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Home My WebLink AboutEDN 2025-0002CITY OF ATASCADERO COMMUNITY DEVELOPMENT DEPARTMENT Notice of Intent to Adopt Mitigated Negative Declaration PROJECT NO. DEV24-0084 Environmental Document No. 2025-0002 PROJECT TITLE Atascadero Mutual Water Company Water Treatment Plant Project APPLICANT NAME & PHONE NUMBER Atascadero Mutual Water Company (805) 466-2428 Email jneil@amwc.us MAILING ADDRESS: 5005 El Camino Real Atascadero, CA 93422 STAFF CONTACT: Kelly Gleason (805) 470-3446 Kgleason@atascadero.org PROJECT ADDRESS: 6575 Sycamore Road Atascadero, CA 93422 APN: 028-111-008, 028- 111-006 PROJECT DESCRIPTION: The proposed Atascadero Mutual Water Company (AMWC) Water Treatment Plant (WTP) project involves construction of a facility to treat for per- and polyfluoroalkyl substances detected within the AMWC production wells located adjacent to the Salinas River between State Route 41 and Chico Road. The WTP would be located within a portion of AMWC’s existing Corporation Yard at the northwest corner of the overpass of State Route 41 over Sycamore Road. Several components of the WTP would be located under metal canopies, the treatment vessels would be located in the open air, and the Operations Center would be enclosed in a prefabricated metal building that would be about 20 feet in height and approximately 3,800 square feet in size. Chemical storage facilities would be located under a metal canopy with covered chain-link fencing surrounding the chemical containment areas. The project includes installation of new outdoor lighting, including downward- facing pole-mounted lights and chain-mounted LED lights under canopies (shielded by quarter-height panels). Native landscape plants would be placed along the Sycamore Road frontage. Due to existing geotechnical conditions at the project site, ground improvements including over-excavation of materials, rapid impact compaction, and reconstruction of the over-excavation materials into a structural backfill would be conducted in certain areas to densify the ground beneath the project site and improve the soil conditions to be suitable for the proposed project. The proposed project would not result in increased groundwater extraction from AMWC’s production wells beyond baseline conditions. The project site is not located in an area that is listed as a hazardous materials site compiled pursuant to Government Code Section 65962.5. LEAD AGENCY: City of Atascadero Community Development Department 6500 Palma Avenue Atascadero, CA 93422 DOCUMENT AVAILABLE ONLINE: http://www.atascadero.org/environmentaldocs STATE CLEARINGHOUSE REVIEW: ☒ Yes No ☐ REVIEW PERIOD BEGINS: 11/26/2025 REVIEW PERIOD ENDS: 12/26/2025 PUBLIC HEARING REQUIRED: ☒No ☐ Yes PUBLIC NOTICE: The City of Atascadero is releasing a draft Initial Study and Mitigated Negative Declaration for the above project for review and comment to all effected agencies, organizations, and interested parties. Reviewers should focus on the content and accuracy of the report and the potential impacts upon the environment. The notice for this project is in compliance with the California Environmental Quality Act (CEQA). Persons responding to this notice are urged to submit their comments in writing. Written comments should be delivered the City (lead agency) no later than 5pm on the date listed as “review period ends”. Submittal of written comments via email is also accepted and should be directed to the Staff contact at the above email address. This document may be viewed by visiting the Community Development Department, listed under the lead agency address, or accessed via the City’s website as listed above. Initial Study Summary – Environmental Checklist Project No. DEV24-0084 Environmental Document No. 2025-0002 Project Title Atascadero Mutual Water Company Water Treatment Plant Project Environmental Factors Potentially Affected The proposed project could have a “Potentially Significant Impact” for at least one of the environmental factors checked below. Please refer to the attached pages for discussion on mitigation measures or project revisions to either reduce these impacts to less-than-significant levels or require further analysis. □ Aesthetics □ Agriculture and Forestry Resources □ Air Quality ■ Biological Resources ■ Cultural Resources □ Energy □ Geology and Soils □ Greenhouse Gas Emissions □ Hazards and Hazardous Materials □ Hydrology and Water Quality ■ Land Use and Planning □ Mineral Resources ■ Noise □ Population and Housing □ Public Services □ Recreation □ Transportation □ Tribal Cultural Resources □ Utilities and Service Systems □ Wildfire ■ Mandatory Findings of Significance Determination On the basis of this initial evaluation, the Community Development Director finds that: □ The proposed project COULD NOT have a significant effect on the environment, and a NEGATIVE DECLARATION will be prepared. ■ Although the proposed project could have a significant effect on the environment, there will not be a significant effect in this case because revisions to the project have been made by or agreed to by the project proponent. A MITIGATED NEGATIVE DECLARATION will be prepared. □ The proposed project MAY have a significant effect on the environment, and an ENVIRONMENTAL IMPACT REPORT is required. □ The proposed project MAY have a “potentially significant impact” or “less than significant with mitigation incorporated” impact on the environment, but at least one effect (1) has been adequately analyzed in an earlier document pursuant to applicable legal standards, and (2) has been addressed by mitigation measures based on the earlier analysis as described on attached sheets. An ENVIRONMENTAL IMPACT REPORT is required, but it must analyze only the effects that remain to be addressed. □ Although the proposed project could have a significant effect on the environment, because all potential significant effects (a) have been analyzed adequately in an earlier EIR or NEGATIVE DECLARATION pursuant to applicable standards, and (b) have been avoided or mitigated pursuant to that earlier EIR or NEGATIVE DECLARATION, including revisions or mitigation measures that are imposed upon the proposed project, nothing further is required. Prepared by: November 25, 2025 Signature Date Ethan Knox Environmental Planner Printed Name Title Reviewed by: November 25, 2025 Signature Date Kelly Gleason Planning Manager Printed Name Title Atascadero Mutual Water Company Water Treatment Plant Project Initial Study – Mitigated Negative Declaration prepared by City of Atascadero Community Development Department 6500 Palma Avenue Atascadero, California 93422 Contact: Kelly Gleason, Planning Manager prepared with the assistance of Rincon Consultants, Inc. 1530 Monterey Street, Suite D San Luis Obispo, California 93401 November 2025 Table of Contents Initial Study – Mitigated Negative Declaration i Table of Contents Initial Study Summary – Environmental Checklist ................................................................................... i Environmental Factors Potentially Affected ............................................................................................ i Determination ........................................................................................................................................ ii Project Environmental Analysis .............................................................................................................. 1 Proposed Project, Existing Setting, and Environmental Analysis ........................................................... 3 1. Proposed Project ................................................................................................................. 3 2. Existing Setting ..................................................................................................................10 Evaluation of Environmental Impacts ..................................................................................................15 Initial Study Checklist ............................................................................................................................17 1 Aesthetics ..........................................................................................................................17 2 Agriculture and Forestry Resources ..................................................................................21 3 Air Quality .........................................................................................................................23 4 Biological Resources ..........................................................................................................35 5 Cultural Resources ............................................................................................................41 6 Energy ...............................................................................................................................45 7 Geology and Soils ..............................................................................................................49 8 Greenhouse Gas Emissions ...............................................................................................57 9 Hazards and Hazardous Materials ....................................................................................63 10 Hydrology and Water Quality ...........................................................................................69 11 Land Use and Planning ......................................................................................................77 12 Mineral Resources ............................................................................................................83 13 Noise .................................................................................................................................85 14 Population and Housing ....................................................................................................95 15 Public Services ...................................................................................................................97 16 Recreation .........................................................................................................................99 17 Transportation ................................................................................................................101 18 Tribal Cultural Resources ................................................................................................105 19 Utilities and Service Systems ..........................................................................................109 20 Wildfire............................................................................................................................113 21 Mandatory Findings of Significance ................................................................................117 Initial Study References and Outside Agency Contacts ......................................................................123 Bibliography ................................................................................................................................123 Outside Agency Contacts ............................................................................................................128 Reference Materials....................................................................................................................129 List of Preparers ..........................................................................................................................130 City of Atascadero Community Development Department Atascadero Mutual Water Company Water Treatment Plant Project ii Tables Table 1 Health Effects Associated with Non-Attainment Criteria Pollutants ................................24 Table 2 Estimated Maximum Daily Construction Emissions (pounds/day) ...................................28 Table 3 Estimated Maximum Quarterly Construction Emissions (tons/quarter)1 .........................29 Table 4 Estimated Maximum Daily Operational Emissions (pounds/day) ....................................30 Table 5 Estimated Annual Operational Emissions (tons/year) ......................................................30 Table 6 Estimated Fuel Consumption during Construction ...........................................................46 Table 7 Estimated Construction GHG Emissions ...........................................................................59 Table 8 Combined Annual Emissions of Greenhouse Gases .........................................................60 Table 9 Project Consistency with the Land Use Policies of the City’s General Plan ......................78 Table 10 Exterior Noise Limits .........................................................................................................87 Table 11 FTA Daytime Construction Noise Criteria .........................................................................87 Table 12 FTA Groundborne Vibration Criteria – Architectural Damage ..........................................87 Table 13 Estimated Daytime Construction Noise Levels .................................................................88 Table 14 Estimated Nighttime Construction Noise Levels...............................................................89 Table 15 Estimated Operational Noise Levels .................................................................................90 Table 16 Estimated Operational Noise Levels - Mitigated ..............................................................94 Figures Figure 1 Regional Location ................................................................................................................ 4 Figure 2 Project Location and Study Area ......................................................................................... 5 Figure 3 Preliminary Project Site Plan ............................................................................................... 