Ascent Cultural Resources
City of Roseville
Roseville Environmental Utilities Operations Center Project Draft EIR 3.6-5 LOCAL
City of Roseville 2035 General Plan
The City of Roseville 2035 General Plan EIR lists the following policies related to archaeological, historic, cultural, and Tribal cultural resources that may be applicable to the project (City of Roseville 2020):
Policy OS4.1 Consult with local Native American Tribes that are traditionally and culturally affiliated with resources that could be affected by City plans or projects, identify areas that may be of cultural or tribal cultural significance, and determine appropriate treatment for the areas. Policy OS4.2 When items of historical, cultural, or archaeological significance are discovered within the City, a qualified archaeologist or historian shall be called to evaluate the find and to recommend proper action. Policy OS4.4 The City shall coordinate with the appropriate federal, state, local agencies, and Native American Most Likely Descendant (MLD) Tribes upon discovery of artifacts. The City shall offer the Maidu Museum & Historic Site as a temporary housing location for artifacts that are discovered and subsequently determined to be “removable.”
3.6.2 Environmental Setting
The following information is from the Cultural Resources Technical Report for the Roseville Environmental Utilities Center Project (Ascent 2025).
REGIONAL PREHISTORY
A tripartite classification system for cultural change in California’s Sacramento River Valley has been standard since the 1930s. This system has recently been adjusted based on modern calibration curves for radiocarbon dates.
Radiocarbon dating is a crucial technique in archaeology for determining the age of organic materials up to approximately 50,000 years old. It relies on the radioactive decay of carbon-14 (¹⁴C), a naturally occurring isotope present in all living organisms (plants and animals). By measuring the remaining ¹⁴C in a sample, archaeologists can estimate the time since the organism died.
The following classification system has been defined for the pre-contact period: Paleo-Indian (13,500–10,550 calibrated [cal] before present [BP], Lower Archaic (10,550–7550 cal BP), Middle Archaic (7550–2550 cal BP), Upper Archaic (2550-900 cal BP), and Emergent or Late Prehistoric Period (900-200 cal BP).
Subsequent to the Paleo-Indian and Lower Archaic periods, the cultural framework is further divided into three regionally based “patterns.” Specific to the project area, there are three regionally based patterns. These are the Windmiller, Berkeley, and Augustine patterns. The patterns mark distinct changes in artifact types, subsistence practices, and settlement patterns, which began circa 7550 cal BP and lasted until European contact in the mid-1800s.
They were initially identified at three archaeological sites: the Windmiller site near the Cosumnes River in Sacramento County; the West Berkeley site on the east side of the San Francisco Bay in Alameda County; and the Augustine site in the Sacramento–San Joaquin Delta. In general, the patterns conform to three temporal divisions: Middle Archaic Period/Windmiller Pattern, Upper Archaic Period/Berkeley Pattern, Late Prehistoric Period/Augustine Pattern.
Paleo-Indian and Lower Archaic Periods (13,500–7550 cal BP) There is little evidence of the Paleo-Indian and Lower Archaic periods in the Central Valley. Recent geoarchaeological studies have found that large segments of the Late Pleistocene landscape throughout the California lowlands have been buried or removed by periodic episodes of deposition and erosion. Periods of climate change and associated alluvial deposition occurred at the end of the Pleistocene (approximately 11,000 cal BP) and at the beginning of the early Middle Holocene (approximately 7550 cal BP). Earlier studies had also estimated that Paleo-Indian and Lower Archaic sites along the lower stretch of the Sacramento River and San Joaquin River drainage systems had been buried by Holocene alluvium up to 33 feet thick that was deposited during the last 5,000 to 6,000 years. The
Cultural Resources Ascent
City of Roseville
3.6-6 Roseville Environmental Utilities Operations Center Project Draft EIR formation of the Sacramento–San Joaquin Delta began during the early Middle Holocene. After approximately 3,000 cal BP during the Late Holocene, there were renewed episodes of alluvial fan and floodplain deposition.
The archaeological evidence that is available for the Paleo-Indian Period is primarily defined by basally thinned, fluted projectile points. These points are morphologically similar to well-dated Clovis points found elsewhere in North America. In the Central Valley, fluted points have been recovered from remnant features of the Pleistocene landscape at only three archaeological localities, the Woolfsen Mound in Merced County; Tracey Lake in San Joaquin County; and Tulare Lake basin in Kings County.
Middle Archaic Period/Windmiller Pattern (7550–2550 cal BP) Archaeological sites dating to the first 3,000 years of the Middle Archaic are relatively scarce in the Sacramento River Valley, mainly due to natural geomorphic processes. On the valley floor, sites are more common after 4550 cal. BP.
The archaeological record in the valley and foothills indicates the subsistence system during this period included a wide range of natural resources (e.g., plants, small and large mammals, fish, and waterfowl) indicating people followed a seasonal foraging strategy. Some researchers suggest populations may have occupied lower elevations during the winter and moved to higher elevations in the summer. Others suggest there was increasing residential stability along Central Valley river corridors during the Middle Archaic.
Excavations at Windmiller Pattern sites have yielded abundant remains of terrestrial fauna (deer, tule elk, pronghorn, and rabbits) and fish (sturgeon, salmon, and smaller fishes). Projectile points with triangular blades and contracting stems are common at Windmiller Pattern sites. A variety of fishing implements such as angling hooks, composite bone hooks, spears, and baked clay artifacts, which may have been used as net or line sinkers, are also relatively common. The points are classified within the Sierra Contracting Stem and Houx Contracting Stem series. The presence of milling implements (grinding slabs, handstones, and mortar fragments) indicate that acorns or seeds were an important part of the Middle Archaic diet.
The presence of numerous exotic trade goods within Middle Archaic assemblages indicate that populations were already part of a complex regional trade network. Obsidian sources include eastern Sierra sources (e.g., Bodie Hills, Casa Diablo, Coso, and Mount Hicks), North Coast Range (e.g., Napa Valley and Borax Lake), and southern Cascades (e.g., Tuscan). Olivella shell beads make their first appearance in the study area during the Early Period, indicating trade with Southern California coastal groups. Lastly, burial complexes with large populations and elaborate grave offerings indicate extended residential occupancy.
Upper Archaic Period/Berkeley Pattern (2550-900 cal BP) The Upper Archaic is characterized by a shift over a 1,000-year period to the more specialized, adaptive Berkeley Pattern. Excavated archaeological sites dating to the Upper Archaic indicate an increase in mortar and pestle groundstone technology. This change is supported by dated palaeobotanical remains and a decrease in slab milling stones and handstones. Archaeologists generally agree mortars and pestles are better suited to crushing and grinding acorns, while milling slabs and handstones may have been used primarily for grinding wild grass grains and seeds. New types of shell beads, charmstones, bone tools, and ceremonial blades are additional evidence of the more specialized technology present during this period.
The artifact assemblage in Berkeley Pattern sites demonstrates that populations continued to exploit a variety of plant and animal resources from different environmental zones, including grassland, riparian, and freshwater marsh settings. Deposits of this temporal period have a characteristic well-developed brown midden containing hearth features, fire-fractured rock, storage pits, and house floors. These features indicate that Upper Archaic sites were intensively occupied by large populations.
Berkeley Pattern artifact assemblages are also characterized by split, saddle, and saucer shaped Olivella shell beads, Haliotis ornaments, and a variety of bone tool types. Charmstones are fishtail and asymmetrical spindle-shaped.
Mortuary patterns are characterized by flexed burials in variable orientations and a paucity of grave goods. Some cremations have also been recorded in Middle Period cemeteries. Inhumations (human burials) are sometimes accompanied by animal bones and animal-only burials have also been recorded. Obsidian from the North Coast Ranges and the east side of the Sierra Nevada Range indicate a slight shift in trade patterns away from more northernly sources.
Ascent Cultural Resources
City of Roseville
Roseville Environmental Utilities Operations Center Project Draft EIR 3.6-7 Emergent Period/Augustine Pattern (900-200 cal BP)
The archaeological record for the Emergent or Late Prehistoric Period shows an increase in the number of archaeological sites associated with the Augustine Pattern in the Sacramento River Valley, as well as an increase in the number and diversity of artifacts. The Emergent Period was shaped by a number of cultural innovations, such as the bow and arrow and intricate fishing technology, as well as an elaborate social and ceremonial organization. Cultural patterns typical of the Emergent Period appear to be reflected in the cultural traditions known from historic period Native American groups.
Faunal and botanical remains recovered at Emergent Period archaeological sites indicate occupants relied on a diverse assortment of mammals, fish, and plant, including acorns and pine nuts. Hopper mortars, shaped mortars, and pestles are among the new technologies that appear during this time period. Small, Gunther barbed series projectile points have been found at sites dating to the early part of the period, while Desert-side notched points appear later in the period. The Stockton serrated arrow point also appears in archaeological assemblages dating to this period and in some parts of the lower Sacramento River Valley Cosumnes Brownware ceramics are present. The appearance of ceramics during this period is likely a direct improvement on the prior baked clay industry. Complex fishing instruments appear, such as the serrated fish harpoons, composite bone hooks, and the toggle harpoon.
During the Emergent Period, villages were located along major waterways with smaller settlements found in outlying areas. Settlements on natural levees and high spots in floodplains were common. House floors or other structural remains have been preserved at some sites dating to this period. The increase in sedentism and population growth led to the development of social stratification, with an elaborate social and ceremonial organization. Examples of items associated with rituals and ceremonials include flanged tubular pipes, incised patterned bird bone tubes and whistles, and baked clay effigies representing animals and humans. Mortuary practices changed to include flexed burials (fetal position), cremations with grave goods and offerings, and pre-interment burning in a burial pit.
Currency, in the form of clamshell disk beads, also developed during the later part of the period together with extensive exchange networks that included the Pacific Northwest and southern California.
HISTORIC SETTING
Historic land use around Pleasant Grove Creek within the project site has changed little in the last 160 years. The earliest Euro-American use of the project area occurred in late 1840s, when argonauts entered the area searching for placer gold. That played out quickly and as early as 1854, small-scale ranching began. Around this same time, a man named Lee acquired 10,500 acres of land through government script and settled on Pleasant Grove Creek. In 1856, he sold his parcel to Stephen A. Boutwell, who began to acquire other land near the California and Oregon Railroad (now Southern Pacific). Boutwell and his partner, William Dunlap, used their land for a sheep ranch, combining their holdings with those of a new partner, James W. Kaseberg, in 1864. During the 1870s, as many as 30,000 head of sheep were sheared on the ranch each year. The Boutwell, Dunlap, and Kasberg ranch was also home of the first thoroughbred and trotting horses raised in California.
Another important early farming family in the area was the Fiddyments. The Fiddyment family has a long history in the Roseville area and their ranch borders the project site on the east side. Elizabeth Jane Fiddyment came to the Sacramento area from Illinois in 1854, a widow with a four-year-old son, Walter Frederick Fiddyment. Upon arriving in the Elk Grove area in southern Sacramento County, she met and married a local farmer and stock-raiser, George Hill.
The new family moved to the Pleasant Grove District in Roseville in 1856 to live and work with her sister's family on their farming operation. Around this time, Elizabeth's brother-in-law repaid a debt to her with a parcel of land, the first of what would eventually become extensive land holdings.
In 1879, Elizabeth's son, Walter, left his mother's home when he married Ella Bond. Walter bought 80 acres in the Pleasant Grove District, the first of 240 acres he eventually owned in the area. When the soil and natural irrigation proved too poor for farming, Walter turned to raising horses and mules, which also proved unprofitable. He then turned to raising cattle and sheep. Walter’s son Russell even tried a turkey farm on the ranch in the 1920s. In the 1970s, the family added a pistachio orchard to their endeavors. Today, the family continues to raise cattle and grow pistachios near Pleasant Grove Creek.
Cultural Resources Ascent
City of Roseville
3.6-8 Roseville Environmental Utilities Operations Center Project Draft EIR In the mid-1970s, the land in and around the project site began to be re-contoured to accommodate rice cultivation on both sides of Pleasant Grove Creek. Rice cultivation continued up until sometime after 2002 and, in some places, is still ongoing. After that, most of the land was converted to irrigated pasture and a retention basin was excavated just south of Pleasant Grove Creek. Today, the land is still used for agriculture (including rice cultivation) and cattle grazing.
ARCHAEOLOGICAL SENSITIVITY
There is one geologic unit present in the project site, the Qr (of Quaternary age), and the surficial soils within the project site are the Alamo, Fiddyment, Cometa, and San Joaquin series. Because the Qr material formed long before the first human occupation of the area, it is very unlikely to contain or to have buried archaeological resources. The overlying soils of the San Joaquin Series are younger, dating to the Late Holocene (2,000 to 150 years ago), and so are generally more sensitive for buried cultural remains. The Alamo, Fiddyment, and Cometa series are older soils dating to the Pleistocene, which was before human occupation, are unlikely to contain or to have buried archaeological resources.
Landscape evolution and historic and modern development can affect the visibility of the archaeological record, but research has shown that archaeological sites tend to occur in specific geo-environmental settings (e.g., near reliable water sources and on stable land surfaces) rather than randomly throughout the landscape. For example, geoarchaeological studies have found that distance to water sources (e.g., stream, lake, spring) and landform slope (generally <18 percent) are two environmental variables that help accurately predict a location’s potential to contain buried archaeological deposits. The topography of the terrain in the project site is relatively flat. The Pleasant Grove Creek runs roughly east/west directly north of the project site. The project site has been historically used for agriculture and graded for that purpose. Therefore, the geography, geology, soils, and topography across most of the project site suggest that the potential for the presence of buried deposits of cultural resources in the project site is low. Furthermore, based on the site’s historic agricultural use, the potential for intact buried deposits is very low.
RECORDS SEARCH AND SURVEY
Records Search
On February 23, 2024, a search of records concerning the project site and a one-half-mile radius around the project area was conducted at the North Central Information Center (NCIC), at California State University, Sacramento (PLA21-36). The following information was reviewed as part of the records search:
site records of previously recorded cultural resources, previous cultural studies,
NRHP and CRHR listings,
the California Historic Resources Inventory,
Built Environment Resource Directory for Placer County, and Historical Maps (USGS Topographic and GLO Plat maps).
The records search revealed no previously recorded resources within the project site and only four within a one-halfmile radius. The search also found that one previous investigation included the entirety of the project area, four previous investigations included only a portion of the project area, and five investigations have occurred within one-half-mile.
Survey
Field work for the project was conducted on December 11, 2024, by Ascent cultural resources staff. Overall, the survey found no presence of anthropogenic soils (i.e., midden), hearth features, or concentrations of shell, bone, or lithic materials that would have indicated the presence of a pre-contact indigenous deposit. Three built-environment features were recorded and evaluated.
Ascent Cultural Resources
City of Roseville
Roseville Environmental Utilities Operations Center Project Draft EIR 3.6-9 As described in Chapter 2, “Project Description,” the project includes extension of an existing 60 kilovolt (kV) line from the Roseville Energy Park to the project site, roughly along Phillip Road. This alignment, which is referred to as the Public Utility Easement (PUE) area, was not surveyed for this project because the final location has not yet been determined at the time of this EIR. The extended line would also serve other proposed projects in the area, including the Phillip Road Project and the Pleasant Grove Stormwater Retention Basin Facility, and cultural resource evaluations of the PUE area are ongoing.
8100 Phillip Road is a rural residential property. There is no information in the archival record that indicates that the subject property is associated with events or people that have made a significant contribution to history; therefore, it does not appear to be eligible for the NRHP/CRHR under Criterion A/1 and B/2. The subject property does not appear to possess sufficient design or construction value to be eligible for the NRHP/CRHR under Criterion C/3.
Criterion D/4 generally applies to archaeological resources or other resources that through study of construction details can provide information that cannot be obtained in other ways. 8100 Phillip Road does not appear to be significant under this criterion because it is not likely to yield any additional important information about our history.
Phillip Road is a narrow two-lane road. There is no information in the archival record that indicates that the road is associated with events or people that have made a significant contribution to history; therefore, it does not appear to be eligible for the NRHP/CRHR under Criterion A/1 and B/2. The road does not appear to possess sufficient design or construction value to be eligible for the NRHP/CRHR under Criterion C/3. Criterion D/4 generally applies to archaeological resources or other resources that through study of construction details can provide information that cannot be obtained in other ways. Phillip Road does not appear to be significant under this criterion because it is not likely to yield any additional important information about our history.
The Rio Oso-Lockeford transmission line is a 65.13-mile lattice steel tower type, approximately 1,326 feet of which runs through the project site. There is no information in the archival record that indicates that the transmission line is associated with events or people that have made a significant contribution to history; therefore, it does not appear to be eligible for the NRHP/CRHR under Criterion A/1 and B/2. The transmission line also does not appear to possess sufficient design or construction value to be eligible for the NRHP/CRHR under Criterion C/3. Criterion D/4 generally applies to archaeological resources or other resources that through study of construction details can provide information that cannot be obtained in other ways. The transmission line does not appear to be significant under this criterion because it is not likely to yield any additional important information about our history.
3.6.3 Impacts and Mitigation Measures
METHODOLOGY
The impact analysis for cultural resources is based on the findings and recommendations of the Cultural Resources Technical Report for the Roseville Environmental Utilities Center Project (Ascent 2025). The analysis is also informed by the provisions and requirements of federal, state, and local laws and regulations that apply to cultural resources.
PRC Section 21083.2(g) defines a “unique archaeological resource” as an archaeological artifact, object, or site about which it can be clearly demonstrated that, without merely adding to the current body of knowledge, there is a high probability that it meets one or more of the following CRHR-related criteria: (1) that it contains information needed to answer important scientific research questions and that there is a demonstrable public interest in that information; (2) that it as a special and particular quality, such as being the oldest of its type or the best available example of its type; or (3) that it is directly associated with a scientifically recognized important prehistoric or historic event or person. An impact on a resource that is not unique is not a significant environmental impact under CEQA (State CEQA Guidelines Section 15064.5[c][4]). If an archaeological resource qualifies as a resource under CRHR criteria, then the resource is treated as a unique archaeological resource for the purposes of CEQA.
For the purposes of the impact discussion, “historical resource” is used to describe built-environment historic-period resources. Archaeological resources (both prehistoric and historic-period), which may qualify as “historical resources” pursuant to CEQA, are analyzed separately from built-environment historical resources.
Cultural Resources Ascent
City of Roseville
3.6-10 Roseville Environmental Utilities Operations Center Project Draft EIR
THRESHOLDS OF SIGNIFICANCE
Thresholds of significance are based on Appendix G of the State CEQA Guidelines. The project would cause a significant impact related to cultural resources if it would:
cause a substantial adverse change in the significance of a historical resource pursuant to Section 15064.5 of the State CEQA Guidelines;
cause a substantial adverse change in the significance of an archaeological resource pursuant to Section 15064.5 of the State CEQA Guidelines; or
disturb any human remains, including those interred outside of dedicated cemeteries.
ISSUES NOT DISCUSSED FURTHER
The records search revealed no previously recorded historical resources within the project site (Ascent 2025). As described above, the pedestrian survey identified three historic-age built-environment features, which were evaluated and recommended ineligible for both the NRHP and CRHR; therefore, they are not historical resources under CEQA.
For this reason, project construction and operation would have no impact on historical resources, and this issue is not analyzed further.
ENVIRONMENTAL IMPACTS AND MITIGATION MEASURES
Impact 3.6-1: Cause a Substantial Adverse Change in the Significance of Unique Archaeological Resources
Phase 1
Results of the records search and pedestrian survey did not result in the identification of archaeological resources within the project site. However, project-related ground-disturbing activities associated with Phase 1, including off-site roadway and utility improvements, could result in discovery or damage of yet undiscovered archaeological resources as defined in State CEQA Guidelines Section 15064.5 or PRC Section 21083.2(g). This would be a potentially significant impact.
The NCIC records search revealed that no prehistoric or historic-period archaeological sites have been previously documented within the project site and only four have been documented within a one-half-mile radius. The pedestrian survey found no anthropogenic soils (i.e., midden), above ground features, or concentrations of shell, bone, or lithic materials that would have indicated the presence of a precontact indigenous archaeological deposit. In addition, no unique archaeological resources as defined in PRC Section 21083.2(g) or archaeological resources as defined in State CEQA Guidelines Section 15064.5 were identified during the survey.
A records search and pedestrian survey were not conducted for the off-site PUE area because the final alignment is not known. The extended 60 kV line would also serve other proposed projects in the area, including the Phillip Road Project and the Pleasant Grove Stormwater Retention Basin Facility, and cultural resource evaluations of the PUE area are ongoing. Because a records search and pedestrian survey were not conducted for the off-site PUE area, it is unknown if this area contains archaeological resources that could be discovered or damaged during project-related ground-disturbing activities.
As discussed previously, the geography, geology, soils, and topography across most of the project site suggest that the potential for the presence of buried archaeological deposits in the project site is low. Furthermore, based on the site’s historic use, the potential for intact buried deposits is very low. While the potential for ground disturbance during Phase 1 construction to encounter previously undiscovered or unrecorded archaeological sites and materials is low, it is not zero. These activities could damage or destroy previously undiscovered archaeological resources. This would be a potentially significant impact.
Ascent Cultural Resources
City of Roseville
Roseville Environmental Utilities Operations Center Project Draft EIR 3.6-11 Mitigation Measures
Mitigation Measure 3.6-1a: Conduct Records Search and Archaeological Resources Surveys for Off-Site Utilities, and Avoid Archaeological Resources
Once the final design and route of off-site utilities have been determined, and at least a month prior to the start of construction, a qualified archeologist who meets the US Secretary of the Interior Professional Qualifications Standards for Archaeology shall conduct a records search and perform archeological resources surveys for the off-site utilities that have not yet been surveyed. For the purposes of this mitigation measure, all archaeological resources discovered during surveys shall be assumed to be unique archaeological resources or historical resources as defined by State CEQA Guidelines Section 15064.5 and will be recorded by a qualified archaeologist on a California Department of Parks and Recreation DPR 523 primary form or equivalent documentation. Each such resource will be indicated, such as via a GIS device, through Environmentally Sensitive Area (ESA) mapping, with flagging tape, safety fencing, and/or signage designating it as an ESA to ensure that construction crews and heavy equipment will not intrude on these sites during construction. At the discretion of the City, monitoring may be done in lieu of or in addition to marking. If it is determined that the project cannot avoid impacts on one or more of the sites, then the City shall redesign the project site so that the archaeological sites will be completely avoided.
Mitigation Measure 3.6-1b: Halt Ground Disturbance Upon Discovery of Subsurface Archaeological Features In the event that any subsurface archaeological features or deposits, including locally darkened soil (“midden”) and concentrations of charcoal, flaked stone, glass, metal, or ceramic, are discovered during construction, all grounddisturbing activity within 100 feet of the find shall be halted and a qualified professional archaeologist shall be retained to assess the significance of the find. If the qualified archaeologist determines the archaeological material to be Native American in nature, the applicant shall contact the appropriate Native American tribe for their input on the preferred treatment of the find (consistent with Mitigation Measure 3.7-1b). If the find is determined to be significant (i.e., because it is determined to constitute a unique archaeological resource), the archaeologist shall develop, and the applicant shall implement, appropriate procedures to protect the integrity of the resource and ensure that no additional resources are affected. Procedures could include but would not necessarily be limited to preservation in place, archival research, subsurface testing, or contiguous block unit excavation and data recovery.
Significance after Mitigation
Implementation of Mitigation Measures 3.6-1a and 3.6-1b would reduce impacts associated with archaeological resources to a less-than-significant level because it would require the performance of a records search and pedestrian survey of the off-site PUE area, as well as professionally accepted and legally compliant procedures for the discovery and protection of previously undocumented significant archaeological resources.
Phase 2
Results of the records search and pedestrian survey did not result in the identification of archaeological resources within the project site. However, similar to Phase 1, project-related ground-disturbing activities associated with Phase 2, including off-site roadway and utility improvements, could result in discovery or damage of yet undiscovered archaeological resources as defined in State CEQA Guidelines Section 15064.5 or PRC Section 21083.2(g). This would be a potentially significant impact.
As discussed for Phase 1, the NCIC records search revealed that no prehistoric or historic-period archaeological sites have been previously documented within the project site and only four have been documented within a one-halfmile radius. The pedestrian survey found no anthropogenic soils (i.e., midden), above ground features, or concentrations of shell, bone, or lithic materials that would have indicated the presence of a pre-contact indigenous archaeological deposit. In addition, no unique archaeological resources as defined in PRC Section 21083.2(g) or archaeological resources as defined in State CEQA Guidelines Section 15064.5 were identified during the survey.
As described for Phase 1, a records search and pedestrian survey were not conducted for the off-site PUE area because the final alignment is not known; however, the Phase 2 footprint does not include the off-site PUE area because the new electrical substation, 60 kV line extension, and other associated infrastructure would be installed during Phase 1.
Cultural Resources Ascent
City of Roseville
3.6-12 Roseville Environmental Utilities Operations Center Project Draft EIR Nonetheless, similar to Phase 1, ground disturbance during Phase 2 construction could encounter previously undiscovered or unrecorded archaeological sites and materials on the project site. These activities could damage or destroy previously undiscovered archaeological resources. This would be a potentially significant impact.
Mitigation Measures
Implement Mitigation Measure 3.6-1b, described above.
Significance after Mitigation
Implementation of Mitigation Measure 3.6-1b would reduce impacts associated with archaeological resources to a less-than-significant level because it would require the performance of professionally accepted and legally compliant procedures for the discovery and protection of previously undocumented significant archaeological resources.
Impact 3.6-2: Disturb Human Remains
Phase 1
Based on documentary research, no evidence suggests that any precontact or historic-period marked or un-marked human interments are present within or in the immediate vicinity of the project site. However, ground-disturbing construction activities could uncover previously unknown human remains. Compliance with California Health and Safety Code Section 7050.5 and California Public Resources Code Section 5097.5(e) would make this impact less than significant.
Based on documentary research, no evidence suggests that any precontact or historic-period marked or un-marked human interments are present within or in the immediate vicinity of the project site. However, the location of grave sites and Native American remains can occur outside of identified cemeteries or burial sites. Therefore, there is a possibility that unmarked, previously unknown Native American or other graves could be present within the project site and could be uncovered by project-related construction activities.
California law recognizes the need to protect Native American human burials, skeletal remains, and items associated with Native American burials from vandalism and inadvertent destruction. The procedures for the treatment of Native American human remains are contained in California Health and Safety Code Section 7050.5 and California PRC Section 5097.5(e).
These statutes require that, if human remains are discovered, potentially damaging ground-disturbing activities in the area of the remains shall be halted immediately, and the appropriate County coroner shall be notified immediately. If the remains are determined by the coroner to be Native American, NAHC shall be notified within 24 hours and the guidelines of the NAHC shall be adhered to in the treatment and disposition of the remains. Following the coroner’s findings, the NAHC-designated Most Likely Descendant, and the landowner shall determine the ultimate treatment and disposition of the remains and take appropriate steps to ensure that additional human interments, if present, are not disturbed. The responsibilities for acting upon notification of a discovery of Native American human remains are identified in PRC Section 5097.94.
Compliance with California Health and Safety Code Section 7050.5 and California PRC Section 5097.5(e) would provide an opportunity to avoid or minimize the disturbance of human remains, and to appropriately treat any remains that are discovered. Therefore, this impact would be less than significant.
Mitigation Measures
No mitigation is required.
Ascent Cultural Resources
City of Roseville
Roseville Environmental Utilities Operations Center Project Draft EIR 3.6-13 Phase 2
Based on documentary research, no evidence suggests that any precontact or historic-period marked or un-marked human interments are present within or in the immediate vicinity of the project site. However, similar to Phase 1, ground-disturbing construction activities associated with Phase 2 could uncover previously unknown human remains.
Compliance with California Health and Safety Code Section 7050.5 and California Public Resources Code Section 5097.5(e) would make this impact less than significant.
As discussed for Phase 1, no evidence suggests that any precontact or historic-period marked or un-marked human interments are present within or in the immediate vicinity of the project site, which includes Phase 2. However, the location of grave sites and Native American remains can occur outside of identified cemeteries or burial sites.
Therefore, there is a possibility that unmarked, previously unknown Native American or other graves could be present within the project site and could be uncovered by project-related construction activities.
Similar to Phase 1, compliance with California Health and Safety Code Section 7050.5 and California PRC Section 5097.5(e) would provide an opportunity to avoid or minimize the disturbance of human remains, and to appropriately treat any remains that are discovered. Therefore, this impact would be less than significant.
