of stream data:
Stream Flow rate TC Rainfall Intensity
No. (CFS) (min) (In/Hr)
1 8.415 13.89 2.249
2 7.149 22.60 1.696
3 10.747 11.15 2.555
Largest stream flow has longer or shorter time of concentration Qp = 10.747 + sum of
Qa Tb/Ta
8.415 * 0.803 = 6.757
Item Number: 1.
8 Qa Tb/Ta
7.149 * 0.493 = 3.526
Qp = 21.030
Total of 3 streams to confluence:
Flow rates before confluence point:
8.415 7.149 10.747
Area of streams before confluence:
5.300 3.000 4.300
Results of confluence:
Total flow rate = 21.030(CFS)
Time of concentration = 11.150 min.
Effective stream area after confluence = 12.600(Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 30.000 to Point/Station 31.000 **** IMPROVED CHANNEL TRAVEL TIME ****
______________________________________________________________________ Upstream point elevation = 645.500(Ft.)
Downstream point elevation = 641.000(Ft.)
Channel length thru subarea = 685.000(Ft.)
Channel base width = 50.000(Ft.)
Slope or 'Z' of left channel bank = 4.000
Slope or 'Z' of right channel bank = 4.000
Estimated mean flow rate at midpoint of channel = 21.723(CFS) Manning's 'N' = 0.030
Maximum depth of channel = 5.000(Ft.)
Flow(q) thru subarea = 21.723(CFS)
Depth of flow = 0.262(Ft.), Average velocity = 1.622(Ft/s) Channel flow top width = 52.099(Ft.)
Flow Velocity = 1.62(Ft/s)
Travel time = 7.04 min.
Time of concentration = 18.19 min.
Sub-Channel No. 1 Critical depth = 0.180(Ft.)
' ' ' Critical flow top width = 51.438(Ft.)
' ' ' Critical flow velocity= 2.384(Ft/s)
' ' ' Critical flow area = 9.114(Sq.Ft)
Adding area flow to channel
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.671
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 67.00
Pervious area fraction = 1.000; Impervious fraction = 0.000 Rainfall intensity = 1.923(In/Hr) for a 10.0 year storm Subarea runoff = 1.290(CFS) for 1.000(Ac.)
Total runoff = 22.321(CFS) Total area = 13.600(Ac.)
Depth of flow = 0.267(Ft.), Average velocity = 1.639(Ft/s) Sub-Channel No. 1 Critical depth = 0.184(Ft.)
' ' ' Critical flow top width = 51.469(Ft.)
' ' ' Critical flow velocity= 2.396(Ft/s)
' ' ' Critical flow area = 9.315(Sq.Ft)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 31.000 to Point/Station 32.000 **** IMPROVED CHANNEL TRAVEL TIME ****
______________________________________________________________________ Upstream point elevation = 641.000(Ft.)
Downstream point elevation = 629.000(Ft.)
Channel length thru subarea = 1060.000(Ft.)
Channel base width = 50.000(Ft.)
Slope or 'Z' of left channel bank = 4.000
Slope or 'Z' of right channel bank = 4.000
Item Number: 1.
9 Estimated mean flow rate at midpoint of channel = 23.322(CFS) Manning's 'N' = 0.030
Maximum depth of channel = 5.000(Ft.)
Flow(q) thru subarea = 23.322(CFS)
Depth of flow = 0.233(Ft.), Average velocity = 1.968(Ft/s) Channel flow top width = 51.861(Ft.)
Flow Velocity = 1.97(Ft/s)
Travel time = 8.98 min.
Time of concentration = 27.16 min.
Sub-Channel No. 1 Critical depth = 0.188(Ft.)
' ' ' Critical flow top width = 51.500(Ft.)
' ' ' Critical flow velocity= 2.451(Ft/s)
' ' ' Critical flow area = 9.516(Sq.Ft)
Adding area flow to channel
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.629
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 67.00
Pervious area fraction = 1.000; Impervious fraction = 0.000 Rainfall intensity = 1.524(In/Hr) for a 10.0 year storm Subarea runoff = 1.917(CFS) for 2.000(Ac.)
Total runoff = 24.238(CFS) Total area = 15.600(Ac.)
Depth of flow = 0.238(Ft.), Average velocity = 1.998(Ft/s) Sub-Channel No. 1 Critical depth = 0.193(Ft.)
' ' ' Critical flow top width = 51.547(Ft.)
' ' ' Critical flow velocity= 2.469(Ft/s)
' ' ' Critical flow area = 9.818(Sq.Ft)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 32.000 to Point/Station 33.000 **** IMPROVED CHANNEL TRAVEL TIME ****
______________________________________________________________________ Upstream point elevation = 629.000(Ft.)
Downstream point elevation = 626.500(Ft.)
Channel length thru subarea = 460.000(Ft.)
Channel base width = 50.000(Ft.)
Slope or 'Z' of left channel bank = 4.000
Slope or 'Z' of right channel bank = 4.000
Estimated mean flow rate at midpoint of channel = 24.518(CFS) Manning's 'N' = 0.030
Maximum depth of channel = 5.000(Ft.)
Flow(q) thru subarea = 24.518(CFS)
Depth of flow = 0.298(Ft.), Average velocity = 1.605(Ft/s) Channel flow top width = 52.388(Ft.)
Flow Velocity = 1.60(Ft/s)
Travel time = 4.78 min.
Time of concentration = 31.94 min.
Sub-Channel No. 1 Critical depth = 0.195(Ft.)
' ' ' Critical flow top width = 51.563(Ft.)
' ' ' Critical flow velocity= 2.472(Ft/s)
' ' ' Critical flow area = 9.918(Sq.Ft)
Adding area flow to channel
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.611
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 67.00
Pervious area fraction = 1.000; Impervious fraction = 0.000 Rainfall intensity = 1.387(In/Hr) for a 10.0 year storm Item Number: 1.
10 Subarea runoff = 0.508(CFS) for 0.600(Ac.)
Total runoff = 24.746(CFS) Total area = 16.200(Ac.)
Depth of flow = 0.300(Ft.), Average velocity = 1.610(Ft/s) Sub-Channel No. 1 Critical depth = 0.195(Ft.)
' ' ' Critical flow top width = 51.563(Ft.)
' ' ' Critical flow velocity= 2.495(Ft/s)
' ' ' Critical flow area = 9.918(Sq.Ft)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 33.000 to Point/Station 70.000 **** IMPROVED CHANNEL TRAVEL TIME ****
______________________________________________________________________ Upstream point elevation = 626.500(Ft.)
Downstream point elevation = 622.000(Ft.)
Channel length thru subarea = 310.000(Ft.)
Channel base width = 50.000(Ft.)
Slope or 'Z' of left channel bank = 4.000
Slope or 'Z' of right channel bank = 4.000
Estimated mean flow rate at midpoint of channel = 24.992(CFS) Manning's 'N' = 0.030
Maximum depth of channel = 5.000(Ft.)
Flow(q) thru subarea = 24.992(CFS)
Depth of flow = 0.225(Ft.), Average velocity = 2.181(Ft/s) Channel flow top width = 51.801(Ft.)
Flow Velocity = 2.18(Ft/s)
Travel time = 2.37 min.
Time of concentration = 34.31 min.
Sub-Channel No. 1 Critical depth = 0.197(Ft.)
' ' ' Critical flow top width = 51.578(Ft.)
' ' ' Critical flow velocity= 2.495(Ft/s)
' ' ' Critical flow area = 10.019(Sq.Ft)
Adding area flow to channel
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.603
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 67.00
Pervious area fraction = 1.000; Impervious fraction = 0.000 Rainfall intensity = 1.331(In/Hr) for a 10.0 year storm Subarea runoff = 0.401(CFS) for 0.500(Ac.)
Total runoff = 25.147(CFS) Total area = 16.700(Ac.)
Depth of flow = 0.226(Ft.), Average velocity = 2.186(Ft/s) Sub-Channel No. 1 Critical depth = 0.197(Ft.)
' ' ' Critical flow top width = 51.578(Ft.)
' ' ' Critical flow velocity= 2.510(Ft/s)
' ' ' Critical flow area = 10.019(Sq.Ft)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 70.000 to Point/Station 70.000 **** CONFLUENCE OF MAIN STREAMS ****
______________________________________________________________________ The following data inside Main Stream is listed:
In Main Stream number: 1
Stream flow area = 16.700(Ac.)
Runoff from this stream = 25.147(CFS)
Time of concentration = 34.31 min.
Rainfall intensity = 1.331(In/Hr)
Program is now starting with Main Stream No. 2
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Item Number: 1.
11 Process from Point/Station 15.000 to Point/Station 41.000 **** INITIAL AREA EVALUATION ****
______________________________________________________________________ Initial area flow distance = 520.000(Ft.)
Top (of initial area) elevation = 656.500(Ft.)
Bottom (of initial area) elevation = 654.400(Ft.)
Difference in elevation = 2.100(Ft.)
Slope = 0.00404 s(percent)= 0.40
TC = k(0.300)*[(length^3)/(elevation change)]^0.2
Initial area time of concentration = 11.022 min.