7 Figure 4 Vegetation Communities and Land Covers .......................................................................12 Figure 5 Representative Site Photographs .....................................................................................14 Appendices Appendix A Biological Resource Assessment Appendix B Air Quality and Greenhouse Gas Modeling Appendix C Geotechnical Report Appendix D Energy Calculations Appendix E Topographic Survey Map Appendix F Noise Modeling Project Environmental Analysis Initial Study – Mitigated Negative Declaration 1 Project Environmental Analysis The City of Atascadero’s environmental review process incorporates all of the requirements for completing the Initial Study as required by the California Environmental Quality Act (CEQA) and the CEQA Guidelines. The Initial Study includes Staff’s on-site inspection of the project site and surrounding area and a detailed review of the information on file for the proposed project. In addition, available background information is reviewed for each project. Relevant information regarding soil types and characteristics, geological information, significant vegetation and/or wildlife resources, water availability, wastewater disposal service, existing land uses and surrounding land use categories, and other information relevant to the environmental review process are evaluated for each project. The Initial Study References and Outside Agency Contacts section includes the references used as well as the agencies or groups that were contacted as a part of this Initial Study. The City of Atascadero uses the checklist to summarize the results of the research accomplished during the initial environmental review of the project. Persons, agencies, or organizations interested in obtaining more information regarding the environmental review process for a project should contact the Community Development Department at 6500 Palma Avenue, Atascadero, California 93422 or call (805) 461-5000. City of Atascadero Community Development Department Atascadero Mutual Water Company Water Treatment Plant Project 2 This page intentionally left blank. Proposed Project, Existing Setting, and Environmental Analysis Initial Study – Mitigated Negative Declaration 3 Proposed Project, Existing Setting, and Environmental Analysis 1. Proposed Project Project Title Atascadero Mutual Water Company Water Treatment Plant Project Lead Agency Name and Address City of Atascadero 6500 Palma Avenue Atascadero, California 93422 Lead Agency Contact Person and Phone Number Kelly Gleason, Planning Manager 805-470-3446 Project Sponsor’s Name and Address Atascadero Mutual Water Company (AMWC) John B. Neil, General Manager 5005 El Camino Real Atascadero, California 93422 Project Location The project site is located within a portion of AMWC’s existing Corporation Yard at the northwest corner of the overpass of State Route (SR) 41 over Sycamore Road. Figure 1 shows the regional project site location, and Figure 2 shows the project site location in a local context. Assessor’s Parcel Number(s) 028-111-008 and 028-111-006 Latitude 35°30'3.39"N Longitude 120°39'37.54"W City of Atascadero Community Development Department Atascadero Mutual Water Company Water Treatment Plant Project 4 Figure 1 Regional Location Proposed Project, Existing Setting, and Environmental Analysis Initial Study – Mitigated Negative Declaration 5 Figure 2 Project Location and Study Area City of Atascadero Community Development Department Atascadero Mutual Water Company Water Treatment Plant Project 6 Description of Project The proposed AMWC Water Treatment Plant (WTP) project (herein referred to as “project” or “proposed project”) involves installation of a groundwater treatment facility to address per- and polyfluoroalkyl substances (PFAS) for AMWC’s existing production wells located adjacent to the Salinas River between SR 41 and Chico Road.1 The WTP would ultimately be developed in two phases – the WTP would be sized to meet current peak summer demand of 8.1 million gallons per day (MGD) under Phase I and would be upgraded to a capacity of 12 MGD under Phase II. However, at this time, only Phase I is proposed for development and therefore constitutes the proposed project. The proposed WTP would not result in increased groundwater extraction from AMWC’s production wells adjacent to the Salinas River between SR 41 and Chico Road beyond baseline conditions. No off-site improvements would be required to connect the proposed WTP to existing production wells. The WTP would consist of the following components: ▪ A high service pump station to convey water from the treatment plant inlet to the treatment system ▪ A 0.5-million-gallon prestressed concrete or welded steel tank that would serve as a forebay for the treatment plant with an aboveground tank bypass assembly and influent flow control/flow metering system to supply water to the tank from the Northern and Sycamore wellfields ▪ A transfer pump station and surge tank to convey water from the raw water forebay to the treatment vessels ▪ Improvements to the existing pre-treatment chemical feed and storage building ▪ Up to eight sets of treatment vessels, each with a 12-foot diameter and 26 feet in height, with granular activated carbon (GAC) technology and cartridge filters for PFAS treatment ▪ A partially-belowground 2.0-million-gallon prestressed concrete clearwell that would be approximately 150-feet diameter by 15 feet deep ▪ Up to four 500-kilowatt emergency generators powered by natural gas ▪ A self-supporting tower assembly, ranging in height between 50 and 60 feet, for supervisory control and data acquisition (SCADA) communications ▪ A belowground concrete backwash waste sump and waste discharge riser ▪ A post-treatment chemical storage and injection facility ▪ Offices for operation of the treatment plant (Operations Center) and new septic tank adjacent to the Operations Center building ▪ Associated belowground yard piping, including for backwash, utility, and fire water supply systems ▪ Paved parking lots, landscaping, and an improved facility driveway leading to Sycamore Road ▪ Pipeline connection to the existing distribution system in Sycamore Road ▪ Security fencing and cameras Figure 3 presents the preliminary project site plan. 1 All wells are currently operational, and PFAS levels in three wells exceed the Response Levels established by the California State Water Resources Control Board’s Division of Drinking Water. However, water from these affected wells is being blended with water from other wells to reduce PFAS levels below Response Levels. Proposed Project, Existing Setting, and Environmental Analysis Initial Study – Mitigated Negative Declaration 7 Figure 3 Preliminary Project Site Plan Source: MKN & Associates 2025 City of Atascadero Community Development Department Atascadero Mutual Water Company Water Treatment Plant Project 8 The high service pump station, transfer pump station, chemical storage area, and aeration system would be located under metal canopies with covered chain-link fencing surrounding the chemical containment areas, and the treatment vessels would be located in the open air. The Operations Center would be enclosed in a prefabricated metal building that would be about 20 feet in height and approximately 3,800 square feet in size. Heating, ventilation, and air conditioning (HVAC) equipment would be installed in the Operations Center offices and would include variable refrigerant flow split systems with indoor fan coils and multiple exterior condensing units. The outdoor units would be located at grade on a concrete pad. To address existing geotechnical conditions at the project site, the project design involves completing ground improvements, including over-excavation of approximately 15 feet of random backfill overlying the natural alluvial material, processing the random backfill to remove unwanted debris, and stockpiling it for use as structural backfill to restore the site to existing topographic conditions; deep ground consolidation improvements using rapid impact compaction; 2 and placement of the over-excavated material as structural backfill. These ground improvements would be conducted under the majority of the WTP site including the proposed raw water forebay, the granular activated carbon treatment tanks, and the clearwell. The project includes installation of new outdoor lighting, including downward-facing pole-mounted lights to illuminate access roads and chain-mounted LED lights under canopies (shielded by quarter- height panels) to illuminate air stripping and booster pump systems. The project also includes conversion of five existing production wells from natural gas to electric power. Native landscape plants would be placed along the Sycamore Road frontage. Stormwater drainage systems at the project would be designed to comply with the City’s post- construction stormwater control requirements outlined in the Atascadero Municipal Code (AMC) and the City’s Stormwater Control Plan Permit Documentation guidance (2014). Stormwater runoff would be directed and/or piped to AMWC’s existing stormwater infiltration basins within the Corporation Yard facility, adjacent to the proposed WTP. The project includes installation of a new precast concrete septic tank adjacent to the Operations Center building that would serve the new restroom in the Operations Center. The septic tank would be designed to be watertight and leakproof and would have a capacity of approximately 1,000 gallons. The septic tank would be buried approximately 9.5 feet below the ground surface, and effluent from the septic tank would flow via plastic pipes with sealed joints into an existing leach field within the AMWC’s existing Corporation Yard facility, which currently serves the facility’s existing septic tank. Construction Project construction for the raw water forebay, water treatment equipment, and the clearwell is expected to begin as soon as spring of 2026 and estimated to take up to between 18 and 24 months, depending on the lead time associated with the supply of the treatment and electrical equipment. Construction activities would typically occur between 7:00 a.m. and 3:30 p.m. on weekdays, with occasional nighttime work required for temperature-sensitive activities such as coating/painting and concrete placement. Project construction would involve ground disturbance of approximately 4.5 acres, and approximately 3.5 acres of impervious surfaces would be added to the 2 Rapid impact compaction is a technique that densifies soils. Rapid impact compaction involves using a hydraulic hammer to repeatedly strike an impact plate on the ground surface, transferring energy to underlying loose granular soils and rearranging soil particles into a denser formation. Proposed Project, Existing Setting, and Environmental Analysis Initial Study – Mitigated Negative Declaration 9 project site. The maximum depth of ground disturbance would be approximately 35 feet associated with the over-excavation and the deep ground improvements via rapid impact compaction. Up to approximately 32,670 cubic yards of soil would be excavated, replaced, and recompacted in association with the structural backfilling, effectively restoring the project site to the existing topographic conditions. Construction staging areas would be located within the project site, and construction workers would park in the existing parking lot of the AMWC Corporation Yard. No lane or road closures would be required during project construction, and no tree removal is proposed. Groundwater may be encountered during project construction. In this event, produced groundwater would be discharged to the on-site well flushing basins, where it would percolate into the underlying groundwater basin. Groundwater dewatering may be required for approximately three months during construction of the clearwell and influent flow structures. Upon the completion of construction, the new infrastructure would be flushed and disinfected with potable water that would be dechlorinated prior to discharge to the existing on-site well flushing basins. Operation The AMWC WTP would operate up to 24 hours per day, 365 days per year and would treat approximately 8.1 MGD. The WTP would require daily operation and maintenance activities, including water quality sampling, inspections, calibrating and maintaining instrumentation, replacing consumables (e.g., cartridge filters and chemicals), and executing an asset management program that examines the replacement frequency of key equipment around the WTP. These maintenance tasks would be integrated into existing staff rounds in the local area. AMWC would require at least one new operator to support the proposed AMWC WTP. Operation of the WTP would require approximately 12,100 kilowatt-hours of electricity daily, or approximately 4,420 megawatt-hours (MWh) annually.3 Electricity would be provided by Pacific Gas and Electric (PG&E). The emergency generators would require a natural gas connection. Chemical deliveries to the WTP via 45-foot semi-trailers would occur approximately one to two times each month. These deliveries would include up to two 4,500-gallon deliveries of sodium hypochlorite (chlorine) and up to two 800-gallon deliveries of orthophosphate corrosion inhibitor. These chemicals would be stored at the proposed WTP in a completely enclosed structure with proper containment, venting, and sumps for spill control. Sodium hypochlorite is a liquid disinfection agent added to the water and is commonly referred to as “bleach.” Sodium hypochlorite is not the equivalent of chlorine gas, and chlorine gas would not be used or released during project operation. In accordance with standard operating practice, AMWC would submit an emergency response/contingency plan as part of a Hazardous Materials Business Plan to the California Environmental Reporting System for the proposed facility. Spent GAC cartridge filters, which may be considered a hazardous waste depending on the concentration of PFAS, would be removed every six to nine months by the cartridge filter supplier, who would be required to transport and dispose of the material in accordance with all applicable regulations. The anticipated lifetime of the proposed project is 50 years. 3 The total estimated design load of 1,095 full-load amps was multiplied by the estimated voltage of 460 volts, which equals 503,700 watts (Word 2024). The wattage was then multiplied by 24 hours per day and divided by 1,000 to obtain the estimated daily electricity use in kilowatt-hours (12,089 kilowatt-hours per day, rounded to 12,100). To obtain annual electricity usage in megawatt-hours, the estimated daily electricity use was multiplied by 365.25 days per year and divided by 1,000 (4,420 megawatt-hours per year). City of Atascadero Community Development Department Atascadero Mutual Water Company Water Treatment Plant Project 10 Other Public Agencies Whose Approval is Required Permits/approvals would be required for the proposed project from the following agencies: ▪ City of Atascadero Building Division – building permit ▪ City of Atascadero Floodplain Administrator – permit review and map determination ▪ State Water Resources Control Board Division of Drinking Water – water supply permit amendment ▪ Federal Emergency Management Agency (FEMA) – Conditional Letter of Map Revision or Letter of Map Revision Public Resources Code Section 21080.3.1 Documentation In accordance with Public Resources Code Section 21080.3.1, the City of Atascadero initiated the tribal consultation process to ensure the protection of tribal cultural resources potentially affected by the Project. On September 25, 2024, the City of Atascadero issued notification letters to the following California Native American tribes that are traditionally and culturally affiliated with the geographic area of the proposed project, informing them of the proposed project and inviting them to engage in consultation: ▪ Barbareño/Ventureño Band of Mission Indians ▪ Chumash Council of Bakersfield ▪ Coastal Band of the Chumash Nation ▪ Northern Chumash Tribal Council ▪ Salinan Tribe of Monterey, San Luis Obispo Counties ▪ Santa Ynez Band of Chumash Indians ▪ Tule River Indian Tribe ▪ Xolon-Salinan Tribe ▪ yak tityu tityu yak tiłhini – Northern Chumash Tribe The tribes were given 30 days from the date of the notification (i.e., by October 25, 2024) to respond and request consultation, as mandated by Public Resources Code Section 21080.3.1. As discussed further in Initial Study Checklist Section 18, Tribal Cultural Resources, the City did not receive any requests for consultation. This documentation reflects the City’s commitment to fulfilling the requirements of Public Resources Code Section 21080.3.1 and our dedication to respecting and protecting the cultural heritage of California Native American tribes. 