Mitigation Measures
No mitigation is required.
Cultural Resources Ascent
City of Roseville
3.6-14 Roseville Environmental Utilities Operations Center Project Draft EIR This page is intentionally left blank.
Ascent Tribal Cultural Resources
City of Roseville
Roseville Environmental Utilities Operations Center Project Draft EIR 3.7-1
3.7 TRIBAL CULTURAL RESOURCES
This section evaluates the potential impacts of the project on known and unknown Tribal cultural resources. Tribal cultural resources, as defined by Assembly Bill (AB) 52, Statutes of 2014, in Public Resources Code (PRC) Section 21074, are sites, features, places, cultural landscapes, sacred places and objects, with cultural value to a tribe. A Tribal cultural landscape is defined as a geographic area (including both cultural and natural resources and the wildlife therein), associated with a historic event, activity, or person or exhibiting other cultural or aesthetic values.
One comment letter regarding Tribal cultural resources was received in response to the notice of preparation (see Appendix A). The Native American Heritage Commission (NAHC) requested AB 52 and Senate Bill (SB) 18 compliance information; SB 18 is not a CEQA requirement and, therefore, is not discussed in this EIR. AB 52 compliance is described below. In addition, one tribe, the United Auburn Indian Community (UAIC), responded during the AB 52 consultation. Consultation concluded in July 2025.
3.7.1 Regulatory Setting
FEDERAL
There are no federal regulations that apply to Tribal cultural resources.
STATE
California Register of Historical Resources
All properties in California that are listed in or formally determined eligible for listing in the National Register of Historic Places (NRHP) are also listed in the California Register of Historical Resources (CRHR); a definition of the NRHP is given in Section 3.6.1. The CRHR is a listing of State of California resources that are significant in the context of California’s history. It is a Statewide program with a scope and with criteria for inclusion similar to those used for the NRHP. In addition, properties designated under municipal or county ordinances are also eligible for listing in the CRHR.
A historical resource must be significant at the local, state, or national level under one or more of the criteria defined in the California Code of Regulations Title 15, Chapter 11.5, Section 4850 to be included in the CRHR. The CRHR criteria are tied to CEQA because any resource that meets the criteria below is considered a significant historical resource under CEQA. As noted above, all resources listed in or formally determined eligible for listing in the NRHP are automatically listed in the CRHR.
The CRHR uses four evaluation criteria:
Criterion 1. Is associated with events that have made a significant contribution to the broad patterns of local or regional history, or the cultural heritage of California or the United States.
Criterion 2. Is associated with the lives of persons important to local, California, or national history.
Criterion 3. Embodies the distinctive characteristics of a type, period, region, or method of construction; represents the work of a master; or possesses high artistic values.
Criterion 4. Has yielded, or has the potential to yield, information important to the prehistory or history of the local area, California or the nation.
Similar to the NRHP, a historical resource must meet one of the above criteria and retain integrity to be listed in the CRHR. The CRHR uses the same seven aspects of integrity used by the NRHP.
Tribal Cultural Resources Ascent
City of Roseville
3.7-2 Roseville Environmental Utilities Operations Center Project Draft EIR California Environmental Quality Act
CEQA requires public agencies to consider the effects of their actions on “Tribal cultural resources.” PRC Section 21084.2 establishes that “[a] project with an effect that may cause a substantial adverse change in the significance of a Tribal cultural resource is a project that may have a significant effect on the environment." Tribal Cultural Resources
CEQA requires lead agencies to consider whether projects will affect Tribal cultural resources. PRC Section 21074 states:
a) “Tribal cultural resources” are either of the following:
1) Sites, features, places, cultural landscapes, sacred places, and objects with cultural value to a California Native American tribe that are either of the following:
A) Included or determined to be eligible for inclusion in the California Register of Historical Resources.
B) Included in a local register of historical resources as defined in subdivision (k) of Section 5020.1. 2) A resource determined by the lead agency, in its discretion and supported by substantial evidence, to be significant pursuant to criteria set forth in subdivision (c) of Section 5024.1. In applying the criteria set forth in subdivision (c) of Section 5024.1 for the purposes of this paragraph, the lead agency shall consider the significance of the resource to a California Native American tribe. b) A cultural landscape that meets the criteria of subdivision (a) is a Tribal cultural resource to the extent that the landscape is geographically defined in terms of the size and scope of the landscape. c) A historical resource described in Section 21084.1, a unique archaeological resource as defined in subdivision (g) of Section 21083.2, or a “nonunique archaeological resource” as defined in subdivision (h) of Section 21083.2 may also be a Tribal cultural resource if it conforms with the criteria of subdivision (a).
Public Resources Code Section 21080.3
AB 52, signed by the California Governor in September of 2014, established a new class of resources under CEQA: “Tribal cultural resources,” defined in PRC Section 21074 (described above). Pursuant to PRC Sections 21080.3.1, 21080.3.2, and 21082.3, lead agencies undertaking CEQA review must, upon written request of a California Native American Tribe, begin consultation before the release of an EIR, negative declaration, or mitigated negative declaration.
PRC Section 21080.3.2 states:
Within 14 days of determining that a project application is complete, or to undertake a project, the lead agency must provide formal notification, in writing, to the tribes that have requested notification of proposed projects in the lead agency’s jurisdiction. If it wishes to engage in consultation on the project, the tribe must respond to the lead agency within 30 days of receipt of the formal notification. The lead agency must begin the consultation process with the tribes that have requested consultation within 30 days of receiving the request for consultation.
Consultation concludes when either: 1) the parties agree to measures to mitigate or avoid a significant effect, if a significant effect exists, on a Tribal cultural resource, or 2) a party, acting in good faith and after reasonable effort, concludes that mutual agreement cannot be reached.
Health and Safety Code, Section 7050.5
Section 7050.5 of the Health and Safety Code requires that construction or excavation be stopped in the vicinity of discovered human remains until the coroner conducts an inquiry and can determine whether the remains are those of a Native American. If they are determined to be those of a Native American, the coroner must contact NAHC.
California Native American Historical, Cultural, and Sacred Sites Act The California Native American Historical, Cultural, and Sacred Sites Act (PRC Section 5097.9) applies to both State and private lands. The act requires, upon discovery of human remains, that construction or excavation activity cease and that the county coroner be notified. If the remains are those of a Native American, the coroner must notify the NAHC, which
Ascent Tribal Cultural Resources
City of Roseville
Roseville Environmental Utilities Operations Center Project Draft EIR 3.7-3 notifies (and has the authority to designate) the most likely descendants of the deceased. The act stipulates the procedures the descendants may follow for treating or disposing of the remains and associated grave goods.
Public Resource Code Section 5097
PRC Section 5097 specifies the procedures to be followed in the event of the unexpected discovery of human remains on nonfederal land. The disposition of Native American human burials falls within the jurisdiction of the NAHC. Section 5097.5 of the Code states the following:
No person shall knowingly and willfully excavate upon, or remove, destroy, injure, or deface any historic or prehistoric ruins, burial grounds, archaeological or vertebrate paleontological site, including fossilized footprints, inscriptions made by human agency, or any other archaeological, paleontological or historical feature, situated on public lands, except with the express permission of the public agency having jurisdiction over such lands. Violation of this section is a misdemeanor.
LOCAL
City of Roseville’s 2035 General Plan
The City of Roseville 2035 General Plan includes the following policies related to Tribal cultural resources that may be applicable to the project (City of Roseville 2020):
Policy OS4.1 Consult with local Native American Tribes that are traditionally and culturally affiliated with resources that could be affected by City plans or projects, identify areas that may be of cultural or Tribal cultural significance, and determine appropriate treatment for the areas. Policy OS4.2 When items of historical, cultural, or archaeological significance are discovered within the City, a qualified archaeologist or historian shall be called to evaluate the find and to recommend proper action. Policy OS4.4 The City shall coordinate with the appropriate federal, state, local agencies, and Native American Most Likely Descendant (MLD) Tribes upon discovery of artifacts. The City shall offer the Maidu Museum & Historic Site as a temporary housing location for artifacts that are discovered and subsequently determined to be removable.
3.7.2 Environmental Setting
The following information is from the Cultural Resources Technical Report for the Roseville Environmental Utilities Center Project (Ascent 2025).
ETHNOGRAPHY
The Native Americans who occupied the project area at the time of Euro-American contact (ca. 1850s) are known as the Nisenan, also referred to as the Southern Maidu. Several ethnographers have studied the Maidu people and generally agree that Nisenan territory included the drainages of the Bear, American, Yuba, and southern Feather rivers. Their permanent settlements were generally located on ridges separating parallel streams, either on crests, knolls, or terraces, part way up these ridges.
A typical village consisted of several conical houses covered with bark slabs. The nearest ethnographic village in relationship to the project was called Pichiku. The name Pich-u-gut is also given for a village site in Roseville. Many long-time residents of Roseville indicate that a village was in the vicinity of present-day Roseville Square off Douglas Boulevard. Also, a village site has been identified and preserved at Maidu Park in Roseville.
Nisenan territory offered abundant year-round food sources. Food gathering was based on seasonal ripening, but hunting, gathering, and fishing went on all year, with the greatest activity in late summer and early fall. They gathered many different staples, not depending on one crop.
Tribal Cultural Resources Ascent
City of Roseville
3.7-4 Roseville Environmental Utilities Operations Center Project Draft EIR Seasonal harvests were gathered for both communal and personal family use. Most activities and social behaviors such as status, sharing, trading, ceremonies, and disagreements were important adjuncts to the gathering and distribution of food. Extended families or whole villages of hill Nisenan would gather acorns. Men would hunt while women and children gathered the acorns knocked from the trees. Buckeye nuts, sugar and digger pine nuts, and hazelnuts were also gathered. Acorns were cracked on an acorn anvil and shelled. They were then ground into flour using a bedrock mortar (grinding rock) and a soaproot brush to control scattering the resulting flour. The flour was leached to remove the tannin then cooked in watertight baskets. Cooking was done with fire heated stones that were lifted with two sticks, dipped in water to clean them, and then dropped into the cooking basket. Enough soup and mush were usually prepared to last several days.
Roots were dug with a digging stick in the spring and summer and were eaten raw, steamed, baked, or dried and pounded in mortars and pressed into cakes to be stored for winter use. Wild onion (chan), sweet potato (sí kum), and “Indian potato” (dúbus) were the most desired. Wild carrot (ba) was used as medicine while wild garlic was used to wash the head and body.
Grasses, herbs, and rushes provided food and material for clothing and baskets. Clover (Trifolium willdenovii) was an important food for Nisenan people as it was the first fresh herb available after winter, and its emergence set the timing of the Nisenan spring flower dance. Seeds were gathered using a seed beater and tray. They were then parched, steamed, dried, or made into mush. Many varieties of wild plums, native berries, grapes, and other native fruits were eaten. Manzanita berries were often traded to the valley or made into a cider-like drink.
Deer drives were common, with several villages participating and the best marksman doing the killing. The animals were often driven into a circle of fire then killed. Deer were also hunted using deadfalls, snares, and deerskin and antler decoys. Sometimes they were run down on soft ground or snow. Antelope were taken by surround, drives, and flag decoys while elk were usually killed along waterways on soft ground. The bear hunt was very ceremonial. Black bears were usually hunted in the winter. Lighted brands were often used to drive them from their dens. Grizzlies that lived on the valley floor were greatly feared and rarely hunted. Wildcats and California mountain lions were hunted for food and their skins. Rabbits and other small game were killed with blunted arrows and sticks. Traps, nets, snares, fire, and rodent hooks were also used. In the foothills and valley nets were made into a fence where driven rabbits were entangled and clubbed. Drives generally took place in the late spring. The man in charge of the drive divided the catch. Other small animals were often caught and killed, with exception to the coyote. Game meat was baked, roasted, or dried.
Weirs, traps, harpoons, nets, and gorge hooks, as well as tule balsas and log canoes were used in fishing. Fish were poisoned using turkey mullein and soaproot or driven into shallow water and caught by hand. Freshwater mussels were obtained in the larger rivers. On the lower courses, sturgeon and salmon were netted and speared. Whitefish, suckers, and trout were caught at higher elevations. Waterfalls were eel fishing (freshwater lamprey) stations; Salmon Falls, on the south fork of the American River was one such location.
Birds were taken with nets, arrows, snares, traps, and nooses. Owls, vultures, and condors were not killed. Bird skins and feathers were used for regalia, clothing, and decoration. Salt was acquired from springs near Lincoln, Cool, and Latrobe. It was also acquired from a plant with cabbage-like leaves gathered in the summer.
The Nisenan hunting and gathering cycle was altered drastically with the discovery of gold in Coloma in 1848. As miners poured into the Roseville and Auburn areas, the Native Americans were forced out of their winter villages, land was fenced, streams were silted, and food resources became increasingly difficult to procure. Despite this, many Nisenan continued to remain in their homeland, working for Euro-Americans in mines or on ranches. Within the project vicinity, some ranchers, such as the Kasebergs and Fiddyments, also allowed Maidu families to continue to collect acorns, tubers, and grasshoppers on the lands they now owned along Pleasant Grove Creek. Today, descendants of the Nisenan continue to strive to maintain kinship and cultural ties to their ancestral lands despite continual disruptions to time-honored lifeways.
Ascent Tribal Cultural Resources
City of Roseville
Roseville Environmental Utilities Operations Center Project Draft EIR 3.7-5
CONTEMPORARY NATIVE AMERICAN SETTING
Defining Tribal cultural resources involves the knowledge and expertise of living California Native Americans. As the embodiment of a continuous connection between Tribal history and the landscape, they are uniquely qualified to act as the interpreters and stewards of their culture, including the ability to define the significance of the material remains and landscapes of their ancestor’s lifeways. Today, many descendants of Valley Nisenan and Plains Miwok still reside on lands once inhabited by their ancestors or on lands set aside for Tribal communities by the federal government, which may or may not been traditionally inhabited by their ancestors.
Contemporary Californian Native American tribes with ancestral connections to the project site and to the Valley Nisenan and Plains Miwok heritage include UAIC, Shingle Springs Band of Miwok Indians (SSBMI), Ione Band of Miwok, and Wilton Rancheria. These tribes today maintain connection to their history and culture in a multitude of ways, including through ceremony, language and traditional knowledge instruction, community service, and Tribal governance. For example, a “Big Time” is typically celebrated every September to mark the start of autumn and acorn gathering time at Chaw’se Grinding Rock State Park in Pine Grove. This celebration includes serving traditional foods, traditional dancing, healing rituals, and worship in the roundhouse. Language and traditional skill classes are offered by most of the tribes, including by the SSBMI, which has a Traditional Ecological Knowledge department to assist members with learning about respectful and traditional uses of plants and animals, and the UAIC, which has a Pre-K through 8th grade school where key aspects of Indian culture and critical thinking are taught to prepare Tribal members to face future challenges (Private School Review 2025; SSBMI 2025a). Tribal community service departments provide family support services to adults and children to promote the health and well-being of Tribal community members and their families as well as connection to their heritage. Common services offered by all tribes include Indian Child Welfare Act advocacy and intervention, housing assistance, health care assistance, elder programs, and grants and scholarships for higher education (Ione Band of Miwok Indians 2025; SSBMI 2025a; UAIC 2025; Wilton Rancheria 2025a). Governance on Tribal lands is typically outlined by tribally prepared constitutions, codes and/or ordinances, and are carried out by Tribal departments that are in turn typically overseen by the Tribal council. This includes the office of Tribal Historic Preservation Officer (THPO). Because tribes retain inherent sovereign powers over their members and territory, SSBMI and the Wilton Rancheria also have Tribal Courts that serve as culturally sensitive, independent judicial forums where Tribal cultural values are held at the forefront of dispute resolutions (SSBMI 2025b; Wilton Rancheria 2025b).
This knowledge of traditions and culture are conveyed through the expertise of the traditionally and culturally affiliated California Native American tribe during consultation with lead agencies, as required by AB 52. During the consultation process, Tribal cultural bearers can share information related to the project areas, such as: what event took/takes place here, and how is that event important to the Tribe; what artistic, professional, and/or ceremonial cultural tradition is represented by the resource; or how can this resource be used to teach others in the Tribe and convey Tribal values.
NATIVE AMERICAN TRIBAL CONSULTATION
Tribal Consultation
On June 11, 2024, the City of Roseville sent AB 52 notification letters to the following Tribal representatives:
United Auburn Indian Community (UAIC), Anna Starkey, Cultural Regulatory Specialist Tsi Akim Maidu, Don Ryberg, Chairperson
Ione Band of Miwok Indians, Sara D. Setshwaelo, Cultural Committee Chair Shingle Springs Band of Miwok Indians, Regina Cuellar, Chairperson Wilton Rancheria, Jesus Tarango, Chairperson
On June 20, 2024, UAIC responded, requesting consultation and a site visit. On December 11, 2024, UAIC, City staff, and Ascent’s archaeologists conducted a survey of the project area as a part of the consultation process. Although
Tribal Cultural Resources Ascent
City of Roseville
3.7-6 Roseville Environmental Utilities Operations Center Project Draft EIR UAIC did not identify any Tribal cultural resources in the project site, the Tribe did provide recommended mitigation measures on May 7, 2025; these are incorporated below. UAIC and the City mutually agreed to close consultation on July 17, 2025.
On April 23, 2025, Wilton Rancheria reached out to the EIR consultant to inquire whether the City would consult but the 30-day response period (as defined in PRC 21080.3.1(d) to request consultation had closed, and as such, the City declined at that time. On August 21, 2025, the City followed up with Wilton Rancheria indicating that the 30-day response period to request consultation had closed, that Wilton Rancheria would receive notification of availability of the Draft EIR, and that Wilton Rancheria is welcome to review and comment during the Draft EIR public review period.
TRIBAL CULTURAL RESOURCES
Tribal cultural resources are defined in CEQA statute Section 21074 and may include:
Resource Collection Location: This is a location where Native Americans have historically gone, and are known or believed to go today, to collect resources in accordance with traditional cultural rules of practice. Spiritual Location: This is a location where Native American religious practitioners have historically gone, and are known or believed to go today, to perform ceremonial activities in accordance with traditional cultural rules of practice.
Traditional Location: This is a location associated with the traditional beliefs of a Native American group about its origins, its cultural history, or the nature of the world. Cemetery: A cemetery is a location that has been selected for human burial or interment. This also includes the soil.
In addition, different types of Tribal cultural resources may also be archaeological resources; they include the following features:
Village Site: Village sites are locations of continuous and concentrated habitation that typically have a large, welldeveloped cultural soil deposit. They may also contain burials, rock art, bedrock milling stations, or other features.
Burial Site: A burial site or cemetery is a location where intentional human interments are found, either articulated or disarticulated. Burial soils and offerings are included as significant. Milling Site: This is a boulder or group of boulders or bedrock outcrops that contain at least one modified surface (mortar, slick, or metate) caused by the processing of food or other natural resources. Tribes still consider these as the “kitchens” of their ancestors.
Lithic Scatter: A lithic scatter is a distribution of stone flakes and tool fragments reflecting purposeful modification of parent stone through percussion and/or pressure detachment. Shell Middens: Shell middens are locations with large amounts of marine shell that extend to an appreciable depth below ground surface.
Mounds: These habitation and burial sites were constructed to be areas of high ground during seasonal flooding.
Because they were maintained continuously for hundreds or thousands of years in a floodplain where soil was being seasonally deposited, these Mounds are often dozens of feet deep. Rock Art: Rock art consists of designs or design elements on rock surfaces created by surface applications (pictographs) or by etching (petroglyphs).
Rock Shelters: These are natural caves or crevices in rock outcrops in which human use has left artifactual remains.
Cultural Objects: Objects of cultural significance, such as hand stones or projectile points, that are not directly associated with a known cultural site.
Ascent Tribal Cultural Resources
City of Roseville
Roseville Environmental Utilities Operations Center Project Draft EIR 3.7-7
RECORDS SEARCHES AND SURVEY
Records Search
As part of the Tribal inventory effort for this project, pertinent literature and historic maps were reviewed; a records search using UAIC’s (as the only consulting Tribe under AB52 for this project) Tribal Historic Information System (THRIS); and a pedestrian survey were conducted. The THRIS database used by UAIC incorporates information from the California Historic Resources Information System (CHRIS) and is accessed by the THPO Access Policy. The Policy allows THPO Tribes access to all the cultural resource data housed in the regional Information Centers. Also included in the THRIS database are UAIC’s areas of oral history, ethnographic history, and places of cultural and religious significance, including UAIC Sacred Lands that are submitted to the NAHC. The THRIS resources shown in this region include previously recorded indigenous resources identified through the CHRIS North Central Information Center (NCIC) as well as historic resources and survey data.
Tribal Survey
On December 11, 2024, UAIC Representative René Guerrero conducted a tribal survey for the identification of Tribal cultural resources. Surface visibility was good and there were no limitations to the survey. No resources or landscapes of cultural significance were identified.
Sacred Lands File Search
On February 22, 2024, a letter was sent to the NAHC requesting a search of the Sacred Lands File for the project area.
NAHC responded by letter dated February 27, 2024, stating that no cultural resources significant to local Native American tribes had been previously reported to the NAHC as being present on the project site or its immediate vicinity.
BURIED SITE SENSITIVITY
There is one geologic unit present in the project site, the Qr, and the surficial soils within the project site are the Alamo, Fiddyment, Cometa, and San Joaquin series. Because the Qr material formed long before the first human occupation of the area, it is very unlikely to contain or to have buried Tribal cultural resources. The overlying soils of the San Joaquin Series are younger, dating to the Late Holocene (2,000 to 150 years ago), and so are generally more sensitive for buried cultural remains. The Alamo, Fiddyment, and Cometa series are older soils dating to the Pleistocene, which was before human occupation, are unlikely to contain or to have buried Tribal cultural resources.
Landscape evolution and historic and modern development can affect the visibility of the Tribal cultural resources, but tribal knowledge indicates that cultural sites tend to occur in specific geo-environmental settings (e.g., near reliable water sources and on stable land surfaces) rather than randomly throughout the landscape. For example, geoarchaeological studies have found that distance to water sources (e.g., stream, lake, spring) and landform slope (generally <18 percent) are two environmental variables that help accurately predict a location’s potential to contain buried archaeological deposits. The topography of the terrain in the project site is relatively flat. The Pleasant Grove Creek runs roughly east/west directly north of the project site. The project site has been historically used for agriculture and landscaped for that purpose. Therefore, the geography, geology, soils, and topography across most of the project site suggest that the potential for the presence of buried deposits of Tribal cultural resources in the project site is low.
3.7.3 Impacts and Mitigation Measures
METHODOLOGY
Information related to Tribal cultural resources is based on findings reported in the NAHC Sacred Lands File database search and the results of Native American consultation under AB 52. The analysis is also informed by the provisions and requirements of state and local laws and regulations that apply to Tribal cultural resources.
Tribal Cultural Resources Ascent
City of Roseville
3.7-8 Roseville Environmental Utilities Operations Center Project Draft EIR PRC Section 21074 defines “Tribal cultural resources” as “sites, features, places, cultural landscapes, sacred places, and objects with cultural value to a California Native American [T]ribe” that are listed or determined eligible for listing in the CRHR, listed in a local register of historical resources, or otherwise determined by the lead agency to be a Tribal cultural resource.
For the purposes of this impact discussion, “historical resource” is used to describe historic-period, built-environment resources. Tribal cultural resources, which may qualify as “historical resources” pursuant to CEQA, are analyzed separately from built-environment historical resources.
THRESHOLDS OF SIGNIFICANCE
Thresholds of significance are based on Appendix G of the State CEQA Guidelines. The project would cause a significant impact related to Tribal cultural resources if it would:
cause a substantial adverse change in the significance of a Tribal cultural resource, defined in Public Resources Code section 21074 as either a site, feature, place, cultural landscape that is geographically defined in terms of the size and scope of the landscape, sacred place, or object with cultural value to a California Native American tribe, and that is:
Listed or eligible for listing in the California Register of Historical Resources, or in a local register of historical resources as defined in Public Resources Code section 5020.1(k), or A resource determined by the lead agency, in its discretion and supported by substantial evidence, to be significant pursuant to criteria set forth in subdivision (c) of Public Resources Code Section 5024.1. In applying the criteria set forth in subdivision (c) of Public Resources Code Section 5024.1, the lead agency shall consider the significance of the resource to a California Native American tribe.
ISSUES NOT DISCUSSED FURTHER
All potential Tribal cultural resources issues identified in the above thresholds are evaluated below.
ENVIRONMENTAL IMPACTS AND MITIGATION MEASURES
Impact 3.7-1: Cause a Substantial Adverse Change in the Significance of a Tribal Cultural Resource
Phase 1
Although Tribal consultation and the NCIC and NAHC record searches did not result in the identification of any Tribal cultural resources, UAIC expressed concern that resources could be discovered during ground-disturbing activities.
Therefore, impacts to Tribal cultural resources would be potentially significant.
Neither the NAHC Sacred Land File search nor the NCIC record search indicated the presence of indigenous sites within the project site or within a one-half-mile radius. As detailed above, the City sent AB 52 notification letters to five Tribal representatives; only UAIC responded. Consultation with UAIC has not resulted in the identification of any Tribal cultural resources as defined by PRC Section 21074.
As discussed previously, the geography, geology, soils, and topography across most of the project site suggest that the potential for the presence of buried cultural deposits, which could also be Tribal cultural resources, in the project site is low. Nevertheless, UAIC did express concern that the area around Pleasant Grove Creek was sensitive. The Phase 1 area is located over 2,400 feet south of Pleasant Grove Creek; however, it is possible that ground-disturbing construction activities could damage or destroy Tribal cultural resources, and this would be a potentially significant impact.
Ascent Tribal Cultural Resources
City of Roseville
Roseville Environmental Utilities Operations Center Project Draft EIR 3.7-9 Mitigation Measures
Mitigation Measure 3.7-1a: Prepare and Implement a Worker Awareness Training Program for Tribal Cultural Resources
Prior to project-specific ground-disturbing activities, a Tribal cultural resources awareness training program will be provided to all construction personnel active on the project site. A representative or representatives from culturally affiliated Native American Tribe(s) will be invited to participate in the development and delivery of the training program in coordination with a professional archaeologist meeting the United States Secretary of Interior’s qualification standards for archaeology. The program will include relevant information regarding Tribal cultural resources, including applicable laws and regulations, the consequences of violating said laws and regulations, protocols for resource avoidance, and protocols for discoveries, including who to contact in the event of a discovery and what to do upon the discovery of human remains. The program will also underscore the requirement for confidentiality and culturally appropriate treatment of any find of significance to Native Americans and protocols, consistent with Native American Tribal values.
Mitigation Measure 3.7-1b: Unanticipated Discovery of Tribal Cultural Resources During ground-disturbing construction activities, if any suspected Tribal cultural resources are discovered, all work shall cease within 100 feet of the find, and a Tribal monitor from culturally affiliated Native American Tribe(s) shall be retained, if one is not currently on site. The Tribal monitor shall determine if the find is a Tribal cultural resource. The consulting THPO will make recommendations for further evaluation and culturally appropriate treatment of discovered Tribal cultural resources as necessary. Consultation with an archaeologist who meets the secretary of the Interior’s professional qualifications for archaeology may also occur.
Treatment and Documentation:
The culturally affiliated Tribe shall consult with the Lead Agency to (1) identify the boundaries of the new Tribal cultural resource and (2) if feasible, identify appropriate preservation in place and avoidance measures, including redesign or adjustments to the existing construction process, and long-term management, or (3) if avoidance is infeasible, a reburial location in proximity of the find where no future disturbance is anticipated. Permanent curation of Tribal cultural resources will not take place unless approved in writing by the culturally affiliated Tribe.
The construction contractor(s) shall provide secure, on-site storage for culturally sensitive soils or objects that are components of Tribal cultural resources that are found or recovered during construction. Only Tribal Representatives shall have access to the storage. Storage size shall be determined by the nature of the TCR and can range from a small lock box to a conex box (shipping container). A secure (locked), fenced area can also provide adequate on-site storage if larger amounts of material must be stored.
The construction contractor(s) and Lead Agency shall facilitate the respectful reburial of the culturally sensitive soils or objects. This includes providing a reburial location that is consistent with the Tribe’s preferences, excavation of the reburial location, and assisting with the reburial, upon request.