Rainfall intensity = 2.572(In/Hr) for a 10.0 year storm COMMERCIAL subarea type
Runoff Coefficient = 0.853
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 32.00
Pervious area fraction = 0.100; Impervious fraction = 0.900 Initial subarea runoff = 1.316(CFS)
Total initial stream area = 0.600(Ac.)
Pervious area fraction = 0.100
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 41.000 to Point/Station 42.000 **** STREET FLOW TRAVEL TIME + SUBAREA FLOW ADDITION **** ______________________________________________________________________ Top of street segment elevation = 654.400(Ft.)
End of street segment elevation = 651.500(Ft.)
Length of street segment = 780.000(Ft.)
Height of curb above gutter flowline = 6.0(In.)
Width of half street (curb to crown) = 18.000(Ft.)
Distance from crown to crossfall grade break = 14.000(Ft.) Slope from gutter to grade break (v/hz) = 0.020
Slope from grade break to crown (v/hz) = 0.020
Street flow is on [2] side(s) of the street
Distance from curb to property line = 10.000(Ft.)
Slope from curb to property line (v/hz) = 0.025
Gutter width = 2.000(Ft.)
Gutter hike from flowline = 2.000(In.)
Manning's N in gutter = 0.0150
Manning's N from gutter to grade break = 0.0150
Manning's N from grade break to crown = 0.0150
Estimated mean flow rate at midpoint of street = 2.149(CFS) Depth of flow = 0.296(Ft.), Average velocity = 1.269(Ft/s) Streetflow hydraulics at midpoint of street travel:
Halfstreet flow width = 8.484(Ft.)
Flow velocity = 1.27(Ft/s)
Travel time = 10.24 min. TC = 21.27 min.
Adding area flow to street
COMMERCIAL subarea type
Runoff Coefficient = 0.844
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 32.00
Pervious area fraction = 0.100; Impervious fraction = 0.900 Rainfall intensity = 1.757(In/Hr) for a 10.0 year storm Subarea runoff = 1.483(CFS) for 1.000(Ac.)
Total runoff = 2.799(CFS) Total area = 1.600(Ac.)
Street flow at end of street = 2.799(CFS)
Half street flow at end of street = 1.400(CFS)
Depth of flow = 0.318(Ft.), Average velocity = 1.346(Ft/s) Flow width (from curb towards crown)= 9.555(Ft.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 42.000 to Point/Station 43.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** Item Number: 1.
12 ______________________________________________________________________ Upstream point/station elevation = 651.500(Ft.)
Downstream point/station elevation = 651.000(Ft.)
Pipe length = 120.00(Ft.) Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 2.799(CFS)
Nearest computed pipe diameter = 15.00(In.)
Calculated individual pipe flow = 2.799(CFS)
Normal flow depth in pipe = 9.00(In.)
Flow top width inside pipe = 14.70(In.)
Critical Depth = 8.05(In.)
Pipe flow velocity = 3.64(Ft/s)
Travel time through pipe = 0.55 min.
Time of concentration (TC) = 21.81 min.
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 43.000 to Point/Station 43.000 **** SUBAREA FLOW ADDITION ****
______________________________________________________________________ COMMERCIAL subarea type
Runoff Coefficient = 0.844
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 32.00
Pervious area fraction = 0.100; Impervious fraction = 0.900 Time of concentration = 21.81 min.
Rainfall intensity = 1.731(In/Hr) for a 10.0 year storm Subarea runoff = 2.192(CFS) for 1.500(Ac.)
Total runoff = 4.991(CFS) Total area = 3.100(Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 43.000 to Point/Station 44.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 651.000(Ft.)
Downstream point/station elevation = 625.000(Ft.)
Pipe length = 870.00(Ft.) Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 4.991(CFS)
Nearest computed pipe diameter = 12.00(In.)
Calculated individual pipe flow = 4.991(CFS)
Normal flow depth in pipe = 8.19(In.)
Flow top width inside pipe = 11.17(In.)
Critical Depth = 11.00(In.)
Pipe flow velocity = 8.73(Ft/s)
Travel time through pipe = 1.66 min.
Time of concentration (TC) = 23.47 min.
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 44.000 to Point/Station 44.000 **** SUBAREA FLOW ADDITION ****
______________________________________________________________________ UNDEVELOPED (fair cover) subarea
Runoff Coefficient = 0.499
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 50.00
Pervious area fraction = 1.000; Impervious fraction = 0.000 Time of concentration = 23.47 min.
Rainfall intensity = 1.659(In/Hr) for a 10.0 year storm Subarea runoff = 1.738(CFS) for 2.100(Ac.)
Total runoff = 6.729(CFS) Total area = 5.200(Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 44.000 to Point/Station 45.000 Item Number: 1.
13 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 625.000(Ft.)
Downstream point/station elevation = 624.500(Ft.)
Pipe length = 40.00(Ft.) Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 6.729(CFS)
Nearest computed pipe diameter = 15.00(In.)
Calculated individual pipe flow = 6.729(CFS)
Normal flow depth in pipe = 11.46(In.)
Flow top width inside pipe = 12.74(In.)
Critical Depth = 12.50(In.)
Pipe flow velocity = 6.69(Ft/s)
Travel time through pipe = 0.10 min.
Time of concentration (TC) = 23.57 min.
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 45.000 to Point/Station 45.000 **** SUBAREA FLOW ADDITION ****
______________________________________________________________________ COMMERCIAL subarea type
Runoff Coefficient = 0.843
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 32.00
Pervious area fraction = 0.100; Impervious fraction = 0.900 Time of concentration = 23.57 min.
Rainfall intensity = 1.655(In/Hr) for a 10.0 year storm Subarea runoff = 0.977(CFS) for 0.700(Ac.)
Total runoff = 7.705(CFS) Total area = 5.900(Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 45.000 to Point/Station 60.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 624.500(Ft.)
Downstream point/station elevation = 620.000(Ft.)
Pipe length = 165.00(Ft.) Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 7.705(CFS)
Nearest computed pipe diameter = 15.00(In.)
Calculated individual pipe flow = 7.705(CFS)
Normal flow depth in pipe = 9.45(In.)
Flow top width inside pipe = 14.49(In.)
Critical Depth = 13.21(In.)
Pipe flow velocity = 9.47(Ft/s)
Travel time through pipe = 0.29 min.
Time of concentration (TC) = 23.86 min.
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 60.000 to Point/Station 60.000 **** CONFLUENCE OF MINOR STREAMS ****
______________________________________________________________________ Along Main Stream number: 2 in normal stream number 1
Stream flow area = 5.900(Ac.)
Runoff from this stream = 7.705(CFS)
Time of concentration = 23.86 min.
Rainfall intensity = 1.643(In/Hr)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 50.000 to Point/Station 51.000 **** INITIAL AREA EVALUATION ****
______________________________________________________________________ Initial area flow distance = 250.000(Ft.)
Top (of initial area) elevation = 651.000(Ft.)
Bottom (of initial area) elevation = 645.000(Ft.)
Difference in elevation = 6.000(Ft.)
Item Number: 1.
14 Slope = 0.02400 s(percent)= 2.40
TC = k(0.300)*[(length^3)/(elevation change)]^0.2
Initial area time of concentration = 5.758 min.
Rainfall intensity = 3.748(In/Hr) for a 10.0 year storm COMMERCIAL subarea type
Runoff Coefficient = 0.861
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 32.00
Pervious area fraction = 0.100; Impervious fraction = 0.900 Initial subarea runoff = 1.291(CFS)
Total initial stream area = 0.400(Ac.)
Pervious area fraction = 0.100
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 51.000 to Point/Station 52.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 645.000(Ft.)
Downstream point/station elevation = 643.000(Ft.)
Pipe length = 220.00(Ft.) Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 1.291(CFS)
Nearest computed pipe diameter = 9.00(In.)
Calculated individual pipe flow = 1.291(CFS)
Normal flow depth in pipe = 6.19(In.)
Flow top width inside pipe = 8.34(In.)
Critical Depth = 6.28(In.)
Pipe flow velocity = 3.98(Ft/s)
Travel time through pipe = 0.92 min.
Time of concentration (TC) = 6.68 min.
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 52.000 to Point/Station 52.000 **** SUBAREA FLOW ADDITION ****
______________________________________________________________________ COMMERCIAL subarea type
Runoff Coefficient = 0.859
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 32.00
Pervious area fraction = 0.100; Impervious fraction = 0.900 Time of concentration = 6.68 min.
Rainfall intensity = 3.439(In/Hr) for a 10.0 year storm Subarea runoff = 14.776(CFS) for 5.000(Ac.)
Total runoff = 16.067(CFS) Total area = 5.400(Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 52.000 to Point/Station 53.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 643.000(Ft.)
Downstream point/station elevation = 642.500(Ft.)
Pipe length = 85.00(Ft.) Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 16.067(CFS)
Nearest computed pipe diameter = 24.00(In.)
Calculated individual pipe flow = 16.067(CFS)
Normal flow depth in pipe = 18.23(In.)
Flow top width inside pipe = 20.51(In.)
Critical Depth = 17.34(In.)
Pipe flow velocity = 6.27(Ft/s)
Travel time through pipe = 0.23 min.
Time of concentration (TC) = 6.90 min.
Item Number: 1.