2. Existing Setting Land Use Designation APNs 028-11-006 and 028-111-008 have land use designations of Industrial and Open Space. The project site itself is within the portion of the parcels designated Industrial. (City of Atascadero 2011). Proposed Project, Existing Setting, and Environmental Analysis Initial Study – Mitigated Negative Declaration 11 Zoning District APN 028-11-006 is zoned as Open Space and Industrial, and APN 028-111-008 is zoned as Industrial Park, Industrial, and Open Space. The project site itself is within the portion of the parcels zoned Industrial and Industrial Park (City of Atascadero 2022). Parcel Size The project site is approximately 4.5 acres in size and encompasses a portion of two parcels, which has a combined total area of approximately 18.69 acres. Topography and Average Slope The average slope of the project site is approximately 2.5 percent. The elevation of the project site ranges from approximately 823 to 835 feet above mean sea level (amsl) (Appendix A), Mapped soils consist of Corducci and Typic Xerofluvents, 0 to 5 percent slopes; Arbuckle-Positas complex, 9 to 15 percent slopes; and still clay loam, 2 to 9 percent slopes (Appendix A). Vegetation A reconnaissance-level biological survey of the project site was conducted by Rincon on March 24, 2023. The survey aimed to identify and document existing vegetation types as well as any special- status plant species or habitats that may be present. A list of plant species observed during the March 24, 2023, survey is included in Attachment 3 of Appendix A. Four planted coast live oaks (Quercus agrifolia) are present within the project site around existing structures. As mapped in Appendix A, the following vegetation communities and land cover types were documented within the project site: ▪ Developed. Developed areas present within the project site consist of the paved Sycamore Road, existing AMWC facilities, gravel parking areas, access roads, and stockpiles of construction materials. ▪ Ruderal. The ruderal land cover type is often associated with road margins and is typically composed of a mix of annual grasses and forbs. The exact species composition is dependent upon the frequency and severity of disturbance, ranging from sparse individual plants to semi- natural assemblages resembling annual grasslands. It may provide limited habitat suitability for disturbance-tolerant wildlife but is typically poor-quality habitat. Within the project site, the dominant species observed in this land cover type were ripgut brome (Bromus diandrus), fiddlenecks (Amsinckia sp.), black mustard (Brassica nigra), broadleaf filaree (Erodium botrys), pineappleweed (Matricaria discoidea), and burr clover (Medicago polymorpha). Ruderal land cover is present within the project site in patches of the existing AMWC facility. The western portion of the facility has more sparsely vegetated patches, with five coast live oaks planted along the fenceline bordering Sycamore Road. The eastern section of the facility exhibits more continuous vegetation cover and resembles a grassland with a denser cover of annual grasses and forbs. However, the area is still highly disturbed. Ruderal areas are also present along the margins of Sycamore Road within the 100-foot buffer. Figure 4 presents the vegetation communities and land covers of the project site. City of Atascadero Community Development Department Atascadero Mutual Water Company Water Treatment Plant Project 12 Figure 4 Vegetation Communities and Land Covers Proposed Project, Existing Setting, and Environmental Analysis Initial Study – Mitigated Negative Declaration 13 Existing Use The project site is located entirely within the existing, fenced AMWC Corporation Yard and the right- of-way of Sycamore Road. The project site contains a paved access road into the facility, gravel areas used for parking and construction stockpiling, and regularly-mowed ruderal vegetation. Historical imagery indicates the existence of roads and disturbance from facilities present within the project site as early as 1994 (the oldest year with available imagery; Google Earth Pro 2023), with the current layout of the AMWC facility present in 2009. Figure 5 shows representative site photographs of existing conditions. Surrounding Land Uses The project site is within the AMWC Corporation Yard and is immediately surrounded by other portions of the facility to the north, west, and east and Sycamore Road to the south. Beyond the Corporation Yard boundaries, surrounding land uses include SR 41 to the east, the Salinas River to the north, Atascadero Creek and single-family residences to the west, and the Union Pacific Railroad and single-family residences to the south. The nearest residence is approximately 260 feet south of the project site boundary, across the railroad. City of Atascadero Community Development Department Atascadero Mutual Water Company Water Treatment Plant Project 14 Figure 5 Representative Site Photographs Photograph 1. View of project site, facing northwest. Note: Two coast live oaks depicted have since been removed due to conflicts with power lines. Photograph 2. View of coast live oak trees within the project site. Note: The two coast live oaks depicted on the right have since been removed due to conflicts with power lines. Photograph 3. View of project site facing south with small coast live oak along fenceline (not proposed for removal). Photograph 4. View of project site facing northeast. Evaluation of Environmental Impacts Initial Study – Mitigated Negative Declaration 15 Evaluation of Environmental Impacts 1. During the Initial Study process, at least one issue was identified as having a potentially significant environmental effect (see following Initial Study). The potentially significant items associated with the proposed project can be minimized to less than significant levels as explained in the analysis for each checklist item. 2. A brief explanation is required for all answers except “No Impact” answers that are adequately supported by the information sources a lead agency cites in the parentheses following each question. A “No Impact” answer is adequately supported if the referenced information sources show that the impact simply does not apply to projects like the one involved (e.g., the project falls outside a fault rupture zone). A “No Impact” answer should be explained where it is based on project-specific factors as well as general standards (e.g., the project will not expose sensitive receptors to pollutants, based on a project-specific screening analysis). 3. All answers must take account of the whole action involved, including off-site as well as on-site, cumulative as well as project-level, indirect as well as direct, and construction as well as operational impacts. 4. Once the lead agency has determined that a particular physical impact may occur, then the checklist answers must indicate whether the impact is potentially significant, less than significant with mitigation, or less than significant. “Potentially Significant Impact” is appropriate if there is substantial evidence that an effect may be significant. If there are one or more “Potentially Significant Impact” entries when the determination is made, an EIR is required. 5. “Negative Declaration: Less Than Significant With Mitigation Incorporated” applies where the incorporation of mitigation measures has reduced an effect from “Potentially Significant Impact” to a “Less Than Significant Impact.” The lead agency must describe the mitigation measures, and briefly explain how they reduce the effect to a less than significant level (mitigation measures from “Earlier Analyses,” as described in (5) below, may be cross- referenced). 6. Earlier analyses may be used where, pursuant to the tiering, program EIR, or other CEQA process, an effect has been adequately analyzed in an earlier EIR or negative declaration. Section 15063(c)(3)(D). In this case, a brief discussion should identify the following: ▪ Earlier Analysis Used. Identify and state where they are available for review. ▪ Impacts Adequately Addressed. Identify which effects from the above checklist were within the scope of and adequately analyzed in an earlier document pursuant to applicable legal standards, and state whether such effects were addressed by mitigation measures based on the earlier analysis. ▪ Mitigation Measures. For effects that are “Less than Significant with Mitigation Measures Incorporated,” describe the mitigation measures which were incorporated or refined from the earlier document and the extent to which they address site-specific conditions for the project. 7. Lead agencies are encouraged to incorporate into the checklist references to information sources for potential impacts (e.g., general plans, zoning ordinances). Reference to a previously prepared or outside document should, where appropriate, include a reference to the page or pages where the statement is substantiated. City of Atascadero Community Development Department Atascadero Mutual Water Company Water Treatment Plant Project 16 8. Supporting Information Sources: A source list should be attached, and other sources used or individuals contacted should be cited in the discussion. 9. This is only a suggested form, and lead agencies are free to use different formats; however, lead agencies should normally address the questions from this checklist that are relevant to a project’s environmental effects in whatever format is selected. 10. The explanation of each issue should identify: ▪ the significance criteria or threshold, if any, used to evaluate each question; and ▪ the mitigation measure identified, if any, to reduce the impact to less than significance. Initial Study Checklist Aesthetics Initial Study – Mitigated Negative Declaration 17 Initial Study Checklist 1 Aesthetics Potentially Significant Impact Less than Significant with Mitigation Incorporated Less-than - Significant Impact No Impact Except as provided in Public Resources Code Section 21099, would the project: a. Have a substantial adverse effect on a scenic vista? □ □ ■ □ b. Substantially damage scenic resources, including but not limited to, trees, rock outcroppings, and historic buildings within a state scenic highway? □ □ ■ □ c. In non-urbanized areas, substantially degrade the existing visual character or quality of public views of the site and its surroundings? (Public views are those that are experienced from a publicly accessible vantage point). If the project is in an urbanized area, would the project conflict with applicable zoning and other regulations governing scenic quality? □ □ ■ □ d. Create a new source of substantial light or glare that would adversely affect daytime or nighttime views in the area? □ □ ■ □ Existing Setting The project site is located within AMWC’s existing Corporation Yard and is not part of a scenic vista. According to the City’s General Plan, scenic views visible in the vicinity of the project site include gently rolling hills and valleys typical of the Salinas River Valley (City of Atascadero 2016); these are considered scenic vistas for the purpose of this analysis. Scenic vistas of rolling hills in the distant background to the northeast of the project site are intermittently visible to motorists traveling along Sycamore Road to the south of the project site and to motorists traveling northbound along SR 41 to the east of the project site. Scenic vistas of the Salinas River Valley are also visible to motorists traveling northbound and southbound along SR 41 as the highway crosses over the Salinas River. The closest officially designated scenic highway is SR 1 which is approximately 13.3 miles from the project site (California Department of Transportation [Caltrans] 2019). The project site vicinity consists of a mix of residential neighborhoods, open spaces, and riparian areas associated with the Salinas River, with mature oak woodlands and native vegetation contributing to the scenic rural character of the region. Existing sources of light and glare within the project site and its immediate City of Atascadero Community Development Department Atascadero Mutual Water Company Water Treatment Plant Project 18 vicinity include exterior lighting at AMWC’s existing Corporation Yard buildings and a streetlight located at the intersection of Sycamore Road and Capistrano Avenue. Proposed Project a. Would the project have a substantial adverse effect on a scenic vista? The project site consists of previously disturbed land within AMWC’s existing Corporation Yard, which has generally flat topography. Distant views of scenic vistas comprised of gently rolling hills to the northeast of the project site are visible from publicly-accessible vantage points along Sycamore Road and SR 41. The proposed project would introduce new elements to the foreground of views from Sycamore Road, including the proposed WTP and large native trees, which would partially obscure motorists’ existing views of scenic vistas from Sycamore Road. However, this change in views would only affect approximately 315 feet of Sycamore Road, which is not a heavily-trafficked roadway. In addition, the proposed project would not block views of scenic vistas from SR 41 because 1) the line-of-sight of scenic vistas from SR 41 does not cross directly through the project site and 2) SR 41 is elevated approximately 20 feet above ground surface in the vicinity of the project site, which is higher than the majority of proposed infrastructure (with the exception of the proposed self-supporting tower assembly which would range in height between 50 and 60 feet). As a result, the proposed project would not have a substantial adverse effect on a scenic vista, and the impact would be less than significant. LESS-THAN-SIGNIFICANT IMPACT b. Would the project substantially damage scenic resources, including but not limited to, trees, rock outcroppings, and historic buildings within a state scenic highway? No trees, rock outcroppings, or historic buildings will be removed during construction of the project. Due to the distance between the project site and SR 1, combined with the flat topography and rolling hills acting as a natural barrier, there would be no visibility of the project site from SR 1. Therefore, the project would not substantially damage scenic resources, including trees, rock outcroppings, or historic buildings, within a state scenic highway, and impacts would be less than significant. LESS-THAN-SIGNIFICANT IMPACT c. Would the project, in non-urbanized areas, substantially degrade the existing visual character or quality of public views of the site and its surroundings? (Public views are those that are experienced from a publicly accessible vantage point). If the project is in an urbanized area, would the project conflict with applicable zoning and other regulations governing scenic quality? According to Public Resources Code Section 21071(a), Atascadero is classified as a non-urbanized area because it is an incorporated city with a population less than 100,000 persons (United States Census Bureau 2024). The project would be located on previously disturbed land within AMWC’s existing Corporation Yard facility on a site designated and zoned for industrial use. The project site is currently flat and comprised of gravel parking areas and sparse vegetation surrounded by a chain link fence. Public views of the project site are available from several vantage points, including SR 41 and Sycamore Road. The proposed structures and infrastructure would introduce new elements to the foreground of views from Sycamore Road and to the middleground of views from SR 41. The proposed structures would be similar in appearance to the existing structures within AMWC’s Initial Study Checklist Aesthetics Initial Study – Mitigated Negative Declaration 19 Corporation Yard, which include several roll-up door warehouses near the northeast corner of the Sycamore Road and Capistrano Avenue intersection and would be consistent with the industrial nature of the Union Pacific Railroad corridor immediately south of the project site across Sycamore Road. In addition, the proposed facility would be shielded with large native trees that would be planted to screen the facility, which would be consistent in visual character with other mature trees located along the Sycamore Road frontage of AMWC’s Corporation Yard. Therefore, the project would not substantially degrade the existing visual character or quality of public views of the site and its surroundings, and impacts would be less than significant. LESS-THAN-SIGNIFICANT IMPACT d. Would the project create a new source of substantial light or glare that would adversely affect daytime or nighttime views in the area? Project construction would generally occur from 7:00 a.m. to 3:00 p.m., and occasional nighttime construction may be necessary for temperature-sensitive activities such as coating/painting and concrete pours. If nighttime construction