Any discoveries shall be documented on a Department of Parks and Recreation (DPR) 523 form within 4 weeks of the discovery and submitted to the appropriate CHRIS center in a timely manner.
If articulated or disarticulated human remains, or human remains in any state of decomposition or skeletal completeness are discovered during construction activities, the County Coroner and the culturally affiliated Tribe shall be contacted immediately (per PRC 7050.5). Upon determination by the County Coroner that the find is Native American in origin, the Native American Heritage Commission will assign the Most Likely Descendent who will work with the project proponent to define appropriate treatment and disposition of the burials.
Work at the discovery location cannot resume until all necessary investigation, evaluation, and treatment of the discovery under the requirements of the CEQA, specifically PRC Section 21084.3[b], have been satisfied.
Tribal Cultural Resources Ascent
City of Roseville
3.7-10 Roseville Environmental Utilities Operations Center Project Draft EIR Significance after Mitigation
Implementation of Mitigation Measures 3.7-1a and 3.7-1b would reduce impacts associated with Tribal cultural resources to a less-than-significant level by training workers to properly handle inadvertent discovery of sensitive resources and requiring appropriate treatment and proper care of significant Tribal cultural resources, in the case of a discovery.
Phase 2
Although Tribal consultation and the NCIC and NAHC record searches did not result in the identification of any Tribal cultural resources, UAIC expressed concern that resources could be discovered during ground-disturbing activities.
Therefore, impacts to Tribal cultural resources would be potentially significant.
As discussed for Phase 1, neither the NAHC Sacred Land File search nor the NCIC record search indicated the presence of indigenous sites within the project site or within a one-half-mile radius. As detailed above, the City sent AB 52 notification letters to five Tribal representatives; only UAIC responded. Consultation with UAIC has not resulted in the identification of any Tribal cultural resources as defined by PRC Section 21074; however, UAIC expressed concern that the area around Pleasant Grove Creek was sensitive. The Phase 2 area is located over 1,600 feet south of Pleasant Grove Creek. Nonetheless, it is possible that ground-disturbing construction activities could damage or destroy Tribal cultural resources, and this would be a potentially significant impact.
Mitigation Measures
Implement Mitigation Measures 3.7-1a and 3.7-1b, described above.
Significance after Mitigation
Implementation of Mitigation Measures 3.7-1a and 3.7-1b would reduce impacts associated with Tribal cultural resources to a less-than-significant level by training workers to properly handle inadvertent discovery of sensitive resources and requiring appropriate treatment and proper care of significant Tribal cultural resources, in the case of a discovery.
Ascent Energy
City of Roseville
Roseville Environmental Utilities Operations Center Project Draft EIR 3.8-1
3.8 ENERGY
This section was prepared pursuant to the State CEQA Guidelines Section 15126 and Appendix F of the State CEQA Guidelines, which require that EIRs include a discussion of the potential energy impacts of projects. The analysis considers whether the project would result in inefficient, wasteful, and unnecessary consumption of energy. This section also describes potential impacts related to existing electric and natural gas infrastructure, including whether the project would require or result in the relocation or construction of new or expanded electric or natural gas infrastructure, the construction or relocation of which could cause significant environmental effects.
No comments regarding energy were received in response to the notice of preparation (see Appendix A).
3.8.1 Regulatory Setting
Energy conservation is embodied in many federal, state, and local statutes and policies. At the federal level, energy standards apply to numerous products (e.g., the US Environmental Protection Agency’s [EPA] EnergyStar™ program) and transportation (e.g., fuel efficiency standards). At the state level, Title 24 of the California Code of Regulations sets forth energy standards for buildings. Further, the state provides rebates/tax credits for installation of renewable energy systems and offers the Flex Your Power program that promotes conservation in multiple areas. At the local level, individual cities and counties establish policies in their general plans and climate action plans (CAPs) related to the energy efficiency of new development and land use planning and to the use of renewable energy sources.
FEDERAL
Energy Policy and Conservation Act and CAFE Standards
The Energy Policy and Conservation Act of 1975 established nationwide fuel economy standards to conserve oil. Pursuant to this Act, the National Highway Traffic and Safety Administration (NHTSA), part of the US Department of Transportation (DOT), is responsible for revising existing fuel economy standards and establishing new vehicle economy standards.
As discussed in Section 3.4, “Greenhouse Gas Emissions,” the Corporate Average Fuel Economy (CAFE) program was established to determine vehicle manufacturer compliance with the government’s fuel economy standards.
Compliance with the CAFE standards is determined based on each manufacturer's average fuel economy for the portion of their vehicles produced for sale in the county. NHTSA and EPA set the CAFE standards to improve the average fuel economy and reduce fossil fuel consumption and associated greenhouse gas (GHG) emissions generated by cars and light-duty trucks.
Energy Policy Act of 1992 and 2005
The Energy Policy Act of 1992 (EPAct) was passed to reduce the country’s dependence on foreign petroleum and improve air quality. EPAct includes several parts intended to build an inventory of alternative fuel vehicles (AFVs) in large, centrally fueled fleets in metropolitan areas. EPAct requires certain federal, state, and local government and private fleets to purchase a percentage of light-duty AFVs capable of running on alternative fuels each year. In addition, financial incentives are also included in EPAct. Federal tax deductions are allowed for businesses and individuals to cover the incremental cost of AFVs. States are also required by the act to consider a variety of incentive programs to help promote AFVs. The Energy Policy Act of 2005 provides renewed and expanded tax credits for electricity generated by qualified energy sources, such as landfill gas; provides bond financing, tax incentives, grants, and loan guarantees for clean renewable energy and rural community electrification; and establishes a federal purchase requirement for renewable energy.
Energy Independence and Security Act of 2007
The Energy Independence and Security Act of 2007 is designed to improve vehicle fuel economy and help reduce US dependence on oil. It represents a major step forward in expanding the production of renewable fuels, reducing dependence on oil, and confronting global climate change.
Energy Ascent
City of Roseville
3.8-2 Roseville Environmental Utilities Operations Center Project Draft EIR By addressing renewable fuels and the CAFE standards, the Energy Independence and Security Act of 2007 builds upon progress made by the Energy Policy Act of 2005 in setting out a comprehensive national energy strategy for the 21st century.
Construction Equipment Emission Standards
The Code of Federal Regulations established tiered emissions standards for construction equipment (i.e., nonroad diesel engines) to phase in cleaner-burning equipment that will reduce nitrogen oxides (NOX) and particulate matter emissions from exhaust. After 2014, all construction equipment manufactured in the United States is required to meet the highest tier of emission standards, Tier 4. EPA oversees implementation of these regulations (CFR Chapter 40, Parts 1039, 1065, and 1068).
Public Law No. 119-15
On June 12, 2025, Public Law 119-15, enacting House Joint Resolution 87, was signed into law. The law utilized the Congressional Review Act to nullify EPA’s rule that had granted California a waiver to enforce stricter emissions standards for heavy-duty vehicles under the Clean Air Act (CAA). The disapproved rule included programs such as the Advanced Clean Trucks regulation and zero-emission requirements for airport shuttles. Passed under the Congressional Review Act, the law prevents EPA from implementing or reissuing the same or similar rules without new congressional authorization. This effectively blocks California, and other states that follow its standards, from enforcing these specific vehicle emission and warranty regulations.
Public Law No. 119-16
In early May 2025, the US House of Representatives passed House Joint Resolution 88 under the Congressional Review Act, aiming to void EPA’s December 2024 waiver under the CAA that allowed California to implement the Advanced Clean Cars (ACC II) regulation. ACC II includes a zero-emission vehicle (ZEV) mandate targeting 100 percent new lightduty ZEV sales by 2035. In late May 2025, the Senate followed suit, approving the resolution; the first ever occurrence that waivers under the CAA have been revoked from a Congressional Review Act. With both chambers’ approval, the resolution was signed by the President on June 12, 2025, to formally rescind the State’s ability to enforce the ACC II regulation. The implications of this federal resolution on the State’s capability to enforce its independent fuel economy standards are uncertain at this time, as the California Attorney General filed a lawsuit against the federal government on June 12, 2025, to challenge House Joint Resolution 88. Whether this action is successful is unknown, as is the possibility that a federal judge will issue a stay to halt the implementation of the ACC II regulation during the legal process.
Notably, the mobile source emissions calculations and estimates disclosed in this analysis do not account for this regulatory update as emissions factors have not been updated by the California Air Resources Board (CARB) at this time.
STATE
Warren-Alquist Act
The 1975 Warren-Alquist Act established the California Energy Resources Conservation and Development Commission, now known as the California Energy Commission (CEC). The Act established state policy to reduce wasteful, uneconomical, and unnecessary uses of energy by employing a range of measures. The California Public Utilities Commission (CPUC) regulates privately-owned utilities in the energy, rail, telecommunications, and water fields.
State of California Energy Action Plan
CEC is responsible for preparing the State Energy Plan, which identifies emerging trends related to energy supply, demand, conservation, public health and safety, and the maintenance of a healthy economy. The first Energy Action Plan (EAP) emerged in 2003 from a crisis atmosphere in California’s energy markets. The state’s three major energy policy agencies (CEC, CPUC, and the Consumer Power and Conservation Financing Authority [established under deregulation and now defunct]) came together to develop one high-level, coherent approach to meeting California’s electricity and natural gas needs. It was the first time that energy policy agencies formally collaborated to define a common vision and set of strategies to address California’s future energy needs and emphasize the importance of the impacts of energy policy on the California environment. In the October 2005 Energy Action Plan
Ascent Energy
City of Roseville
Roseville Environmental Utilities Operations Center Project Draft EIR 3.8-3 II, CEC and CPUC updated their energy policy vision by adding some important dimensions to the policy areas included in the original EAP, such as the emerging importance of climate change, transportation-related energy issues and research and development activities. CEC adopted an update to the EAP II in February 2008 that supplements the earlier EAPs and examines the state’s ongoing actions in the context of global climate change.
The current plan is the 2021 California Energy Efficiency Action Plan which was published in 2021. The 2021 Energy Efficiency Action Plan was covered in two documents, the 2021 California Building Decarbonization Assessment and the 2021 Integrated Energy Policy Report Volume 1 Building Decarbonization. The 2025 Building Energy Action Plan will be published in late 2025.
Assembly Bill 2076: Reducing Dependence on Petroleum
Pursuant to Assembly Bill (AB) 2076 (Chapter 936, Statutes of 2000), CEC and CARB prepared and adopted a joint agency report in 2003, Reducing California’s Petroleum Dependence. Included in this report are recommendations to increase the use of alternative fuels to 20 percent of on-road transportation fuel use by 2020 and 30 percent by 2030, significantly increase the efficiency of motor vehicles, and reduce per capita vehicle miles traveled (VMT) (CEC 2003).
Integrated Energy Policy Report
Senate Bill (SB) 1389 (Chapter 568, Statutes of 2002) required the CEC to “conduct assessments and forecasts of all aspects of energy industry supply, production, transportation, delivery and distribution, demand, and prices. The Energy Commission shall use these assessments and forecasts to develop energy policies that conserve resources, protect the environment, ensure energy reliability, enhance the state’s economy, and protect public health and safety” (Public Resources Code [PRC] Section 25301[a]). This work culminated in the Integrated Energy Policy Report (IEPR).
CEC adopts an IEPR every two years and an update every other year. The 2023 IEPR, the most recent IEPR, was adopted in February 2024. The 2023 IEPR summarizes California’s priority energy issues, outlining strategies and recommendations to further the state’s goal of ensuring reliable, affordable, and environmentally responsible energy sources. Energy topics covered in the report include progress toward statewide renewable energy targets and issues facing future renewable development; efforts to increase energy efficiency in existing and new buildings; progress by utilities in achieving energy efficiency targets and potential; improving coordination among the state’s energy agencies; streamlining power plant licensing processes; results of preliminary forecasts of electricity, natural gas, and transportation fuel supply and demand; future energy infrastructure needs; the need for research and development efforts to statewide energy policies; and issues facing California’s nuclear power plants (CEC 2024a).
Advanced Clean Fleets
CARB’s 2022 Advanced Clean Fleets regulation was developed to reduce diesel particulate matter through the transition of medium- and heavy-duty trucks to become fully electric by 2045. In January 2025, California withdrew its request for a waiver and authorization for the addition of the Advanced Clean Fleets regulation to its emissions control program (CARB 2025a). CARB is not enforcing the existing portions of the Advanced Clean Fleets regulation that require a federal waiver or authorization, such as the portions of the Advanced Clean Fleet regulation that apply to high-priority and drayage fleets. However, not all elements of the Advanced Clean Fleets regulation require a federal waiver or authorization (CARB 2025b). State and local government fleets will still be required to be fully electric by 2045.
Senate Bill 1383
SB 1383 (Chapter 249, Statutes of 2016) required CARB to approve and implement a plan by January 2018 to achieve reductions of short-lived climate pollutants such as methane, and tropospheric ozone. SB 1383 also sets a target for reduction of methane emissions to 40 percent below 2013 levels by 2030. Pursuant to SB 605 and SB 1383, CARB subsequently developed the Short-Lived Climate Pollutant Reduction Strategy, adopted in March 2017. As part of this strategy, the California Department of Resources Recycling and Recovery (CalRecycle), in consultation with CARB, was required to develop regulations to reduce statewide disposal of organic waste by 50 percent of 2014 levels by 2020, and by 75 percent of 2014 levels by 2025, including recovery of at least 20 percent of edible food for human consumption. CalRecycle adopted these regulations in 2017, and they became effective on January 1, 2022. The proposed project is designed to address SB 1383 goals.
Energy Ascent
City of Roseville
3.8-4 Roseville Environmental Utilities Operations Center Project Draft EIR Climate Change Scoping Plan
The California legislature enacted AB 1279 in 2022, which establishes the policy of the state to achieve net zero emissions as soon as possible but no later than 2045; to maintain net negative GHG emissions thereafter; and to ensure that by no later than 2045, statewide anthropogenic GHG emissions are reduced by at least 85 percent below 1990 levels. CARB released the final 2022 Scoping Plan for Achieving Carbon Neutrality (2022 Scoping Plan) on November 16, 2022, as directed by AB 1279 (CARB 2022). The 2022 Scoping Plan traces the pathway for the state to achieve the goals set forth in AB 1279 and includes several regulations, plans, and policies directed to reduce energy consumption, improve energy efficiency, and increase renewable energy resources within the state. CARB adopted the 2022 Scoping Plan on December 16, 2022.
California Energy Efficiency Action Plan
The 2021 California Building Decarbonization Assessment is the initial report addressing the mandates codified in AB 3232 (Friedman, Chapter 373, Statutes of 2018). The report analyzes scenarios to reduce GHG emissions by at least 40 percent by 2030 and identifies several strategies that will lead to significant emission reductions related to electricity and natural gas use in buildings, as well as from refrigerants. The strategies include electrification, electricity generation decarbonization, energy efficiency, refrigerant leakage reduction, distributed energy resources, decarbonizing the gas system, and demand flexibility. The assessment shows that California can achieve significantly more than a 40 percent reduction by 2030 through these strategies.
California Building Energy Efficiency Standards (Title 24, Part 6) California's energy consumption of new residential and nonresidential buildings is regulated by the California Code of Regulations Title 24, Part 6, Building Energy Efficiency Standards (California Energy Code). CEC updates the California Energy Code every three years with more stringent design requirements for reduced energy consumption, resulting in fewer GHG emissions. The 2022 California Energy Code went into effect on January 1, 2023. The 2022 California Energy Code advances the on-site energy generation progress started in the 2019 California Energy Code by encouraging electric heat pump technology and use, establishing electric-ready requirements when natural gas is installed, expanding solar photovoltaic (PV) system and battery storage standards, and strengthening ventilation standards to improve indoor air quality. CEC estimates that the 2022 California Energy Code will save consumers $1.5 billion and reduce GHGs by 10 million metric tons of carbon dioxide-equivalent over the next 30 years (CEC 2021).
California Green Building Standards (Title 24, Part 11) The California Green Building Standards Code, also known as the CALGreen Code, is a portion of the California Building Code developed by CEC that consists of both voluntary and mandatory requirements related to green building standards for statewide residential and non-residential construction. The voluntary provisions of the CALGreen Code often guide the adoption of local reach codes by incorporated cities and unincorporated counties. The current version is the 2022 CALGreen Code, which took effect on January 1, 2023. Compared to the 2019 CALGreen Code, the 2022 CALGreen Code strengthened sections pertaining to electric vehicle (EV) and bicycle parking, water efficiency and conservation, and material conservation and resource efficiency, among other sections of the CALGreen Code. The CALGreen Code sets design requirements equivalent to or more stringent than those of the California Energy Code for energy efficiency, water efficiency, waste diversion, and indoor air quality. These codes are adopted by local agencies that enforce building codes and are used as guidelines by state agencies for meeting the requirements of Executive Order B-18-12.
The 2025 CALGreen Code was adopted on September 11, 2024, and goes into effect for commercial uses on January 1, 2026. Relative to the 2022 CALGreen Code, the 2025 version includes increased requirements for EV charging infrastructure (i.e., a higher percentage of parking spaces that must be equipped with EV chargers and more stringent requirements for the types of chargers that must be installed) in both residential and non-residential buildings. The 2025 CALGreen Code also includes required analysis of Embodied Carbon in Building Materials, which was not required under the 2022 CALGreen Code. Lastly, the 2025 CALGreen Code includes updates to energy efficiency standards aimed at further reducing energy consumption in buildings and promoting the use of renewable energy sources.
Ascent Energy
City of Roseville
Roseville Environmental Utilities Operations Center Project Draft EIR 3.8-5 LOCAL
City of Roseville General Plan 2035
The City of Roseville General Plan 2035 contains several policies applicable to the proposed project that address energy (City of Roseville 2020). Key provisions from the Air Quality and Climate Change Element are summarized below.
Air Quality and Climate Change Element Policies
Policy AQ1.11 Promote local purchase and use of electric vehicles through incentives and strategic expansion of charging infrastructure.
Policy AQ1.17 Conserve energy and reduce air pollutant emissions by encouraging energy efficient building designs and transportation systems and promoting energy efficiency retrofits of existing structures. Policy AQ1.18 Promote building and transportation energy efficiency in new residential and commercial development by encouraging and incentivizing implementation measures early in the design and development process. Policy AQ1.19 Encourage energy efficiency by identifying potential cost savings, resource, and health benefits.
General Plan Implementation Measures
Appendix A of the General Plan identifies the General Plan’s implementation measures, which are proactive activities designed to implement General Plan policies. The following may apply to the project:
Development Review Process
Project review should address energy efficient building and site designs, as well as the proper storage, use, and disposal of hazardous materials.
Air Quality and Climate Change Mitigation Strategies - Land Use (Ongoing) Encourage development to be located and designed to minimize greenhouse gas and air pollutant emissions and avoid exposure to substantial pollutant concentrations by doing the following:
Provide for mixed-use and transit-supportive development that reduces the length and frequency of vehicle trips or reduces the need for vehicle trips by providing practical pedestrian, bicycle, and transit options.
The City of Roseville General Plan 2035 (City of Roseville 2020) contains the following policies applicable to the proposed project that address electric resources and privately owned utilities:
Public Facilities Element Policies
Policy PF4.1: Secure supply-side and demand-side electric resources, as necessary, to meet forecasted demand and reserve requirements.
Policy PF4.2: Provide improvements to the sub-transmission and distribution system, consistent with facility planning studies, to maintain a reliable source of electricity. Policy PF4.3: Develop siting and land use compatibility standards for energy facilities. Policy PF4.4: Comply with federal, state, and local greenhouse gas reduction targets, renewable portfolio standards and carbon-free electricity requirements.
Policy PF4.5: Maintain an Integrated Resource Plan, incorporating energy efficiency, demand- and supply-side management, greenhouse gas reduction, renewable portfolio standard compliance, conservation, load management, and reliability strategies.
Policy PF4.6: Pursue reasonable and cost-effective energy efficiency, conservation, and load management programs that provide benefits to the community.
Policy PF4.7: Pursue effective measures to enhance reliability through interconnection of the electric utility system with the region-wide grid.
Energy Ascent
City of Roseville
3.8-6 Roseville Environmental Utilities Operations Center Project Draft EIR Policy PF4.8: Require new development to pay a fair share of the cost of new sub-transmission and distribution needed to serve the development and to dedicate sites and easements needed for substations, transmission, sub-transmission, and distribution.
Policy PF9.6: Require large electricity users to submit a use and conservation plan concurrent with development review specifying measures to be taken to minimize demand. Policy PF9.7: Enforce energy requirements and encourage development and construction standards that promote energy efficiency and conservation.
City of Roseville Communitywide Sustainability Action Plan The Roseville Communitywide Sustainability Action Plan (SAP) sets forth a comprehensive strategy to reduce GHG emissions and improve energy efficiency, as well as to promote economic growth based on clean technology and sustainable practices (City of Roseville 2010). While the 2035 General Plan includes goals and policies that guide the City’s approach to addressing sustainability and climate change, the SAP serves as a more detailed strategy to implement the City’s sustainability and climate change policies. The following are some of the energy measures suggested by the SAP that are relevant to the project.
Measure E-1.2
Qualifying existing commercial buildings should strive to achieve ENERGY STAR performance criteria. This rating denotes that the building’s estimated energy use is intended to be in the top 25% compared to similar buildings throughout the nation.
For building types not qualifying for ENERGY STAR, the design should strive for a 15% reduction in the overall energy budget over California Title 24 performance standards.
Measure E-1.5
Continue to explore innovative ways to promote energy efficiency and renewable energy use in the community.
Measure WR-2.1
Maximize reuse, recycling, and composting programs.
3.8.2 Environmental Setting
PHYSICAL SETTING
Energy Types and Sources
California relies on a regional power system composed of a diverse mix of natural gas, renewable, hydroelectric, and nuclear generation resources. One-third of energy commodities consumed in California are natural gas. In 2024, renewable resources, including hydroelectric power and small-scale solar power, supplied 57 percent of California’s in-state electricity generation. Natural gas fueled another 35 percent, and nuclear power provided almost all the rest (EIA 2025).
Alternative Fuels
A variety of alternative fuels are used to reduce demand for petroleum-based fuel. The use of these fuels is encouraged through various statewide regulations and plans (e.g., Low Carbon Fuel Standard, AB 32 Scoping Plan).
Conventional gasoline and diesel may be replaced (depending on the capability of the vehicle) with many transportation fuels, including biodiesel/renewable diesel, electricity, ethanol, and hydrogen.
California has a growing number of alternative fuel vehicles through the joint efforts of CEC, CARB, local air districts, federal government, transit agencies, utilities, and other public and private entities. As of July 2025, California contained nearly 70,490 stations with alternative fuels (AFDC 2025).
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City of Roseville
Roseville Environmental Utilities Operations Center Project Draft EIR 3.8-7 Commercial Energy Use
Commercial buildings represent just under one-fifth of US energy consumption, with office space, retail space, and educational facilities representing about half of commercial sector energy consumption. The commercial sector accounted for 8 percent of total energy in the US in 2023. In comparison, the residential sector accounted for approximately 7 percent of US energy consumption (EIA 2025).
Energy Use for Transportation
In 2024, the transportation sector comprised the largest end-use sector of energy in the state totaling 42 percent, followed by the industrial sector totaling 22 percent, the residential sector at 17 percent, and the commercial sector at 17 percent (EIA 2025). CEC reported retail sales of 163 million and 18 million gallons of gasoline and diesel, respectively, in Placer County in 2023 (the most recent data available) (CEC 2024b).
Energy Use and Climate Change
Scientists and climatologists have produced evidence that the burning of fossil fuels by vehicles, power plants, industrial facilities, residences, and commercial facilities has led to an increase of the earth’s temperature. For an analysis of greenhouse gas production and the project’s impacts on climate change, refer to Section 3.4, “Greenhouse Gas Emissions.”
Electrical and Natural Gas Infrastructure
Roseville Electric provides electrical service to customers within the City limits. The City’s utility obtains power from a variety of sources. In 2023, Roseville Electric consisted of 29 percent renewable energy, which consisted of solar, wind, hydroelectric, geothermal, and biomass (Roseville Electric 2023). The nearest point of connection to the project site is an existing 12 kilovolt (kV) line located near Blue Oaks Boulevard. The Pacific Gas and Electric Company (PG&E) is the natural gas service provider for the City. PG&E’s underground transmission pipelines are located throughout City rights-of-way to serve existing development. Expansion of electrical facilities would be required to serve the proposed project. The project would not require the installation of new or expansion of existing natural gas infrastructure; however, compressed natural gas (CNG) would be consumed by on-road trucks as part of the project.
3.8.3 Impacts and Mitigation Measures
METHODOLOGY
Appendix G of the State CEQA Guidelines requires consideration of the energy implications of a project. CEQA requires mitigation measures to reduce “wasteful, inefficient and unnecessary” energy usage (PRC Section 21100, subdivision [b][3]). Neither the law nor the State CEQA Guidelines establish criteria that define wasteful, inefficient, or unnecessary use. Therefore, impacts related to energy are addressed qualitatively.
Levels of construction- and operation-related energy consumption by the project were estimated and measured in megawatt-hours of electricity, gallons of natural gas, gallons of gasoline, gallons of diesel fuel, and kilograms of hydrogen. Energy consumption estimates for construction and operational activities were calculated using the proposed phasing of the project, the California Emissions Estimator Model (CalEEMod) version 2020.4.0 computer program, and fuel consumption rates obtained from CARB’s OFFROAD and EMission FACtors (EMFAC) model for Placer County.
Where project-specific information was not known, CalEEMod default values based on the project’s location were used.
THRESHOLDS OF SIGNIFICANCE
Thresholds of significance are based on Appendix G of the State CEQA Guidelines. The project would cause a significant impact related to energy if it would:
result in a potentially significant environmental impact due to wasteful, inefficient, or unnecessary consumption of energy, or wasteful use of energy resources, during project construction or operation; or conflict with or obstruct a state or local plan for renewable energy or energy efficiency.
Energy Ascent
City of Roseville
3.8-8 Roseville Environmental Utilities Operations Center Project Draft EIR
ISSUES NOT DISCUSSED FURTHER
All issues related to energy are discussed in the analysis below.
ENVIRONMENTAL IMPACTS AND MITIGATION MEASURES
Impact 3.8-1: Wasteful, Inefficient, or Unnecessary Consumption of Energy, During Project Construction or Operation
Phase 1
Implementation of the project would result in the consumption of additional energy supplies during construction in the form of gasoline and diesel fuel as well as electricity and hydrogen. However, this energy expenditure would not be considered wasteful or inefficient as construction activities associated with Phase 1 would be temporary, completed in an efficient manner, and would not increase long-term energy or fuel demand. Operation of Phase 1 would result in increased energy consumption. However, Phase 1 of the project would be constructed in accordance with applicable building codes which include measures for energy efficiency. In addition, because operation of Phase 1 would be aligned with SB 1383 goals, which addresses emissions of short-lived climate pollutants and GHG, the increase in energy demand at the project site would not be considered wasteful, inefficient, or unnecessary. For these reasons, this impact would be less than significant.
Construction
The project site is predominantly agricultural in use and is leased for rice and hay farming. Several structures are located on the site and although most would be demolished prior to project development, the former residence could be used as a temporary office or by a vendor as the vendor lease office. Construction activities would include demolition, grading, construction of buildings, and paving. Energy would be required to construct, operate, and maintain construction equipment and to produce and transport construction materials associated with construction of Phase 1 of the project. A range of 40 to 60 construction personnel would be on-site throughout Phase 1 construction. The onetime energy expenditure required to construct the physical buildings and infrastructure associated with the project would be nonrecoverable. Most energy consumption would result from the operation of construction equipment and vehicle trips associated with commutes by construction workers and haul trucks supplying materials. See Table 3.8-1 for an estimate of fuel needed for construction activities associated with the project.
Table 3.8-1 Construction Energy Consumption
Construction Component Gasoline (gallons) Diesel (gallons) Electricity (megawatt hours) Phase 1
Project Earthwork 7,990 556 29,571
RRTO Phase 1 18,542 8,526 68,625
EU Service Facility 19,845 36,727 73,446
Fleet Service Equip Maintenance 21,148 46,378 78,267
Vendor Lease Area 9,206 8,839 34,071
Phillips Rd and Force Main Improvements 23,884 16,278 88,392 Electrical Substation 17,240 187 63,803
Phase 2
RRTO Phase 2 23,840 12,344 88,232
Compost/Biomass 23,840 15,319 88,232
Source: Calculations by Ascent in 2025.