15 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 53.000 to Point/Station 53.000 **** SUBAREA FLOW ADDITION ****
______________________________________________________________________ COMMERCIAL subarea type
Runoff Coefficient = 0.859
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 32.00
Pervious area fraction = 0.100; Impervious fraction = 0.900 Time of concentration = 6.90 min.
Rainfall intensity = 3.373(In/Hr) for a 10.0 year storm Subarea runoff = 6.664(CFS) for 2.300(Ac.)
Total runoff = 22.731(CFS) Total area = 7.700(Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 53.000 to Point/Station 54.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 642.500(Ft.)
Downstream point/station elevation = 641.500(Ft.)
Pipe length = 600.00(Ft.) Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 22.731(CFS)
Nearest computed pipe diameter = 33.00(In.)
Calculated individual pipe flow = 22.731(CFS)
Normal flow depth in pipe = 28.97(In.)
Flow top width inside pipe = 21.61(In.)
Critical Depth = 18.90(In.)
Pipe flow velocity = 4.11(Ft/s)
Travel time through pipe = 2.43 min.
Time of concentration (TC) = 9.34 min.
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 54.000 to Point/Station 54.000 **** SUBAREA FLOW ADDITION ****
______________________________________________________________________ COMMERCIAL subarea type
Runoff Coefficient = 0.855
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 32.00
Pervious area fraction = 0.100; Impervious fraction = 0.900 Time of concentration = 9.34 min.
Rainfall intensity = 2.832(In/Hr) for a 10.0 year storm Subarea runoff = 7.263(CFS) for 3.000(Ac.)
Total runoff = 29.994(CFS) Total area = 10.700(Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 54.000 to Point/Station 55.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 641.500(Ft.)
Downstream point/station elevation = 640.500(Ft.)
Pipe length = 600.00(Ft.) Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 29.994(CFS)
Nearest computed pipe diameter = 39.00(In.)
Calculated individual pipe flow = 29.994(CFS)
Normal flow depth in pipe = 28.64(In.)
Flow top width inside pipe = 34.45(In.)
Critical Depth = 20.75(In.)
Pipe flow velocity = 4.59(Ft/s)
Travel time through pipe = 2.18 min.
Time of concentration (TC) = 11.51 min.
Item Number: 1.
16 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 55.000 to Point/Station 55.000 **** SUBAREA FLOW ADDITION ****
______________________________________________________________________ COMMERCIAL subarea type
Runoff Coefficient = 0.852
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 32.00
Pervious area fraction = 0.100; Impervious fraction = 0.900 Time of concentration = 11.51 min.
Rainfall intensity = 2.507(In/Hr) for a 10.0 year storm Subarea runoff = 6.411(CFS) for 3.000(Ac.)
Total runoff = 36.405(CFS) Total area = 13.700(Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 55.000 to Point/Station 56.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 640.500(Ft.)
Downstream point/station elevation = 640.000(Ft.)
Pipe length = 360.00(Ft.) Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 36.405(CFS)
Nearest computed pipe diameter = 42.00(In.)
Calculated individual pipe flow = 36.405(CFS)
Normal flow depth in pipe = 33.38(In.)
Flow top width inside pipe = 33.93(In.)
Critical Depth = 22.48(In.)
Pipe flow velocity = 4.44(Ft/s)
Travel time through pipe = 1.35 min.
Time of concentration (TC) = 12.86 min.
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 56.000 to Point/Station 56.000 **** SUBAREA FLOW ADDITION ****
______________________________________________________________________ COMMERCIAL subarea type
Runoff Coefficient = 0.851
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 32.00
Pervious area fraction = 0.100; Impervious fraction = 0.900 Time of concentration = 12.86 min.
Rainfall intensity = 2.351(In/Hr) for a 10.0 year storm Subarea runoff = 12.603(CFS) for 6.300(Ac.)
Total runoff = 49.008(CFS) Total area = 20.000(Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 56.000 to Point/Station 56.000 **** SUBAREA FLOW ADDITION ****
______________________________________________________________________ COMMERCIAL subarea type
Runoff Coefficient = 0.851
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 32.00
Pervious area fraction = 0.100; Impervious fraction = 0.900 Time of concentration = 12.86 min.
Rainfall intensity = 2.351(In/Hr) for a 10.0 year storm Subarea runoff = 3.601(CFS) for 1.800(Ac.)
Total runoff = 52.608(CFS) Total area = 21.800(Ac.)
Item Number: 1.
17 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 56.000 to Point/Station 57.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 640.000(Ft.)
Downstream point/station elevation = 638.000(Ft.)
Pipe length = 970.00(Ft.) Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 52.608(CFS)
Nearest computed pipe diameter = 45.00(In.)
Calculated individual pipe flow = 52.608(CFS)
Normal flow depth in pipe = 35.30(In.)
Flow top width inside pipe = 37.01(In.)
Critical Depth = 26.68(In.)
Pipe flow velocity = 5.66(Ft/s)
Travel time through pipe = 2.86 min.
Time of concentration (TC) = 15.72 min.
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 57.000 to Point/Station 57.000 **** SUBAREA FLOW ADDITION ****
______________________________________________________________________ COMMERCIAL subarea type
Runoff Coefficient = 0.848
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 32.00
Pervious area fraction = 0.100; Impervious fraction = 0.900 Time of concentration = 15.72 min.
Rainfall intensity = 2.093(In/Hr) for a 10.0 year storm Subarea runoff = 2.308(CFS) for 1.300(Ac.)
Total runoff = 54.917(CFS) Total area = 23.100(Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 57.000 to Point/Station 58.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 638.000(Ft.)
Downstream point/station elevation = 637.500(Ft.)
Pipe length = 50.00(Ft.) Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 54.917(CFS)
Nearest computed pipe diameter = 33.00(In.)
Calculated individual pipe flow = 54.917(CFS)
Normal flow depth in pipe = 28.31(In.)
Flow top width inside pipe = 23.04(In.)
Critical Depth = 28.95(In.)
Pipe flow velocity = 10.12(Ft/s)
Travel time through pipe = 0.08 min.
Time of concentration (TC) = 15.80 min.
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 58.000 to Point/Station 58.000 **** SUBAREA FLOW ADDITION ****
______________________________________________________________________ COMMERCIAL subarea type
Runoff Coefficient = 0.848
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 32.00
Pervious area fraction = 0.100; Impervious fraction = 0.900 Time of concentration = 15.80 min.
Rainfall intensity = 2.087(In/Hr) for a 10.0 year storm Subarea runoff = 1.062(CFS) for 0.600(Ac.)
Item Number: 1.
18 Total runoff = 55.978(CFS) Total area = 23.700(Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 58.000 to Point/Station 58.000 **** SUBAREA FLOW ADDITION ****
______________________________________________________________________ COMMERCIAL subarea type
Runoff Coefficient = 0.848
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 32.00
Pervious area fraction = 0.100; Impervious fraction = 0.900 Time of concentration = 15.80 min.
Rainfall intensity = 2.087(In/Hr) for a 10.0 year storm Subarea runoff = 0.354(CFS) for 0.200(Ac.)
Total runoff = 56.332(CFS) Total area = 23.900(Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 58.000 to Point/Station 59.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 637.500(Ft.)
Downstream point/station elevation = 637.000(Ft.)
Pipe length = 110.00(Ft.) Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 56.332(CFS)
Nearest computed pipe diameter = 39.00(In.)
Calculated individual pipe flow = 56.332(CFS)
Normal flow depth in pipe = 32.44(In.)
Flow top width inside pipe = 29.18(In.)
Critical Depth = 28.76(In.)
Pipe flow velocity = 7.65(Ft/s)
Travel time through pipe = 0.24 min.
Time of concentration (TC) = 16.04 min.
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 59.000 to Point/Station 59.000 **** SUBAREA FLOW ADDITION ****
______________________________________________________________________ COMMERCIAL subarea type
Runoff Coefficient = 0.848
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 32.00
Pervious area fraction = 0.100; Impervious fraction = 0.900 Time of concentration = 16.04 min.
Rainfall intensity = 2.069(In/Hr) for a 10.0 year storm Subarea runoff = 27.891(CFS) for 15.900(Ac.)
Total runoff = 84.223(CFS) Total area = 39.800(Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 59.000 to Point/Station 60.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 637.000(Ft.)
Downstream point/station elevation = 620.000(Ft.)
Pipe length = 220.00(Ft.) Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 84.223(CFS)
Nearest computed pipe diameter = 27.00(In.)
Calculated individual pipe flow = 84.223(CFS)
Normal flow depth in pipe = 21.61(In.)
Flow top width inside pipe = 21.59(In.)
Critical depth could not be calculated.
Pipe flow velocity = 24.68(Ft/s)
Item Number: 1.
19 Travel time through pipe = 0.15 min.
Time of concentration (TC) = 16.19 min.
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 60.000 to Point/Station 60.000 **** CONFLUENCE OF MINOR STREAMS ****
______________________________________________________________________ Along Main Stream number: 2 in normal stream number 2
Stream flow area = 39.800(Ac.)
Runoff from this stream = 84.223(CFS)
Time of concentration = 16.19 min.