lighting is required, lighting would be shielded and downcast to limit light spillover on adjacent properties. The project also includes installation of new outdoor lighting, consisting of downward-facing, pole-mounted lights and shielded, chain-mounted LED lights under canopies (shielded by quarter-height panels) to illuminate air stripping and booster pump systems. These new lighting systems would be designed to minimize light spillover to adjacent properties. In addition, the nearest residence is approximately 260 feet south of the project site boundary, across the railroad, and is shielded from the project site by existing mature trees and other vegetation which would further block the transmission of light. The proposed project also does not include substantial sources of glare such as glass building façades or metal finishes. Therefore, the project would not create a new source of substantial light or glare that would adversely affect daytime or nighttime views in the area, and impacts would be less than significant. LESS-THAN-SIGNIFICANT IMPACT Mitigation/Conclusion No significant impacts are expected. No mitigation is required. City of Atascadero Community Development Department Atascadero Mutual Water Company Water Treatment Plant Project 20 This page intentionally left blank. Initial Study Checklist Agriculture and Forestry Resources Initial Study – Mitigated Negative Declaration 21 2 Agriculture and Forestry Resources Potentially Significant Impact Less than Significant with Mitigation Incorporated Less-than - Significant Impact No Impact Would the project: a. Convert Prime Farmland, Unique Farmland, or Farmland of Statewide Importance (Farmland), as shown on maps prepared pursuant to the Farmland Mapping and Monitoring Program of the California Resources Agency, to non-agricultural use? □ □ □ ■ b. Conflict with existing zoning for agricultural use or a Williamson Act contract? □ □ □ ■ c. Conflict with existing zoning for, or cause rezoning of, forest land (as defined in Public Resources Code Section 12220(g)); timberland (as defined by Public Resources Code Section 4526); or timberland zoned Timberland Production (as defined by Government Code Section 51104(g))? □ □ □ ■ d. Result in the loss of forest land or conversion of forest land to non-forest use? □ □ □ ■ e. Involve other changes in the existing environment which, due to their location or nature, could result in conversion of Farmland to non-agricultural use or conversion of forest land to non-forest use? □ □ □ ■ Existing Setting The project site is located within AMWC’s existing Corporation Yard facility and the right-of-way of Sycamore Road, which do not contain agricultural lands, forest lands, or timberlands. In addition, according to the California Department of Conservation’s (DOC) Important Farmland Finder (2025a), the project site is classified as Urban and Built-Up Land and Grazing Land. There are also no agricultural lands, forest lands, or timberlands in the immediate vicinity of the project site. City of Atascadero Community Development Department Atascadero Mutual Water Company Water Treatment Plant Project 22 Proposed Project a. Would the project convert Prime Farmland, Unique Farmland, or Farmland of Statewide Importance (Farmland), as shown on maps prepared pursuant to the Farmland Mapping and Monitoring Program of the California Resources Agency, to non-agricultural use? The project site and its immediate surroundings do not contain Prime Farmland, Unique Farmland, or Farmland of Statewide Importance (DOC 2025a). Therefore, the project would not convert Prime Farmland, Unique Farmland, or Farmland of Statewide Importance to non-agricultural use, and no impact would occur. NO IMPACT b. Would the project conflict with existing zoning for agricultural use or a Williamson Act contract? The project site is not zoned for agricultural use and is not located within or adjacent to lands under a Williamson Act contract (DOC 2025b). Therefore, the project would not conflict with existing zoning for agricultural use or a Williamson Act contract, and no impact would occur. NO IMPACT c. Would the project conflict with existing zoning for, or cause rezoning of, forest land (as defined in Public Resources Code Section 12220(g)); timberland (as defined by Public Resources Code Section 4526); or timberland zoned Timberland Production (as defined by Government Code Section 51104(g))? The project site and its immediate surroundings are not zoned for forest land, timberland, or timberland production. Therefore, the project would not conflict with existing zoning, or cause rezoning of forest land, timberland, or land zoned Timberland Production. No impact would occur. NO IMPACT d. Would the project result in the loss of forest land or conversion of forest land to non-forest use? The project site and its immediate surroundings do not contain forest land. Therefore, the project would not result in the loss of forest land or the conversion of forest land to non-forest use, and no impact would occur. NO IMPACT e. Would the project involve other changes in the existing environment which, due to their location or nature, could result in conversion of Farmland to non-agricultural use or conversion of forest land to non-forest use? Because the project site and its immediate surroundings do not contain agricultural land or forest land, the project does not have the potential to result in the conversion of farmland to non- agricultural use or forest land to non-forest use. No impact would occur. NO IMPACT Mitigation/Conclusion No impacts are expected. No mitigation is required. Initial Study Checklist Air Quality Initial Study – Mitigated Negative Declaration 23 3 Air Quality Potentially Significant Impact Less than Significant with Mitigation Incorporated Less-than - Significant Impact No Impact Would the project: a. Conflict with or obstruct implementation of the applicable air quality plan? □ □ □ ■ b. Result in a cumulatively considerable net increase of any criteria pollutant for which the project region is non- attainment under an applicable federal or state ambient air quality standard? □ □ ■ □ c. Expose sensitive receptors to substantial pollutant concentrations? □ □ ■ □ d. Result in other emissions (such as those leading to odors) adversely affecting a substantial number of people? □ □ ■ □ Existing Setting The project site is located in the South Central Coast Air Basin (SCCAB), which is under the jurisdiction of the San Luis Obispo County Air Pollution Control District (SLOAPCD). The City and SLOAPCD work to create policies and programs to maintain local and regional air quality. The project site is within AMWC’s existing Corporation Yard facility. There are no substantial sources of air pollution within the project site itself. Sources of existing air pollutant emissions associated with AMWC’s Corporation Yard facility as a whole generally consist of vehicle exhaust and fugitive dust emissions generated by vehicle trips to and from the facility as well as diesel particulate matter (DPM) emissions generated during the use of heavy equipment (e.g., backhoes, front-end loaders, dump trucks) to load and handle materials as well as infrequent routine testing of existing emergency generators. Sensitive receptors are facilities or land uses that include members of the population who are particularly sensitive to the effects of air pollutants, such as children, the elderly, and people with illnesses. According to the California Air Resources Board, locations where sensitive receptors are most likely to spend time include schools and schoolyards, parks and playgrounds, daycare centers, nursing homes, hospitals, and residential communities (California Air Resources Board [CARB] 2005). The sensitive receptors nearest to the project site are residences located approximately 250 feet to the south. Air Quality Standards and Attainment As the local air quality management agency, SLOAPCD is required to monitor air pollutant levels to ensure the National Ambient Air Quality Standards (NAAQS) and California Ambient Air Quality Standards (CAAQS) are met and, if they are not met, to develop strategies to meet the standards. City of Atascadero Community Development Department Atascadero Mutual Water Company Water Treatment Plant Project 24 Depending on whether the standards are met or exceeded, the SCCAB is classified as being in “attainment” or “nonattainment.” In areas designated as non-attainment for one or more air pollutants, a cumulative air quality impact exists for those air pollutants, and the human health impacts associated with these criteria pollutants, presented in Table 1, are already occurring in that area as part of the environmental baseline condition. Under state law, air districts are required to prepare a plan for air quality improvement for pollutants for which the district is in non-compliance. The San Luis Obispo County portion of the SCCAB is designated nonattainment for the one-hour and eight-hour CAAQS for ozone and the 24-hour and annual CAAQS for particulate matter measuring 10 microns or less in diameter (PM10). In addition, eastern San Luis Obispo County is designated marginal nonattainment for the eight-hour ozone NAAQS. However, the project site is located in the western portion of the county that is designated attainment for this federal standard (SLOAPCD 2023).4 Table 1 Health Effects Associated with Non-Attainment Criteria Pollutants Pollutant Adverse Effects Ozone (1) Short-term exposures: (a) pulmonary function decrements and localized lung edema in humans and animals and (b) risk to public health implied by alterations in pulmonary morphology and host defense in animals; (2) long-term exposures: risk to public health implied by altered connective tissue metabolism and altered pulmonary morphology in animals after long-term exposures and pulmonary function decrements in chronically exposed humans; (3) vegetation damage; and (4) property damage. Suspended particulate matter (PM10) (1) Excess deaths from short-term and long-term exposures; (2) excess seasonal declines in pulmonary function, especially in children; (3) asthma exacerbation and possibly induction; (4) adverse birth outcomes including low birth weight; (5) increased infant mortality; (6) increased respiratory symptoms in children such as cough and bronchitis; and (7) increased hospitalization for both cardiovascular and respiratory disease (including asthma). Source: United States Environmental Protection Agency 2024a The major local sources for PM10 in the region are agricultural operations, vehicle dust, grading, and dust produced by high winds. Ozone is a secondary pollutant that is not produced directly by a source, but rather is formed by a reaction between nitrogen oxides (NOX) and reactive organic gases (ROG) in the presence of sunlight. Reductions in ozone concentrations are dependent on reducing the atmospheric quantities of these precursors. In San Luis Obispo County, the major sources of ROG are motor vehicles, organic solvents, the petroleum industry, and pesticides, and the major sources of NOX are motor vehicles, public utility power generation, and fuel combustion by various industrial sources (SLOAPCD 2001). Air Quality Management Under state law, the SLOAPCD is required to prepare an overall plan for air quality improvement, which is known as the Clean Air Plan, for their jurisdiction within the SCCAB. The most recent Clean Air Plan was prepared in 2001.5 The 2001 Clean Air Plan describes the air quality setting for the county and is intended to bring the county into attainment of the ozone CAAQS through a comprehensive set of control measures designed to reduce ozone precursor emissions from a wide variety of stationary and mobile sources. 4 The eastern portion of San Luis Obispo County that has been designated nonattainment for the federal 8-hour ozone standard consists of the region east of the -120.4 degree longitude line in areas of San Luis Obispo County that are south of the 35.45 degree latitude line and the region east of the -120.3 degree longitude line in areas of San Luis Obispo County that are north of the 35.45 degree latitude line. 5 The 2001 CAP is incorporated by reference. Initial Study Checklist Air Quality Initial Study – Mitigated Negative Declaration 25 In July 2005, SLOAPCD adopted a Particulate Matter Report in order to update the jurisdiction’s control measures for particulate matter, as required by Senate Bill 656 (SLOAPCD 2005). In January 2020, SLOAPCD adopted an Ozone Emergency Episode Plan, in compliance with the federal Clean Air Act, in order to provide the basis for taking actions when ambient ozone concentrations reach a level that could endanger public health in San Luis Obispo County (SLOAPCD 2020). Air Emission Thresholds The SLOAPCD has adopted the CEQA Air Quality Handbook (2023) for quantifying and determining the significance of air quality emissions. The quarterly construction thresholds apply to projects that would require construction activities for more than one quarter. Quarterly thresholds are subdivided into Tier 1 and Tier 2 mitigation requirements. The CEQA Air Quality Handbook indicates a project’s emissions would be potentially significant if they exceed the following thresholds of significance: ▪ Emissions of more than 137 pounds of ROG and NOX (combined) daily, 2.5 tons of ROG and NOX (combined) quarterly (Tier 1), or 6.3 tons of ROG and NOX (combined) quarterly (Tier 2) during construction. ▪ Emissions of more than 7 pounds of DPM daily, 0.13 ton of DPM quarterly (Tier 1) or 0.32 ton DPM quarterly (Tier 2) during construction. ▪ Emissions of more than 2.5 tons of PM10 quarterly during construction. ▪ Emissions of more than 25 pounds per day of ROG and NOX (combined), 1.25 pounds per day of DPM, 25 pounds per day of PM10, or 550 pounds per day of carbon monoxide during operation. ▪ Emissions of more than 25 tons per year of ROG and NOX (combined) or 25 tons per year of PM10 during operation. SLOAPCD has not established quantitative thresholds for CO for construction. For projects with emissions exceeding the Tier 1 thresholds, SLOAPCD requires implementation of standard mitigation measures and Best Available Control Technology (BACT). For projects with emissions exceeding the higher Tier 2 thresholds, SLOAPCD requires implementation of more stringent mitigation measures such as a construction activity management plan and off-site mitigation. In addition, as of October 2016, SLOAPCD has determined that projects must implement Standard Mitigation Measures anytime a project exceeds the construction-phase ROG and NOX threshold of 137 pounds per day, regardless of whether construction activities would last for over 90 days (one quarter). SLOAPCD has developed significance thresholds for the emissions of toxic air contaminants (TAC)s based on health risks associated with elevated exposure to such compounds. For carcinogenic compounds, cancer risk is assessed in terms of incremental excess cancer risk. A project would result in a potentially significant impact if it would generate an incremental excess cancer risk of 10 in one million (1 x 10-6) (SLOAPCD 2023). Methodology Air pollutant emissions generated by project construction and operation were estimated using the California Emissions Estimator Model (CalEEMod) version 2022.1. CalEEMod uses project-specific information, including the project’s land uses, location, and construction parameters, to model construction and operational emissions. The analysis reflects the construction and operation of the project as described under Section 1, Description of Project. City of Atascadero Community Development Department Atascadero Mutual Water Company Water Treatment Plant Project 26 Construction emissions modeled include emissions generated by on-site construction equipment and vehicle trips associated with construction, such as workers, vendors, and water truck