Ascent Energy
City of Roseville
Roseville Environmental Utilities Operations Center Project Draft EIR 3.8-9 Although construction activities would require fuel and other energy sources, these energy needs would be temporary. In addition, to maximize their profitability, construction contractors strive to complete construction projects in an efficient manner to meet project schedules and minimize cost. Thus, only the necessary amount of fuel would be consumed to complete construction of Phase 1. Furthermore, all construction equipment would be subject to applicable regulations relating to diesel equipment (see “Construction Equipment Emission Standards” above under Section 3.8.1, “Regulatory Setting”).
Operations
Implementation of Phase 1 of the project would increase electricity consumption in the region relative to existing conditions. Energy in the form of electricity would be consumed from the operation of equipment (e.g., disc screen, optical sorters) and utilities (e.g., water, heating, and air conditioning). Energy would also be consumed during maintenance activities such as landscaping. Gasoline, diesel fuel, and electricity would be consumed during employee and haul trips to the site. As detailed in Chapter 2, “Project Description,” the total estimated power demand of Phase 1 is approximately 5 megawatts (MW) with an estimated utility service size of 5 megavolt amperes (MVA). See Table
3.8-2 for an estimate of Phase 1 operational energy needs.
Table 3.8-2 Operational Energy Consumption at Full Operation (2058) Operational Component Gasoline (gallons) Diesel (gallons) Natural Gas (gallons)1 Electricity (megawatt hours) Phase 1 (2028)
Mobile - Trucks 0 253,206 51,688 0
Mobile - Worker Commute 213,009 222 0 198
Building Energy 0 0 0 2,412
On-site Equipment 0 15,184 0 19,290
Total Annual Energy Demand 213,009 268,612 51,688 21,9002 Phase 2 (2040)
Mobile - Trucks 0 395,616 85,811 0
Mobile - Worker Commute 119,674 53 0 1,313
Building Energy 0 0 0 8,769
On-site Equipment 0 76,403 0 63,379
Total Annual Energy Demand 119,674 472,073 85,811 74,4602 Full Operation (2058)
Mobile - Trucks 0 657,656 149,296 0
Mobile - Worker Commute 46,932 15 0 2,006
Building Energy 0 0 0 8,769
On-site Equipment 0 90,202 0 63,685
Total Annual Energy Demand 46,932 747,873 149,296 74,4602 Notes:
1 Compressed natural gas (CNG) used by on-road trucks is assumed to have an energy content of 114,000 British thermal units (Btu) per gallon. 2 The project’s total anticipated electricity demand for each phase was estimated as the annual output of the substation at its full capacity (5 MW for Phase 1 operation and 17 MW for Phase 2 and Full operation, assuming 50 percent actual output and continuous operation (8,760 hours per year).
Electricity demand from mobile sources was estimated based on anticipated worker commute trips. Building energy demand was estimated using default demand factors for industrial/office buildings in CalEEMod. Mobile energy demand was combined with building energy demand and the sum was subtracted from the project’s total energy demand to obtain electricity demand associated with the on-site equipment.
Source: Calculations by Ascent in 2025.
Energy Ascent
City of Roseville
3.8-10 Roseville Environmental Utilities Operations Center Project Draft EIR Implementation of Phase 1 would result in energy consumption of 213,009 gallons of gasoline; 268,612gallons of diesel; 51,688 gallons of natural gas; and 21,900 MW of electricity as shown in Table 3.8-2. Although implementation of Phase 1 would increase overall energy use at the project site, it would support compliance with SB 1383 goals that address reduced methane (i.e., a potent short-lived climate pollutant) in the state. (See Section 3.4, “Greenhouse Gas Emissions,” for further discussion of SB 1383.) In addition, all new buildings would, at a minimum, be constructed in accordance with the most recent and applicable building codes (e.g., Title 24) at the time of construction, which includes energy efficiency requirements. Because electricity associated with the project would support SB 1383 implementation goals and the project would be constructed in accordance with applicable building codes, the associated increased energy demand would not be considered wasteful, inefficient, or unnecessary. The project would also include design features such as water-efficient landscaping to improve energy efficiency and prevent wasteful or inefficient use of energy for building operations.
Summary
Implementation of Phase 1 of the project would increase energy demand for temporary construction activities related to vehicle use and material transport. However, construction activities would be temporary and would not permanently increase long-term energy or fuel demand. In addition, construction activities would consume the necessary amount of fuel/energy to complete work in an efficient and timely manner. Phase 1 of the project would support SB 1383 implementation goals and would be constructed in accordance with applicable building codes, which include energy efficiency requirements. For these reasons, the increased energy demand associated with construction and implementation of Phase 1 would not be considered wasteful, inefficient, or unnecessary. This impact would be less than significant.
Mitigation Measures
No mitigation is required.
Phase 2
Similar to Phase 1, construction activities associated with Phase 2 would be temporary and would not increase longterm energy or fuel demand. Operation of Phase 2 (2040) and full operation (2058) would result in increased energy consumption. However, because operation of Phase 2 would be aligned with SB 1383 goals, which address emissions of short-lived climate pollutants and GHG, the increase in energy demand at the project site would not be considered wasteful, inefficient, or unnecessary. For these reasons, this impact would be less than significant.
Phase 2 of the project would involve the construction and operation of an additional 122,000 square feet of building area at the RRTO and the construction and operation of 37,000 square feet of building area for a potential Future Organics Processing Facility.
Construction
Construction of the additional square footage at the RRTO would be constructed on an as-needed basis and construction of the potential Future Organics Processing Facility would begin in 2035. Similar to Phase 1 construction, a range of 40 to 60 construction personnel would be on-site throughout Phase 2 construction. Energy would be required to construct, operate, and maintain construction equipment and to produce and transport construction materials associated with the construction of the project. See Table 3.8-1 for an estimate of fuel needed for Phase 2 construction activities. Although construction activities would require fuel and other energy sources, these energy needs would be temporary. In addition, to maximize their profitability, construction contractors strive to complete construction projects in an efficient manner to meet project schedules and minimize cost. Thus, only the necessary amount of fuel would be consumed to complete construction of Phase 2. Furthermore, all construction equipment would be subject to the most recent applicable regulations relating to diesel equipment.
Operations
Operation of Phase 2 (2040) and full operation (2058) would include the potential Future Organics Processing Facility, which may involve a composting facility and/or a biomass facility. The potential future compost facility would involve the composting of green waste, wood, and food wastes. The potential future biomass facility would convert biomass (woody
Ascent Energy
City of Roseville
Roseville Environmental Utilities Operations Center Project Draft EIR 3.8-11 materials) into energy using thermal means and would likely include food, agricultural, and yard trimming waste. Phase 2 operations would involve the continued operation of the RRTO facility and vendor lease area. During operations, energy in the form of electricity and natural gas would be consumed from the operation of appliances (e.g., optical sorters, on-site trucks). Table 3.8-2 provides a summary of the estimated operational energy consumption associated with Phase 2 of the project and full operation (2058). Model inputs and outputs are included in Appendix C.
Implementation of Phase 2 would result in annual energy demand for 119,674 gallons of gasoline; 472,073 gallons of diesel; 85,811 gallons of natural gas; and 74,460 MWh of electricity as shown in Table 3.8-2. At full operation (2058), the project would generate annual energy demand for 46,933 gallons of gasoline; 747,873 gallons of diesel; 149,296 gallons of natural gas; and 74,460 MWh of electricity. Although Phase 2 and full operation of the project would increase overall energy use at the project site, it would support compliance with SB 1383 goals that address reduced methane (i.e., a potent short-lived climate pollutant) in the state with incorporation of the composting and biomass facility which diverts organic waste from landfills. (See Section 3.4, “Greenhouse Gas Emissions,” for further discussion of SB 1383.) In addition, as with Phase 1, all new buildings would, at a minimum, be constructed in accordance with the most recent and applicable building codes (e.g., Title 24) at the time of construction, which includes energy efficiency requirements. Further, no natural gas infrastructure is proposed. In addition, while the precise process and technology associated with the future biomass facility is currently unknown, it is anticipated that the biomass facility would be a gasification unit that uses woody biomass to generate electricity. This cogeneration process would result in increased renewable energy sources that could power on-site structures or feed back into the electrical grid, increasing the project’s proportion of renewable energy to fossil fuel.
Because electricity associated with the project would support SB 1383 implementation goals and the project would be constructed in accordance with applicable building codes, the associated increased energy demand would not be considered wasteful, inefficient, or unnecessary. The project would also include design features such as water-efficient landscaping to improve energy efficiency and prevent wasteful or inefficient use of energy for building operations.
For these reasons, this impact would be less than significant.
Summary
Construction of Phase 2 and full operation (2058) of the project would increase energy demand for temporary construction activities related to vehicle use and material transport. However, construction activities would be temporary and would not permanently increase long-term energy or fuel demand. In addition, construction activities would consume the necessary amount of fuel/energy to complete work in an efficient and timely manner. Phase 2 of the project would continue to support SB 1383 implementation goals and would be constructed in accordance with applicable building codes which include energy efficiency requirements. For these reasons, the increased energy demand associated with construction and implementation of Phase 2 would not be considered wasteful, inefficient, or unnecessary. This impact would be less than significant.
Mitigation Measures
No mitigation is required.
Impact 3.8-2: Conflict with or Obstruct a State or Local Plan for Renewable Energy or Energy Efficiency
Phase 1
Implementation of Phase 1 of the project would include the construction and operation of a RRTO Facility that would provide an on-site materials recovery facility to segregate recyclable material as well as an area for receiving, processing, and transferring organic waste. The project would enable the City to manage its waste and recyclable materials locally while maintaining compliance with state requirements such as SB 1383, which required CARB to approve and implement a plan to achieve reductions of short-lived climate pollutants such as methane and tropospheric ozone. Reduction of short-lived climate pollutants is identified as a key strategy in the 2022 Scoping Plan. The project was designed to address SB 1383 goals; therefore, the project would not conflict with or obstruct a state or local plan for renewable energy or energy efficiency and this impact would be less than significant.
Energy Ascent
City of Roseville
3.8-12 Roseville Environmental Utilities Operations Center Project Draft EIR The relevant plan that pertains to the efficient use of energy is the 2022 Scoping Plan. The 2022 Scoping Plan identifies specific actions directed to reduce energy consumption, improve energy efficiency, and increase renewable energy resources within the state. The 2022 Scoping Plan identifies strategies for achieving the reduction target of SB 1383, including expanding infrastructure to reduce landfill disposal with strategies such as composting, investing in infrastructure needed to support growth in organic recycling capacity, and reducing emissions from landfills through improvements in operational practices (CARB 2022). Phase 1 of the project would include the partial construction of the RRTO Facility that would provide an onsite materials recovery facility to segregate recyclable material; an area for receiving and transferring municipal solid waste; and an area for receiving, processing, and transferring organic waste; the Vendor Lease Area for prospective vendors to commit materials to the RRTO Facility; and the Corporation Yard, which includes the EU Operations Facility that would provide office and storage space for the EU Department and an equipment maintenance facility. As discussed in Impact 3.8-1, although implementation of Phase 1 of the project has the potential to result in the overall increase in consumption of energy resources during construction and operation of new buildings and facilities, the project in and of itself would provide a waste and recycling facility that would enable the City to manage its waste and recyclable materials locally while maintaining compliance with state requirements. Thus, the project would not conflict with or obstruct a state or local plan for renewable energy or energy efficiency and the impact would be less than significant.
Mitigation Measures
No mitigation is required.
Phase 2
Implementation of Phase 2 of the project would further allow the City to manage its waste and recyclable materials locally while maintaining compliance with state requirements such as SB 1383 and the 2022 Scoping Plan. Therefore, the project would not conflict with or obstruct a state or local plan for renewable energy or energy efficiency and this impact would be less than significant.
As discussed in Impact 3.8-1, Phase 2 of the project would include an additional 122,000 square feet of building area for the RRTO Facility and the construction of 37,000 square feet of building area for the potential Future Organics Processing Facility. Phase 2 and full operation (2058) of the project would include continued and expanded operations at the RRTO as well as a potential future compost facility and/or biomass facility which would be sized to accommodate the combined quantities of the City’s forecasted organic wastes and organic wastes from sources outside the City. Thus, implementation of Phase 2 and full operation (2058) would further enhance the City’s ability to manage its waste and recyclable materials as well as divert organic materials from landfills pursuant to SB 1383. As discussed above, the 2022 Scoping Plan identifies strategies for achieving the reduction target of SB 1383, including expanding infrastructure to reduce landfill disposal with strategies such as composting, investing in infrastructure needed to support growth in organic recycling capacity, and reducing emissions from landfills through improvements in operational practices (CARB 2022). Although implementation of Phase 2 of the project has the potential to result in the overall increase in consumption of energy resources during construction and operation of new buildings and facilities, the project in and of itself would provide a waste and recycling facility that would enable the City to further manage its waste and recyclable materials locally while maintaining compliance with state requirements. Thus, the project would not conflict with or obstruct a state or local plan for renewable energy or energy efficiency and the impact would be less than significant.
Mitigation Measures
No mitigation is required.
Ascent Geology and Soils
City of Roseville
Roseville Environmental Utilities Operations Center Project Draft EIR 3.9-1
3.9 GEOLOGY AND SOILS
This section describes current conditions related to geology and soils at the project site. It includes a description of the site’s geology and soils, an analysis of environmental impacts, and recommendations for mitigation measures for any significant or potentially significant impacts. The primary source of information used for this analysis is the Preliminary Conceptual Design Geotechnical Report (Preliminary Geotechnical Report) prepared by the City of Roseville (HDR 2024).
No comment letters regarding geology and soils were received in response to the notice of preparation (see Appendix A).
3.9.1 Regulatory Setting
FEDERAL
National Earthquake Hazards Reduction Act
In October 1977, the US Congress passed the Earthquake Hazards Reduction Act to reduce the risks to life and property from future earthquakes in the United States. To accomplish this, the act established the National Earthquake Hazards Reduction Program (NEHRP). The mission of NEHRP includes improved understanding, characterization, and prediction of hazards and vulnerabilities; improved building codes and land use practices; risk reduction through post‐earthquake investigations and education; development and improvement of design and construction techniques; improved mitigation capacity; and accelerated application of research results. The NEHRP designates the Federal Emergency Management Agency as the lead agency of the program and assigns several planning, coordinating, and reporting responsibilities.
National Pollutant Discharge Elimination System Program Under Section 402 of the Clean Water Act, the National Pollutant Discharge Elimination System (NPDES) regulates point sources of pollution of waters of the United States. The California State Water Resources Control Board administers the NPDES permit program in California. Projects that disturb 1 acre or more of soil must obtain coverage under the state’s NPDES General Permit for Discharges of Storm Water Associated with Construction Activity. A stormwater pollution prevention plan (SWPPP) must be developed and implemented that provides specific construction-related best management practices (BMPs) to prevent soil erosion and loss of topsoil. The required components and BMPs commonly included in a SWPPP are described in greater detail in Section 3.11, “Hydrology and Water Quality.” STATE
Alquist-Priolo Earthquake Fault Zoning Act
The purpose of the Alquist-Priolo Earthquake Fault Zoning Act of 1972 (Public Resources Code [PRC] Section 2621-2630) is to reduce the risk to life and property from surface fault rupture during earthquakes by regulating construction in active fault corridors, and by prohibiting the location of most types of structures intended for human occupancy across the traces of active faults. The act defines criteria for identifying active faults, giving legal support to terms such as active and inactive, and establishes a process for reviewing building proposals in Earthquake Fault Zones. Under the AlquistPriolo Act, faults are zoned and construction along or across these zones is strictly regulated if they are “sufficiently active” and “well-defined.” A fault is considered sufficiently active if one or more of its segments or strands shows evidence of surface displacement during Holocene time (defined for purposes of the act as within the last 11,000 years).
A fault is considered well defined if its trace can be clearly identified by a trained geologist at the ground surface or in the shallow subsurface, using standard professional techniques, criteria, and judgment (Bryant and Hart 2007). Before a project can be permitted in a designated Alquist‐Priolo Earthquake Fault Zone, cities and counties must require a geologic investigation to demonstrate that proposed buildings would not be constructed across active faults. The law addresses only the hazard of surface fault rupture and is not directed toward other earthquake hazards.
Geology and Soils Ascent
City of Roseville
3.9-2 Roseville Environmental Utilities Operations Center Project Draft EIR Seismic Hazards Mapping Act
The purpose of the Seismic Hazards Mapping Act of 1990 (PRC Section 2690–2699.6) is to reduce damage resulting from earthquakes. While the Alquist-Priolo Act addresses surface fault rupture, the Seismic Hazards Mapping Act addresses other earthquake-related hazards, including ground shaking, liquefaction, and seismically induced landslides. The act’s provisions are similar in concept to those of the Alquist-Priolo Act: The State is charged with identifying and mapping areas at risk of strong ground shaking, liquefaction, landslides, and other corollary hazards, and cities and counties are required to regulate development within mapped Seismic Hazard Zones. Under the Seismic Hazards Mapping Act, permit review is the primary mechanism for local regulation of development.
California Building Code
The California Building Code (CBC) (California Code of Regulations, Title 24) is based on the International Building Code. The CBC has been modified from the International Building Code for California conditions, with more detailed and/or more stringent regulations. Specific minimum seismic safety and structural design requirements are set forth in Chapter 16 of the CBC. The CBC identifies seismic factors that must be considered in structural design. Chapter 18 of the CBC regulates the excavation of foundations and retaining walls, while Chapter 18A regulates construction on unstable soils, such as expansive soils and areas subject to liquefaction. Appendix J of the CBC regulates grading activities, including drainage and erosion control. The CBC contains a provision that provides for a preliminary soil report to be prepared to identify “…the presence of critically expansive soils or other soil problems which, if not corrected, would lead to structural defects.” (CBC Chapter 18 Section 1803.1.1.1).
LOCAL
City of Roseville General Plan
The General Plan Safety Element of the Roseville 2035 General Plan (City of Roseville 2020a) includes policies intended to address potential geology, soils, and seismic impacts. These policies are implemented through the Building Permit process (for structures) and the Design and Construction Standards. The specific goals and policies that may be applicable to the project are:
Policy SAFE1.3: Minimize soil erosion and sedimentation though suitable building placement, maximum lot coverage standards, context-sensitive designs, and appropriate construction techniques. Policy SAFE1.4: Comply with state seismic and building standards in the design and siting of critical facilities, including police and fire stations, school facilities, hospitals, hazardous material manufacture and storage facilities, bridges, and large public assembly halls.
City of Roseville 2025 Design and Construction Standards The City of Roseville Design and Construction Standards (last amended in January 2025) provide a reference to the City’s requirements for the design and construction of civil improvement projects, which are to be dedicated to the public and accepted by the City for maintenance or operation, and to provide for coordinated development of those facilities to be used by and for the protection of the public (City of Roseville 2025).
City of Roseville Guidance for Stormwater Quality Best Management Practices Control of construction site stormwater runoff is required by the NPDES stormwater permit that the SWRCB issued to the City in 2004. The Stormwater Quality BMP Guidance Manual for Construction (City of Roseville 2011) is designed to facilitate compliance with the City’s Stormwater Management Plan. See Section 3.11, “Hydrology and Water Quality,” for additional discussion of SWPPP requirements and BMPs.
Grading Ordinance
Section 16.20.040 of the Roseville Municipal Code regulates stockpiling and grading and addresses conditions under which permits and grading plans are required. Section 16.20.070 identifies grading plan performance standards. Both Minor and Major grading plans are required by the City. A Major grading plan is required for any project that would result in the placement of fill in a channel or tributary that carries flow of 200 cubic feet/second or more during a 10-
Ascent Geology and Soils
City of Roseville
Roseville Environmental Utilities Operations Center Project Draft EIR 3.9-3 year storm event. Major grading plans must be reviewed and approved by the Planning Commission. All grading plans must comply with the following criteria:
A. Fill or cut slopes with a height exceeding five feet shall not exceed a slope of 4:1.
B. When grading around native oak trees:
1. Cut or fill slopes exceeding two feet in height shall not be permitted within a distance of 1.5 times the radius of the tree’s protected zone,
2. the grade shall not be raised or lowered around more than 50 percent of the protected zone, and
3. the grading shall not change the drainage pattern within a distance of 1.5 times the radius of the tree’s protected zone.
Section 16.20.020 requires that all grading be performed in accordance with either City Improvement Standards or Chapter 16 of the Zoning Ordinance, whichever is more restrictive. A project applicant must have an Improvement and/or Grading Plan along with a site-specific SWPPP prior to the start of grading activities. Slopes or banks along creek channels must be designed with proper slope protection to prevent soil erosion and channel-bank undercutting.
3.9.2 Environmental Setting
REGIONAL GEOLOGY
The project site is located in the Great Valley geomorphic province, which consists of the central part of California between the Coast Range and the Sierra Nevada. The Great Valley is an alluvial plain that is approximately 50 miles wide and 400 miles long where sediment has been deposited almost continually for roughly 160 million years. The proposed project would be located in the northern part of the Great Valley, which is drained by the Sacramento River (CGS 2002).
LOCAL GEOLOGY
The geology of the area consists of transitional formations between alluvial deposits of the valley and volcanic material of the Sierra Nevada. The City of Roseville is characterized by flat and rolling terrain, as well as rounded knolls and ridges separated by intermittent streams. Consequently, the geology in the project vicinity is entirely alluvial outwash deposits. The geology in the project vicinity consists of sedimentary deposits from the coalesced American River – Pleasant Grove Creek alluvial fan. These include, from west to east, the Riverbank, Modesto, Turlock Lake, and Mehrten Formations (HDR 2024).
The project site and vicinity are composed of the Riverbank Formation, and younger, unconsolidated Quaternary alluvium. The Riverbank Formation consists of weathered gravel, sand, and silt that were deposited between 0.13 million years ago and 0.45 million years ago. These stratigraphic units are all generally characterized by nested alluvial fans, grading larger from west to east (HDR 2024). The site topography has been modified to provide a series of terraced farm fields. The terracing steps down towards the north and northwest ranging in elevation from 72 feet down to 61 feet. As illustrated in the Preliminary Grading Plan (Figure 3.9-1), the project site is mainly flat with minimal slope.
SOILS
Subsurface conditions at the project site are generally defined by the characteristics present in the alluvial deposits of the Riverbank Formation and other, younger local alluvial deposits in shallow deposits. Soil limitations have been well-characterized in these units, and include slow or variable permeability, low-to-moderate soil strength, and lowto-moderate shrink-swell potential associated with clay content. Specific soil units mapped by NRCS in the project area include the following (HDR 2024):
Geology and Soils Ascent
City of Roseville
3.9-4 Roseville Environmental Utilities Operations Center Project Draft EIR Cometa-Fiddyment complex (141), 1 to 5 percent slope: approximately 68 percent of the site area located in the central and eastern site area. The Cometa-Fiddyment complex ranges from low to high shrink-swell potential (depending on specific site conditions), has a moderate risk of corrosion of concrete, and has a moderate risk of corrosion to steel. In addition, Fiddyment soil is moderately deep silty and clayey loam over hardpan. Fiddyment Loam (146), 1 to 8 percent slope: approximately 27 percent of the site area limited to the eastern portion of the site. The Fiddyment series consists of moderately deep, well drained soils formed in material weathered from consolidated sediments of mixed rock sources. Alamo-Fiddyment complex (104), 0 to 5 percent slopes: approximately 4.4 percent of the site area located in the lowest lying area of the site in the floodplain. The Alamo-Fiddyment complex consists of moderately deep and somewhat poorly drained soils on hill terraces, with very slow permeability and slow surface runoff. The complex has a low to moderately high erosion hazard.
Based on the geotechnical investigation performed at the project site, cross sections indicate that the subsurface conditions become fine grained below 48 feet elevation. Above 48 feet elevation, the subsurface conditions are highly varied between clay, silts, silty and clayey sands, and poorly graded sands that are discontinuous reflecting the historical cycle of material deposition and formation of infilled shallow erosion channels that has occurred in the last few thousand years (HDR 2024).
SUBSIDENCE
Land subsidence is the gradual settling or sinking of an area with very little horizontal motion. Subsidence can be induced by both natural and human phenomena. Natural phenomena include shifting of tectonic plates and dissolution of limestone resulting in sinkholes. Subsidence related to human activity includes pumping water, oil, and gas from underground reservoirs; collapse of underground mines; drainage of wetlands; and soil compaction.
The project site is not located within an area of known or reported land subsidence, and based on field observations and site reconnaissance, there is no evidence to support that the project site is susceptible to land subsidence (USGS 2025).
EXPANSIVE SOILS
Expansive soils (also known as shrink-swell soils) are soils that contain expansive clay minerals that can absorb significant amounts of water. The presence of these clay minerals makes the soil prone to large changes in volume in response to changes in water content. When an expansive soil becomes wet, water is absorbed and it increases in volume, and as the soil dries it contracts and decreases in volume. This repeated change in volume over time can produce enough force and stress on buildings, underground utilities, and other structures to damage foundations, pipes, and walls.
The quantity and type of expansive clay minerals affects the potential for the soil to expand or contract. Where native soils still exist, soil types may be expected to be similar to those of the nearby areas. However, potentially expansive soils were not identified during the geotechnical investigation conducted by HDR and the potential for them to occur is considered low (HDR 2024).
Ascent Geology and Soils
City of Roseville
Roseville Environmental Utilities Operations Center Project Draft EIR 3.9-5 Source: Image produced and provided by HDR in 2025; adapted by Ascent in 2025.
Figure 3.9-1 Preliminary Grading Plan
Ascent Geology and Soils
City of Roseville
Roseville Environmental Utilities Operations Center Project Draft EIR 3.9-7
FAULTS AND SEISMICITY
Seismically induced ground rupture, the physical displacement of surface deposits in response to an earthquake’s seismic waves, is considered most likely along faults that have a record of displacement sometime in the past 11,000 years (the Holocene Epoch). These faults are considered active. Faults on which an event is believed to have occurred during the Quaternary time (approximately the last 1.6 million years) are considered potentially active. All other faults are considered inactive.
The nearest known active fault is the Spenceville Fault, located approximately 19.5 miles east of the project site, within the Foothill Fault System. The Dunnigan Hills and Deadman faults, which both have unknown histories of activity and are located approximately 19 and 20 miles from the project site, respectively, present the second highest potential to produce ground shaking at the project site. Ground shaking could also originate from seismic activity along the larger, but relatively distant San Andreas fault system, the nearest components of which are approximately 55 miles away from the City of Roseville (City of Roseville 2023).
There are also three inactive faults located near Roseville: the Volcano Hill fault, the Linda Creek fault, and one unnamed fault. The Volcano Hill fault is located northwest of Volcano Hill and extends northwesterly for approximately 1 mile starting just east of the city limits. The Linda Creek fault, the existence of which is disputed because of lack of recorded activity, is suspected to extend along a portion of Linda Creek through Roseville and a portion of Sacramento County. The unnamed fault extends in an east-west direction between Folsom Lake and the City of Rocklin. Portions of this unnamed fault are concealed, and it is possible that the fault is connected to the Bear Mountain Fault near Folsom Lake (City of Roseville 2023:11-9).
Seismic hazards resulting from earthquakes include surface fault rupture, ground shaking, liquefaction, and landslides. Each of these potential hazards is discussed below.
Surface Fault Rupture
Surface rupture is the surface expression of movement along a fault. Structures built over an active fault can be torn apart if the ground ruptures. The potential for surface rupture is based on the concepts of recency and recurrence.
Surface rupture along faults is generally limited to a linear zone a few meters wide. The Alquist-Priolo Act (see the Regulatory Setting discussion above) was created to prohibit the location of structures designed for human occupancy across, or within 50 feet of, an active fault, thereby reducing the loss of life and property from an earthquake. The project site is not located within an Alquist-Priolo active fault zone (Bryant and Hart 2007), and there is no evidence of active faulting within or near the project site (City of Roseville 2023).
Ground Shaking
Ground shaking is a general term referring to all aspects of motion of the earth’s surface resulting from an earthquake, and is normally the major cause of damage in seismic events. The extent of ground shaking is controlled by the magnitude and intensity of the earthquake, distance from the epicenter, and local geologic conditions.