Rainfall intensity = 2.058(In/Hr)
Summary of stream data:
Stream Flow rate TC Rainfall Intensity
No. (CFS) (min) (In/Hr)
1 7.705 23.86 1.643
2 84.223 16.19 2.058
Largest stream flow has longer or shorter time of concentration Qp = 84.223 + sum of
Qa Tb/Ta
7.705 * 0.678 = 5.228
Qp = 89.451
Total of 2 streams to confluence:
Flow rates before confluence point:
7.705 84.223
Area of streams before confluence:
5.900 39.800
Results of confluence:
Total flow rate = 89.451(CFS)
Time of concentration = 16.191 min.
Effective stream area after confluence = 45.700(Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 60.000 to Point/Station 61.000 **** IMPROVED CHANNEL TRAVEL TIME ****
______________________________________________________________________ Upstream point elevation = 620.000(Ft.)
Downstream point elevation = 619.000(Ft.)
Channel length thru subarea = 260.000(Ft.)
Channel base width = 50.000(Ft.)
Slope or 'Z' of left channel bank = 4.000
Slope or 'Z' of right channel bank = 4.000
Estimated mean flow rate at midpoint of channel = 90.376(CFS) Manning's 'N' = 0.030
Maximum depth of channel = 5.000(Ft.)
Flow(q) thru subarea = 90.376(CFS)
Depth of flow = 0.719(Ft.), Average velocity = 2.376(Ft/s) Channel flow top width = 55.755(Ft.)
Flow Velocity = 2.38(Ft/s)
Travel time = 1.82 min.
Time of concentration = 18.01 min.
Sub-Channel No. 1 Critical depth = 0.461(Ft.)
' ' ' Critical flow top width = 53.688(Ft.)
' ' ' Critical flow velocity= 3.782(Ft/s)
' ' ' Critical flow area = 23.897(Sq.Ft)
Adding area flow to channel
UNDEVELOPED (fair cover) subarea
Runoff Coefficient = 0.533
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 50.00
Item Number: 1.
20 Pervious area fraction = 1.000; Impervious fraction = 0.000 Rainfall intensity = 1.934(In/Hr) for a 10.0 year storm Subarea runoff = 1.752(CFS) for 1.700(Ac.)
Total runoff = 91.202(CFS) Total area = 47.400(Ac.)
Depth of flow = 0.723(Ft.), Average velocity = 2.384(Ft/s) Sub-Channel No. 1 Critical depth = 0.461(Ft.)
' ' ' Critical flow top width = 53.688(Ft.)
' ' ' Critical flow velocity= 3.817(Ft/s)
' ' ' Critical flow area = 23.897(Sq.Ft)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 61.000 to Point/Station 62.000 **** IMPROVED CHANNEL TRAVEL TIME ****
______________________________________________________________________ Upstream point elevation = 619.000(Ft.)
Downstream point elevation = 618.000(Ft.)
Channel length thru subarea = 120.000(Ft.)
Channel base width = 50.000(Ft.)
Slope or 'Z' of left channel bank = 4.000
Slope or 'Z' of right channel bank = 4.000
Estimated mean flow rate at midpoint of channel = 94.470(CFS) Manning's 'N' = 0.015
Maximum depth of channel = 5.000(Ft.)
Flow(q) thru subarea = 94.470(CFS)
Depth of flow = 0.389(Ft.), Average velocity = 4.716(Ft/s) Channel flow top width = 53.109(Ft.)
Flow Velocity = 4.72(Ft/s)
Travel time = 0.42 min.
Time of concentration = 18.44 min.
Sub-Channel No. 1 Critical depth = 0.477(Ft.)
' ' ' Critical flow top width = 53.813(Ft.)
' ' ' Critical flow velocity= 3.819(Ft/s)
' ' ' Critical flow area = 24.737(Sq.Ft)
Adding area flow to channel
COMMERCIAL subarea type
Runoff Coefficient = 0.846
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 32.00
Pervious area fraction = 0.100; Impervious fraction = 0.900 Rainfall intensity = 1.908(In/Hr) for a 10.0 year storm Subarea runoff = 6.459(CFS) for 4.000(Ac.)
Total runoff = 97.661(CFS) Total area = 51.400(Ac.)
Depth of flow = 0.396(Ft.), Average velocity = 4.776(Ft/s) Sub-Channel No. 1 Critical depth = 0.484(Ft.)
' ' ' Critical flow top width = 53.875(Ft.)
' ' ' Critical flow velocity= 3.882(Ft/s)
' ' ' Critical flow area = 25.157(Sq.Ft)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 62.000 to Point/Station 63.000 **** IMPROVED CHANNEL TRAVEL TIME ****
______________________________________________________________________ Upstream point elevation = 618.000(Ft.)
Downstream point elevation = 610.000(Ft.)
Channel length thru subarea = 630.000(Ft.)
Channel base width = 100.000(Ft.)
Slope or 'Z' of left channel bank = 4.000
Slope or 'Z' of right channel bank = 4.000
Estimated mean flow rate at midpoint of channel = 100.460(CFS) Manning's 'N' = 0.030
Item Number: 1.
21 Maximum depth of channel = 5.000(Ft.)
Flow(q) thru subarea = 100.460(CFS)
Depth of flow = 0.356(Ft.), Average velocity = 2.779(Ft/s) Channel flow top width = 102.852(Ft.)
Flow Velocity = 2.78(Ft/s)
Travel time = 3.78 min.
Time of concentration = 22.22 min.
Sub-Channel No. 1 Critical depth = 0.313(Ft.)
' ' ' Critical flow top width = 102.500(Ft.)
' ' ' Critical flow velocity= 3.175(Ft/s)
' ' ' Critical flow area = 31.641(Sq.Ft)
Adding area flow to channel
UNDEVELOPED (fair cover) subarea
Runoff Coefficient = 0.506
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 50.00
Pervious area fraction = 1.000; Impervious fraction = 0.000 Rainfall intensity = 1.713(In/Hr) for a 10.0 year storm Subarea runoff = 5.546(CFS) for 6.400(Ac.)
Total runoff = 103.207(CFS) Total area = 57.800(Ac.)
Depth of flow = 0.362(Ft.), Average velocity = 2.808(Ft/s) Sub-Channel No. 1 Critical depth = 0.320(Ft.)
' ' ' Critical flow top width = 102.563(Ft.)
' ' ' Critical flow velocity= 3.181(Ft/s)
' ' ' Critical flow area = 32.442(Sq.Ft)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 63.000 to Point/Station 63.000 **** SUBAREA FLOW ADDITION ****
______________________________________________________________________ COMMERCIAL subarea type
Runoff Coefficient = 0.844
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 32.00
Pervious area fraction = 0.100; Impervious fraction = 0.900 Time of concentration = 22.22 min.
Rainfall intensity = 1.713(In/Hr) for a 10.0 year storm Subarea runoff = 24.858(CFS) for 17.200(Ac.)
Total runoff = 128.065(CFS) Total area = 75.000(Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 63.000 to Point/Station 63.000 **** SUBAREA FLOW ADDITION ****
______________________________________________________________________ COMMERCIAL subarea type
Runoff Coefficient = 0.844
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 32.00
Pervious area fraction = 0.100; Impervious fraction = 0.900 Time of concentration = 22.22 min.
Rainfall intensity = 1.713(In/Hr) for a 10.0 year storm Subarea runoff = 1.879(CFS) for 1.300(Ac.)
Total runoff = 129.944(CFS) Total area = 76.300(Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Item Number: 1.
22 Process from Point/Station 63.000 to Point/Station 70.000 **** IMPROVED CHANNEL TRAVEL TIME ****
______________________________________________________________________ Upstream point elevation = 610.000(Ft.)
Downstream point elevation = 609.500(Ft.)
Channel length thru subarea = 100.000(Ft.)
Channel base width = 50.000(Ft.)
Slope or 'Z' of left channel bank = 4.000
Slope or 'Z' of right channel bank = 4.000
Manning's 'N' = 0.015
Maximum depth of channel = 5.000(Ft.)
Flow(q) thru subarea = 129.944(CFS)
Depth of flow = 0.547(Ft.), Average velocity = 4.552(Ft/s) Channel flow top width = 54.376(Ft.)
Flow Velocity = 4.55(Ft/s)
Travel time = 0.37 min.
Time of concentration = 22.58 min.
Sub-Channel No. 1 Critical depth = 0.586(Ft.)
' ' ' Critical flow top width = 54.688(Ft.)
' ' ' Critical flow velocity= 4.237(Ft/s)
' ' ' Critical flow area = 30.670(Sq.Ft)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 70.000 to Point/Station 70.000 **** CONFLUENCE OF MAIN STREAMS ****
______________________________________________________________________ The following data inside Main Stream is listed:
In Main Stream number: 2
Stream flow area = 76.300(Ac.)
Runoff from this stream = 129.944(CFS)
Time of concentration = 22.58 min.
Rainfall intensity = 1.696(In/Hr)
Summary of stream data:
Stream Flow rate TC Rainfall Intensity
No. (CFS) (min) (In/Hr)
1 25.147 34.31 1.331
2 129.944 22.58 1.696
Largest stream flow has longer or shorter time of concentration Qp = 129.944 + sum of
Qa Tb/Ta
25.147 * 0.658 = 16.552
Qp = 146.496
Total of 2 main streams to confluence:
Flow rates before confluence point:
25.147 129.944
Area of streams before confluence:
16.700 76.300
Results of confluence:
Total flow rate = 146.496(CFS)
Time of concentration = 22.584 min.