trips. Construction of the proposed project was analyzed based on the building characteristics provided by the project engineer. Project construction was modeled to start in March 2026 and end in September 2027. Daytime construction equipment was modeled using CalEEMod defaults; nighttime construction equipment would include an excavator, concrete truck, and generator. Project construction was assumed to involve no export or import of soil material. It was assumed that construction equipment would be diesel-powered and that the project would be required to comply with all applicable regulations, such as SLOAPCD Rules 401 (Visible Emissions), 403 (Particulate Matter Emission Standards), and 417 (Control of Fugitive Emissions of Volatile Organic Compounds). Operational emissions modeled include mobile source emissions (i.e., vehicle emissions), area source emissions, and stationary source emissions. Mobile source emissions would be generated by vehicle trips to and from the project site. It is assumed that an additional operator would be needed to maintain the project and would make two roundtrips per day. In addition, there would be approximately two roundtrip delivery truck trips to the project site per month and one roundtrip truck trip per six months to remove spent cartridge filters. The trip generation rates in CalEEMod were adjusted to account for the worst-case daily mobile emissions from the delivery trucks, assuming all three deliveries occur on the same day. Area source emissions would be generated by landscape maintenance equipment, consumer products, and architectural coatings. The project would consume natural gas; therefore, the project would generate on-site air pollutant emissions associated with energy use. HVAC equipment in the Operations Center building would be powered by natural gas, which was included in the modeling. The conversion of five existing production wells from natural gas to electric power was conservatively not included in the modeling but would result in a decrease in on-site air pollutant emissions associated with energy use due to reduced natural gas combustion. Stationary source emissions would be generated by up to four proposed 500- kilowatt natural gas emergency generators. The WTP is essential critical infrastructure necessary for public safety within the AMWC service area, and these emergency generators function to pump water to maintain the production of potable water for the service area and firefighting water supply The modeling assumes up to 100 hours of operation per generator per year for maintenance and readiness testing procedures. Emission factors for the emergency generators for volatile organic compounds (i.e., ROG), NOₓ, carbon monoxide, and carbon dioxide (CO2) were conservatively based on exhaust emissions data for a Kohler 500REZXD 570-kW gas generator set. Default emission factors were used for all remaining criteria air pollutants. Proposed Project a. Would the project conflict with or obstruct implementation of the applicable air quality plan? The proposed project would be consistent with the 2001 Clean Air Plan, which is the most recent air quality plan adopted for the county, if it would result in an increase in population that is equal to or less than the population estimates used in the 2050 Regional Growth Forecast for San Luis Obispo County6 and if it is consistent with the transportation and land use strategies outlined in the Clean Air Plan (SLOAPCD 2001). 6 Guidance provided by SLOAPCD indicates analyses should use 2050 Regional Growth Forecast population data in place of projections in the 2001 Clean Air Plan. Initial Study Checklist Air Quality Initial Study – Mitigated Negative Declaration 27 As discussed in Initial Study Checklist Section 14, Population and Housing, the proposed project would not result in the construction of new homes and therefore would not directly induce population growth. The project consists of a groundwater treatment facility and would not represent a new water supply source but would rather provide treatment of an existing groundwater supply source. The proposed project would not be utilized to increase the amount of water currently being supplied to existing customers or to provide water to areas currently not serviced by AMWC. Rather, the project would enable AMWC to continue providing water supplies to its existing customers and supplying water to future development in Atascadero as anticipated by the City’s General Plan (2016) and AMWC’s 2020 Urban Water Management Plan (2021). As such, the proposed project would not increase water supply such that it would facilitate the development of land that previously could not be developed due to water service constraints. In addition, project operation would require at least one new AMWC employee, who would likely be sourced from the existing local or regional workforce. Therefore, the proposed project would not alter current population trends for the region. The transportation control measures included in the 2001 Clean Air Plan are designed for implementation at the county and state levels and are not intended for implementation at the project level. State programs identified in the 2001 Clean Air Plan include the Carl Moyer Memorial Air Quality Standards Attainment Program, which provides grant funding for low emission engines and equipment to reduce NOx and PM10 from heavy duty engines. County programs include the SLOAPCD’s Motor Vehicle Emissions Reduction program, which provides funding for transportation- related projects, Regional Ridesharing Program, Public Transit Systems, Transportation Management Associations (a public/private partnership to implement transportation demand management strategies to reduce traffic congestion), and system improvements (improvements that reduce air impacts through synchronization of signals, intersection channelization, design of one-way streets and turn lanes, etc.). Therefore, while the proposed project would result in a small increase in daily air pollutant emissions in the region, the project would not impede the transportation control measures and strategies as outlined in the Clean Air Plan. The land use control measures included in the 2001 Clean Air Plan encourage construction of mixed- use developments, improving the jobs and housing balance, and planning compact communities. These measures propose changes to the arrangement and distribution of land uses to reduce trips and VMT, making alternative transportation options more appealing. The proposed project would add at least one new AMWC employee but would result in minimal operational mobile trips for operation and maintenance activities. Therefore, the project would not impede the transportation control measures and strategies as outlined in the Clean Air Plan. As such, the proposed project would be consistent with the land use and transportation control measures and strategies outlined in the 2001 Clean Air Plan. Therefore, the proposed project would be consistent with the 2001 Clean Air Plan, and no impact would occur. NO IMPACT City of Atascadero Community Development Department Atascadero Mutual Water Company Water Treatment Plant Project 28 b. Would the project result in a cumulatively considerable net increase of any criteria pollutant for which the project region is non-attainment under an applicable federal or state ambient air quality standard? Construction Emissions Project construction would generate temporary air pollutant emissions associated with fugitive dust (PM10 and PM2.5) and exhaust emissions (ROG + NOX, DPM7) from heavy construction equipment and construction vehicles in addition to ROG emissions that would be released during the drying phase of architectural coating. Table 2 summarizes the estimated maximum daily air pollutant emissions during project construction, and Table 3 summarizes the estimated quarterly air pollutant emissions during project construction. As shown therein, construction-related emissions would not exceed SLOAPCD daily or quarterly thresholds. Therefore, project construction would not result in a cumulatively considerable net increase of any criteria pollutant for which the project region is non- attainment under an applicable federal or state ambient air quality standard. Impacts would be less than significant. Table 2 Estimated Maximum Daily Construction Emissions (pounds/day) Construction Year ROG + NOx DPM1 2026 (Ground Improvements) 32 1 2027 (WTP Construction) 24 <1 Maximum Daily Emissions 32 1 SLOAPCD Thresholds 137 7 Threshold Exceeded? No No ROG = reactive organic gases; DPM = diesel particulate matter Note: SLOAPCD has not adopted daily thresholds for fugitive dust emissions during construction. 1 DPM estimates were derived from the “PM2.5E” output from CalEEMod, which is a conservative assumption given that 90 percent of DPM is a subset of PM2.5 (CARB 2024). Notes: All emissions modeling was completed using CalEEMod. See Appendix B for modeling results. Some numbers may not add up due to rounding. 7 More than 90 percent of DPM is less than one micrometer in diameter (about 1/70th the diameter of a human hair) and thus is a subset of PM2.5 (CARB 2024). Initial Study Checklist Air Quality Initial Study – Mitigated Negative Declaration 29 Table 3 Estimated Maximum Quarterly Construction Emissions (tons/quarter)1 Construction Year ROG + NOX DPM2 Fugitive Particulate Matter (PM10), Dust3 2026 0.5 0.02 0.06 2027 0.3 0.01 <0.01 Maximum Quarterly Emissions 0.5 0.02 0.06 SLOAPCD Tier 1 Thresholds 2.5 0.13 2.5 Threshold Exceeded? No No No SLOAPCD Tier 2 Thresholds 6.3 0.32 n/a Threshold Exceeded? No No No ROG = reactive organic gases; DPM = diesel particulate matter; PM10 = particulate matter measuring 10 microns or less in diameter 1 Annual construction emissions were divided by four to estimate quarterly emissions. 2 DPM estimates were derived from the “PM2.5E” output from CalEEMod, which is a conservative assumption given that 90 percent of DPM is a subset of PM2.5 (CARB 2024). 3 Dust is equal to “PM10D” reported by CalEEMod. Notes: All emissions modeling was completed using CalEEMod. See Appendix B for modeling results. Some numbers may not add up due to rounding. Operational Emissions Operation of the project would generate criteria air pollutant emissions associated with area sources (e.g., architectural coatings, consumer products, and landscaping equipment), mobile sources (i.e., vehicle trips to and from the project site), and stationary sources (i.e., emergency generators). Table 4 summarizes the project’s maximum daily operational air pollutant emissions by emission source, and Table 5 summarizes the project’s annual operational air pollutant emissions by emission source. As shown therein, operational emissions would not exceed SLOACPD’s daily or annual thresholds. Therefore, project operation would not result in a cumulatively considerable net increase of any criteria pollutant for which the project region is in non-attainment, and impacts would be less than significant. City of Atascadero Community Development Department Atascadero Mutual Water Company Water Treatment Plant Project 30 Table 4 Estimated Maximum Daily Operational Emissions (pounds/day) Emissions Source ROG + NOX DPM1 Dust2 CO Mobile <1 <1 <1 <1 Area 1 <1 0 1 Energy <1 <1 0 <1 Stationary3 1 <1 0 1 Total 2 <1 <1 3 SLOAPCD Daily Thresholds 25 1.25 25 550 Threshold Exceeded? No No No No ROG = reactive organic gases; NOX =nitrogen oxides; DPM = diesel particulate matter; CO = carbon monoxide. 1 DPM estimates were derived from the “PM2.5E” output from CalEEMod, which is a conservative assumption given that 90 percent of DPM is a subset of PM2.5 (CARB 2024). 2 Dust is equal to “PM10D” reported by CalEEMod. 3 The emissions estimate conservatively assumes operation of all four emergency generators simultaneously during routine testing and maintenance, each for two hours in a single day. Notes: All emissions modeling was completed using CalEEMod. See Appendix B for modeling results. Some numbers may not add up due to rounding. Table 5 Estimated Annual Operational Emissions (tons/year) Emissions Source ROG + NOX Dust1 Mobile <1 <1 Area <1 0 Energy <1 0 Stationary <1 0 Total <1 <1 SLOAPCD Annual Thresholds 25 25 Threshold Exceeded? No No ROG = reactive organic gases; NOX =nitrogen oxides 1 Dust is equal to “PM10D” reported by CalEEMod. Notes: All emissions modeling was completed using CalEEMod. See Appendix B for modeling results. Some numbers may not add up due to rounding. LESS-THAN-SIGNIFICANT IMPACT c. Would the project expose sensitive receptors to substantial pollutant concentrations? As previously mentioned, the sensitive receptors nearest to the project site are residences located approximately 250 feet to the south. The project does not include new sensitive receptors. Toxic Air Contaminants TACs are defined by California law as air pollutants that may cause or contribute to an increase in mortality or an increase in serious illness, or which may pose a present or potential hazard to human health. The following subsections discuss the project’s potential to result in impacts related to TAC emissions during construction and operation. Initial Study Checklist Air Quality Initial Study – Mitigated Negative Declaration 31 Construction Project construction would result in short-term emissions of DPM exhaust emissions from off-road, heavy-duty diesel equipment for site preparation, grading, building construction, infrastructure installation, and other construction activities. DPM was identified as a TAC by CARB in 1998. The potential cancer risk from the inhalation of DPM (discussed in the following paragraphs) outweighs the potential non-cancer health impacts and is therefore the focus of this analysis (CARB 2024). Generation of DPM from construction projects typically occurs in a single area for a short period. Construction of the proposed project would occur over approximately 18 months. The dose to which receptors are exposed is the primary factor used to determine health risk. Dose is a function of the concentration of a substance or substances in the environment and the extent of exposure that a person has to the substance. Dose is positively correlated with time, meaning that a longer exposure period would result in a higher exposure level for the Maximally Exposed Individual. The risks estimated for a Maximally Exposed Individual are higher if a fixed exposure occurs over a longer period of time. According to the California Office of Environmental Health Hazard Assessment, health risk assessments, which determine the exposure of sensitive receptors to toxic emissions, should be based on a 30-year exposure period (assumed to be the approximate time that a person spends in a household). The California Office of Environmental Health Hazard Assessment recommends this risk be bracketed with 9-year and 70-year exposure periods. Health risk assessments should be limited to the period/duration of activities associated with the project. Maximum emissions of particulate matter measuring 2.5 microns in diameter or less, which are used to represent DPM emissions for this analysis, would occur during site preparation and grading activities. While site preparation and grading emissions represent the worst-case condition, such activities would occur for 107 days, which is approximately three percent for a 9-year health risk calculation period and less than one percent for 30-year and 70-year health risk calculation periods. PM2.5 emissions would decrease for the remaining construction period because construction activities such as building construction, infrastructure installation, architectural coating, and paving would require less construction equipment. In addition, as indicated in Table 2 and Table 3, daily and quarterly emissions of DPM would not exceed SLOAPCD thresholds. Furthermore, the project site is 250 feet away from the nearest sensitive