The city is underlain by a relatively stable geology with low seismic shaking potential, but the soil and geologic characteristics still play a role in determining safety procedures (City of Roseville 2020b). An earthquake that registers
5.0 on the Richter magnitude scale (which is used to quantify the energy released by an earthquake) is of moderate intensity and would be widely felt but would not cause damage to buildings unless they are poorly constructed. The last nearby seismic event measuring at least 4.0 on the Richter scale occurred between Placerville and Roseville in 1908 on a north-south fault line between Folsom and Auburn (City of Roseville 2023: 11-6). No significant seismic event has been recorded since that time within the vicinity of Roseville, and the South Placer area is classified as a low severity earthquake zone. No Alquist-Priolo Earthquake Fault Zones are in the City of Roseville or in Placer County (DOC 2025a). The types of damage encountered for magnitudes of earthquakes can vary (Table 3.9-1).
Geology and Soils Ascent
City of Roseville
3.9-8 Roseville Environmental Utilities Operations Center Project Draft EIR Table 3.9-1 The Modified Mercalli Scale of Earthquake Intensities If most of these effects are observed Then the intensity is Shaking: not felt. 1.0
Shaking: weak, felt only by few people at rest, especially on upper floors of buildings 2.0 Shaking: weak, felt noticeably by persons indoors, especially on upper floors of buildings. Many people do not recognize it as an earthquake. Standing motor cars may rock slightly. Vibrations similar to the passing of a truck.
3.0 Shaking: light, felt indoors by many outdoors by few during the day. At night, some awakened. Dishes, windows, doors disturbed; walls make cracking sound. Sensation like heavy truck striking building. Standing motor cars rock noticeably.
4.0 Shaking: moderate, felt by nearly everyone. Many awakened. Some dishes, windows broken. Unstable objects overturned. 5.0 Shaking: strong, felt by all. Many frightened. Some heavy furniture moved. A few instances of fallen plaster. Damage slight. 6.0 Shaking: very strong, damage negligible in buildings of good design and construction. Slight to moderate in well-built ordinary structures. Considerable damage in poorly built or badly designed structures. Some chimneys broken.
7.0 Shaking: severe, damage slight in specially designed structures. Considerable damage in ordinary buildings with partial collapse. Damage great in poorly constructed buildings. Fall of chimneys, factory stacks, columns, monuments, walls heavy furniture overturned.
8.0 Shaking: violent, damage considerable in specially designed structures and well-designed structures. Damage great in substantial buildings, with partial collapse. Buildings shifted on foundations.
9.0 Shaking: extreme, some well-built wooden structures destroyed. Most masonry and frame structures destroyed with foundations. Rails bent.
10.0 Source: USGS 1989.
Liquefaction and Lateral Spreading
Liquefaction is a phenomenon in which loose, saturated, granular soil deposits lose a significant portion of their shear strength because of excess pore water pressure buildup. An earthquake typically causes the increase in pore water pressure and subsequent liquefaction. These soils behave like a liquid during seismic shaking and re-solidify when shaking stops. The potential for liquefaction is highest in areas with high groundwater and loose, fine, sandy soils at depths of less than 50 feet. Based on mapping conducted pursuant to the Alquist-Priolo Act, the project site and surrounding area are not identified as located within an area of potential liquefaction (Bryant and Hart 2007). In addition, a geotechnical investigation conducted (HDR 2024) of the project site identified groundwater ranging from approximately 94 feet to 155 feet below the ground surface (bgs). Due to the material density encountered at the project site, liquefaction potential is considered to be minimal (HDR 2024).
Liquefaction may also lead to lateral spreading. Lateral spreading (also known as expansion) is the horizontal movement or spreading of soil toward an “open face,” such as a streambank, the open side of fill embankments, or the sides of levees. It often occurs in response to liquefaction of soils in an adjacent area. The potential for failure from lateral spreading is highest in areas where there is a high groundwater table, where there are relatively soft and recent alluvial deposits, and where creek banks are relatively high. The city of Roseville is composed of well consolidated to very hard, older Pleistocene- to Eocene-age deposits, and active seismic sources are at least 30 miles away. Therefore, it is unlikely that the city would be subject to liquefaction in the event of a large magnitude earthquake. The Sacramento River is located approximately eight miles to the west of the project site and could offer a potential opportunity for lateral spreading. However, because the project site and vicinity are on flat terrain and relatively distant from the Sacramento River, lateral spreading caused by liquefaction is not expected to be a concern.
Landslides
Landslide susceptibility is based on various combinations of factors such as rainfall, rock and soil types, slope, vegetation, seismic conditions, and human construction activities. Generally, landslides are expected to occur most often on slopes steeper than 15 percent, in areas with a history of landslides, and in areas underlain by geologic units that are weakly cemented (City of Roseville 2020b). A landslide susceptibility database provided by the California Department of Conservation (DOC) indicates that the project site is located in an area where susceptibility to land
Ascent Geology and Soils
City of Roseville
Roseville Environmental Utilities Operations Center Project Draft EIR 3.9-9 sliding is considered low due to the general flat terrain at the project site and surrounding area (DOC 2025b). In addition, as illustrated in Figure 3.9-1, slopes on the site are very gradual. Given the gentle nature of the slopes on the site and in the surrounding area, the probability of a landslide is considered low.
PALEONTOLOGICAL RESOURCES
Significant nonrenewable vertebrate and invertebrate fossils and unique geologic units have been documented throughout California. The fossil-yielding potential of a particular area is highly dependent on the geologic age and origin of the underlying rocks (refer to geologic timescale in Table 3.9-2). Paleontological potential refers to the likelihood that a rock unit will yield a unique or significant paleontological resource. All sedimentary rocks, some volcanic rocks, and some low-grade metamorphic rocks have potential to yield paleontological resources. Depending on location, the paleontological potential of subsurface materials generally increases with depth beneath the surface, as well as with proximity to known fossiliferous deposits.
Table 3.9-2 Divisions of Geologic Time
Era Period Time in Millions of Years Ago (approximately) Epoch Cenozoic Quaternary < 0.01
2.6 Pleistocene
Tertiary 5.3 Pliocene
23 Miocene
34 Oligocene
56 Eocene
65 Paleocene
Mesozoic Cretaceous 145
Jurassic 200
Triassic 251
Paleozoic Permian 299
Carboniferous 359
Devonian 416
Silurian 444
Ordovician 488
Cambrian 542
Precambrian 2,500
Source: USGS 2018.
Pleistocene or older (older than 11,000 years) continental sedimentary deposits are considered as having a high paleontological potential while Holocene-age deposits (less than 11,000 years old) are generally considered to have a low paleontological potential because they are geologically immature and are unlikely to have fossilized the remains of organisms. Metamorphic and igneous rocks have a low paleontological potential, either because they formed beneath the surface of the earth (such as granite), or because they have been altered under high heat and pressures, chaotically mixed or severely fractured. Generally, the processes that form igneous and metamorphic rocks are too destructive to preserve identifiable fossil remains.
As described above, the project site is located in the northern part of the Great Valley geomorphic province, which is drained by the Sacramento River (CGS 2002). Geology in the area consists of transitional formations between alluvial deposits of the central valley and volcanic material of the Sierra Nevada. The project site is located entirely within the Holocene
Geology and Soils Ascent
City of Roseville
3.9-10 Roseville Environmental Utilities Operations Center Project Draft EIR Riverbank Formation, which is made up primarily of Pleistocene-age sediments, and is considered paleontologically sensitive (City of Roseville 2020b).
3.9.3 Environmental Impacts and Mitigation Measures
METHODOLOGY
The examination of geology and soils is based on information obtained from reviews of:
available literature, including documents published by the City of Roseville and state and federal agencies; applicable elements from City of Roseville General Plan; and the Preliminary Conceptual Design Geotechnical Report prepared for the project (HDR 2024).
THRESHOLDS OF SIGNIFICANCE
Thresholds of significance are based on Appendix G of the State CEQA Guidelines. The project would cause a significant impact related to geology and soils if it would:
directly or indirectly expose people or structures to potential substantial adverse impacts, including the risk of loss, injury, or death through the rupture of a known earthquake fault, strong seismic shaking, seismic-related ground failure, soil liquefaction, or landslides;
result in substantial soil erosion or the loss of topsoil; locate project facilities on a geologic unit or soil that is unstable, or that would become unstable as a result of the project, and potentially result in on-site or off-site landslide, lateral spreading, subsidence, liquefaction, or collapse;
locate project facilities on expansive soil, creating substantial direct or indirect risks to property; have soils incapable of adequately supporting the use of septic tanks or alternative waste water disposal systems where sewers are not available for the disposal of waste water; or directly or indirectly destroy a unique paleontological resource or site or unique geologic feature.
ISSUES NOT DISCUSSED FURTHER
Fault rupture impacts are limited to areas in the immediate vicinity of an earthquake fault. As previously discussed, the project site is not located in a state-designated Alquist-Priolo Earthquake Fault Zone, and there are no known fault traces that extend through, or occur in the immediate vicinity of, the project site. As described in the Preliminary Geotechnical Report, the project site is not located in an earthquake fault zone, no known faults are located on the project site, and no evidence of recent or active faulting was observed during the field study (HDR 2024). Therefore, surface fault rupture on-site is not anticipated to occur. In addition, the project would be required to comply with CBC requirements for municipal land uses. Compliance with the CBC would ensure that potential impacts related to fault rupture would be minimized. This issue is not discussed further.
As discussed above, the project site is not located in an area susceptible to landslides (DOC 2025b). Because of the generally flat topography that the project site would have following grading and construction activities, the probability of a landslide is considered low. A landslide susceptibility database provided by DOC indicates that the project site is located in an area where land sliding is considered low. As part of standard construction activities, the project site would be appropriately graded for municipal development, which would further reduce the gradient slopes on-site. Compliance with the CBC would ensure soil stability on the site is maintained. For these reasons, the risk of slope instability is negligible. This issue is not discussed further.
Ascent Geology and Soils
City of Roseville
Roseville Environmental Utilities Operations Center Project Draft EIR 3.9-11 The project does not propose the addition of septic tanks or other alternative wastewater disposal systems. The project would be connected to the City’s existing sewer lines and collection system and wastewater would be conveyed by a force main off-site to the Pleasant Grove Wastewater Treatment Plant. As a result, no impact to soils from the use of septic tanks or alternative wastewater disposal systems would occur. This issue is not discussed further.
ENVIRONMENTAL IMPACTS AND MITIGATION MEASURES
Impact 3.9-1: Loss, Injury, or Death Resulting from Seismic Hazards Phase 1
Construction and operation of the project would not exacerbate existing seismic hazards. Compliance with the most recent version of the CBC’s building standards requirements and incorporation of the recommendations of the Preliminary Geotechnical Report into the project design would minimize the project’s potential to cause substantial adverse effects, including risk of loss, injury, or death involving strong seismic ground shaking. This impact would be less than significant.
The city is identified as having relatively low potential for seismic activity and a review of published geologic maps in the General Plan EIR and the Preliminary Geotechnical Report confirm that project implementation is not likely to cause potential adverse effects associated with strong seismic shaking. Excavation and grading would occur on the project site during project construction of Phase 1. However, excavation and grading activities would not alter fault conditions or exacerbate seismic risks. Project structures and final grading would be subject to CBC standards, including Chapter 18, Soils and Foundations, as well as the City of Roseville Design and Construction Standards, which identifies general building foundation design requirements. The project would also be required to comply with the CBC regarding Chapter 16, Structural Design, which identifies both general building structural design requirements and specific seismic safety design requirements for projects. These seismic design criteria are also included as recommendations in the Preliminary Geotechnical Report (HDR 2024). Standard regulatory compliance with the CBC and incorporation of the Preliminary Geotechnical Report recommendations would minimize the project’s potential to cause direct or indirect adverse effects, including risk of loss, injury, or death, involving strong seismic shaking.
Therefore, this impact would be less than significant.
Mitigation Measures
No mitigation is required.
Phase 2
As described above for Phase 1, construction and operation of Phase 2 would not exacerbate existing seismic hazards.
Compliance with the most recent version of the CBC’s building standards requirements and incorporation of the recommendations of the Preliminary Geotechnical Report into the project design would minimize the project’s potential to cause substantial adverse effects, including risk of loss, injury, or death involving strong seismic ground shaking. This impact would be less than significant.
For the same reasons described above for Phase 1, compliance with the CBC and incorporation of the Preliminary Geotechnical Report recommendations would minimize the project’s potential to cause direct or indirect adverse effects, including risk of loss, injury, or death involving strong seismic shaking. This impact would be less than significant.
Mitigation Measures
No mitigation is required.
Geology and Soils Ascent
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3.9-12 Roseville Environmental Utilities Operations Center Project Draft EIR Impact 3.9-2: Result in Substantial Soil Erosion or the Loss of Topsoil Phase 1
The construction activities associated with Phase 1 would involve ground disturbance and soil compaction, which could lead to increased erosion. However, the project site is not located in an area that is highly susceptible to erosion. In addition, project construction would be required to comply with the City of Roseville’s grading ordinance (Section 16.20) and municipal NPDES permit conditions requiring temporary and permanent erosion control best management practices (BMPs). Therefore, the potential for development of the project site to result in increased erosion would be a less-than-significant impact.
Phase 1 would include vegetation removal and mass rough grading of the entire project site (150 acres), including the Phase 2 area. Excavation would be required for the installation of storm drains, utilities, and foundations. Grading of the site would involve approximately 225,000 cubic yards of cut and approximately 333,500 cubic yards of fill, for a net fill of approximately 105,500 cubic yards (Figure 3.9-1). As described in Chapter 2, “Project Description,” it is estimated that approximately 114,000 cubic yards of material would be imported to the site during construction of Phase 1.
These activities would result in temporary disturbance of soil and would expose disturbed areas to storm events. Rain of sufficient intensity and duration could dislodge soil particles, generate runoff, and cause localized erosion. Soil disturbance during the summer months could result in loss of topsoil because of wind erosion. Heavy equipment traffic on the site could result in soil compaction, which would reduce the water holding capacity of the soil, increasing the potential for runoff and erosion. However, because the soils of the project site have low to moderate runoff potential and the site is flat to gently sloped, erosion would be unlikely under normal conditions.
In addition, because Phase 1 would disturb more than one acre of land, a NPDES permit would be required for construction activities, including a SWPPP, prepared by a qualified SWPPP practitioner. The SWPPP would detail the BMPs that would be implemented to minimize erosion, reduce sediment transport, and control stormwater flow from the project area. In addition, the SWPPP would address grading and slope stabilization methods, as well as construction waste disposal methods. Typical temporary BMPs include properly installed physical barriers such as berms, silt fencing, wattles, straw bales, and gabions. Temporary BMPs would be installed before beginning site grading and would be maintained throughout construction until permanent erosion control features are functioning.
The required elements of a SWPPP are discussed in greater detail in Section 3.11, “Hydrology and Water Quality.” The project site is not located in an area that is highly susceptible to erosion. In addition, project construction would be required to comply with City ordinances and NPDES permit conditions requiring temporary and permanent erosion control BMPs. Therefore, the potential for project construction to result in increased erosion would be a lessthan-significant impact.
Mitigation Measures
No mitigation is required.
Phase 2
As described above, mass rough grading of the entire project site (150 acres), including the Phase 2 area, would occur during Phase 1. The project site is not located in an area that is highly susceptible to erosion and project construction would be required to comply with the City of Roseville’s grading ordinance (Section 16.20) and municipal NPDES permit conditions requiring temporary and permanent erosion control BMPs. Therefore, the potential for development of the project site to result in increased erosion would be a less-than-significant impact.
As described above, mass rough grading of the entire project site (150 acres), including the Phase 2 area, would occur during Phase 1. Similar to Phase 1, future development at the project site would require earthwork activities that could temporarily increase the likelihood of erosion and loss of topsoil from wind or stormwater runoff. However, the potential for increased erosion would be addressed through compliance with the City and SWRCB erosion control requirements and project design, as described for Phase 1. Therefore, this impact would be less than significant.
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Roseville Environmental Utilities Operations Center Project Draft EIR 3.9-13 Mitigation Measures
No mitigation is required.
Impact 3.9-3: Be Located on a Geologic Unit or Soil That is Unstable, or That Would Become Unstable as a Result of the Project
Phase 1
The project site has a relatively flat and level topography and does not contain hills or sharp gradients or slopes that would otherwise have the potential to become unstable. In addition, the project site is not located within an area prone to landslides or liquefaction. Therefore, the project would not be located on a geologic unit or soil that is unstable or that would become unstable as a result of the project. This impact would be less than significant.
As described in Chapter 2, “Project Description,” Phase 1 may involve the demolition and site clearing of existing structures located on the project site, including a former residence, remnants from a former pheasant club, as well as agricultural support structures. As discussed above, the project site is relatively flat topographically and does not contain hills or sharp gradients or slopes that would otherwise have the potential to become unstable due to project construction. In addition, the project site is not identified as being within an area prone to liquefaction or landslides (DOC 2025a).
Based on the CGS’s Earthquake Fault Zone map, which identifies liquefaction- and landslide-prone areas, the project site is not located in an area prone to liquefaction (DOC 2025b). The Preliminary Geotechnical Report concluded that, due to the distance to earthquake fault and seismic hazard zones, the potential for damage on the site from liquefaction, lateral spreading, seismic settlement, and slope instability/landslides is negligible (HDR 2024). In addition, the Preliminary Geotechnical Report states that the soils underlying the project site and depth to groundwater indicate that the project has a low potential for impact due to liquefaction from a seismic event.
The geotechnical recommendations are based on a review of existing geotechnical reports and a review of published geologic reports and maps of the region. A subsurface investigation was conducted and the interpretation of surface soil conditions based on the laboratory test results conducted during the investigation is provided in the Preliminary Geotechnical Report. Recommendations regarding soils included parameters for soil compaction; properly stripping the site of vegetation and reusing or stockpiling topsoil for fill; proper disposal of organic debris; parameters under which materials generated during construction can be reused; recommendations regarding the proper abandonment of any existing utility pipelines, if encountered, which extend beyond the limits of the proposed construction; and over-excavation recommendations for building foundations.
Furthermore, implementation of the recommendations of the Preliminary Geotechnical Report pertaining to site grading and earthwork improvements would further stabilize on-site soils. These geotechnical recommendations would be incorporated into the site’s Improvement Plans, which the City would be responsible for monitoring and enforcing, and would require that the soils underlying the project site would be properly stabilized. Further, these recommendations would require that the project is constructed to the proper specifications and design standards of the most up to date codes and regulations governing building construction, materials, and safety provided in Section
16.20 of the Roseville Municipal Code and the 2022 CBC regarding geotechnical and soil stability.
Therefore, the project would not be located on a geologic unit or soil that is unstable, or that would become unstable as a result of the project. This impact would be less than significant.
Mitigation Measures
No mitigation is required.
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3.9-14 Roseville Environmental Utilities Operations Center Project Draft EIR Phase 2
As described above for Phase 1, the project site has a relatively flat and level topography and does not contain hills or sharp gradients or slopes that would otherwise have the potential to become unstable. In addition, the project site is not located within an area prone to landslides or liquefaction. Therefore, the project would not be located on a geologic unit or soil that is unstable or that would become unstable as a result of the project. This impact would be less than significant.
Similar to Phase 1, implementation of the recommendations of the Preliminary Geotechnical Report pertaining to site grading and earthwork improvements would further stabilize onsite soils. These geotechnical recommendations would be incorporated into the site’s Improvement Plans, which the City would be responsible for monitoring and enforcing, and would require that the soils underlying the project site would be properly stabilized. Further, these recommendations would require that the project is constructed to the proper specifications and design standards of the most up to date codes and regulations governing building construction, materials, and safety provided in Section
16.20 of the Roseville Municipal Code and the 2022 CBC regarding geotechnical and soil stability.
Therefore, the project would not be located on a geologic unit or soil that is unstable, or that would become unstable as a result of the project. This impact would be less than significant.
Mitigation Measures
No mitigation is required.
Impact 3.9-4: Directly or Indirectly Destroy a Unique Paleontological Resource or Site or Unique Geologic Feature
Phase 1
As identified in the Preliminary Geotechnical Report, the project site consists of geologic conditions common in the region and does not contain unique geologic features. Nonetheless, the potential to discover paleontological resources on-site still exists. Project-related ground-disturbing activities associated with Phase 1, including off-site roadway and utility improvements, may result in inadvertent discovery of unique paleontological resources. If a unique paleontological resource or site is encountered during excavation, it could be damaged or destroyed if protective measures are not in place. As a result, this impact would be potentially significant.
Construction of Phase 1 would result in 116 acres of ground disturbance and could affect unique paleontological resources. The project vicinity and project site are composed of the Riverbank Formation, and younger, unconsolidated Quaternary alluvium, an area which is considered paleontologically sensitive (City of Roseville 2020b).
However, although shallow excavations in younger Quaternary alluvium are unlikely to expose significant fossils, inadvertent discovery is possible if excavation extends below the topsoil into deeper, older Quaternary deposits.
As described in the Preliminary Geotechnical Report, excavation associated with preparation of the project site would involve depths of up to 6 feet bgs for the proposed building pads, stormwater retention basins, and underground utilities, before receiving imported fill. Therefore, the project would have the potential to unearth as-yet unknown paleontological resources. Because the project would involve excavation at depths up to 6 feet bgs, there is potential for inadvertent discovery of as-yet unknown paleontological resources on-site during construction activities. If a unique paleontological resource or site is encountered during excavation, it could be damaged or destroyed if protective measures are not in place. This impact would be potentially significant.
Mitigation Measures
Mitigation Measure 3.9-4a: Provide Paleontological Training for Construction Personnel Before construction begins, the City shall ensure that all construction workers who will be on-site during construction receive training materials provided by a qualified paleontologist meeting the Secretary of the Interior’s qualifications
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Roseville Environmental Utilities Operations Center Project Draft EIR 3.9-15 to ensure that construction personnel can correctly identify fossilized materials in the event of inadvertent discovery.
The training materials could be in the form of a presentation (live or recorded) and/or written materials provided to construction workers.
Mitigation Measure 3.9-4b: Implement Procedures for the Inadvertent Discovery of Paleontological Resources If any paleontological resources are encountered during project construction, the construction contractor shall ensure that all activities in the immediate area of the find are halted and that the City is informed. The City shall then retain a qualified paleontologist meeting the Secretary of the Interior’s qualifications to evaluate the discovery, prepare a report evaluating the discovery, and include recommendations in the report pursuant to the guidelines established by the Society of Vertebrate Paleontology, including, if applicable, development and implementation of a paleontological resource impact mitigation program for treatment of the discovery.
Significance after Mitigation
Implementation of Mitigation Measures 3.9-4a and 3.9-4b would reduce impacts to unique paleontological resources because construction personnel would be properly trained on the discovery of unique paleontological resources, and in the event fossil specimens are encountered during construction activities, a paleontologist would be retained to evaluate the fossil and recommend appropriate actions. As a result, implementation of these mitigation measures would reduce the project’s potential impact associated with inadvertent discovery of paleontological resources to a less-than-significant level.
Phase 2
As mentioned above, the project site consists of geologic conditions common in the region and does not contain unique geologic features. Nonetheless, the potential to discover paleontological resources on-site still exists. Projectrelated ground-disturbing activities associated with Phase 2, including off-site roadway and utility improvements, may result in inadvertent discovery of unique paleontological resources. If a unique paleontological resource or site is encountered during excavation, it could be damaged or destroyed if protective measures are not in place. As a result, this impact would be potentially significant.
Construction of Phase 2 would result in 34 acres of ground disturbance and could affect unique paleontological resources. Similar to Phase 1, excavation associated with preparation of the project site would involve depths of up to 6 feet bgs during construction activities. Therefore, the project would have the potential to unearth as-yet unknown paleontological resources. If a unique paleontological resource or site is encountered during excavation, it could be damaged or destroyed if protective measures are not in place. This impact would be potentially significant.
Mitigation Measures
Implement Mitigation Measures 3.9-4a and 3.9-4b, described above.
Significance after Mitigation
Implementation of Mitigation Measures 3.9-4a and 3.9-4b would reduce impacts to unique paleontological resources because construction personnel would be properly trained on the discovery of unique paleontological resources, and in the event fossil specimens are encountered during construction activities, a paleontologist would be retained to evaluate the fossil and recommend appropriate actions. As a result, implementation of these mitigation measures would reduce the project’s potential impact associated with inadvertent discovery of paleontological resources to a less-than-significant level.
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Roseville Environmental Utilities Operations Center Project Draft EIR 3.10-1
3.10 HAZARDS AND HAZARDOUS MATERIALS
This section describes the potential impacts of the proposed Environmental Utilities (EU) Operations Center (project) related to hazards and hazardous materials. Potential impacts to emergency response services, including fire, medical, and police services, are addressed in Section 3.14, “Public Services.” Potential impacts related to wildfire and evacuation are addressed in Section 3.17, “Wildfire.”
The evaluation provided in this section is based on a review of the Phase I Environmental Site Assessment (ESA) and Phase II ESA completed for the project by Rosewood Environmental Engineering (REE) (REE 2002, 2003), and an updated data search of various agency lists of hazardous materials sites, including the California Department of Toxic Substances Control’s (DTSC) EnviroStor Database (DTSC 2025a) and the State Water Resources Control Board’s (SWRCB) GeoTracker Database (SWRCB 2025).
For purposes of this section, the term “hazardous materials” refers to both hazardous substances and hazardous wastes. A “hazardous material” is defined in the Code of Federal Regulations (CFR) as “a substance or material that … is capable of posing an unreasonable risk to health, safety, and property when transported in commerce” (49 CFR 171.8). California Health and Safety Code Section 25501 defines a hazardous material as follows:
“Hazardous material” means any material that, because of its quantity, concentration, physical, or chemical characteristics, poses a significant present or potential hazard to human health and safety or to the environment if released into the workplace or the environment. “Hazardous materials” include, but are not limited to, hazardous substances, hazardous waste, and any material which a handler or the administering agency has a reasonable basis for believing that it would be injurious to the health and safety of persons or harmful to the environment if released into the workplace or the environment. “Hazardous wastes” are defined in California Health and Safety Code Section 25141(b) as wastes that:
… because of their quantity, concentration, or physical, chemical, or infectious characteristics, [may either] cause, or significantly contribute to an increase in mortality or an increase in serious illness [or] pose a substantial present or potential hazard to human health or the environment when improperly treated, stored, transported, disposed of, or otherwise managed.
One comment letter regarding hazards and hazardous materials was received in response to the notice of preparation (see Appendix A). Placer County Division of Environmental Health requested that the City consider the potential impacts related to the receipt and/or handling of hazardous waste as part of project operation.
3.10.1 Regulatory Setting
FEDERAL
Management of Hazardous Materials
Various federal laws address the proper handling, use, storage, and disposal of hazardous materials, as well as requiring measures to prevent or mitigate injury to health or the environment if such materials are accidentally released. The US Environmental Protection Agency (EPA) is the agency primarily responsible for enforcement and implementation of federal laws and regulations pertaining to hazardous materials. Applicable federal regulations pertaining to hazardous materials are primarily contained in CFR Titles 29, 40, and 49. Hazardous materials, as defined in the Code of Federal Regulations, are listed in 49 CFR 172.101. Management of hazardous materials is governed by the following laws. The Toxic Substances Control Act of 1976 (15 US Code [USC] Section 2601 et seq.) regulates the manufacturing, inventory, and disposition of industrial chemicals, including hazardous materials. Section 403 of the Toxic Substances Control Act establishes standards for lead-based paint hazards in paint, dust, and soil.
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3.10-2 Roseville Environmental Utilities Operations Center Project Draft EIR The Resource Conservation and Recovery Act of 1976 (42 USC 6901 et seq.) is the law under which EPA regulates hazardous waste from the time the waste is generated until its final disposal (“cradle to grave”). The Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (also called the Superfund Act or CERCLA) (42 USC 9601 et seq.) gives EPA authority to seek out parties responsible for releases of hazardous substances and ensure their cooperation in site remediation. The Superfund Amendments and Reauthorization Act of 1986 (Public Law 99-499; USC Title 42, Chapter 116), also known as SARA Title III or the Emergency Planning and Community Right-to-Know Act of 1986 (EPCRA), imposes hazardous materials planning requirements to help protect local communities in the event of accidental release.