Effective stream area after confluence = 93.000(Ac.)
End of computations, total study area = 93.00 (Ac.)
The following figures may
be used for a unit hydrograph study of the same area.
Area averaged pervious area fraction(Ap) = 0.290
Area averaged RI index number = 37.5
Item Number: 1.
Item Number: 1.
B. 100-YEAR STORM
Item Number: 1.
1 Riverside County Rational Hydrology Program
CIVILCADD/CIVILDESIGN Engineering Software,(c) 1989 - 2014 Version 9.0 Rational Hydrology Study Date: 02/10/25 File:39143prop.out ------------------------------------------------------------------------ Hydrology Study for TPM 39143
In the City of Desert Hot Springs
Proposed Condition Onsite Areas
100-year Storm
------------------------------------------------------------------------ ********* Hydrology Study Control Information ********** English (in-lb) Units used in input data file
------------------------------------------------------------------------ Program License Serial Number 6406
------------------------------------------------------------------------ Rational Method Hydrology Program based on
Riverside County Flood Control & Water Conservation District 1978 hydrology manual
Storm event (year) = 100.00 Antecedent Moisture Condition = 2 2 year, 1 hour precipitation = 0.454(In.)
100 year, 1 hour precipitation = 1.690(In.)
Storm event year = 100.0
Calculated rainfall intensity data:
1 hour intensity = 1.690(In/Hr)
Slope of intensity duration curve = 0.5800
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 10.000 to Point/Station 11.000 **** INITIAL AREA EVALUATION ****
______________________________________________________________________ Initial area flow distance = 280.000(Ft.)
Top (of initial area) elevation = 660.900(Ft.)
Bottom (of initial area) elevation = 657.000(Ft.)
Difference in elevation = 3.900(Ft.)
Slope = 0.01393 s(percent)= 1.39
TC = k(0.530)*[(length^3)/(elevation change)]^0.2
Initial area time of concentration = 11.867 min.
Rainfall intensity = 4.326(In/Hr) for a 100.0 year storm UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.781
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 67.00
Pervious area fraction = 1.000; Impervious fraction = 0.000 Initial subarea runoff = 2.028(CFS)
Total initial stream area = 0.600(Ac.)
Pervious area fraction = 1.000
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 11.000 to Point/Station 30.000 **** NATURAL CHANNEL TIME + SUBAREA FLOW ADDITION ****
______________________________________________________________________ Top of natural channel elevation = 657.000(Ft.)
End of natural channel elevation = 645.000(Ft.)
Length of natural channel = 430.000(Ft.)
Item Number: 1.
2 Estimated mean flow rate at midpoint of channel = 9.972(CFS) Natural valley channel type used
L.A. County flood control district formula for channel velocity:
Velocity(ft/s) = (7 + 8(q(English Units)^.352)(slope^0.5) Velocity using mean channel flow = 4.17(Ft/s)
Correction to map slope used on extremely rugged channels with drops and waterfalls (Plate D-6.2)
Normal channel slope = 0.0279
Corrected/adjusted channel slope = 0.0279
Travel time = 1.72 min. TC = 13.59 min.
Adding area flow to channel
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.773
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 67.00
Pervious area fraction = 1.000; Impervious fraction = 0.000 Rainfall intensity = 4.000(In/Hr) for a 100.0 year storm Subarea runoff = 14.533(CFS) for 4.700(Ac.)
Total runoff = 16.561(CFS) Total area = 5.300(Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 30.000 to Point/Station 30.000 **** CONFLUENCE OF MINOR STREAMS ****
______________________________________________________________________ Along Main Stream number: 1 in normal stream number 1
Stream flow area = 5.300(Ac.)
Runoff from this stream = 16.561(CFS)
Time of concentration = 13.59 min.
Rainfall intensity = 4.000(In/Hr)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 15.000 to Point/Station 16.000 **** INITIAL AREA EVALUATION ****
______________________________________________________________________ Initial area flow distance = 150.000(Ft.)
Top (of initial area) elevation = 656.500(Ft.)
Bottom (of initial area) elevation = 655.300(Ft.)
Difference in elevation = 1.200(Ft.)
Slope = 0.00800 s(percent)= 0.80
TC = k(0.300)*[(length^3)/(elevation change)]^0.2
Initial area time of concentration = 5.847 min.
Rainfall intensity = 6.522(In/Hr) for a 100.0 year storm COMMERCIAL subarea type
Runoff Coefficient = 0.873
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 32.00
Pervious area fraction = 0.100; Impervious fraction = 0.900 Initial subarea runoff = 2.277(CFS)
Total initial stream area = 0.400(Ac.)
Pervious area fraction = 0.100
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 16.000 to Point/Station 17.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 655.300(Ft.)
Downstream point/station elevation = 655.000(Ft.)
Pipe length = 45.00(Ft.) Manning's N = 0.013
Item Number: 1.
3 No. of pipes = 1 Required pipe flow = 2.277(CFS)
Nearest computed pipe diameter = 12.00(In.)
Calculated individual pipe flow = 2.277(CFS)
Normal flow depth in pipe = 7.99(In.)
Flow top width inside pipe = 11.32(In.)
Critical Depth = 7.74(In.)
Pipe flow velocity = 4.10(Ft/s)
Travel time through pipe = 0.18 min.
Time of concentration (TC) = 6.03 min.
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 17.000 to Point/Station 17.000 **** SUBAREA FLOW ADDITION ****
______________________________________________________________________ COMMERCIAL subarea type
Runoff Coefficient = 0.872
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 32.00
Pervious area fraction = 0.100; Impervious fraction = 0.900 Time of concentration = 6.03 min.
Rainfall intensity = 6.407(In/Hr) for a 100.0 year storm Subarea runoff = 2.236(CFS) for 0.400(Ac.)
Total runoff = 4.513(CFS) Total area = 0.800(Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 17.000 to Point/Station 18.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 655.000(Ft.)
Downstream point/station elevation = 654.900(Ft.)
Pipe length = 360.00(Ft.) Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 4.513(CFS)
Nearest computed pipe diameter = 27.00(In.)
Calculated individual pipe flow = 4.513(CFS)
Normal flow depth in pipe = 19.55(In.)
Flow top width inside pipe = 24.14(In.)
Critical Depth = 8.65(In.)
Pipe flow velocity = 1.46(Ft/s)
Travel time through pipe = 4.10 min.
Time of concentration (TC) = 10.13 min.
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 18.000 to Point/Station 18.000 **** SUBAREA FLOW ADDITION ****
______________________________________________________________________ COMMERCIAL subarea type
Runoff Coefficient = 0.866
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 32.00
Pervious area fraction = 0.100; Impervious fraction = 0.900 Time of concentration = 10.13 min.
Rainfall intensity = 4.742(In/Hr) for a 100.0 year storm Subarea runoff = 2.465(CFS) for 0.600(Ac.)
Total runoff = 6.977(CFS) Total area = 1.400(Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 18.000 to Point/Station 18.000 **** SUBAREA FLOW ADDITION ****
______________________________________________________________________ COMMERCIAL subarea type
Runoff Coefficient = 0.866
Item Number: 1.
4 Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 32.00
Pervious area fraction = 0.100; Impervious fraction = 0.900 Time of concentration = 10.13 min.
Rainfall intensity = 4.742(In/Hr) for a 100.0 year storm Subarea runoff = 2.876(CFS) for 0.700(Ac.)
Total runoff = 9.853(CFS) Total area = 2.100(Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 18.000 to Point/Station 19.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 654.900(Ft.)
Downstream point/station elevation = 654.000(Ft.)
Pipe length = 495.00(Ft.) Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 9.853(CFS)
Nearest computed pipe diameter = 24.00(In.)
Calculated individual pipe flow = 9.853(CFS)
Normal flow depth in pipe = 20.16(In.)
Flow top width inside pipe = 17.60(In.)
Critical Depth = 13.48(In.)
Pipe flow velocity = 3.50(Ft/s)
Travel time through pipe = 2.36 min.
Time of concentration (TC) = 12.49 min.
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 19.000 to Point/Station 19.000 **** SUBAREA FLOW ADDITION ****
______________________________________________________________________ COMMERCIAL subarea type
Runoff Coefficient = 0.864
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 32.00
Pervious area fraction = 0.100; Impervious fraction = 0.900 Time of concentration = 12.49 min.
Rainfall intensity = 4.200(In/Hr) for a 100.0 year storm Subarea runoff = 1.814(CFS) for 0.500(Ac.)
Total runoff = 11.667(CFS) Total area = 2.600(Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 19.000 to Point/Station 19.000 **** SUBAREA FLOW ADDITION ****
______________________________________________________________________ COMMERCIAL subarea type
Runoff Coefficient = 0.864
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 32.00
Pervious area fraction = 0.100; Impervious fraction = 0.900 Time of concentration = 12.49 min.
Rainfall intensity = 4.200(In/Hr) for a 100.0 year storm Subarea runoff = 0.725(CFS) for 0.200(Ac.)
Total runoff = 12.392(CFS) Total area = 2.800(Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 19.000 to Point/Station 20.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 654.000(Ft.)
Item Number: 1.
5 Downstream point/station elevation = 653.500(Ft.)
Pipe length = 125.00(Ft.) Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 12.392(CFS)
Nearest computed pipe diameter = 24.00(In.)