receptors, and construction activities would also be required to comply with California regulations limiting the idling of heavy‐duty construction equipment to no more than five minutes, which would reduce nearby sensitive receptors’ exposure to temporary and variable DPM emissions. Therefore, given the relatively short-term nature of project construction activities, estimated construction-phase DPM emissions below SLOAPCD thresholds, regulatory compliance with idling restrictions, and the distance from the nearest sensitive receptors, project construction is not expected to create conditions where the probability that the Maximally Exposed Individual would contract cancer is greater than SLOAPCD’s 10 in one million threshold and would not expose sensitive receptors to substantial TAC concentrations. Impacts would be less than significant. Operation CARB’s Air Quality and Land Use Handbook: A Community Health Perspective (2005) provides recommendations regarding the siting of new sensitive land uses near potential sources of air toxic emissions (e.g., freeways, distribution centers, rail yards, ports, refineries, chrome plating facilities, dry cleaners, and gasoline dispensing facilities). CARB guidelines recommend siting distances both for the development of sensitive land uses in proximity to TAC sources and for the addition of new TAC sources in proximity to existing sensitive land uses. The water treatment chemicals stored on City of Atascadero Community Development Department Atascadero Mutual Water Company Water Treatment Plant Project 32 site would not generate air emissions due to the proposed containment structures. The proposed project involves installation of up to four new 500-kilowatt natural gas emergency generators that would generate electricity to power the WTP and pump water into the distribution system in the event of a loss of electrical power supplied by PG&E. The WTP is essential critical infrastructure necessary for public safety within the AMWC service area, and these emergency generators would function to maintain the production of and pump the potable water into the service area. These generators would operate on an infrequent, periodic basis for routine maintenance and readiness testing procedures throughout the year and in the event of a loss of electrical power supplied by PG&E, which could be due to events such as high winds, earthquakes, wildfires, or equipment failures. Natural gas combustion produces lower particulate emissions than diesel, making it a cleaner alternative. Pursuant to SLOAPCD Rules 202 and 431, AMWC would also be required to obtain a permit from SLOAPCD for the emergency generators and comply with associated requirements governing annual hourly usage for maintenance operations (defined as testing, repair, and routine maintenance to verify readiness for emergency standby use). In addition, as shown in Table 4, operational DPM emissions would not exceed SLOAPCD’s threshold of 1.25 pounds per day. Therefore, project operation would not expose sensitive receptors to substantial TAC concentrations, and impacts would be less than significant. Naturally-Occurring Asbestos Naturally-occurring asbestos has been identified by CARB as a TAC. Serpentine and ultramafic rocks are common in San Luis Obispo County and may contain naturally occurring asbestos. According to the SLOAPCD Naturally-Occurring Asbestos Map for San Luis Obispo County, the project area is not located in an area that is known to contain naturally-occurring asbestos (SLOAPCD 2018). Therefore, the proposed project would not expose sensitive receptors to substantial asbestos concentrations, and impacts would be less than significant. LESS-THAN-SIGNIFICANT IMPACT d. Would the project result in other emissions (such as those leading to odors) adversely affecting a substantial number of people? During construction activities, heavy equipment and vehicles would emit odors associated with vehicle and engine exhaust and during idling. However, these odors would be intermittent and temporary, disperse with distance, and cease upon completion. Therefore, project construction would not generate other emissions, such as those leading to odors, affecting a substantial number of people, and impacts would be less than significant. Table 3-3 in the SLOAPCD 2023 CEQA Air Quality Handbook provides screening distances for land uses that have the potential to generate substantial odor complaints. The uses in the table include wastewater treatment plants, sanitary landfills, transfer stations, refineries, coffee roasters, food processing facilities, composting facilities, asphalt batch plants, oil fields, fiberglass manufacturing, and chemical manufacturing (SLOAPCD 2023). The project involves construction of a WTP to address PFAS in AMWC’s production wells and would not include components with the potential to generate odors. In particular, although the project includes a new septic tank that would discharge additional wastewater effluent to the existing leach field at the AMWC Corporation Yard facility, properly- functioning leach fields do not generate odors. Therefore, project operation would not generate other emissions, such as those leading to odors, affecting a substantial number of people, and no impacts would occur. LESS-THAN-SIGNIFICANT IMPACT Initial Study Checklist Air Quality Initial Study – Mitigated Negative Declaration 33 Mitigation/Conclusion No significant impacts are expected. No mitigation is required. City of Atascadero Community Development Department Atascadero Mutual Water Company Water Treatment Plant Project 34 This page intentionally left blank. Initial Study Checklist Biological Resources Initial Study – Mitigated Negative Declaration 35 4 Biological Resources Potentially Significant Impact Less than Significant with Mitigation Incorporated Less-than - Significant Impact No Impact Would the project: a. Have a substantial adverse effect, either directly or through habitat modifications, on any species identified as a candidate, sensitive, or special status species in local or regional plans, policies, or regulations, or by the California Department of Fish and Wildlife or U.S. Fish and Wildlife Service? □ ■ □ □ b. Have a substantial adverse effect on any riparian habitat or other sensitive natural community identified in local or regional plans, policies, or regulations, or by the California Department of Fish and Wildlife or U.S. Fish and Wildlife Service? □ □ □ ■ c. Have a substantial adverse effect on state or federally protected wetlands (including, but not limited to, marsh, vernal pool, coastal, etc.) through direct removal, filling, hydrological interruption, or other means? □ □ □ ■ d. Interfere substantially with the movement of any native resident or migratory fish or wildlife species or with established native resident or migratory wildlife corridors, or impede the use of native wildlife nursery sites? □ □ ■ □ e. Conflict with any local policies or ordinances protecting biological resources, such as a tree preservation policy or ordinance? □ □ □ ■ f. Conflict with the provisions of an adopted Habitat Conservation Plan, Natural Community Conservation Plan, or other approved local, regional, or state habitat conservation plan? □ □ □ ■ The following analysis is based on the project-specific Biological Resources Assessment prepared by Rincon Consultants, Inc. (Rincon) in September 2024, and included as Appendix A. City of Atascadero Community Development Department Atascadero Mutual Water Company Water Treatment Plant Project 36 Existing Setting The project site is located entirely within the existing AMWC Corporation Yard facility, which contains developed structures, roads, and ruderal vegetation within a 100-foot buffer around the project site, including Sycamore Road and its associated roadside margins. Mapped soils underlying the project site consist of Corducci and Typic Xerofluvents, 0 to 5 percent slopes; Arbuckle-Positas complex, 9 to 15 percent slopes; and still clay loam, 2 to 9 percent slopes. Historical imagery indicates the existence of roads and disturbance from facilities present within the project site as early as 1994 (the oldest year with available imagery), with the current AMWC Corporation Yard facility present in 2009 (Appendix A). For the purposes of this section, the Biological Study Area (BSA) is defined as the project site and a 100-foot surrounding buffer. A reconnaissance-level biological survey of the BSA was conducted by Rincon on March 24, 2023. The survey aimed to identify and document existing vegetation types as well as any special-status plant and animal species or habitats that may be present. The survey found the BSA is comprised of developed and ruderal land cover types. The developed areas within the BSA consist of AMWC Corporation Yard buildings, gravel parking areas, access roads, and the paved Sycamore Road. Ruderal land cover is present within the BSA in patches of the existing AMWC Corporation Yard facility. The western portion of the facility has more sparsely vegetated patches. The eastern section of the BSA exhibits more continuous vegetation cover and resembles a grassland with a denser cover of annual grasses and forbs. However, the area is still highly disturbed. Ruderal areas are also present along the margins of Sycamore Road within the 100-foot buffer of the BSA. Four planted coast live oaks (Quercus agrifolia) are present within the BSA, primarily along the fenceline bordering Sycamore Road.8 The project site, which is adjacent to residential development and transportation infrastructure, supports common wildlife adapted to urban and suburban areas (e.g., a variety of common avian and small mammal species). No special- status plant species were detected within the BSA during the reconnaissance survey (Appendix A). Proposed Project a. Would the project have a substantial adverse effect, either directly or through habitat modifications, on any species identified as a candidate, sensitive, or special status species in local or regional plans, policies, or regulations, or by the California Department of Fish and Wildlife or U.S. Fish and Wildlife Service? Special-status species are those plants and animals that are: 1) listed, proposed for listing, or candidates for listing as Threatened or Endangered by the United States Fish and Wildlife Service (USFWS) and National Marine Fisheries Service under the Federal Endangered Species Act; 2) those listed or proposed for listing as Rare, Threatened, or Endangered by the California Department of Fish and Wildlife (CDFW) under the California Endangered Species Act; 3) those recognized as Species of Special Concern or Fully Protected by CDFW; and 4) plants occurring on lists 1 and 2 of the CDFW California Rare Plant Rank system. In addition, special-status wildlife and plant species are ranked with global conservation status (G) and substantial conservation status (S) 1 through 5 based on NatureServe's (2010) methodologies. Although not considered special-status, most nesting birds are afforded protection under the federal Migratory Bird Treaty Act and/or California Fish and Game Code 3505. A list of special-status plant and wildlife species with potential to occur on site was 8 The Biological Resources Assessment indicates six planted coast live oak trees were observed within the BSA during the reconnaissance- level biological survey. However, two of these trees were removed subsequent to completion of the survey due to conflicts with power lines, and only four trees are currently present. Initial Study Checklist Biological Resources Initial Study – Mitigated Negative Declaration 37 developed based on a review of the CDFW California Natural Diversity Database (CNDDB) and the online California Native Plant Society Inventory of Rare and Endangered Vascular Plants of California within the Templeton United States Geological Survey (USGS) quad and the eight surrounding USGS quads (i.e., Adelaida, Paso Robles, Estrella, York Mountain, Creston, Morro Bay North, Atascadero, and Santa Margarita, California) (nine-quad search area). Special-Status Plant Species There are 42 special-status plant species tracked by the CDFW CNDDB and the California Native Plant Society within the nine-quad search area. The project site does not provide suitable habitat for most of these special-status plant species given its disturbance history, lack of suitable soils, inappropriate hydrologic conditions, or absence of appropriate vegetation communities. Of the 42 species evaluated, none have a moderate or high potential to occur within the project site based on factors ranging from the existing developed nature of the project site, history of disturbance of the project site, lack of suitable soils, inappropriate hydrologic conditions, absence of appropriate vegetation communities, and lack of observation during the reconnaissance survey, which was conducted during the blooming period for many species. In addition, the CNDDB occurrences for a number of species are historical, dating to the mid-1900s or earlier (Appendix A). Therefore, because no special-status plant species have a moderate or high potential to occur within the project site, the project would not have a substantial adverse effect, either directly or through habitat modifications, on any plant species identified as a candidate, sensitive, or special-status species in local or regional plans, policies, or regulations, or by CDFW or USFWS, and no impact would occur. Special-Status Wildlife Species There are 29 special-status wildlife species tracked by the CNDDB and CNPS within the nine-quad search area. Of the 29 species evaluated, none have a moderate or high potential to occur within the project site based on factors ranging from the existing developed nature of the project site, history of disturbance of the BSA, absence of appropriate vegetation communities, lack of suitable soils, inappropriate hydrologic conditions, and lack of observation during the reconnaissance survey. In addition, the CNDDB occurrences for a number of species are historical, dating to the mid-1900s or earlier (Appendix A). Therefore, because no special-status wildlife species have a moderate or high potential to occur within the project site, the project would not have a substantial adverse effect, either directly or through habitat modifications, on any plant species identified as a candidate, sensitive, or special-status species in local or regional plans, policies, or regulations, or by CDFW or USFWS, and no impact would occur. Nesting Birds Migratory or other common nesting birds, while not designated as special-status species, are protected by the California Fish and Game Code (CFGC) and the Migratory Bird Treaty Act (MBTA) and may nest on site in trees and shrubs located within the project site as well as in vegetation adjacent to the project site. Therefore, construction of the project has the potential to directly (by destroying a nest) or indirectly (construction noise, dust, and other human disturbances that may cause a nest to fail) impact nesting birds protected under the CFGC and MBTA, and impacts would be potentially significant (Appendix A). Implementation of Mitigation Measure BIO-1 would be required to reduce impacts to nesting birds to less than significant. LESS THAN SIGNIFICANT WITH MITIGATION INCORPORATED City of Atascadero Community Development Department Atascadero Mutual Water Company Water Treatment Plant Project 38 b. Would the project have a substantial adverse effect on any riparian habitat or other sensitive natural community identified in local or regional plans, policies, or regulations, or by the California Department of Fish and Wildlife or U.S. Fish and Wildlife Service? No sensitive plant communities or riparian habitat occur within the project site (Appendix A). The project site is over 260 feet from the Salinas River riparian corridor and is separated