Department of Transportation Hazardous Materials Regulations The US Department of Transportation (USDOT) regulates transport of hazardous materials between states and is responsible for protecting the public from dangers associated with such transport. The federal hazardous materials transportation law, 49 USC 5101 et seq. (formerly the Hazardous Materials Transportation Act 49 USC 1801 et seq.) is the basic statute regulating transport of hazardous materials in the United States. This is also covered in 49 Code of Federal Regulations Part 100 through 185 (49 CFR 100-185), which covers all aspects of hazardous materials packaging, handling, and transportation. Parts 107 (Hazard Materials Program), 130 (Oil Spill Prevention and Response), 172 (Emergency Response), 173 (Packaging Requirements), 177 (Highway Transportation), 178 (Packaging Specifications), and 180 (Packaging Maintenance) would all apply to goods movement to and from the project site. Hazardous materials transport regulations are enforced by the Federal Highway Administration (FHWA), the US Coast Guard, the Federal Railroad Administration, and the Federal Aviation Administration (FAA). Enforcement of these USDOT regulations is shared by each of the following administrations under delegations from the Secretary of the USDOT:
Research and Special Programs Administration is responsible for container manufacturers, reconditioners, and retesters and shares authority over shippers of hazardous materials. FHWA enforces all regulations pertaining to motor carriers. Federal Railroad Administration enforces all regulations pertaining to rail carriers. FAA enforces all regulations pertaining to air carriers. US Coast Guard enforces all regulations pertaining to shipments by water.
Occupational Safety and Health Act of 1970
The federal Occupational Safety and Health Administration (OSHA) is the agency responsible for assuring worker safety in the handling and use of chemicals identified in the Occupational Safety and Health Act of 1970 (Public Law 91-596, 9 USC 651 et seq.). OSHA has adopted numerous regulations pertaining to worker safety, contained in 29 CFR 1910 Subpart H regarding hazardous materials and 29 CFR 1926 Subpart H regarding construction activities. These regulations set standards for safe workplaces and work practices, including training, outreach, and education regarding the standards of safely handling hazardous materials. A major component of the Act is the requirement that employers implement the OSHA Hazard Communication Standard to provide information to employees about the existence and potential risks of exposure to hazardous substances in the workplace. As part of the Hazard Communication Standard, employers must:
obtain material safety data sheets from chemical manufacturers that identify the types and handling requirements of hazardous materials used in given areas; make the material safety data sheets available to their employees; label chemical containers in the workplace;
develop and maintain a written hazard communication program; and develop and implement programs to train employees about hazardous materials.
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Roseville Environmental Utilities Operations Center Project Draft EIR 3.10-3 STATE
Superfund Amendments and Reauthorization Act, Emergency Planning and Community Rightto-Know Act In California, both federal and state community right-to-know laws are coordinated through the Governor’s Office of Emergency Services. The federal law, SARA Title III or EPCRA, described above, encourages and supports emergency planning efforts at the state and local levels and to provide local governments and the public with information about potential chemical hazards in their communities. Because of the community right-to-know laws, information is collected from facilities that handle (e.g., produce, use, store) hazardous materials above certain quantities. The provisions of EPCRA apply to four major categories:
emergency planning,
emergency release notification,
reporting of hazardous chemical storage, and
inventory of toxic chemical releases.
California Health and Safety Code
The corresponding state law is Chapter 6.95 of the California Health and Safety Code (Health and Safety Code). This program consolidates, coordinates, and makes consistent the administrative requirements, permits, inspections, and enforcement activities of the environmental and emergency response programs and provides authority to the Certified Unified Program Agency (CUPA). The CUPA Program was created by Senate Bill 1082 in 1993 to consolidate, coordinate, and make consistent the administrative requirements, permits, inspections, and enforcement activities of six environmental and emergency management programs (CalCUPA Forum 2025). The CUPA Program is intended to provide relief to businesses complying with the overlapping and sometimes conflicting requirements of formerly independently managed programs. Cities and counties can apply to become a CUPA and receive delegated authority from state agencies to enforce laws in their jurisdiction. Placer County Environmental Health is the designated CUPA for all areas of the county, except within the City of Roseville. The Roseville Fire Department is the CUPA for the City of Roseville and therefore has jurisdiction over the project site and is responsible for implementing and enforcing the following:
California Accidental Release Prevention Program. This program requires any business that handles more than threshold quantities of an extremely hazardous substance to develop a Risk Management Plan. The Risk Management Plan is implemented by the business to prevent or mitigate releases of regulated substances that could have offsite consequences through hazard identification, planning, source reduction, maintenance, training, and engineering controls.
Hazardous Materials Business Plan/Hazardous Materials Inventory Statements. Hazardous Materials Business Plans contain basic information regarding the location, type, quantity, health risks of hazardous materials and/or waste, emergency response procedures including emergency spill cleanup supplies and equipment. Each business must prepare a Hazardous Material Business Plan if that business uses, handles, or stores a hazardous material and/or waste or an extremely hazardous material in quantities greater than or equal to the following:
55 gallons for a liquid;
500 pounds for a solid;
200 cubic feet for any compressed gas; or
Threshold planning quantities of an extremely hazardous substance Hazardous Waste Generator Program. This program regulates businesses that generate any amount of a hazardous waste. Proper handling, recycling, treating, storing, and disposing of hazardous waste are key elements to this program.
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3.10-4 Roseville Environmental Utilities Operations Center Project Draft EIR California Department of Toxic Substances Control
DTSC, a division of the California Environmental Protection Agency, has primary regulatory responsibility over hazardous materials in California, working in conjunction with EPA to enforce and implement hazardous materials laws and regulations. As required by Section 65962.5 of the California Government Code, DTSC maintains a hazardous waste and substances site list for the State, known as the Cortese List. Individual regional water quality control boards (RWQCBs) are the lead agencies responsible for identifying, monitoring, and cleaning up leaking underground storage tanks (LUSTs). The project site is located in Region 5, the Central Valley Region, and governed by the Central Valley Regional Water Quality Control Board (see also Section 3.11, “Hydrology and Water Quality”).
California Department of Transportation
The State of California has adopted USDOT regulations for the movement of hazardous materials originating within the state and passing through the state; state regulations are contained in 26 California Code of Regulations (CCR).
State agencies with primary responsibility for enforcing state regulations and responding to hazardous materials transportation emergencies are the California Highway Patrol (CHP) and the California Department of Transportation.
Together, these agencies determine container types used and license hazardous waste haulers to transport hazardous waste on public roads. California has developed an emergency response plan to coordinate emergency services provided by federal, state, and local governments and private agencies. Response to hazardous materials incidents is one part of the plan. The plan is managed by the Governor’s Office of Emergency Services, which coordinates the responses of other agencies in the project vicinity.
Porter-Cologne Water Quality Act
Through the Porter-Cologne Water Quality Act and the National Pollution Discharge Elimination System (NPDES) program, RWQCBs have the authority to require proper management of hazardous materials during project construction. For a detailed description of the Porter-Cologne Water Quality Act, the NPDES program, and the role of the Central Valley RWQCB, see Section 3.11, “Hydrology and Water Quality.” The State Water Board adopted the statewide NPDES General Permit in August 1999. The state requires that projects disturbing more than one acre of land during construction file a Notice of Intent with the RWQCB to be covered under this permit. Construction activities subject to the Construction General Permit include clearing, grading, stockpiling, and excavation. Dischargers are required to eliminate or reduce non-stormwater discharges to storm sewer systems and other waters. A stormwater pollution prevention plan (SWPPP) must be developed and implemented for each site covered by the permit. The SWPPP must include best management plans (BMPs) designed to prevent construction pollutants from contacting stormwater and keep products of erosion from moving off‐site into receiving waters throughout the construction and life of the project; the BMPs must address source control and, if necessary, pollutant control.
SWRCB also maintains GeoTracker, which is the data management system for sites that affect, or have the potential to affect, water quality in California, with an emphasis on groundwater. GeoTracker contains records for sites that require cleanup, such as LUSTs, Department of Defense sites, and Cleanup Program sites. GeoTracker also contains records for various unregulated projects as well as permitted facilities, including irrigated lands, oil and gas production, operating permitted USTs, and land disposal sites.
California Occupational Safety and Health Administration The California Occupational Safety and Health Administration (Cal/OSHA) assumes primary responsibility for developing and enforcing workplace safety regulations within the state. Cal/OSHA standards are typically more stringent than federal OSHA regulations and are presented in Title 8 of the CCR. Cal/OSHA conducts onsite evaluations and issues notices of violation to enforce necessary improvements to health and safety practices.
California Labor Code (Division 5 Parts 1 and 7)
California Labor Code regulations ensure appropriate training regarding the use and handling of hazardous materials and the operation of equipment and machines that use, store, transport, or dispose of hazardous materials. For example, Division 5, Part 1, Chapter 2.5, requires that employees who handle hazardous materials are appropriately trained and informed about the materials; Division 5, Part 7, requires that employees who work with volatile flammable liquids are outfitted with appropriate safety gear and clothing.
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Roseville Environmental Utilities Operations Center Project Draft EIR 3.10-5 Emergency Response and Evacuation Plans
The State of California Emergency Plan was adopted on October 1, 2017, and describes how state government mobilizes and responds to emergencies and disasters in coordination with partners in all levels of government, the private sector, non-profits, and community-based organizations. The Plan also works in conjunction with the California Emergency Services Act and outlines a robust program of emergency preparedness, response, recovery, and mitigation for all hazards, both natural and human-caused. All local governments with a certified disaster council are required to develop their own emergency operations plan for their jurisdiction that meets state and federal requirements. Local emergency operations plans contain specific emergency planning considerations, such as evacuation and transportation, sheltering, hazard specific planning, regional planning, public-private partnerships, and recovery planning (California Governor’s OES 2017). As of the writing of this document, the 2024 State Emergency Plan is being developed and is currently undergoing public review. See the website for additional information (https://www.caloes.ca.gov/office-of-the-director/ operations/planning-preparedness-prevention/planning-preparedness/california-state-emergency-plan/).
LOCAL
City of Roseville General Plan
The Safety Element of the City of Roseville General Plan (2020a) contains the following policies that may be applicable to the project:
Policy SAFE 4.1: Continue to pursue and promote fire prevention programs and standards. Policy SAFE 4.4: Provide a comprehensive emergency medical services program to deliver basic and advanced life support services.
Policy SAFE 4.5: Provide highly trained personnel to ensure effective suppression of fires and safety for firefighters. Policy SAFE 4.7: Phase the timing of the construction of fire stations to be available to serve the surrounding service area.
Policy SAFE 4.8: Continually update the Roseville Emergency Operations Plan and ensure that participants are prepared to efficiently carry out assigned functions.
City of Roseville 2025 Design and Construction Standards Section 8 of the Roseville design standards require a minimum flow of water for fire protection in accordance with the California Fire Code, as adopted by the Roseville Fire Department. The required fire flow for multi-family, commercial, business, industrial, and school areas is determined on a case-by-case basis by the Roseville Fire Department, but may not exceed 4,000 gallons per minute, provided the buildings are fully sprinklered. For buildings that are not sprinklered, project applicants must contact the Roseville Fire Department.
Fire hydrants shall be placed at street intersections wherever possible. Fire hydrants and blow-offs not located at intersections shall be installed on property lines between lots. Fire hydrants and blow-offs shall have a maximum spacing of 500 feet measured along the street frontage in residential areas and a maximum spacing of 350 feet in all other areas. Hydrants shall be required within a cul-de-sac or dead-end street measuring more than 250 feet as measured from the curb return of the intersecting street and the end of the bulb or street.
Sections 5, 6, and 7 of the Roseville design standards contain requirements that are intended to provide safe access to property and on streets throughout the City for motorists and emergency vehicles including driveways, turn lanes, streets, and traffic lights.
Roseville Emergency Operations Plan and Multi-Hazard Mitigation Plan The City of Roseville’s Emergency Operations Plan (City of Roseville 2011) describes organizational and operational responsibilities in the event of an emergency, including hazardous materials emergencies and clean up and decontamination procedures. The Emergency Operations Plan is an extension of the City’s Multi-Hazard Mitigation Plan and follows nationally adopted Incident Command System guidelines.
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3.10-6 Roseville Environmental Utilities Operations Center Project Draft EIR The City’s Multi-Hazard Mitigation Plan: 2023 Update, adopted in November 2023, was developed to evaluate hazards within the City and identifies planning tools, policy changes, programs, projects, and other activities that can mitigate the impacts of hazards (City of Roseville 2023). Through mutual aid agreements, the Roseville Fire Department can also request services from the Placer County, City of Sacramento, and Sacramento Metropolitan Fire District Hazardous Materials Response Teams in the event of a large-scale incident. The Roseville Fire Department also assists the CHP, OES, and other responding agencies as requested, in the event of a hazardous materials spill on State Route 65 or Interstate 80.
City of Roseville Fire Department
Fire suppression services for the City of Roseville, including the project site, are provided by local fire stations operated by the Roseville Fire Department. The City of Roseville Fire Department has a Fire & Life Safety Division that manages a comprehensive inspection program that includes annual fire inspections, CUPA inspections, and construction inspections.
City of Roseville Municipal Code
Chapter 9.60 of the Roseville Municipal Code establishes regulations for the identification and disclosure of hazardous materials use and its management within the City.
3.10.2 Environmental Setting
The following describes existing conditions related to hazards and hazardous materials at and near the project site, including the degree to which sensitive receptors (i.e., schools and residences) are located nearby.
PHASE I ESA
A Phase I ESA for a 427-acre property (that includes the project site) located at 8100 Phillip Road, near Pleasant Grove, California, was completed by REE in September 2002 (REE 2002). A review of available historical information for the site indicates that the site has been continuously cultivated since at least the 1930s with rotational crops, primarily hay and rice; various herbicides are used at the site to control weeds in the rice fields and pesticides are used as needed, depending on the year’s prevalence of rice-destroying organisms, and the pest-control chemicals are subcontracted such that no products are stored onsite (REE 2002). The pesticides and herbicides used on the site have low environmental persistence in soil and water; however, persistent chemicals may have been used from the 1940s through the 1970s (REE 2002). Due to this, a screening-level assessment was recommended for these substances in the soil to determine any potential health hazards or need for disposal. The results of the screening assessment are provided below.
Diesel fuels, hydrocarbon-based lubricants, and hydraulic fluid have been used in conjunction with farming operations onsite for several decades and soil staining was observed near the storage and transfer areas of these substances; the staining indicates a release of petroleum products onto the land surface (REE 2002). Other hazardous substances, including lead-acid batteries, paint, and pesticides are stored in the equipment yard or barn on the property, and these potentially hazardous substances require proper disposal if not utilized prior to demolition (REE 2002). No indication of hazardous waste or refuse disposals, such as artificially mounded soil, ground settlement, chemical odors, or empty hazardous material containers were observed during the site reconnaissance.
As a result of the Phase I ESA analysis, further environmental assessment was recommended to characterize the substances and evaluate the vertical and horizontal extent of the stained soil in areas of the equipment yard and adjacent to the irrigation wells. As a result of these conclusions, a Phase II ESA was conducted for the project site in February 2003.
PHASE II ESA
A Phase II ESA was completed to screen soil samples in certain stained areas for possible residual persistent pesticides related to past agricultural activities onsite and for petroleum products in the area of aboveground fuel tanks and 55-gallon drums (REE 2003). The results of the Phase II ESA concluded that petroleum hydrocarbon
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Roseville Environmental Utilities Operations Center Project Draft EIR 3.10-7 staining onsite is very minor and does not represent a significant or reportable environmental concern. In the area of the 250-gallon aboveground storage tank located southwest of the former residence (where the Vendor Lease Area would be located), it is estimated that approximately 5 cubic yards of soil are affected. The Phase II ESA recommended sampling and evaluation of this soil prior to building demolition and/or ground disturbance to determine the potential for contaminants.
HAZARDOUS MATERIALS DATABASE RESULTS
A record search was conducted to identify any onsite or nearby known contamination site. As shown on the DTSC EnviroStor database, the project is not located on a site which is included on a list of hazardous materials sites compiled pursuant to Government Code Section 65962.5 (DTSC 2025a). The project site is also not listed on GeoTracker, which is the SWRCB data management system for sites that impact or have the potential to impact water quality in California, with an emphasis on groundwater (SWRCB 2025).
SCHOOLS
The nearest school to the project site is Orchard Ranch Elementary School, which is 2.25 miles southeast of the project site and approximately 1 mile southeast of the easternmost point of Philip Road that would be improved as part of the project. Orchard Ranch Elementary School serves transitional kindergarten through 5th grade.
AIRPORTS
The nearest airport is Lincoln Regional Airport, which is approximately 8 miles northeast of the project site in the City of Lincoln. The Lincoln Regional Airport is a public airport. The project site is not within an airport land use plan area.
3.10.3 Environmental Impacts and Mitigation Measures
METHODOLOGY
The following reports and data sources document potential hazardous conditions at the project site and were reviewed for this analysis:
the DTSC EnviroStor Database (DTSC 2025a);
the SWRCB GeoTracker Database (SWRCB 2025);
the Safety Element of the City of Roseville General Plan (City of Roseville 2020a); the City of Roseville Final Environmental Impact Report for the 2035 General Plan Update (City of Roseville 2020b);
the Phase I ESA prepared for the project site (REE 2002); and the Phase II ESA prepared for the project site (REE 2003).
Project construction and operation were evaluated together with the hazardous materials information gathered from these sources to determine whether any risks to public health and safety or other conflicts would occur.
THRESHOLDS OF SIGNIFICANCE
Thresholds of significance are based on Appendix G of the State CEQA Guidelines. The project would cause a significant impact related to hazards and hazardous materials if it would:
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3.10-8 Roseville Environmental Utilities Operations Center Project Draft EIR create a significant hazard to the public or the environment through the routine transport, use, or disposal of hazardous materials;
create a significant hazard to the public or the environment through reasonably foreseeable upset and/or accident conditions involving the release of hazardous materials into the environment; emit hazardous emissions or handle hazardous or acutely hazardous materials, substances, or waste within onequarter mile of an existing or proposed school; be located on a site which is included on a list of hazardous materials sites compiled pursuant to Government Code Section 65962.5 and, as a result, would it create a significant hazard to the public or the environment; for a project located within an airport land use plan or, where such a plan has not been adopted, within two miles of a public airport or public use airport, would the project result in a safety hazard or excessive noise for people residing or working in the project area; or
impair implementation of or physically interfere with an adopted emergency response plan or emergency evacuation plan.
ISSUES NOT DISCUSSED FURTHER
The school nearest to the project site is Orchard Ranch Elementary School, which is 2.25 miles southeast of the project site. Because there are no schools within 0.25-mile of the site, this issue is not discussed further in this Draft EIR.
The project site is not on a list of hazardous materials sites compiled pursuant to Government Code Section 65962.5 (Cortese List). Therefore, this issue is not discussed further in this Draft EIR.
The nearest airport is Lincoln Regional Airport, which is 7.5 miles northeast of the project site in the city of Lincoln.
The project site is not within an airport land use plan area or within 2 miles of a public airport or public use airport, or within the vicinity of a private airstrip. Implementing the project would not result in an aviation-related safety hazard for people residing or working in the project area. Therefore, this issue is not discussed further in this Draft EIR.
ENVIRONMENTAL IMPACTS AND MITIGATION MEASURES
Impact 3.10-1: Create a Significant Hazard to the Public or the Environment through the Routine Transport, Use, Storage, or Disposal of Hazardous Materials Phase 1
Construction of Phase 1 of the project would involve the storage, use, and transport of hazardous materials at the project site. Handling hazardous materials would be required to comply with existing local, state, and federal regulations. Operation of Phase 1 of the project would also require storage, use, and transport of hazardous materials. Additionally, the project includes a household hazardous waste drop off facility, which would receive, classify, bulk, store, and ship hazardous waste. Because the transport, use, storage, and disposal of hazardous materials would be required to comply with laws and regulations intended to reduce potential impacts to workers and the environment, this impact would be less than significant.
Phase 1 of the project would include the partial construction of the Resource Recovery and Transfer Operations (RRTO) Facility that would provide an onsite materials recovery facility to segregate recyclable material; an area for receiving and transferring municipal solid waste; and an area for receiving, processing, and transferring organic waste; the Vendor Lease Area for prospective vendors to commit materials to the RRTO Facility; and the Corporation Yard, which includes the EU Operations Facility that would provide office and storage space for the EU Department and an equipment maintenance facility. The total acreage for Phase 1 is 116 acres and includes 402,400 square feet of building area (see Table 2-2 in Section 2, “Project Description”).
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Roseville Environmental Utilities Operations Center Project Draft EIR 3.10-9 The project site is predominantly agricultural in use and is leased for rice and hay farming. Several structures are located on the site and these structures would be demolished prior to project development, although the former residence may be used as a temporary office or by a vendor as the vendor lease office.
Construction activities would include demolition, grading, construction of buildings, and paving. This would involve the temporary transport, use, storage, and disposal of typical construction-related hazardous materials and petroleum products, such as cement products, fuels, lubricants, solvents, and cleaning agents with strong basic or acidic chemicals. Use of hazardous materials during construction would be in small quantities and would be temporary.
These materials would be required to be properly stored, handled, used, transported, and disposed of in accordance with applicable regulations and laws, which include the Resource Conservation and Recovery Act (RCRA), US DOT Hazardous Materials Regulations, the Health and Safety Code, Labor Code, NPDES Construction General Permit, and Roseville Municipal Code Chapter 9.60, all of which are discussed above under Section 3.10.1, “Regulatory Setting.” For example, because project construction activities would disturb an overall area of more than one acre of land, the project would be subject to the SWRCB NPDES Construction General Permit requirements. This would require the implementation of a SWPPP to address spill prevention and containment plans to avoid spills and the release of hazardous materials and wastes into the environment. In addition, BMPs would also be implemented as part of the SWPPP to minimize stormwater pollution and erosion control measures, which may include scheduling construction activity during dry weather when possible; drainage swales to control runoff flow; protection of storm drainage inlets with gravel bags or catch basin inserts; perimeter sediment control with silt fencing or fiber rolls; sediment traps to retain sediment onsite; and stabilized construction exits to limit the amount of mud, dirt, and rocks transported onto public roads. Hazardous waste is required to be transported only by California registered hazardous waste transporters to a state-permitted treatment, storage, or disposal facility (DTSC 2025b). These transporters are registered by the DTSC and CHP and hazardous waste must be packaged and labeled for transportation in accordance with USDOT standards for transport. In addition, Cal/OSHA provides specific standards for maintaining safe and healthy working conditions pertaining to hazardous materials in Title 8 of the CCR. Adherence to these regulations would minimize the potential for significant hazards to the public or environment during construction.
As described in Chapter 2, “Project Description,” the project would include a household hazardous waste (HHW) receiving, storing, and shipping/transfer area. HHW materials typically consist of leftover household products that can catch fire, react, or explode under certain circumstances, or those that are corrosive or toxic. This can include anything from paints, cleaners, pesticides, and oils to “universal wastes,” including batteries, electronics, and certain types of light bulbs. HHW would be received at the RRTO Facility in two ways: entrained in the mixed waste or recyclables materials streams, or collected separately by the City’s HHW waste collection vehicles from residents and businesses within the City and delivered to the RRTO Facility. HHW materials observed in the arriving waste or recycling materials streams would be gathered by waste transfer or recycling staff and taken to the HHW area. Waste collection trucks that have obtained HHW from generators within the City and collected by the City would be received at the HHW area where the materials would be unloaded from the collection trucks.
The HHW area would occupy approximately 6,000 square feet of the waste transfer portion of the RRTO Facility.
HHW operators would receive these materials and categorize them into areas with compatible materials for temporary storage. Then, HHW operators would combine compatible materials or pack the materials into containers used to transfer the materials to a designated off-site facility where the materials would be properly disposed.
Project operation may require the storage, use, and transport of larger quantities of hazardous materials (e.g., fuels, lubricants, paint, solvents, cleaners) in the long-term. Any storage or use of hazardous materials during project operation would be required to comply with appropriate regulatory agency standards such as CFR Titles 29, 40, and 49, and Chapter 6.95 of the California Health and Safety Code designed to avoid releases of hazardous materials.
Examples of these requirements include preparation and implementation of a spill prevention, control, and countermeasures plan; a hazardous business materials plan; and compliance with the DTSC Hazardous Waste Generator Program. In particular, operation of the RRTO Facility would involve a household hazardous waste drop off facility to ensure proper disposal of household hazardous materials and wastes, the handling and storing of which would be subject to the RCRA regarding responsibility over “cradle to grave” from the time the waste is generated until its final disposal; US DOT Hazardous Materials Regulations regarding any operational transport of hazardous
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3.10-10 Roseville Environmental Utilities Operations Center Project Draft EIR materials (enforced at the state-level by the CHP); the Health and Safety Code, Labor Code, and Cal/OSHA pertaining to the safe and proper handling of hazardous materials and waste; compliance with CUPA enforcement and regular inspections; and the Roseville Municipal Code Chapter 9.60 to comply with regulations for the identification and disclosure of hazardous materials use and their management within the City. Because the transport, use, storage, and disposal of hazardous materials would be required to comply with laws and regulations intended to reduce potential impacts to workers and the environment, this impact would be less than significant.
Mitigation Measures
No mitigation is required.
Phase 2
Phase 2 of the project would involve the construction and operation of additional square footage at the RRTO and the construction and operation of a Potential Future Organics Processing Facility. Construction of Phase 2 of the project would involve the storage, use, and transport of hazardous materials at the project site. Handling hazardous materials would be required to comply with existing local, state, and federal regulations. Operation of Phase 2 of the project would also require storage, use, and transport of hazardous materials, including at the Potential Future Organics Processing Facility. Because the transport, use, storage, and disposal of hazardous materials would be required to comply with laws and regulations intended to reduce potential impacts to workers and the environment, this impact would be less than significant.
Phase 2 of the project would be operational by 2040 and would include an additional 122,000 square feet of building area for the RRTO Facility and the construction of 37,000 square feet of building area for the Potential Future Organics Processing Facility (including the development of 34 acres of land). Similar to Phase 1, construction of Phase 2 would involve the transport, storage, and disposal of hazardous materials and hazardous wastes, handling of hazardous materials would be required to comply with existing local, state, and federal regulations.
Operation of Phase 2 would include a Potential Future Organics Processing Facility, which may involve a composting facility and/or biomass facility. The potential future compost facility would involve the composting of green waste, wood, and food waste. The potential future biomass facility would convert biomass (woody materials) into energy using thermal means and would likely include food, agricultural, and yard trimming waste. The specific type of biomass device is not yet known, and the potential biomass facility would be developed at a later time after being evaluated by the City on its financial, environmental, and regulatory merits. Operation of a future composting and/or biomass facility could involve the handling and storage of materials such as fuels, lubricants, cleaning agents, and processing additives, as well as the generation of byproducts such as leachate, bioaerosols, or ash containing trace metals. Depending on facility design and feedstock characteristics, there is also potential for accidental releases of hazardous substances associated with equipment maintenance, waste decomposition, or combustion processes.
However, these risks are expected to be reduced to a less-than-significant level through compliance with applicable hazardous materials management, worker safety, and air quality regulations, as well as standard BMPs for composting and biomass operations. In addition, Phase 2 operations would involve the continued operation of the household hazardous waste drop off facility (constructed as part of Phase 1) to ensure proper management and disposal of household hazardous materials and wastes. Post-construction, the operational handling and storage of hazardous materials and wastes would continue to comply with existing local, state, and federal regulations, as described for Phase 1. Because the transport, use, storage, and disposal of hazardous materials would be required to comply with laws and regulations intended to reduce potential impacts to workers and the environment, this impact would be less than significant.
Mitigation Measures
No mitigation is required.
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Roseville Environmental Utilities Operations Center Project Draft EIR 3.10-11 Impact 3.10-2: Result in Foreseeable Upset and/or Accident Conditions Involving Release of Hazardous Materials into the Environment
Phase 1
Agricultural and farming uses could have resulted in soil and/or groundwater contamination, specifically within the area of the project site that is designated for the Vendor Lease Area. Site disturbance could expose people in the area to hazardous materials from existing soil contamination. This impact would be potentially significant.
As discussed in Impact 3.10-1, Phase 1 of the project would include the partial construction of the RRTO, the Vendor Lease Area, and the Corporation Yard, for a total developed area of 116 acres and 402,400 square feet of building area. As described above, the project site is predominantly agricultural in use and is leased for rice and hay farming.
Several structures are located on the site (where the Vendor Lease Area would be located) and these structures would be demolished prior to project development, although the former residence may be used as a temporary office or by a vendor as the vendor lease office.