Calculated individual pipe flow = 12.392(CFS)
Normal flow depth in pipe = 17.25(In.)
Flow top width inside pipe = 21.58(In.)
Critical Depth = 15.19(In.)
Pipe flow velocity = 5.13(Ft/s)
Travel time through pipe = 0.41 min.
Time of concentration (TC) = 12.90 min.
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 20.000 to Point/Station 20.000 **** SUBAREA FLOW ADDITION ****
______________________________________________________________________ COMMERCIAL subarea type
Runoff Coefficient = 0.863
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 32.00
Pervious area fraction = 0.100; Impervious fraction = 0.900 Time of concentration = 12.90 min.
Rainfall intensity = 4.122(In/Hr) for a 100.0 year storm Subarea runoff = 0.712(CFS) for 0.200(Ac.)
Total runoff = 13.104(CFS) Total area = 3.000(Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 20.000 to Point/Station 21.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 653.500(Ft.)
Downstream point/station elevation = 646.500(Ft.)
Pipe length = 90.00(Ft.) Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 13.104(CFS)
Nearest computed pipe diameter = 15.00(In.)
Calculated individual pipe flow = 13.104(CFS)
Normal flow depth in pipe = 9.49(In.)
Flow top width inside pipe = 14.46(In.)
Critical depth could not be calculated.
Pipe flow velocity = 16.01(Ft/s)
Travel time through pipe = 0.09 min.
Time of concentration (TC) = 12.99 min.
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 21.000 to Point/Station 30.000 **** IMPROVED CHANNEL TRAVEL TIME ****
______________________________________________________________________ Upstream point elevation = 646.500(Ft.)
Downstream point elevation = 645.500(Ft.)
Channel length thru subarea = 400.000(Ft.)
Channel base width = 50.000(Ft.)
Slope or 'Z' of left channel bank = 4.000
Slope or 'Z' of right channel bank = 4.000
Manning's 'N' = 0.030
Maximum depth of channel = 5.000(Ft.)
Flow(q) thru subarea = 13.104(CFS)
Depth of flow = 0.259(Ft.), Average velocity = 0.992(Ft/s) Channel flow top width = 52.071(Ft.)
Flow Velocity = 0.99(Ft/s)
Travel time = 6.72 min.
Time of concentration = 19.71 min.
Sub-Channel No. 1 Critical depth = 0.129(Ft.)
' ' ' Critical flow top width = 51.031(Ft.)
' ' ' Critical flow velocity= 2.012(Ft/s)
Item Number: 1.
6 ' ' ' Critical flow area = 6.512(Sq.Ft)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 30.000 to Point/Station 30.000 **** CONFLUENCE OF MINOR STREAMS ****
______________________________________________________________________ Along Main Stream number: 1 in normal stream number 2
Stream flow area = 3.000(Ac.)
Runoff from this stream = 13.104(CFS)
Time of concentration = 19.71 min.
Rainfall intensity = 3.223(In/Hr)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 25.000 to Point/Station 26.000 **** INITIAL AREA EVALUATION ****
______________________________________________________________________ Initial area flow distance = 460.000(Ft.)
Top (of initial area) elevation = 655.500(Ft.)
Bottom (of initial area) elevation = 651.000(Ft.)
Difference in elevation = 4.500(Ft.)
Slope = 0.00978 s(percent)= 0.98
TC = k(0.300)*[(length^3)/(elevation change)]^0.2
Initial area time of concentration = 8.793 min.
Rainfall intensity = 5.148(In/Hr) for a 100.0 year storm COMMERCIAL subarea type
Runoff Coefficient = 0.868
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 32.00
Pervious area fraction = 0.100; Impervious fraction = 0.900 Initial subarea runoff = 14.746(CFS)
Total initial stream area = 3.300(Ac.)
Pervious area fraction = 0.100
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 26.000 to Point/Station 27.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 651.000(Ft.)
Downstream point/station elevation = 650.500(Ft.)
Pipe length = 80.00(Ft.) Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 14.746(CFS)
Nearest computed pipe diameter = 24.00(In.)
Calculated individual pipe flow = 14.746(CFS)
Normal flow depth in pipe = 16.59(In.)
Flow top width inside pipe = 22.17(In.)
Critical Depth = 16.59(In.)
Pipe flow velocity = 6.36(Ft/s)
Travel time through pipe = 0.21 min.
Time of concentration (TC) = 9.00 min.
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 27.000 to Point/Station 27.000 **** SUBAREA FLOW ADDITION ****
______________________________________________________________________ COMMERCIAL subarea type
Runoff Coefficient = 0.868
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 32.00
Pervious area fraction = 0.100; Impervious fraction = 0.900 Time of concentration = 9.00 min.
Item Number: 1.
7 Rainfall intensity = 5.078(In/Hr) for a 100.0 year storm Subarea runoff = 4.406(CFS) for 1.000(Ac.)
Total runoff = 19.152(CFS) Total area = 4.300(Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 27.000 to Point/Station 28.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 650.500(Ft.)
Downstream point/station elevation = 645.800(Ft.)
Pipe length = 220.00(Ft.) Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 19.152(CFS)
Nearest computed pipe diameter = 21.00(In.)
Calculated individual pipe flow = 19.152(CFS)
Normal flow depth in pipe = 14.55(In.)
Flow top width inside pipe = 19.37(In.)
Critical Depth = 18.92(In.)
Pipe flow velocity = 10.76(Ft/s)
Travel time through pipe = 0.34 min.
Time of concentration (TC) = 9.34 min.
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 28.000 to Point/Station 30.000 **** IMPROVED CHANNEL TRAVEL TIME ****
______________________________________________________________________ Upstream point elevation = 645.800(Ft.)
Downstream point elevation = 645.500(Ft.)
Channel length thru subarea = 100.000(Ft.)
Channel base width = 50.000(Ft.)
Slope or 'Z' of left channel bank = 4.000
Slope or 'Z' of right channel bank = 4.000
Manning's 'N' = 0.030
Maximum depth of channel = 5.000(Ft.)
Flow(q) thru subarea = 19.152(CFS)
Depth of flow = 0.308(Ft.), Average velocity = 1.216(Ft/s) Channel flow top width = 52.460(Ft.)
Flow Velocity = 1.22(Ft/s)
Travel time = 1.37 min.
Time of concentration = 10.71 min.
Sub-Channel No. 1 Critical depth = 0.164(Ft.)
' ' ' Critical flow top width = 51.313(Ft.)
' ' ' Critical flow velocity= 2.305(Ft/s)
' ' ' Critical flow area = 8.311(Sq.Ft)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 30.000 to Point/Station 30.000 **** CONFLUENCE OF MINOR STREAMS ****
______________________________________________________________________ Along Main Stream number: 1 in normal stream number 3
Stream flow area = 4.300(Ac.)
Runoff from this stream = 19.152(CFS)
Time of concentration = 10.71 min.
Rainfall intensity = 4.590(In/Hr)
Summary of stream data:
Stream Flow rate TC Rainfall Intensity
No. (CFS) (min) (In/Hr)
1 16.561 13.59 4.000
2 13.104 19.71 3.223
3 19.152 10.71 4.590
Largest stream flow has longer or shorter time of concentration Qp = 19.152 + sum of
Qa Tb/Ta
16.561 * 0.789 = 13.062
Item Number: 1.
8 Qa Tb/Ta
13.104 * 0.544 = 7.123
Qp = 39.337
Total of 3 streams to confluence:
Flow rates before confluence point:
16.561 13.104 19.152
Area of streams before confluence:
5.300 3.000 4.300
Results of confluence:
Total flow rate = 39.337(CFS)
Time of concentration = 10.715 min.
Effective stream area after confluence = 12.600(Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 30.000 to Point/Station 31.000 **** IMPROVED CHANNEL TRAVEL TIME ****
______________________________________________________________________ Upstream point elevation = 645.500(Ft.)
Downstream point elevation = 641.000(Ft.)
Channel length thru subarea = 685.000(Ft.)
Channel base width = 50.000(Ft.)
Slope or 'Z' of left channel bank = 4.000
Slope or 'Z' of right channel bank = 4.000
Estimated mean flow rate at midpoint of channel = 40.757(CFS) Manning's 'N' = 0.030
Maximum depth of channel = 5.000(Ft.)
Flow(q) thru subarea = 40.757(CFS)
Depth of flow = 0.382(Ft.), Average velocity = 2.071(Ft/s) Channel flow top width = 53.056(Ft.)
Flow Velocity = 2.07(Ft/s)
Travel time = 5.51 min.
Time of concentration = 16.23 min.
Sub-Channel No. 1 Critical depth = 0.273(Ft.)
' ' ' Critical flow top width = 52.188(Ft.)
' ' ' Critical flow velocity= 2.917(Ft/s)
' ' ' Critical flow area = 13.971(Sq.Ft)
Adding area flow to channel
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.761
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 67.00
Pervious area fraction = 1.000; Impervious fraction = 0.000 Rainfall intensity = 3.608(In/Hr) for a 100.0 year storm Subarea runoff = 2.747(CFS) for 1.000(Ac.)
Total runoff = 42.084(CFS) Total area = 13.600(Ac.)