from it by other portions of AMWC’s Corporation Yard facility. As a result, the project would not have a substantial adverse effect on any riparian habitat or other sensitive natural community identified in local or regional plans, policies, or regulations, or by CDFW or USFWS, and no impacts would occur. NO IMPACT c. Would the project have a substantial adverse effect on state or federally protected wetlands (including, but not limited to, marsh, vernal pool, coastal, etc.) through direct removal, filling, hydrological interruption, or other means? No potentially jurisdictional waters or wetlands occur within the project site (Appendix A). Therefore, no impacts to jurisdictional waters or wetlands would occur. NO IMPACT d. Would the project interfere substantially with the movement of any native resident or migratory fish or wildlife species or with established native resident or migratory wildlife corridors, or impede the use of native wildlife nursery sites? Wildlife corridors, or habitat linkages, are generally defined as connections between habitat patches that allow for physical and genetic exchange between otherwise isolated animal populations. Such linkages may serve a local purpose, such as between foraging and denning areas, or they may be regional in nature, allowing movement across the landscape. Some habitat linkages may serve as migration corridors, wherein animals periodically move away from an area and then subsequently return. Others may be important as dispersal corridors for young animals. A group of habitat linkages in an area can form a wildlife corridor network. The project site is located along the interface between developed residential areas and the open space surrounding the Salinas River and floodplain. The Salinas River and floodplain is a large-scale habitat corridor that wildlife use for local and regional movement (Appendix A). The project site is situated within the existing AMWC Corporation Yard and Sycamore Road right-of-way, which offer little to no value to wildlife movement due to the small facility size, lack of natural vegetation communities, and proximity to residential areas. As such, the proposed project would not directly affect localized or regional wildlife movement through habitat fragmentation or isolation in the region. In addition, the WTP facility has an existing fence that currently limits local wildlife movement through the project site, and the proposed project would not modify this fencing. Temporal effects to wildlife movement through the Salinas River corridor may occur while construction is ongoing due to noise and dust; however, the project site is limited in area and adjacent to existing disturbed areas. In addition, numerous alternative movement corridors are present within the Salinas River floodplain and surrounding open space. Potential indirect impacts to wildlife movement near the site would thus be short term and negligible. No additional nocturnal noise-generating activities are proposed that could indirectly affect wildlife movement during or after the project is constructed (Appendix A). Therefore, the project would not interfere substantially with the movement of any native resident or migratory fish or wildlife species or with Initial Study Checklist Biological Resources Initial Study – Mitigated Negative Declaration 39 established native resident or migratory wildlife corridors, or impede the use of native wildlife nursery sites, and impacts would be less than significant. LESS-THAN-SIGNIFICANT IMPACT e. Would the project conflict with any local policies or ordinances protecting biological resources, such as a tree preservation policy or ordinance? Native and heritage trees are protected under the City of Atascadero’s Native Tree Regulations (AMC Section 9-11). Pursuant to this ordinance, a tree removal permit must be obtained prior to removing any native trees that are two inches in diameter at breast height or greater for deciduous native oaks, California sycamore (Platanus racemosa), and madrones (Arbutus menziesii), or four inches in diameter at breast height or greater for all other protected native trees. In addition, a permit is required for any pruning that would remove more than 25 percent of the live canopy of native trees. Native trees are defined in AMC Section 9-11.104 as any of the following species: madrone, toyon (Heteromeles arbutifolia), California black walnut (Juglans hindsii), California sycamore (Platanus racemosa), coast live oak (Quercus agrifolia), blue oak/desert oak (Quercus alvordiana), scrub oak (Quercus dumosa), leather oak (Quercus durata), blue oak (Quercus douglasii), valley oak (Quercus lobata), desert oak (Quercus turbinella), and California bay laurel (Umbellularia californica). Heritage trees are defined as any native or non-native tree recognized by City Council resolution for its age, size, location, historical, and/or cultural significance. The heritage tree list is published in the City’s Tree Guidelines (AMC Section 9-11.111). In addition to obtaining a permit for native and heritage tree removals, a tree protection plan is required if project activities (e.g., remodeling or new construction, grading, road building, utility trenching) occur within 20 feet of the dripline of any native tree (AMC Section 9-11.106) (Appendix A). Four coast live oaks protected by the AMC are located within the project site, but there are no heritage trees within the project site (Appendix A). However, no trees would be trimmed or removed as part of the proposed project. In addition, for project construction activities that would occur within 20 feet of the drip line of native trees, the AMC requires preparation of a tree protection plan to the specification of a certified arborist following the criteria outlined in AMC Section 9-11.106. Because the proposed project would be required to prepare a tree protection plan for project construction activities that require work near native trees, the proposed project would not conflict with local policies and ordinances protecting biological resources, and no impact would occur. NO IMPACT f. Would the project conflict with the provisions of an adopted Habitat Conservation Plan, Natural Community Conservation Plan, or other approved local, regional, or state habitat conservation plan? The project site is not located in an area subject to an adopted Habitat Conservation Plan, Natural Community Conservation Plan, or other approved local, regional, or state habitat conservation plan (Appendix A). Therefore, the project would not conflict with such plans, and no impact would occur. NO IMPACT City of Atascadero Community Development Department Atascadero Mutual Water Company Water Treatment Plant Project 40 Mitigation/Conclusion Mitigation Measure BIO-1 Project-related activities shall occur outside of the bird breeding season (February 1 to August 31) to the extent practicable. If construction must occur within the bird breeding season, then no more than 10 days prior to initiation of ground disturbance and/or vegetation removal, a nesting bird pre-construction survey shall be conducted by a qualified biologist within the disturbance footprint plus a 100-foot buffer (300 feet for raptors), where accessible. If project construction is phased or construction activities stop for more than one week, a subsequent pre-construction nesting bird survey shall be conducted prior to each phase of construction if occurring during the bird breeding season. The pre-construction nesting bird survey shall be conducted during the time of day when birds are active and shall factor in sufficient time to perform the survey adequately and completely. A report of the nesting bird survey results, if applicable, shall be submitted to the lead agency for review and approval within two weeks of survey completion. If nests are found, their locations shall be flagged. An appropriate avoidance buffer ranging in size from 25 to 50 feet for passerines, and up to 300 feet for raptors, depending upon the species and the proposed work activity, shall be determined and demarcated by a qualified biologist with bright orange construction fencing or other suitable flagging. Active nests shall be monitored at a minimum of once per week until it has been determined the nest is no longer being used by either the young or adults. No ground disturbance shall occur within this buffer until the qualified biologist confirms the breeding/nesting is complete and all the young have fledged. If project activities must occur within the buffer, they shall be conducted at the discretion of the qualified biologist. If no nesting birds are observed during pre-construction survey, no further action would be necessary. Significance after Mitigation Implementation of Mitigation Measure BIO-1 would reduce the potential for project construction activities to result in the loss of active bird nests through a pre-construction nesting bird survey and establishment of avoidance buffers around active nests, if present. Implementation of Mitigation Measure BIO-1 would reduce project impacts to nesting birds to a less-than-significant level. Initial Study Checklist Cultural Resources Initial Study – Mitigated Negative Declaration 41 5 Cultural Resources Potentially Significant Impact Less than Significant with Mitigation Incorporated Less-than - Significant Impact No Impact Would the project: a. Cause a substantial adverse change in the significance of a historical resource pursuant to §15064.5? □ □ □ ■ b. Cause a substantial adverse change in the significance of an archaeological resource pursuant to §15064.5? □ ■ □ □ c. Disturb any human remains, including those interred outside of formal cemeteries? □ □ ■ □ The following analysis is based on the project-specific Cultural Resources Assessment prepared by Rincon in September 2024 (Rincon 2024). Existing Setting Rincon completed background and archival research in support of the Cultural Resources Assessment, which consisted of consulting a variety of primary and secondary source materials, including historical maps, aerial photographs, topographic maps, written histories of the area, and the project-specific Geotechnical Report (Appendix C). On March 13, 2023, Rincon received California Historical Resources Information System (CHRIS) records search results from the Central Coast Information Center (CCIC, which is the official State repository for cultural resources records and reports for San Luis Obispo County. The records search was conducted to identify previously recorded cultural resources as well as previously conducted cultural resources studies within the project site and a 0.5-mile radius surrounding it. Rincon also reviewed the National Register of Historic Places, the California Register of Historical Resources, the California Historical Landmarks list, the Archaeological Determination of Eligibility list, and the Built Environment Resources Directory as well as its predecessor the California State Historic Property Data File. The CHRIS records search and background research identified two cultural resources studies that include a portion of the project site and four that include areas directly adjacent to the project site. No cultural resources are recorded within the project site, but one – a lithic and marine shell scatter - is recorded adjacent to the project site (P-40-001372; Rincon 2024). Rincon also contacted the Native American Heritage Commission (NAHC) on March 3, 2023, to request a search of the Sacred Lands File (SLF). On March 15, 2023, the NAHC responded, indicating the SLF search was positive, which means a sacred land is recorded within the Public Lands Survey System section that encompasses the project site. Although the SLF results were positive, the sacred land may be located anywhere within the section, which typically encompasses up to 640 acres (Rincon 2024). Potential project impacts to tribal cultural resources are discussed in Initial Study Checklist Section 18, Tribal Cultural Resources. City of Atascadero Community Development Department Atascadero Mutual Water Company Water Treatment Plant Project 42 Rincon conducted cultural resources pedestrian surveys of the project site on March 24, 2023, and September 3, 2024. The project site was noted to be disturbed by past and current construction activities associated with AMWC, including grading, installation of overground and underground utilities, and soil removal. An isolated find was observed during the 2023 survey, consisting of a rusted metal can on the surface of exposed soils. Two isolated finds were noted in the 2024 survey, including a shard of patinated brown glass and a sherd of blue-glazed ceramic. None of these finds could be reliably determined to be of historical age. No archaeological resources or intact archaeological deposits were noted during the field survey (Rincon 2024). The earliest historical topographic map from 1919 depicts the project site as sparsely developed land along the Salinas River, with an early iteration of Sycamore Road and the Union Pacific Railroad running along the southwestern boundary. Historical topographic maps from 1952 depict buildings within the project site, and development continues to grow to the west of this portion of the project site in the form of residential neighborhoods. Aerial imagery of the project site from 1956 to 1965 depict residential buildings present in the current location of the AMWC Corporation Yard buildings, and the eastern portion of the project site is depicted as an undeveloped riverbed. In aerial imagery from 1981, the residential buildings appear to have been demolished and replaced by a paved concrete platform, while the eastern portion remains undeveloped with a dirt road around the western and northern perimeter, The western portion of the project site is further developed in aerial imagery from 1994, with two large buildings appearing north of Sycamore Road. Aerial imagery from 2005 shows further development in the western portion, with two additional buildings and an expanded paved platform with parking spaces. Development within the project site continued to grow from 2009 to 2020 with the addition of one building and expansion of graded dirt lots shown in aerial imagery. Sycamore Road appears as a dirt road in imagery from 1956 until 1965, when it appears as an upgraded two-lane road. The geotechnical report conducted for the project site indicates the site has been heavily disturbed. A total of nine borings were completed, and artificial fill was encountered at depths between 10 and 20 feet below the ground surface. Alluvial deposits were encountered below the artificial fill (Rincon 2024). Proposed Project a. Would the project cause a substantial adverse change in the significance of a historical resource pursuant to §15064.5? A historical resource is defined as a resource listed in, or determined to be eligible for listing in, the CRHR; a resource included in a local register of historical resources; or any object, building, structure, site, area, place, record, or manuscript a lead agency determines to be historically significant (CEQA Guidelines Section 15064.5[a][1-3]). To more clearly differentiate between archaeological and built environment resources, the analysis of potential impacts to historical resources under this threshold is limited to built environment resources. Archaeological resources, including those that may be considered historical resources pursuant to CEQA Guidelines Section 15064.5 and those that may be considered unique archaeological resources pursuant to Public Resources Code (PRC) Section 21083.2, are considered under threshold 5(b). The field survey and background research did not identify any built environment historical resources in or adjacent to the project site (Rincon 2024). Therefore, the project would result in no impact to historical resources. NO IMPACT Initial Study Checklist Cultural Resources Initial Study – Mitigated Negative Declaration 43 b. Would the project cause a substantial adverse change in the significance of an archaeological resource pursuant to §15064.5? 