As discussed in the Phase I ESA, soil staining was observed in association with petroleum hydrocarbons such as diesel fuel, and hydraulic fuels used in conjunction with farming operations onsite. Other hazardous substances, including lead-acid batteries, paint, and pesticides are or were stored in the equipment yard or barn on the property, and these potentially hazardous substances require proper disposal if not utilized prior to demolition (REE 2002). Further investigation in the Phase II ESA concluded that the stained soil from petroleum products is very minor and does not represent a significant or reportable environmental concern (REE 2003). In the area of the 250-gallon aboveground storage tank located southwest of the former residence (where the Vendor Lease Area would be located), an estimated 5 cubic yards of soil is affected. The Phase II ESA recommended sampling and evaluation of this soil to determine the potential for contaminants. If not mitigated, this minor contamination on the project site could result in a significant effect to the public or environment. This impact would be potentially significant.
Mitigation Measures
Mitigation Measure 3.10-2: Evaluate Site Soils
As recommended in the Phase II ESA prepared for the project site, the contractor shall implement the following measure during building demolition and/or ground disturbance in the portion of the project site that is designated as potentially contaminated in the Phase I or Phase II ESAs for the Vendor Lease Area. This measure would also be incorporated into the site’s Improvement Plans, which the City would be responsible for monitoring and enforcing. When on-site buildings are being demolished or the site graded to prepare for future use, the affected soil shall be excavated and stockpiled on a visqueen sheet and sampled in four locations. The four samples shall be composited together to analyze for petroleum hydrocarbons as diesel and for lead to determine proper soil disposal. If the concentrations indicate no carcinogenic constituents (and are in the range of 0 to 100 ppm), the soil can be used as fill onsite. If the range is 100 to 600 ppm, the soil can be used as road base or beneath building foundations. If the range exceeds those concentrations, disposal at a Class II landfill shall be investigated.
Significance after Mitigation
The site investigation required by Mitigation Measure 3.10-2 would reduce potential impacts related to potential soil and/or groundwater contamination by identifying site soils requiring remediation and abating the hazard in compliance with applicable local, state, and federal regulations. After mitigation, the project would have a less-thansignificant impact related to existing soil contamination.
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3.10-12 Roseville Environmental Utilities Operations Center Project Draft EIR Phase 2
The Phase 2 area does not include the Vendor Lease Area, and no other portions of the project site were identified in the Phase I or Phase II ESAs as having significant or reportable environmental concerns (REE 2002, 2003). Therefore, Phase 2 of the project would not expose people in the area to hazardous materials from existing soil and/or groundwater contamination. This impact would be less than significant.
As discussed in Impact 3.10-1, Phase 2 of the project would include an additional 122,000 square feet of building area for the RRTO Facility and the construction of 37,000 square feet of building area for the Potential Future Organics Processing Facility (including the development of 34 acres of land). The Phase 2 area does not include the Vendor Lease Area, and no other portions of the project site were identified in the Phase I or Phase II ESAs as having significant or reportable environmental concerns (REE 2002, 2003). Therefore, Phase 2 of the project would not expose people in the area to hazardous materials from existing soil and/or groundwater contamination. This impact would be less than significant.
Mitigation Measures
No mitigation is required.
Impact 3.10-3: Impair an Adopted Emergency Response Plan or Emergency Evacuation Plan Phase 1
The City of Roseville maintains an Emergency Operations Plan (City of Roseville 2011) that serves as the official emergency plan for the city as well as a Multi-Hazard Mitigation Plan (City of Roseville 2023). As part of project operation, adequate emergency access routes to and from the project site would be established and emergency response would not be impaired. However, construction activities associated with Phase 1 of the project could result in temporary lane closures, increased traffic, and other roadway conditions that could interfere with or slow down emergency vehicle access and services. This impact would be potentially significant.
The City of Roseville’s Emergency Operations Plan (EOP) describes organizational and operational responsibilities in the event of an emergency, including hazardous materials emergencies and clean up and de-contamination procedures (City of Roseville 2011). The EOP is an extension of the City’s Multi-Hazard Mitigation Plan (MHMP) and follows nationally adopted Incident Command System guidelines. The City’s 2023 Multi-Hazard Mitigation Plan was developed to evaluate hazards within the City and identifies planning tools, policy changes, programs, projects, and other activities that can mitigate the impacts of hazards (City of Roseville 2023). The Roseville Fire Department assists the CHP, OES, and other responding agencies as requested, in the event of a hazardous materials spill on State Route 65 or Interstate 80.
Construction of Phase 1 of the project would primarily occur on the project site but would also involve improvements to Phillip Road and offsite utility extensions. Phillip Road improvements would include road widening along the frontage of the project site and east to the westerly terminus of Blue Oaks Boulevard. The project would also extend a new 16-inch diameter water supply line for approximately 3 miles along Phillip Road from the existing water supply line located underneath Blue Oaks Road. In addition, the project would also require the construction of an approximately 4-mile force main sewer line to reach the Pleasant Grove Wastewater Treatment Plant.
Therefore, it is possible that project construction would require temporary lane closures along Phillip Road along the frontage of the project site and east to the westerly terminus of Blue Oaks Boulevard. These lane closures, if required, would be designed and constructed in accordance with the City’s Design and Construction Standards, Sections 5 through 7, which contain specific requirements that are intended to provide safe access to property by both automobiles and pedestrians, as well as emergency vehicles, including designs for roadway width, sight lines from street view, markings, signals, location of driveways, and turn lanes. During construction, Phillip Road would also be required to maintain access for emergency vehicles. When needed, these temporary lane closures would be coordinated with, and approved by, the appropriate City department in coordination with emergency response services.
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Roseville Environmental Utilities Operations Center Project Draft EIR 3.10-13 In the long-term, Phase 1 of the project would result in approximately 604 employees (including 165 relocated employees and 439 new employees) working onsite that would increase the use of Phillip Road, Blue Oaks Boulevard, and other area roadways. Additionally, Phillip Road would be improved from its current condition, thus improving emergency access. Multiple emergency response resources are in place to address emergencies within the City, including the Roseville Fire Department, Roseville Police Department, and mutual aid resources from other fire and law enforcement agencies. If there is an incident, evacuation of the project site would be at the discretion of the Incident Commander, who may keep everyone on-site in a safe refuge area, have people shelter in place, or call for an evacuation depending on the conditions of the emergency (Bradley, pers. comm., 2025). These emergency response resources would adequately allow for the evacuation of the project site with emergency alert notifications, rapid dispatch and emergency response, and law enforcement coordination to implement evacuation operations.
Further, adequate emergency access routes to and from the project site would be established as required by state and local regulations, and with input and approval from the Roseville Fire Department.
Regulatory compliance with the City’s Design and Construction Standards, as well as obtaining the proper approval from the City, would ensure that implementation of the project would not have a significant impact on emergency vehicle access, or the goals and objectives of the EOP and MHMP. Nevertheless, construction activities would involve truck traffic that could result in temporary lane closures, increased traffic, and other roadway conditions that could interfere with or slow down emergency vehicle access and services. This impact would be potentially significant.
Mitigation Measures
Mitigation Measure 3.10-3a: Implement a Construction Traffic Management Plan A Construction Traffic Management Plan (CTMP) shall be developed/updated by the contractor and approved by the City of Roseville before construction begins on any component of the project. The CTMP shall be implemented during all phases of project construction and shall include, but not limited to, the following:
name and telephone number of a contact person regarding traffic complaints or emergency situations; community notification procedures and contact information for local police, fire, and emergency response organizations and procedures for the continuous coordination of construction activity; procedures for training the flag person(s) used in implementing the plan; the location, times, and estimated duration of any temporary lane closures; developing, and once approved, managing the haul route plan and construction parking management plan; timing of disruptive construction activities; scheduling of deliveries, pick-ups and hauling of material during nonpeak travel periods to the extent possible; and the contractor will provide an estimate of truck volume and schedule. Areas will be designated by the City for the staging of all trucks. All earth-moving and ready-mix trucks will be equipped with two-way radios so that the drivers at the staging areas are linked to a person controlling traffic at the project site. Trucks will follow a cityapproved route to the project site.
Mitigation Measure 3.10-3b: Establish Evacuation Routes via a Hazard Mitigation Plan The City shall, in coordination with the Roseville Fire Department, develop a Hazard Mitigation Plan for project operation that establishes appropriate evacuation routes for the project site. The hazard mitigation plan shall be developed prior to project operation and would be implemented throughout project operation.
Significance after Mitigation
Mitigation Measure 3.10-3a requires the project contractor to develop a CTMP to alleviate potential construction activity impacts during both Phase 1 and Phase 2. Implementation of Mitigation Measure 3.10-3a would require that adequate emergency access is provided during project construction to minimize impacts to emergency responders and evacuation access. Implementation of Mitigation Measure 3.10-3b would require the City to establish appropriate evacuation routes as part of a site-specific hazard mitigation plan. After mitigation, this impact would be less than significant.
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3.10-14 Roseville Environmental Utilities Operations Center Project Draft EIR Phase 2
The City of Roseville maintains an Emergency Operations Plan (City of Roseville 2011) that serves as the official emergency plan for the city as well as a Multi-Hazard Mitigation Plan (City of Roseville 2023). As part of project operation, adequate emergency access routes to and from the project site would be established and emergency response would not be impaired. However, similar to Phase 1, construction activities associated with Phase 2 of the project could result in temporary lane closures, increased traffic, and other roadway conditions that could interfere with or slow down emergency vehicle access and services. This impact would be potentially significant.
Construction of Phase 2 of the project would include an additional 122,000 square feet of building area for the RRTO Facility and the construction of 37,000 square feet of building area for the Potential Future Organics Processing Facility (including the development of 34 acres of land), all of which would be located within the boundaries of the project site and would not encroach on adjacent properties or include improvements to Phillip Road (which would be constructed as part of Phase 1). In addition, the project would be constructed in accordance with the City’s Design and Construction Standards, Sections 5 through 7, which contain specific requirements that are intended to provide safe access to properties by both automobiles and pedestrians, including emergency vehicles, and address designs for roadway width, sight lines from street view, markings, signals, location of driveways, and turn lanes.
In the long-term, Phase 2 of the project would result in approximately 79 new employees (in addition to the 604 employees that would be part of Phase 1) working onsite that would increase the use of Phillip Road, Blue Oaks Boulevard, and other area roadways. As described for Phase 1, multiple emergency response resources are in place to address emergencies within the City, including the Roseville Fire Department, Roseville Police Department, and mutual aid resources from other fire and law enforcement agencies. If there is an incident, evacuation of the project site would be at the discretion of the Incident Commander, who may keep everyone on-site in a safe refuge area, have people shelter in place, or call for an evacuation depending on the conditions of the emergency (Bradley, pers. comm., 2025). These emergency response resources would adequately allow for the evacuation of the project site with emergency alert notifications, rapid dispatch and emergency response, and law enforcement coordination to implement evacuation operations. Further, adequate emergency access routes to and from the development area would be established as required by state and local regulations.
Nevertheless, similar to Phase 1, construction activities associated with Phase 2 of the project would involve truck traffic that could result in temporary lane closures, increased traffic, and other roadway conditions that could interfere with or slow down emergency vehicle access and services. This impact would be potentially significant.
Mitigation Measures
Implement Mitigation Measures 3.10-3a and 3.10-3b, described above.
Significance after Mitigation
Mitigation Measure 3.10-3a requires the project contractor to develop a CTMP to alleviate potential construction activity impacts during both Phase 1 and Phase 2. Implementation of Mitigation Measure 3.10-3a would require that adequate emergency access is provided during project construction to minimize impacts to emergency responders and evacuation access. Implementation of Mitigation Measure 3.10-3b would require the City to establish appropriate evacuation routes as part of a site-specific hazard mitigation plan. After mitigation, this impact would be less than significant.
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Roseville Environmental Utilities Operations Center Project Draft EIR 3.11-1
3.11 HYDROLOGY AND WATER QUALITY
This section identifies the regulatory context and policies related to hydrology and water quality, describes the existing hydrologic conditions at the project site, and evaluates potential hydrology, drainage, and receiving waterquality impacts of the proposed project. Potential effects related to water supply and sewer/wastewater facilities are addressed in Section 3.15, “Public Utilities.”
Two comment letters regarding hydrology and water quality were received in response to the notice of preparation (see Appendix A). The Central Valley Regional Water Quality Control Board (RWQCB) and the Placer County Conservation Program expressed concerns about the regulatory context that would apply to the project and the potential for water quality degradation of Pleasant Grove Creek from project development near the creek.
3.11.1 Regulatory Setting
FEDERAL
Clean Water Act
The US Environmental Protection Agency (EPA) is the lead federal agency responsible for water quality management.
The Clean Water Act (CWA) is the primary federal law that governs and authorizes water quality control activities by EPA as well as the states. Various elements of the CWA address water quality. These are discussed below.
CWA Water Quality Criteria/Standards
Pursuant to federal law, EPA has published water quality regulations under Title 40 of the Code of Federal Regulations. Section 303 of the CWA requires states to adopt water quality standards for all surface waters of the United States. As defined by the CWA, water quality standards consist of designated beneficial uses of the water body in question and criteria that protect the designated uses. Section 304(a) requires EPA to publish advisory water quality criteria that accurately reflect the latest scientific knowledge on the kind and extent of all effects on the environment and health and welfare that may be expected from the presence of pollutants in water. Where multiple uses exist, water quality standards must protect the most sensitive use. As described in the discussion of state regulations below, the State Water Resources Control Board (SWRCB) and its nine RWQCBs have designated authority in California to identify beneficial uses and adopt applicable water quality objectives.
CWA Section 303(d) Impaired Waters List
Under Section 303(d) of the CWA, states are required to develop lists of water bodies that do not attain water quality objectives after implementation of required levels of treatment by point source dischargers (municipalities and industries). Section 303(d) requires that the state develop a total maximum daily load (TMDL) for each of the listed pollutants. The TMDL is the amount of the pollutant that the water body can receive and still comply with water quality objectives. The TMDL is also a plan to reduce loading of a specific pollutant from various sources to achieve compliance with water quality objectives. In California, implementation of TMDLs is achieved through water quality control plans, known as Basin Plans, of the state RWQCBs. See the discussion of state plans, policies, regulations, and laws below.
National Pollutant Discharge Elimination System
The National Pollutant Discharge Elimination System (NPDES) permit program was established in the CWA to regulate municipal and industrial discharges to surface waters of the United States. NPDES permit regulations have been established for broad categories of discharges including point source waste discharges and nonpoint source stormwater runoff. Each NPDES permit identifies limits on allowable concentrations and mass emissions of pollutants contained in the discharge. Sections 401 and 402 of the CWA contain general requirements regarding NPDES permits. “Nonpoint source” pollution originates over a wide area rather than from a definable point. Nonpoint source pollution often enters receiving water in the form of surface runoff and is not conveyed by way of pipelines or
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3.11-2 Roseville Environmental Utilities Operations Center Project Draft EIR discrete conveyances. Two types of nonpoint source discharges are controlled by the NPDES program: discharges caused by general construction activities and the general quality of stormwater in municipal stormwater systems. The goal of the NPDES nonpoint source regulations is to improve the quality of stormwater discharged to receiving waters to the maximum extent practicable. The RWQCBs in California are responsible for implementing the NPDES permit system (see the discussion of state plans, policies, regulations, and laws below).
National Flood Insurance Act
The Federal Emergency Management Agency (FEMA) is tasked with responding to, planning for, recovering from, and mitigating against disasters. The Federal Insurance and Mitigation Administration within FEMA is responsible for administering the National Flood Insurance Program (NFIP) and administering programs that aid with mitigating future damages from natural hazards.
FEMA prepares Flood Insurance Rate Maps (FIRMs) that delineate the regulatory floodplain to assist local governments with the land use planning and floodplain management decisions needed to meet the requirements of NFIP.
Floodplains are divided into flood hazard areas, which are areas designated according to their potential for flooding, as delineated on FIRMs. Special Flood Hazard Areas are the areas identified as having a 1 percent chance of flooding in each year (otherwise known as the 100-year flood). In general, the NFIP mandates that development is not to proceed within the regulatory 100-year floodplain if the development is expected to increase flood elevation by 1 foot or more.
STATE
California Porter-Cologne Act
California’s primary statute governing water quality and water pollution issues with respect to both surface waters and groundwater is the Porter-Cologne Water Quality Control Act of 1970 (Porter-Cologne Act). The Porter-Cologne Act grants the SWRCB and each of the nine RWQCBs power to protect water quality and is the primary vehicle for implementation of California’s responsibilities under the CWA. The applicable RWQCB for the proposed project is the Central Valley RWQCB. The SWRCB and the Central Valley RWQCB have the authority and responsibility to adopt plans and policies, regulate discharges to surface and groundwater, regulate waste disposal sites, and require cleanup of discharges of hazardous materials and other pollutants. The Porter-Cologne Act also establishes reporting requirements for unintended discharges of any hazardous substances, sewage, or oil or petroleum products.
Under the Porter-Cologne Act, each RWQCB must formulate and adopt a water quality control plan (i.e., Basin Plan, as stated above) for its region. The Basin Plan for the Central Valley region includes a comprehensive list of waterbodies within the region and detailed language about the components of applicable Water Quality Objectives (WQOs). The Basin Plan recognizes natural water quality, existing and potential beneficial uses, and water quality problems associated with human activities throughout the Sacramento and San Joaquin River Basins. Through the Basin Plan, the Central Valley RWQCB executes its regulatory authority to enforce the implementation of TMDLs, and to ensure compliance with surface WQOs. The Basin Plan includes both narrative and numerical WQOs designed to provide protection for all designated and potential beneficial uses in all its principal streams and tributaries. Applicable beneficial uses include municipal and domestic water supply, irrigation, non-contact and contact water recreation, groundwater recharge, freshwater replenishment, hydroelectric power generation, and preservation and enhancement of wildlife, fish, and other aquatic resources.
The Central Valley RWQCB also administers the adoption of waste discharge requirements (WDRs), manages groundwater quality, and adopts projects within its boundaries under the NPDES General Permit for Stormwater Discharges Associated with Construction and Land Disturbance Activities (General Permit). With respect to WDRs, Order WQ 2020-0012-DWQ was adopted in 2020 and regulates composting activities. It establishes requirements for two tiers of composting facilities with specific requirements dependent on factors like feedstock, volume of materials, and site conditions.
NPDES General Permit
The SWRCB adopted the statewide NPDES General Permit in August 1999. The state requires that projects disturbing more than 1 acre of land during construction file a Notice of Intent with the RWQCB to be covered under the permit.
Ascent Hydrology and Water Quality
City of Roseville
Roseville Environmental Utilities Operations Center Project Draft EIR 3.11-3 Construction activities subject to the General Permit include clearing, grading, stockpiling, and excavation.
Dischargers are required to eliminate or reduce non stormwater discharges to storm sewer systems and other waters.
A stormwater pollution prevention plan (SWPPP) must be developed and implemented for each site covered by the permit. The SWPPP must include best management practices (BMPs) designed to prevent construction pollutants from contacting stormwater and keep products of erosion from moving off‐site into receiving waters throughout the construction and life of the project; the BMPs must address source control and, if necessary, pollutant control.
NPDES Stormwater Permit for Discharges from Small Municipal Separate Storm Sewer Systems The Municipal Stormwater Permitting Program regulates stormwater discharges from municipal separate storm sewer systems (MS4s). Stormwater is runoff from rain or snow melt that runs off surfaces such as rooftops, paved streets, highways, or parking lots and can carry with it pollutants such as oil, pesticides, herbicides, sediment, trash, bacteria, and metals. The runoff can then drain directly into a local stream, lake, or bay. Often, the runoff drains into storm drains that eventually drain untreated into a local waterbody.
As a Phase II community, the City is currently required to operate under an NPDES Municipal Stormwater Permit administered by the state. The City’s Stormwater Management Plan was adopted and approved by the RWQCB, and the City received a Phase II Stormwater Permit in 2004. The SWRCB is currently updating the General Phase II permit requirements, which are expected to be more in line with the current Phase I requirements. Upon the adoption of the updated General Phase II Permit by the state, the City will update its Stormwater Permit to comply with the new requirements.
California Water Code
The California Water Code is enforced by the California Department of Water Resources (DWR). The mission of DWR is “to manage the water resources of California in cooperation with other agencies, to benefit the state’s people, and to protect, restore, and enhance the natural and human environments.” DWR is responsible for promoting California’s general welfare by ensuring beneficial water use and development statewide.
Groundwater Management
Groundwater Management is outlined in the California Water Code (CWC), Division 6, Part 2.75, Chapters 1-5, Sections 10750 through 10755.4. The Groundwater Management Act was first introduced in 1992 as Assembly Bill (AB) 3030 and has since been modified by Senate Bill (SB) 1938 in 2002, AB 359 in 2011, and the Sustainable Groundwater Management Act (SB 1168, SB 1319, and AB 1739) in 2014. The intent of the Acts is to encourage local agencies to work cooperatively to manage groundwater resources within their jurisdictions and to provide a methodology for developing a Groundwater Management Plan.
The Sustainable Groundwater Management Act of 2014 (SGMA) became law on January 1, 2015 and applies to all groundwater basins in the state (CWC Section 10720.3). By enacting the SGMA, the legislature intended to provide local agencies with the authority and the technical and financial assistance necessary to sustainably manage groundwater within their jurisdiction (CWC Section 10720.1).
Pursuant to the SGMA, any local agency that has water supply, water management, or land use responsibilities within a groundwater basin may elect to be a “groundwater sustainability agency” for that basin (CWC Section 10723). West Placer Groundwater Sustainability Agency (WPGSA) consists of the cities of Roseville and Lincoln, Placer County Water Agency, Nevada Irrigation District, and Placer County. The WPGSA is one of a group of five GSAs formed within the North American Subbasin that consist of the West Placer, Sacramento, South Sutter Water District, Sutter County, and Recreation District 1001 GSAs.
The SGMA also requires DWR to categorize each groundwater basin in the state as high, medium, low, or very low priority to ensure the sustainability of groundwater resources (CWC Sections 10720.7, 10722.4). On December 15, 2014, DWR announced its official “initial prioritization” of the state’s groundwater basins for purposes of complying with the SGMA, and this priority list became effective on January 1, 2015 (DWR 2022a). DWR has ranked the North American Subbasin as “high priority.” The Groundwater Sustainability Plan for the North American Subbasin was published in 2021 (DWR 2021).
Hydrology and Water Quality Ascent
City of Roseville
3.11-4 Roseville Environmental Utilities Operations Center Project Draft EIR Central Valley Flood Protection Act
The Central Valley Flood Protection Act of 2008 establishes the 200-year flood event as the minimum level of protection for urban and urbanizing areas. As part of the state’s FloodSAFE program, those urban and urbanizing areas protected by flood control project levees must receive protection from the 200-year flood event level by 2025.
DWR and Central Valley Flood Protection Board (CVFPB) collaborated with local governments and planning agencies to prepare the 2012 Central Valley Flood Protection Plan (CVFPP), which the CVFPB adopted on June 29, 2012. The Central Valley Flood Protection Act calls for updates to the CVFPP every five years. The 2022 CVFPP Update, adopted in December 2022, serves as California’s strategic and financial blueprint to improve flood risk management in the Central Valley and focuses on flood system climate resiliency; accountability and adaptation through performance tracking; and strategic alignment with other state water management planning efforts (DWR 2022b).
The CVFPB authority and procedures are derived from the California Water Code and Title 23 of the California Code of Regulations (CCR). These regulations provide guidance when determining if a permit is needed for any project that may encroach upon, improve, alter or affect adopted plans of flood control (including federal/State flood control systems, regulated streams and designated floodways under CVFPB’s jurisdiction). An encroachment permit is required for any proposed work that is located:
between or in the vicinity of any Federal Project Levees within a State Plan of Flood Control; within 100-foot proximity of a non-leveed Regulated Stream listed in California Code of Regulations, Title 23, Waters, Division 1, Article 8, Table 8.1;
within a Designated Floodway that has been adopted by the CVFPB; or within a Sacramento San Joaquin Drainage District (SSJDD) Easement.
The project is not located in the vicinity of any Federal Project Levees. Pleasant Grove Creek along the project site's northern boundary is identified in Table 8-1 of Title 23 as a Regulated Stream. However, no project activities are proposed to occur within 100 feet of this stream. The CVFPB has not adopted Pleasant Grove Creek as a Designated Floodway and the project site is not located within a SSJDD easement. Because the project is not located within any of the categories listed above, it does not require an encroachment permit from the CVFPB.
LOCAL
City of Roseville General Plan
The Open Space and Conservation and Safety Elements of the City of Roseville 2035 General Plan (2020a) contain the following policies that may be applicable to the project:
Policy OS2.2: Preserve and restore continuous riparian corridors and adjacent habitat along the City's creeks and waterways.
Policy OS3.1: Utilize cost-effective urban run-off controls, including Best Management Practices, such as low impact development and naturalized stormwater management features, to reduce the rate of stormwater runoff and limit urban pollutants from entering the watercourses. Policy OS3.2: Implement erosion control and topsoil conservation measures to limit sediments within watercourses.
Policy OS3.3: Ensure a buffer area between waterways and urban development to protect water quality and riparian areas.
Policy SAFE2.1: Continue to regulate, through land use, zoning, and other restrictions, all uses and development in areas subject to potential flooding and require new development to comply with the State Plan of Flood Control requirements.
Policy SAFE2.5: Minimize the potential for flood damage to public and emergency facilities, utilities, roadways, and other infrastructure.
Ascent Hydrology and Water Quality
City of Roseville
Roseville Environmental Utilities Operations Center Project Draft EIR 3.11-5 Policy SAFE2.6: Require new developments to evaluate potential flood hazards, and provide mitigation to ensure that the cumulative rate of peak run-off is maintained at pre-development levels. Policy SAFE2.9: Where feasible, maintain natural stream courses and adjacent habitat and combine flood control, recreation, water quality, and open space functions.
Placer County Flood Control and Water Conservation District The Placer County Flood Control and Water Conservation District (PCFCWCD) was established by SB 1312, effective August 23, 1984. The PCFCWCD develops regional strategies for flood control management. In 1990, the PCFCWCD published the Stormwater Management Manual (SWMM) that contains specifications and policies for the design of storm drain facilities. The SWMM criteria are referenced in Section 10 of the City’s Improvement Standards.
City of Roseville Stormwater Management Program
The City’s Stormwater Management Program (SWMP) contains policies, activities, and strategies that comprise the City’s minimum control measures and BMPs that address NPDES requirements for the Phase II Stormwater Permit.
The six minimum control measures required under the NPDES permit are public outreach, public involvement, illicit discharge detection and elimination, construction site runoff, new development and redevelopment, and municipal operations. Some specific control measures described in the SWMP include storm drain labeling, development of a storm sewer system map, establishing a stormwater ordinance, site inspections to identify illicit connections and nonstormwater discharges to the storm sewer, and structural controls (such as detention ponds, vegetative areas, and runoff pretreatment) and non-structural controls (such as alternative construction methods, site design, and zoning) (City of Roseville 2004).
The City adopted the “Urban Stormwater Quality Management and Discharge Control Ordinance” in 2006 to establish a regulatory framework to implement construction and post-construction stormwater controls and regulate illicit discharges and connections to the City’s stormwater conveyance system from both residential and business sources.
The City has adopted the Stormwater Quality BMP Guidance Manual for Construction (City of Roseville 2011) and the West Placer Storm Water Quality Design Manual (Placer County 2022). The City has the authority during plan checks and site inspections to enforce the SWMP. Additionally, prior to final approval, the owner of any stormwater control structure is required to submit an operations and maintenance manual and a proposed maintenance schedule.
Grading Ordinance
Section 16.20.040 of the Roseville Municipal Code regulates stockpiling and grading and addresses conditions under which permits and grading plans are required. Section 16.20.070 identifies grading plan performance standards. Both Minor and Major grading plans are required by the City. A Major grading plan is required for any project that would result in the placement of fill in a channel or tributary that carries flow of 200 cubic feet/second or more during a 10- year storm event. Major grading plans must be reviewed and approved by the Planning Commission. All grading plans must comply with the following criteria:
A. Fill or cut slopes with a height exceeding five feet shall not exceed a slope of 4:1.
B. When grading around native oak trees:
1. Cut or fill slopes exceeding two feet in height shall not be permitted within a distance of 1.5 times the radius of the tree’s protected zone,
2. the grade shall not be raised or lowered around more than 50 percent of the protected zone, and
3. the grading shall not change the drainage pattern within a distance of 1.5 times the radius of the tree’s protected zone.