Depth of flow = 0.389(Ft.), Average velocity = 2.096(Ft/s) Sub-Channel No. 1 Critical depth = 0.277(Ft.)
' ' ' Critical flow top width = 52.219(Ft.)
' ' ' Critical flow velocity= 2.969(Ft/s)
' ' ' Critical flow area = 14.175(Sq.Ft)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 31.000 to Point/Station 32.000 **** IMPROVED CHANNEL TRAVEL TIME ****
______________________________________________________________________ Upstream point elevation = 641.000(Ft.)
Downstream point elevation = 629.000(Ft.)
Channel length thru subarea = 1060.000(Ft.)
Channel base width = 50.000(Ft.)
Slope or 'Z' of left channel bank = 4.000
Slope or 'Z' of right channel bank = 4.000
Item Number: 1.
9 Estimated mean flow rate at midpoint of channel = 44.269(CFS) Manning's 'N' = 0.030
Maximum depth of channel = 5.000(Ft.)
Flow(q) thru subarea = 44.269(CFS)
Depth of flow = 0.341(Ft.), Average velocity = 2.526(Ft/s) Channel flow top width = 52.729(Ft.)
Flow Velocity = 2.53(Ft/s)
Travel time = 6.99 min.
Time of concentration = 23.22 min.
Sub-Channel No. 1 Critical depth = 0.289(Ft.)
' ' ' Critical flow top width = 52.313(Ft.)
' ' ' Critical flow velocity= 2.994(Ft/s)
' ' ' Critical flow area = 14.787(Sq.Ft)
Adding area flow to channel
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.735
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 67.00
Pervious area fraction = 1.000; Impervious fraction = 0.000 Rainfall intensity = 2.931(In/Hr) for a 100.0 year storm Subarea runoff = 4.310(CFS) for 2.000(Ac.)
Total runoff = 46.394(CFS) Total area = 15.600(Ac.)
Depth of flow = 0.351(Ft.), Average velocity = 2.572(Ft/s) Sub-Channel No. 1 Critical depth = 0.297(Ft.)
' ' ' Critical flow top width = 52.375(Ft.)
' ' ' Critical flow velocity= 3.053(Ft/s)
' ' ' Critical flow area = 15.196(Sq.Ft)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 32.000 to Point/Station 33.000 **** IMPROVED CHANNEL TRAVEL TIME ****
______________________________________________________________________ Upstream point elevation = 629.000(Ft.)
Downstream point elevation = 626.500(Ft.)
Channel length thru subarea = 460.000(Ft.)
Channel base width = 50.000(Ft.)
Slope or 'Z' of left channel bank = 4.000
Slope or 'Z' of right channel bank = 4.000
Estimated mean flow rate at midpoint of channel = 47.016(CFS) Manning's 'N' = 0.030
Maximum depth of channel = 5.000(Ft.)
Flow(q) thru subarea = 47.016(CFS)
Depth of flow = 0.440(Ft.), Average velocity = 2.064(Ft/s) Channel flow top width = 53.521(Ft.)
Flow Velocity = 2.06(Ft/s)
Travel time = 3.72 min.
Time of concentration = 26.94 min.
Sub-Channel No. 1 Critical depth = 0.301(Ft.)
' ' ' Critical flow top width = 52.406(Ft.)
' ' ' Critical flow velocity= 3.053(Ft/s)
' ' ' Critical flow area = 15.401(Sq.Ft)
Adding area flow to channel
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.723
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 67.00
Pervious area fraction = 1.000; Impervious fraction = 0.000 Rainfall intensity = 2.689(In/Hr) for a 100.0 year storm Item Number: 1.
10 Subarea runoff = 1.167(CFS) for 0.600(Ac.)
Total runoff = 47.561(CFS) Total area = 16.200(Ac.)
Depth of flow = 0.443(Ft.), Average velocity = 2.073(Ft/s) Sub-Channel No. 1 Critical depth = 0.301(Ft.)
' ' ' Critical flow top width = 52.406(Ft.)
' ' ' Critical flow velocity= 3.088(Ft/s)
' ' ' Critical flow area = 15.401(Sq.Ft)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 33.000 to Point/Station 70.000 **** IMPROVED CHANNEL TRAVEL TIME ****
______________________________________________________________________ Upstream point elevation = 626.500(Ft.)
Downstream point elevation = 622.000(Ft.)
Channel length thru subarea = 310.000(Ft.)
Channel base width = 50.000(Ft.)
Slope or 'Z' of left channel bank = 4.000
Slope or 'Z' of right channel bank = 4.000
Estimated mean flow rate at midpoint of channel = 48.059(CFS) Manning's 'N' = 0.030
Maximum depth of channel = 5.000(Ft.)
Flow(q) thru subarea = 48.059(CFS)
Depth of flow = 0.333(Ft.), Average velocity = 2.814(Ft/s) Channel flow top width = 52.662(Ft.)
Flow Velocity = 2.81(Ft/s)
Travel time = 1.84 min.
Time of concentration = 28.77 min.
Sub-Channel No. 1 Critical depth = 0.305(Ft.)
' ' ' Critical flow top width = 52.438(Ft.)
' ' ' Critical flow velocity= 3.080(Ft/s)
' ' ' Critical flow area = 15.606(Sq.Ft)
Adding area flow to channel
UNDEVELOPED (poor cover) subarea
Runoff Coefficient = 0.718
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 67.00
Pervious area fraction = 1.000; Impervious fraction = 0.000 Rainfall intensity = 2.588(In/Hr) for a 100.0 year storm Subarea runoff = 0.929(CFS) for 0.500(Ac.)
Total runoff = 48.490(CFS) Total area = 16.700(Ac.)
Depth of flow = 0.334(Ft.), Average velocity = 2.824(Ft/s) Sub-Channel No. 1 Critical depth = 0.305(Ft.)
' ' ' Critical flow top width = 52.438(Ft.)
' ' ' Critical flow velocity= 3.107(Ft/s)
' ' ' Critical flow area = 15.606(Sq.Ft)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 70.000 to Point/Station 70.000 **** CONFLUENCE OF MAIN STREAMS ****
______________________________________________________________________ The following data inside Main Stream is listed:
In Main Stream number: 1
Stream flow area = 16.700(Ac.)
Runoff from this stream = 48.490(CFS)
Time of concentration = 28.77 min.
Rainfall intensity = 2.588(In/Hr)
Program is now starting with Main Stream No. 2
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Item Number: 1.
11 Process from Point/Station 15.000 to Point/Station 41.000 **** INITIAL AREA EVALUATION ****
______________________________________________________________________ Initial area flow distance = 520.000(Ft.)
Top (of initial area) elevation = 656.500(Ft.)
Bottom (of initial area) elevation = 654.400(Ft.)
Difference in elevation = 2.100(Ft.)
Slope = 0.00404 s(percent)= 0.40
TC = k(0.300)*[(length^3)/(elevation change)]^0.2
Initial area time of concentration = 11.022 min.
Rainfall intensity = 4.515(In/Hr) for a 100.0 year storm COMMERCIAL subarea type
Runoff Coefficient = 0.865
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 32.00
Pervious area fraction = 0.100; Impervious fraction = 0.900 Initial subarea runoff = 2.344(CFS)
Total initial stream area = 0.600(Ac.)
Pervious area fraction = 0.100
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 41.000 to Point/Station 42.000 **** STREET FLOW TRAVEL TIME + SUBAREA FLOW ADDITION **** ______________________________________________________________________ Top of street segment elevation = 654.400(Ft.)
End of street segment elevation = 651.500(Ft.)
Length of street segment = 780.000(Ft.)
Height of curb above gutter flowline = 6.0(In.)
Width of half street (curb to crown) = 18.000(Ft.)
Distance from crown to crossfall grade break = 14.000(Ft.) Slope from gutter to grade break (v/hz) = 0.020
Slope from grade break to crown (v/hz) = 0.020
Street flow is on [2] side(s) of the street
Distance from curb to property line = 10.000(Ft.)
Slope from curb to property line (v/hz) = 0.025
Gutter width = 2.000(Ft.)
Gutter hike from flowline = 2.000(In.)
Manning's N in gutter = 0.0150
Manning's N from gutter to grade break = 0.0150
Manning's N from grade break to crown = 0.0150
Estimated mean flow rate at midpoint of street = 3.790(CFS) Depth of flow = 0.345(Ft.), Average velocity = 1.443(Ft/s) Streetflow hydraulics at midpoint of street travel:
Halfstreet flow width = 10.893(Ft.)
Flow velocity = 1.44(Ft/s)
Travel time = 9.01 min. TC = 20.03 min.
Adding area flow to street
COMMERCIAL subarea type
Runoff Coefficient = 0.858
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 32.00
Pervious area fraction = 0.100; Impervious fraction = 0.900 Rainfall intensity = 3.193(In/Hr) for a 100.0 year storm Subarea runoff = 2.739(CFS) for 1.000(Ac.)
Total runoff = 5.083(CFS) Total area = 1.600(Ac.)
Street flow at end of street = 5.083(CFS)
Half street flow at end of street = 2.542(CFS)
Depth of flow = 0.373(Ft.), Average velocity = 1.546(Ft/s) Flow width (from curb towards crown)= 12.319(Ft.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 42.000 to Point/Station 43.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** Item Number: 1.
12 ______________________________________________________________________ Upstream point/station elevation = 651.500(Ft.)
Downstream point/station elevation = 651.000(Ft.)
Pipe length = 120.00(Ft.) Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 5.083(CFS)
Nearest computed pipe diameter = 18.00(In.)
Calculated individual pipe flow = 5.083(CFS)
Normal flow depth in pipe = 11.63(In.)
Flow top width inside pipe = 17.22(In.)
Critical Depth = 10.42(In.)
Pipe flow velocity = 4.21(Ft/s)
Travel time through pipe = 0.48 min.
Time of concentration (TC) = 20.51 min.
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 43.000 to Point/Station 43.000 **** SUBAREA FLOW ADDITION ****
______________________________________________________________________ COMMERCIAL subarea type
Runoff Coefficient = 0.857
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 32.00
Pervious area fraction = 0.100; Impervious fraction = 0.900 Time of concentration = 20.51 min.
Rainfall intensity = 3.150(In/Hr) for a 100.0 year storm Subarea runoff = 4.051(CFS) for 1.500(Ac.)
Total runoff = 9.134(CFS) Total area = 3.100(Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 43.000 to Point/Station 44.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 651.000(Ft.)
Downstream point/station elevation = 625.000(Ft.)
Pipe length = 870.00(Ft.) Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 9.134(CFS)
Nearest computed pipe diameter = 15.00(In.)
Calculated individual pipe flow = 9.134(CFS)
Normal flow depth in pipe = 10.31(In.)
Flow top width inside pipe = 13.91(In.)
Critical Depth = 13.91(In.)
Pipe flow velocity = 10.15(Ft/s)
Travel time through pipe = 1.43 min.
Time of concentration (TC) = 21.93 min.
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 44.000 to Point/Station 44.000 **** SUBAREA FLOW ADDITION ****
______________________________________________________________________ UNDEVELOPED (fair cover) subarea
Runoff Coefficient = 0.625
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 50.00
Pervious area fraction = 1.000; Impervious fraction = 0.000 Time of concentration = 21.93 min.
Rainfall intensity = 3.029(In/Hr) for a 100.0 year storm Subarea runoff = 3.976(CFS) for 2.100(Ac.)
Total runoff = 13.110(CFS) Total area = 5.200(Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 44.000 to Point/Station 45.000 Item Number: 1.
13 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 625.000(Ft.)
Downstream point/station elevation = 624.500(Ft.)
Pipe length = 40.00(Ft.) Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 13.110(CFS)
Nearest computed pipe diameter = 21.00(In.)
Calculated individual pipe flow = 13.110(CFS)
Normal flow depth in pipe = 13.45(In.)
Flow top width inside pipe = 20.15(In.)
Critical Depth = 16.18(In.)
Pipe flow velocity = 8.06(Ft/s)
Travel time through pipe = 0.08 min.
Time of concentration (TC) = 22.02 min.
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 45.000 to Point/Station 45.000 **** SUBAREA FLOW ADDITION ****
______________________________________________________________________ COMMERCIAL subarea type
Runoff Coefficient = 0.856
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 32.00
Pervious area fraction = 0.100; Impervious fraction = 0.900 Time of concentration = 22.02 min.
Rainfall intensity = 3.023(In/Hr) for a 100.0 year storm Subarea runoff = 1.812(CFS) for 0.700(Ac.)
Total runoff = 14.922(CFS) Total area = 5.900(Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 45.000 to Point/Station 60.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 624.500(Ft.)
Downstream point/station elevation = 620.000(Ft.)
Pipe length = 165.00(Ft.) Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 14.922(CFS)
Nearest computed pipe diameter = 18.00(In.)
Calculated individual pipe flow = 14.922(CFS)
Normal flow depth in pipe = 12.87(In.)
Flow top width inside pipe = 16.25(In.)
Critical Depth = 16.85(In.)
Pipe flow velocity = 11.04(Ft/s)
Travel time through pipe = 0.25 min.
Time of concentration (TC) = 22.27 min.
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 60.000 to Point/Station 60.000 **** CONFLUENCE OF MINOR STREAMS ****
______________________________________________________________________ Along Main Stream number: 2 in normal stream number 1
Stream flow area = 5.900(Ac.)
Runoff from this stream = 14.922(CFS)
Time of concentration = 22.27 min.
Rainfall intensity = 3.003(In/Hr)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 50.000 to Point/Station 51.000 **** INITIAL AREA EVALUATION ****
______________________________________________________________________ Initial area flow distance = 250.000(Ft.)
Top (of initial area) elevation = 651.000(Ft.)
Bottom (of initial area) elevation = 645.000(Ft.)
Difference in elevation = 6.000(Ft.)
Item Number: 1.
14 Slope = 0.02400 s(percent)= 2.40
TC = k(0.300)*[(length^3)/(elevation change)]^0.2
Initial area time of concentration = 5.758 min.
Rainfall intensity = 6.581(In/Hr) for a 100.0 year storm COMMERCIAL subarea type
Runoff Coefficient = 0.873
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 32.00
Pervious area fraction = 0.100; Impervious fraction = 0.900 Initial subarea runoff = 2.298(CFS)
Total initial stream area = 0.400(Ac.)
Pervious area fraction = 0.100
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 51.000 to Point/Station 52.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 645.000(Ft.)
Downstream point/station elevation = 643.000(Ft.)
Pipe length = 220.00(Ft.) Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 2.298(CFS)
Nearest computed pipe diameter = 12.00(In.)
Calculated individual pipe flow = 2.298(CFS)
Normal flow depth in pipe = 7.23(In.)
Flow top width inside pipe = 11.74(In.)
Critical Depth = 7.78(In.)
Pipe flow velocity = 4.64(Ft/s)
Travel time through pipe = 0.79 min.
Time of concentration (TC) = 6.55 min.
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 52.000 to Point/Station 52.000 **** SUBAREA FLOW ADDITION ****
______________________________________________________________________ COMMERCIAL subarea type
Runoff Coefficient = 0.871
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 32.00
Pervious area fraction = 0.100; Impervious fraction = 0.900 Time of concentration = 6.55 min.
Rainfall intensity = 6.108(In/Hr) for a 100.0 year storm Subarea runoff = 26.615(CFS) for 5.000(Ac.)
Total runoff = 28.913(CFS) Total area = 5.400(Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 52.000 to Point/Station 53.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 643.000(Ft.)
Downstream point/station elevation = 642.500(Ft.)
Pipe length = 85.00(Ft.) Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 28.913(CFS)
Nearest computed pipe diameter = 30.00(In.)
Calculated individual pipe flow = 28.913(CFS)
Normal flow depth in pipe = 22.64(In.)
Flow top width inside pipe = 25.82(In.)
Critical Depth = 22.01(In.)
Pipe flow velocity = 7.27(Ft/s)
Travel time through pipe = 0.19 min.
Time of concentration (TC) = 6.74 min.
Item Number: 1.
15 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 53.000 to Point/Station 53.000 **** SUBAREA FLOW ADDITION ****
______________________________________________________________________ COMMERCIAL subarea type
Runoff Coefficient = 0.871
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 32.00
Pervious area fraction = 0.100; Impervious fraction = 0.900 Time of concentration = 6.74 min.
Rainfall intensity = 6.005(In/Hr) for a 100.0 year storm Subarea runoff = 12.032(CFS) for 2.300(Ac.)
Total runoff = 40.945(CFS) Total area = 7.700(Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 53.000 to Point/Station 54.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 642.500(Ft.)
Downstream point/station elevation = 641.500(Ft.)
Pipe length = 600.00(Ft.) Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 40.945(CFS)
Nearest computed pipe diameter = 42.00(In.)
Calculated individual pipe flow = 40.945(CFS)
Normal flow depth in pipe = 34.31(In.)
Flow top width inside pipe = 32.48(In.)
Critical Depth = 23.89(In.)
Pipe flow velocity = 4.87(Ft/s)
Travel time through pipe = 2.05 min.
Time of concentration (TC) = 8.80 min.
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 54.000 to Point/Station 54.000 **** SUBAREA FLOW ADDITION ****
______________________________________________________________________ COMMERCIAL subarea type
Runoff Coefficient = 0.868
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
RI index for soil(AMC 2) = 32.00
Pervious area fraction = 0.100; Impervious fraction = 0.900 Time of concentration = 8.80 min.
Rainfall intensity = 5.146(In/Hr) for a 100.0 year storm Subarea runoff = 13.402(CFS) for 3.000(Ac.)
Total runoff = 54.347(CFS) Total area = 10.700(Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 54.000 to Point/Station 55.000 **** PIPEFLOW TRAVEL TIME (Program estimated size) **** ______________________________________________________________________ Upstream point/station elevation = 641.500(Ft.)
Downstream point/station elevation = 640.500(Ft.)
Pipe length = 600.00(Ft.) Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 54.347(CFS)
Nearest computed pipe diameter = 48.00(In.)
Calculated individual pipe flow = 54.347(CFS)
Normal flow depth in pipe = 36.52(In.)
Flow top width inside pipe = 40.96(In.)
Critical Depth = 26.59(In.)
Pipe flow velocity = 5.30(Ft/s)
Travel time through pipe = 1.89 min.
Time of concentration (TC) = 10.68 min.
Item Number: 1.