Section 16.20.020 requires that all grading be performed in accordance with either City Improvement Standards or Chapter 16 of the Zoning Ordinance, whichever is more restrictive. A project applicant must have an Improvement and/or Grading Plan along with a site-specific SWPPP prior to the start of grading activities. Slopes or banks along creek channels must be designed with proper slope protection to prevent soil erosion and channel-bank undercutting.
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3.11-6 Roseville Environmental Utilities Operations Center Project Draft EIR Flood Damage Prevention Ordinance
Section 9.80 of the Roseville Municipal Code is the Flood Damage Prevention ordinance. Land uses and development within the City’s regulatory floodplain are restricted to protect residents and structures from risks associated with flooding. Railroads, streets, bridges, utility transmission lines, pipelines, and other similar uses of a primarily open space nature may be permitted in the floodplain with the approval of a flood encroachment permit. All uses permitted within the floodplain must comply with Section 19.80.040 of the municipal code that prohibits any development from increasing peak flows; adversely affecting the stream channel, increasing flood heights, or having an adverse effect on a proposed use. An adverse effect on base flood elevations occurs when the cumulative effect of the proposed development will increase the base flood elevations by one-tenth of one foot or more at any point outside of the property controlled by the developer (Section 9.80.040). Within the floodway, all new development is prohibited unless a certified professional engineer certifies that the encroachment will not result in any increase in flood levels (Section 9.80.210). In addition, the following conditions apply:
Any fill placed in the floodplain must be shown to serve some beneficial purpose, must be limited to the minimum amount necessary to meet its purpose, and any fill or excavation must be protected against erosion by rip-rap, vegetative cover, or bulkheading.
Storage or processing of materials that are buoyant, flammable, toxic, explosive, or could be injurious to animal or plant life in time of flooding is prohibited. Storage of other materials may be allowed if it will not be damaged by floods and is readily removable from the area within the time available after flood warning. All materials stored in the floodplain must be anchored or be readily removable during flood season.
The City Council may grant a variance from these ordinances for a project, taking into consideration public safety, project engineering, and the public service provided by the project (Section 9.80.310).
3.11.2 Environmental Setting
HYDROLOGY AND DRAINAGE
Regional Hydrology
The Pleasant Grove Creek watershed totals approximately 30,000 acres with several tributaries, including South Branch Pleasant Grove Creek, Kaseburg Creek, Coyote Creek, and University Creek. The watershed’s tributaries were historically dry or very nearly dry in the summer months but are now mostly perennial due to urban development and rice farming. Pleasant Grove Creek receives the treated effluent from the City of Roseville’s Pleasant Grove Wastewater Treatment Plant (City of Roseville 2020b).
Pleasant Grove Creek discharges into the Pleasant Grove Creek Canal approximately 4 miles west of the project site in Sutter County, which then flows into the Natomas Cross Canal and finally into the Sacramento River near Verona. The broader Sacramento River Basin covers approximately 26,500 square miles and is bounded by the Sierra Nevada to the east, the Coast Ranges to the west, the Cascade Range and Trinity Mountains to the north, and the Delta-Central Sierra area to the south. The average runoff from the Basin is estimated to be 21.3 million acre-feet (af) per year (City of Roseville 2020b).
The Basin Plan designates the following beneficial uses for the Sacramento River: municipal and domestic supply, agricultural irrigation, contact and non-contact recreation, warm and cold freshwater habitat, warm and cold migration, warm and cold spawning, wildlife habitat, and navigation (Central Valley RWQCB 2019). Applying the Central Valley RWQCB’s “tributary rule,” the beneficial uses of any specifically identified water body generally also apply to all its tributaries.
Local Hydrology
Pleasant Grove Creek is the northern boundary of the project site and flows in an east–west direction. Previous farming activities at the project site have modified the original hydrology/drainage of the site over 70+ years. The
Ascent Hydrology and Water Quality
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Roseville Environmental Utilities Operations Center Project Draft EIR 3.11-7 majority of the project site drains toward Pleasant Grove Creek. Of the 243-acre project site, 114 acres comprise the FEMA designated Pleasant Grove Creek 100-year Floodplain. The southern portion of the site drains into Curry Creek and the Sacramento River (City of Roseville 2020a: V-17). The City of Roseville diverts water from the American River and from Folsom Reservoir (DWR 2021).
Flood Conditions
FEMA published a FIRM for the project site. A conceptual FEMA floodplain map is shown in Figure 3.11-1. The mapping delineates the boundary of the FEMA 100-year and 500-year floodplains. The areas north, northwest, and northeast of the project site are designated as 100-year floodplain for the Pleasant Grove Creek First North Tributary, and the northern portion of the project area adjacent to Pleasant Grove Creek is designated as 100-year floodplain for Pleasant Grove Creek. In addition, a portion of the project site on the southwest corner of the site is considered 500-year floodplain for Pleasant Grove Creek. Additional areas within the 500-year floodplain are located north and east of the project site. As stated above, 114 acres are within the FEMA 100-year floodplain and are also identified as the Roseville’s Regulatory Floodplain. An additional 4 acres are within the FEMA 500-year floodplain (City of Roseville 2020a: VIII-13).
SB 5 (2007) enacted the Central Valley Flood Protection Act of 2008 to provide additional protection for urban areas within the 200-year floodplain (0.5 percent annual exceedance probability) that meet five specific locational criteria:
within the Sacramento-San Joaquin Valley, within an urban area of more than 10,000 people, within a FEMA flood hazard zone, within an area of potential flood depth exceeding 3 feet, and in a watershed of more than 10 square miles. Within the City, the SB 5 requirements apply to Pleasant Grove Creek (the mainstem and the North Branch) (City of Roseville 2020b: 4.13-7).
Placer County and the cities of Roseville, Rocklin, Lincoln, and Auburn participated in the Auburn Ravine, Coon, and Pleasant Grove Creeks Flood Mitigation (PCFCWCD 1993) to address concerns related to flooding related to regional development. The study found that the unmitigated peak flow increases would have the potential to increase flows in the Natomas Cross Canal by less than 3.6 inches along tributary streams, and increased runoff volumes would have the potential to increase flooding by approximately 1.2 inches in the ponding area upstream of the Natomas Cross Canal (PCFCWCD 1993). While shallow, these increases would inundate several hundred additional acres in Sutter County during a major flood. The study recommended a combination of regional and local detention and retention basins, adoption of a regional floodplain management plan, and adoption of grading ordinances and policies to remediate ongoing and prevent future flood hazards. Subsequently, the City has established a fee program to construct a regional retention basin to address the increase in runoff from development within the city.
The project site is part of the City-owned property known as Reason Farms, which totals approximately 1,700 acres.
The City purchased the property in 2003 for the retention basin project. The project was originally known as the Reason Farms Retention Basin Facility and was later renamed to the Pleasant Grove Stormwater Retention Basin Facility. The City is the project proponent for that facility, which was preliminarily designed and had an approved EIR, but was never constructed. The EIR (State Clearinghouse [SCH] #2002072084) for the retention facility was certified in 2003. As of the writing of this EIR, the City is in the process of designing the retention basin, and preparation of a Subsequent EIR is underway; public release of the Draft EIR is planned for fall 2026. The project site is in an area that is no longer needed for the retention basin project (which would be located to the east of the project site).
The preferred alternative for the retention basin project has not been selected as of the writing of this EIR. The volume stored by the project is expected to total between 2,070 af and 3,330 af, within storage areas in a south basin, north basin, and in-channel storage. The City is currently collecting drainage impact fees from new development projects to fund construction of this project, which will be constructed as funds are made available, and is estimated to be completed in 2028.
Groundwater Hydrology
The City of Roseville is located within the approximately 350,000-acre North American Subbasin, which is a groundwater basin that extends beneath western Placer County, southern Sutter County, and northern Sacramento County, and is a subbasin of the broader Sacramento Groundwater Basin (DWR 2006).
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City of Roseville
3.11-8 Roseville Environmental Utilities Operations Center Project Draft EIR Source: Data downloaded from the City of Roseville in 2020 and FEMA in 2025; adapted by Ascent in 2025.
Figure 3.11-1 Flood Zones
Ascent Hydrology and Water Quality
City of Roseville
Roseville Environmental Utilities Operations Center Project Draft EIR 3.11-9 The subbasin is bounded by the Bear River on the north, the Feather and Sacramento Rivers on the west, the American River on the south, and a north/south line extending from the Bear River to Folsom Lake that passes about 2 miles east of the City of Lincoln. DWR estimates that the storage capacity of the North American Subbasin is approximately 5.5 million af (DWR 2021).
The North American Subbasin hydrogeology is characterized by an upper groundwater system and a lower groundwater system. The upper groundwater system exists in the deep Quaternary alluvial deposits. The lower groundwater system is largely confined and exhibits recharge characteristics that indicate that it is somewhat hydraulically isolated from the upper system. Water-bearing features in the upper system are generally limited to loose unconsolidated sediments, with water flowing intermittently. The groundwater table is dropping and becoming deeper over time due to groundwater withdrawal for agricultural use (DWR 2021). More than 77 percent of monitoring wells in the Sacramento River Basin experienced a declining trend for groundwater levels from 1998 to 2018. Most monitoring wells in the region (61 percent) showed a decreasing trend of up to 2.5 feet per year (DWR 2021).
Under natural conditions, groundwater recharge results from infiltration of precipitation (rain and snow). The rate and quantity of water reaching the aquifer depends on factors that include the amount and duration of precipitation, soil type, vertical permeability, clay content, slope, land cover, and the presence of a cemented hardpan or bedrock. Most soils can be categorized into hydrologic soil groups based on runoff-producing characteristics. Soils containing hardpan occupy three-fourths of the valley on the east side of the Sacramento River and these hardpans severely restrict downward movement of water (DWR 2021).
The Pleistocene-age (10,000 to 2 million years ago) Modesto and Riverbank formations are the most widely exposed geologic units in the Subbasin and are underneath the project site (DWR 2021: 4-6). The combined thickness of these two formations can be up to 75 feet. These two formations are moderately permeable but include highly permeable coarse zones (DWR 2021).
The project site is located within the Central Area of the North American Subbasin. Currently the groundwater levels are between 0 and 15 feet below ground surface near the American and Bear Rivers. Over time, groundwater levels have risen in response to decreased groundwater use but levels still vary in response to climatic conditions when surface water availability decreases and groundwater pumping increases. Groundwater levels declined noticeably during the 2012 to 2016 drought but began to recover following the end of that drought. However, they have not generally fully recovered to pre-drought levels (DWR 2021).
Three existing irrigation wells are located on the project site and have been used for the current rice farming and associated agricultural and residential operations. An additional on-site well is a designated domestic use well (HDR 2024). The agricultural wells do not have data on the depth of the wells or their water levels, however, the groundwater irrigation capacity is approximately 1,500, 1,100, and 900 gallons per minute, respectively. In 2023, the North American subbasin was coming out of a drought and the groundwater table was increasing in elevation. The domestic well on-site had a water depth of approximately 210 feet in 1991 when the last measurement was taken (HDR 2024). Over a thirtyyear period between 1962 and 1991, the domestic well had an average depth of 101 feet (HDR 2024).
The City is a member of the WPGSA, which is the Groundwater Sustainability Agency tasked with complying with the SGMA in Roseville. Currently, the City operates six groundwater well facilities. As part of the City’s groundwater program, it has invested in Aquifer Storage and Recovery, which provides the capability to supplement the groundwater basin through direct injection of drinking water into the groundwater basin that can be later recovered for drinking water use during dry periods (City of Roseville 2020a).
Stormwater Drainage
The City manages the stormwater infrastructure and flows within the city. In the city, the stormwater drainage system consists of surface runoff to streets, subsurface storm drainage pipelines, canals, and retention basins. As noted above, the Pleasant Grove Stormwater Retention Basin Project is planned to be located within a 1,700-acre parcel to the east of the project site and would mitigate increased runoff from existing and future development within the watershed. There are no existing stormwater drainage facilities on the project site.
Hydrology and Water Quality Ascent
City of Roseville
3.11-10 Roseville Environmental Utilities Operations Center Project Draft EIR
WATER QUALITY
Surface Water Quality
Treated tertiary effluent from the City’s Pleasant Grove Wastewater Treatment Plant is discharged directly to Pleasant Grove Creek southeast of the project site. In accordance with state requirements, surface water quality samples are collected on a weekly basis and analyzed for a variety of constituents to ensure that the discharge does not adversely affect water quality in Pleasant Grove Creek or the Sacramento River (City of Roseville 2020b).
Pleasant Grove Creek is a 303(d) listed waterbody for pyrethroids, dissolved oxygen, toxicity, cypermethrin, and bifenthrin (SWRCB 2021).
Groundwater Quality
Nitrate concentrations in the Central Area of the North American Subbasin are typically below the maximum contaminant levels for drinking water; however, nitrate concentrations are trending upward in most of the subbasin.
Elevated iron and manganese levels may also be encountered in the Central Area. In the WPGSA area, total dissolved solid levels are generally stable or decreasing. Groundwater wells in the project vicinity had slightly elevated levels of arsenic, but low levels of nitrate, total dissolved solids, boron, iron, and manganese (DWR 2021).
3.11.3 Environmental Impacts and Mitigation Measures
METHODOLOGY
Evaluation of potential hydrologic and water quality impacts is based on a review of existing documents and studies that address water resources in the vicinity of the project. Information obtained from these sources was reviewed and summarized to describe existing conditions and to identify potential environmental effects, based on the standards of significance presented in this section. This analysis incorporates the findings of the Roseville Utilities Operation Facility Water Utility Strategy and Evaluation Report (HDR 2024). This report was prepared to inform project design. In determining the level of significance, the analysis assumes that the project would comply with relevant federal, state, and local laws, ordinances, and regulations.
THRESHOLDS OF SIGNIFICANCE
Thresholds of significance are based on Appendix G of the State CEQA Guidelines. The project would have a significant impact related to hydrology and water quality if it would:
violate any water quality standards or waste discharge requirements or otherwise substantially degrade surface or ground water quality;
substantially decrease groundwater supplies or interfere substantially with groundwater recharge such that the project may impede sustainable groundwater management of the basin; substantially alter the existing drainage pattern of the site or area, including through the alteration of the course of a stream or river, in a manner that would
result in substantial erosion or siltation on- or off-site; result in flooding on-site or off-site;
create or contribute runoff water that would exceed the capacity of existing or planned stormwater- drainage systems or provide substantial additional sources of polluted runoff; impede or redirect flood flows
in flood hazard, tsunami, or seiche zones, risk release of pollutants due to project inundation; or conflict with or obstruct implementation of a water quality control plan or sustainable groundwater management plan.
Ascent Hydrology and Water Quality
City of Roseville
Roseville Environmental Utilities Operations Center Project Draft EIR 3.11-11
ISSUES NOT DISCUSSED FURTHER
The project site is located inland with no large water bodies located in the vicinity, and there is no known history of mud flow in the vicinity. The project would not subject people or structures to a significant risk of inundation from sea level rise, tsunami, seiche, or mudflow. Therefore, there would be no impact, and this issue is not discussed further.
ENVIRONMENTAL IMPACTS AND MITIGATION MEASURES
Impact 3.11-1: Violate Water Quality Standards or Waste Discharge Requirements, Otherwise Degrade Water Quality, or Interfere with Implementation of a Water Quality Control Plan Phase 1
Phase 1 construction activities such as grading, excavation, trenching, and soil pile storage could result in erosion and sedimentation, and discharge of other nonpoint source pollutants. In addition, project operation has the potential to generate polluted runoff associated with storage of chemicals and vehicle/equipment leaks. To avoid or minimize the potential for adverse construction- and operation-related effects on water quality, the City or its contractor would be required to develop and implement a SWPPP and BMPs and comply with the City’s Urban Stormwater Quality Management and Discharge Control Ordinance, West Placer Storm Water Quality Design Manual, PCFCWCD’s Stormwater Management Manual, and Section 16.20.040 of the Roseville Municipal Code that include measures to control, prevent, remove, or reduce pollution. Therefore, short- and long-term impacts on surface and groundwater quality would be less than significant.
Construction
All earth-disturbing activities during construction would be subject to the NPDES. The NPDES Permit Program, administered by the Central Valley RWQCB, helps to control pollution in stormwater by regulating sources of pollution at construction sites that would result in the discharge of pollutants into stormwater and downstream receiving waters during both construction and operational activities. As required by the NPDES, the project would be required to obtain coverage under the General Permit for discharges associated with construction activity (Construction General Permit Order 2022-0057‐DWQ). The NPDES General Permit identifies limits on discharge, monitoring and reporting requirements, and other provisions to ensure that the discharge does not adversely affect water quality or human health. Construction activities subject to the NPDES General Permit include clearing, grading, and other ground‐disturbing activities such as stockpiling or excavation. The NPDES General Permit requires development and implementation of a SWPPP and BMPs such as maintaining or creating drainages to convey and direct surface runoff away from bare areas, and installing physical barriers such as berms, silt fencing, wattles, straw bales, and gabions. Because the project applicant would be required to comply with the provisions of the NPDES General Permit, including preparation of a SWPPP and implementation of all identified BMPs, short‐term construction impacts associated with water quality standards and waste discharge requirements would be minimized.
In addition, the project would be required to comply with the City’s Urban Stormwater Quality Management and Discharge Control Ordinance including implementing measures from the Stormwater BMP Guidance Manual for Construction and the West Placer Storm Water Quality Design Manual (Placer County 2022). The City has the authority during plan checks and site inspections to enforce the City’s SWMP. Stockpiling and grading conducted as part of the project would also be required to comply with Section 16.20.040 of the Roseville Municipal Code.
Operation
Phase 1 includes development of new municipal uses on land that is currently undeveloped. This development would result in approximately 116 acres of new impervious surfaces. Phase 1 also has the potential to generate polluted runoff associated with storage of chemicals and vehicle/equipment leaks. However, the project would be designed to minimize impacts to water quality including providing landscape setbacks that would serve as a buffer along Phillip Road and Pleasant Grove Creek.
Hydrology and Water Quality Ascent
City of Roseville
3.11-12 Roseville Environmental Utilities Operations Center Project Draft EIR The City operates under an NPDES Municipal Stormwater Permit administered by the state. The City’s Stormwater Management Plan was adopted and approved by the Central Valley RWQCB and the City received a Phase II Stormwater Permit in 2004. The waste discharge requirements contained in the NPDES Municipal Stormwater Permit have been designed to be consistent with the water quality standards and goals established in the Central Valley RWQCB’s Basin Plan. In compliance with City’s Urban Stormwater Quality Management and Discharge Control Ordinance including implementing measures from the Stormwater BMP Guidance Manual for Construction, PCFCWCD’s Stormwater Management Manual, and the West Placer Storm Water Quality Design Manual, potential long-term water quality impacts from Phase 1 would be minimized.
Phase 1 would include implementation of design measures, including stormwater detention basins shown in Figure 2- 4 in Chapter 2, “Project Description,” to minimize impacts to Pleasant Grove Creek by limiting runoff from the site and managing it in a manner that is consistent with applicable regulations and historic discharge levels. Additionally, Phase 1 would be required to comply with the City’s Phase II Stormwater Permit, Urban Stormwater Quality Management and Discharge Control Ordinance, West Placer Storm Water Quality Design Manual, and Section
16.20.040 of the Roseville Municipal Code that include measures to control, prevent, remove, or reduce pollution.
Thus, short- and long-term impacts on surface and groundwater quality would be less than significant.
Mitigation Measures
No mitigation is required.
Phase 2
Similar to Phase 1, Phase 2 construction activities such as grading, excavation, trenching, and soil pile storage could result in erosion and sedimentation, and discharge of other nonpoint source pollutants. In addition, project operation has the potential to generate polluted runoff associated with storage of chemicals and vehicle/equipment leaks. To avoid or minimize the potential for adverse construction- and operation-related effects on water quality, the City and/or its contractor would be required to develop and implement a SWPPP and BMPs and comply with the City’s Urban Stormwater Quality Management and Discharge Control Ordinance, West Placer Storm Water Quality Design Manual, PCFCWCD’s Stormwater Management Manual, and Section 16.20.040 of the Roseville Municipal Code that include measures to control, prevent, remove, or reduce pollution. Therefore, short- and long-term impacts on surface and groundwater quality would be less than significant for Phase 2.
Construction
Phase 2 of the project would include an additional 122,000 square feet of building area for the RRTO Facility and the construction of 37,000 square feet of building area for the Potential Future Organics Processing Facility (including the development of 34 acres of land). Similar to Phase 1, construction of Phase 2 would involve grading, excavation, trenching, and soil pile storage, which could result in erosion and sedimentation, and discharge of other nonpoint source pollutants. These activities would be in compliance with existing local, state, and federal regulations cited above.
Operation
Operation of Phase 2 would include a Potential Future Organics Processing Facility, which may involve a composting facility and/or biomass facility. The potential future compost facility would involve the composting of green waste, wood, and food waste. Composting, the processing of food waste, the use of dry fermentation anaerobic digestion processes, the use of wet in-vessel digestion process, and the operation of biogas facilities may all occur at the Potential Future Organics Processing Facility. These operations may create leachate, which (if left untreated) could infiltrate into groundwater or surface water run-off. Phase 2 also has the potential to generate polluted runoff associated with storage of chemicals and vehicle/equipment leaks. However, consistent with applicable WDRs (including WQ 2020-0012-DWQ), leachate would be collected and stored in lined basin(s) for collection, treatment, evaporation, and/or and disposal. The project would be designed to minimize impacts to water quality, including providing landscape setbacks that would serve as a buffer along Phillip Road and Pleasant Grove Creek and on-site retention of runoff sitewide (consistent with NPDES requirements). Should the project connect to the Pleasant Grove Stormwater Retention Basin planned to the east of the project site, leachate associated with the potential organics processing facility would be managed separately
Ascent Hydrology and Water Quality
City of Roseville
Roseville Environmental Utilities Operations Center Project Draft EIR 3.11-13 from the remainder of the developed area of the site (consistent with the requirements of WQ 2020-0012-DWQ).
Additionally, post-construction, the operational handling and storage of materials that may generate polluted run-off would continue to comply with existing local, state, and federal regulations, as described for Phase 1. Because the design, use, and storage of pollutant-generating materials would be in compliance with laws and regulations intended to reduce potential impacts to water quality, this impact would be less than significant.
Mitigation Measures
No mitigation is required.
Impact 3.11-2: Substantially Decrease Groundwater Supplies, Interfere with Groundwater Recharge, or Interfere with Implementation of a Sustainable Groundwater Management Plan Phase 1
Phase 1 would not directly use groundwater as a water supply source and no new wells are proposed. However, the project would receive its water supply from the City of Roseville, which relies on surface water and groundwater supplies. The project site is undeveloped land and implementation of Phase 1 would add approximately 116 acres of impervious surface to the site; however, this would account for less than 0.1 percent of the surface area of the North American Subbasin. Therefore, Phase 1 would not substantially decrease groundwater levels nor interfere with groundwater recharge. This impact would be less than significant.
A Water Utility Strategy and Evaluation Report, prepared for the project in 2024, analyzed four alternatives to providing water to the project site (HDR 2024). Although existing groundwater wells are located on-site, the report found that Alternative B, which does not utilize the groundwater wells, and instead relies on municipal potable water pipeline to provide water for potable, irrigation, non-potable, and fire uses would be the most cost-effective solution (HDR 2024).
Therefore, the project would receive its water supply from the City of Roseville via a 3.19-mile municipal water pipeline extended from surrounding development. The project would connect to this existing infrastructure via a new 16-inch water line. Phase 1 of the project is anticipated to require 21,000 gallons per day (gpd) of potable water and 24,000 gpd of non-potable and irrigation water, resulting in a total water demand for Phase 1 of 45,000 gpd. The proposed project would not directly use groundwater as a water supply source and no new wells are proposed.
The City relies on surface and groundwater supplies. Groundwater makes up approximately 6 percent of the City’s total water supply and is available for use as part of the City’s water supply portfolio in all year types including normal, single dry, or multiple dry year scenarios (see Section 3.15, “Public Utilities,” for a detailed discussion of water supplies). However, the City’s groundwater wells are primarily used for backup water supply and to improve water supply reliability during drought and emergency conditions. As part of the City’s groundwater program, it has invested in Aquifer Storage and Recovery, which provides the capability to supplement the groundwater basin through direct injection of drinking water into the groundwater basin that can be later recovered for drinking water use during dry periods (City of Roseville 2020a). Implementation of Phase 1 is not expected to substantially deplete groundwater supplies or interfere with sustainable management of the groundwater basin.
The project site is undeveloped, and implementation of Phase 1 would add approximately 116 acres of impervious surface to the site, as well as additional acreage for Phillip Road improvements. However, the 93 acres of the project site bordering Pleasant Grove Creek would continue to allow for infiltration. The addition of 116 acres of impervious surfaces would account for less than 0.1 percent of the surface area of the North American Subbasin; therefore, this addition of impervious surfaces would not substantially impede groundwater recharge. Impacts related to groundwater levels and recharge would be less than significant.
Mitigation Measures
No mitigation is required.
Hydrology and Water Quality Ascent
City of Roseville
3.11-14 Roseville Environmental Utilities Operations Center Project Draft EIR Phase 2
As described for Phase 1, Phase 2 would not directly use groundwater as a water supply source and no new wells are proposed. However, like Phase 1, Phase 2 would receive water supplies from the City of Roseville, which relies on surface water and groundwater supplies. Phase 2 would add approximately 34 acres of impervious surface to the site, which as stated above, is less than 0.1 percent of the surface area of the North American Subbasin. Therefore, Phase 2 would not substantially decrease groundwater levels nor interfere with groundwater recharge. This impact would be less than significant.
As stated above for Phase 1, no groundwater from the existing wells on-site would be used for the project (HDR 2024). By 2040 to provide for both Phases 1 and 2, it is anticipated that that project would require 50,000 gpd of potable water and 56,000 gpd of non-potable and irrigation water, resulting in a total water demand for the project (Phases 1 and 2) of 106,000 gpd (HDR 2024). Additionally, the non-potable fire water storage water demand would be 960,000 gallons based on the California Fire Code, with City of Roseville amendments, to meet the potential maximum fire flow demand for the project.
The City of Roseville Environmental Utilities would supply water to the site. As explained above, the City relies on surface and groundwater supplies. Implementation of Phase 2 is not expected to substantially deplete groundwater supplies or interfere with sustainable management of the groundwater basin.
Phase 2 would add approximately 34 acres of impervious surface to the currently undeveloped project site as well as additional acreage for Phillip Road improvements. The 93 acres along Pleasant Grove Creek would remain undisturbed and an additional 34 acres is less than 0.1 percent of land within the North American Subbasin.
Therefore, this addition of impervious surfaces would not substantially impede groundwater recharge. Impacts related to groundwater levels and recharge would be less than significant.
Mitigation Measures
No mitigation is required.
Impact 3.11-3: Substantially Alter the Existing Drainage Pattern of the Site Resulting in Substantial Flooding, Additional Sources of Polluted Runoff, or Exceedance of Existing Stormwater Infrastructure Capacity
Phase 1
Development of the project site and the addition of impervious surfaces would alter the existing drainage rate and pattern of the site. This would result in increased runoff. In addition, portions of the project site are designated as 100-year floodplain and 500-year floodplain for Pleasant Grove Creek. As a result, proposed development of the site could increase the potential for flooding. However, the project would be required to comply with City Improvement Standards, the City’s Stormwater Quality Design Manual, and PCFCWCD’s Stormwater Management Manual that requires stormwater drainage facilities be designed with adequate capacity for stormwater flows from the project site.
The project would also be required to obtain a Letter of Map Revision from FEMA and to remove a portion of the project site out of the flood zone before that area can be developed. Additionally, on-site stormwater runoff would be managed through a series of stormwater retention basins on-site and by participation in the Pleasant Grove Stormwater Retention Basin Project to the east (depending on the implementation schedule for that project), which would be required to comply with West Placer Stormwater Quality Manual. With implementation of these measures, this impact would be less than significant.
The volume and rate of stormwater runoff generated from an area is affected by development through conversion of vegetated or pervious surfaces to impervious surfaces and by the development of drainage systems that connect these impervious surfaces to streams or other water bodies. In this way, development can increase the rate of runoff and eliminate storage, detention, and infiltration that would naturally occur along drainage paths. As water runs off the land surface, it can become concentrated, overwhelming existing storm drain systems, causing flooding in lower watershed areas.