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: 1. Contains information needed to answer important scientific research questions and that there is a demonstrable public interest in that information; 2. Has a special and particular quality such as being the oldest of its type or the best available example of its type; or 3. Is directly associated with a scientifically recognized important prehistoric or historic event or person. If it can be demonstrated that a project would cause damage to a unique archaeological resource, the lead agency may require reasonable efforts be made to permit any or all of these resources to be preserved in place or left in an undisturbed state. To the extent that resources cannot be left undisturbed, mitigation measures are required (PRC Section 21083.2[a-b]). The cultural resource assessment did not identify any archaeological resources or archaeological deposits in the project site (Rincon 2024). However, the lack of surface evidence of archaeological materials does not preclude their subsurface existence. The project site is in close proximity to resource P-40-001372, which is a lithic and marine shell scatter consisting of over 30 Monterey and Franciscan chert flakes, a fragment of a Franciscan chert biface, and less than five pieces of marine shell that was first recorded in 1991. Although this resource could not be relocated and has been subjected to a high level of disturbance by previous construction, as evidenced by a review of historical aerial imagery, there is a possibility that buried archaeological deposits still exist, which may extend into the project site. The location of the project site along the Salinas River and Atascadero Creek is an additional factor indicative of heightened archaeological sensitivity. While the Cultural Resources Assessment did not identify any known archaeological resources within the project site, there remains a possibility that unanticipated archaeological or Native American cultural materials could be encountered during ground-disturbing activities (Rincon 2024). Therefore, impacts to archaeological resources would be potentially significant, and implementation of Mitigation Measures CR-1 and CR-2 would be required to reduce impacts to a less-than- significant level. LESS THAN SIGNIFICANT WITH MITIGATION INCORPORATED c. Would the project disturb any human remains, including those interred outside of formal cemeteries? No human remains are known to be present within the project site. However, the discovery of human remains is always a possibility during ground-disturbing activities. If human remains are found, California Health and Safety Code Section 7050.5 states no further disturbance shall occur until the County Coroner has made a determination of origin and disposition pursuant to Public Resources Code Section 5097.98. In the event of an unanticipated discovery of human remains, the County Coroner must be notified immediately. If the human remains are determined to be of Native American origin, the Coroner will notify the NAHC, which will determine and notify a most likely descendant (MLD). The MLD has 48 hours from being granted site access to make recommendations for the disposition of the remains. If the MLD does not make recommendations within 48 hours, the City of Atascadero Community Development Department Atascadero Mutual Water Company Water Treatment Plant Project 44 landowner shall reinter the remains in an area of the property secure from subsequent disturbance. With adherence to existing regulations, impacts to human remains would be less than significant. LESS-THAN-SIGNIFICANT IMPACT Mitigation/Conclusion Mitigation Measures CR-1 During construction, a Native American representative shall observe all ground-disturbing activities (e.g., site preparation, grading, trenching, excavation, pile driving, vegetation removal). For work that does not entail ground disturbance, such as driving on-site, staging equipment, and clearing vegetation with hand tools, monitoring shall not be required. If archaeological resources are encountered during ground-disturbing activities, work in the immediate area shall halt and the find evaluated for listing in the California Register of Historical Resources (CRHR). Native American monitoring may be reduced or halted at the discretion of the monitor, as warranted by conditions such as encountering bedrock, excavating fill sediments, or observing negative findings during the first 60 percent of sediment removal in a given area. If monitoring is reduced to spot-checking, spot- checking shall occur when ground disturbance moves to a new location in the project site. CR-2 In the event archaeological resources are unexpectedly encountered during ground-disturbing activities, work within 50 feet of the find shall halt and an archaeologist meeting the Secretary of the Interior’s Professional Qualifications Standards for archaeology (National Park Service 1983) shall be contacted immediately to evaluate the resource. If the resource is determined by the qualified archaeologist to be prehistoric, then a Native American representative shall also be contacted to participate in the evaluation of the resource. If the qualified archaeologist and/or Native American representative determines it to be appropriate, archaeological testing for CRHR eligibility shall be completed. If the resource proves to be eligible for the CRHR and significant impacts to the resource cannot be avoided via project redesign, a qualified archaeologist shall prepare a data recovery plan tailored to the physical nature and characteristics of the resource, pursuant to the requirements of the CEQA Guidelines Section 15126.4(b)(3)(C). The data recovery plan shall identify data recovery excavation methods, measurable objectives, and data thresholds to reduce significant impacts to the cultural resource. Pursuant to the data recovery plan, the qualified archaeologist and Native American representative, as appropriate, shall recover and document the scientifically consequential information that justifies the resource’s significance. The City shall review and approve the treatment plan and archaeological testing as appropriate, and the resulting documentation shall be submitted to the regional repository of the CHRIS, pursuant to CEQA Guidelines Section 15126.4(b)(3)(C). Significance after Mitigation Implementation of Mitigation Measures CR-1 and CR-2 would minimize potential impacts to unanticipated discoveries of archaeological resources by requiring Native American monitoring of ground disturbing activities, and implementation of appropriate procedures for evaluation and treatment of any unanticipated discoveries of cultural resources made during construction. Therefore, implementation of Mitigation Measures CR-1 and CR-2 would reduce potential impacts to archeological resources to a less-than-significant level. Initial Study Checklist Energy Initial Study – Mitigated Negative Declaration 45 6 Energy Potentially Significant Impact Less than Significant with Mitigation Incorporated Less-than - Significant Impact No Impact Would the project: a. Result in a potentially significant environmental impact due to wasteful, inefficient, or unnecessary consumption of energy resources, during project construction or operation? □ □ □ ■ b. Conflict with or obstruct a state or local plan for renewable energy or energy efficiency? □ □ □ ■ Existing Setting There are no substantial sources of energy consumption in the project site itself. Sources of energy consumption associated with AMWC’s existing Corporation Yard facility, in which the project site is located, generally consist of electricity used to power lighting in the existing buildings, natural gas used to power HVAC equipment in the existing buildings and Wells No. 1B, 3A, 5, and 5A, and gasoline and diesel fuels used for vehicle trips to and from the facility, the use of heavy equipment (e.g., backhoes, front-end loaders, dump trucks) to load trucks and handle materials, and infrequent routine testing of existing emergency generators. Proposed Project a. Would the project result in a potentially significant environmental impact due to wasteful, inefficient, or unnecessary consumption of energy resources, during project construction or operation? During project construction, energy would be consumed in the form of petroleum-based fuels used to power off-road construction vehicles and equipment on the project site, hauling of materials, and construction worker travel to and from the project site. Total consumption of gasoline and diesel fuel during project construction was estimated using the assumptions and factors from the air pollutant and greenhouse gas (GHG) emissions modeling in CalEEMod, as detailed further in Initial Study Checklist Section 3, Air Quality, and Section 8, Greenhouse Gas Emissions. Table 6 presents estimated energy consumption during project construction. As shown therein, the operation of construction equipment and haul trips would consume approximately 69,000 gallons of diesel fuel, and construction worker trips would consume approximately 4,700 gallons of gasoline. City of Atascadero Community Development Department Atascadero Mutual Water Company Water Treatment Plant Project 46 Table 6 Estimated Fuel Consumption during Construction Source Fuel Consumption (gallons) Gasoline Diesel Construction Equipment & Hauling Trips -- 68,808 Construction Worker Vehicle Trips 4,650 -- See Appendix D for energy calculation sheets. Energy use during construction would be temporary in nature, and construction equipment used would be typical of similar-sized construction projects in the region. In addition, construction contractors would be required to comply with the provisions of Title 13 California Code of Regulations Sections 2449 and 2485, which prohibit off-road diesel vehicles and diesel-fueled commercial motor vehicles, respectively, from idling for more than five minutes and would minimize unnecessary fuel consumption. Construction equipment would be subject to the United States Environmental Protection Agency Construction Equipment Fuel Efficiency Standard, and water and haul trucks would be subject to CARB’s Advanced Clean Trucks regulation, both of which would also minimize inefficient, wasteful, or unnecessary fuel consumption. These regulations would result in the efficient use of energy necessary to construct the project. Furthermore, in the interest of cost- efficiency, construction contractors would not be anticipated to utilize fuel in a manner that is wasteful or unnecessary. Therefore, project construction would not result in wasteful, inefficient, or unnecessary consumption of energy resources, and no impact would occur. Project operation would require daily operation and maintenance activities, including water quality sampling, inspections, calibrating and maintaining instrumentation, replacing consumables (e.g., cartridge filters and chemicals), and executing an asset management program that examines the replacement frequency of key equipment around the WTP. These maintenance tasks would be integrated into existing staff rounds in the local area. Routine testing of the new emergency generators would result in minor natural gas consumption, and vehicle trips to and from the project site for operation and maintenance activities would result in a negligible increase in gasoline consumption. The project includes conversion of five existing production wells from natural gas to electric power, which would result in a minor decrease in natural gas consumption and a corresponding minor increase in electricity consumption. The project would also consume electricity to convey water through the proposed treatment equipment and to power lighting in the Operations Center building. HVAC equipment in the Operations Center building would be powered by both electricity and natural gas. Buildings associated with the project would be required to comply with standards set in the latest iteration of the California Building Standards Code (California Code of Regulations Title 24), which would minimize the wasteful, inefficient, or unnecessary consumption of energy resources by the built environment during operation. California’s CALGreen standards (California Code of Regulations Title 24, Part 11) require implementation of energy- efficient light fixtures and building materials into the design of new construction projects. In addition, the 2022 Building Energy Efficiency Standards (California Code of Regulations Title 24, Part 6) require newly constructed buildings to meet energy performance standards set by the California Energy Commission. These standards are specifically crafted for new buildings to result in energy efficient performance so that the buildings do not result in wasteful, inefficient, or unnecessary consumption of energy. Pursuant to CALGreen, all appliances used for the proposed project would be high-efficiency, which would minimize the potential for the inefficient or wasteful consumption of energy related to electricity. Furthermore, the use of electricity to operate the WTP and natural gas for routine testing of the emergency generators are necessary to address elevated levels of PFAS Initial Study Checklist Energy Initial Study – Mitigated Negative Declaration 47 in AMWC’s production wells adjacent to the Salinas River between SR 41 and Chico Road, which would enable AMWC to continue providing drinking water supplies to Atascadero, and ensure operational continuity in the event of an electrical power outage. As such, this increase in electricity and natural gas consumption would be neither wasteful nor unnecessary. Therefore, project operation would not result in wasteful, inefficient, or unnecessary consumption of energy resources, and no impact would occur. NO IMPACT b. Would the project conflict with or obstruct a state or local plan for renewable energy or energy efficiency? The City’s General Plan includes policies pertaining to renewable energy and energy efficiency under Goal LOC 10, which is to “conserve energy and resources by preventing or correcting degradation of the environment.” The proposed project would be consistent with the following energy conservation policies of the City’s General Plan because it would result in minimal solid waste generation, as discussed further in Initial Study Checklist Section 19, Utilities and Service Systems (City of Atascadero 2016): ▪ Policy 10.1.5: Ensure efficient and adequate solid waste disposal by reduction waste volumes through recycling and other methods. Support actions which conserve energy and encourage energy conservation. Consumption of non-renewable resources should be minimized. Renewable resources should be recycled or replenished. The project would also include energy-efficient appliances in the Operations Center building consistent with the 2022 Title 24 Building Energy Efficiency Standards. In addition, Senate Bill 100 mandates 100 percent clean electricity for California by 2045. Because the proposed project would be powered by the existing electricity grid, the project would eventually be powered by renewable energy mandated by Senate Bill 100 and would not conflict with statewide plans for renewable energy. Therefore, the project would not conflict with or obstruct a state or local plan for renewable energy or energy efficiency, and no impact would occur. NO IMPACT Mitigation/Conclusion No significant impacts are expected. No mitigation is required. City of Atascadero Community Development Department Atascadero Mutual Water Company Water Treatment Plant Project 48 This page intentionally left blank. Initial Study Checklist Geology and Soils Initial Study – Mitigated Negative Declaration 49 7 Geology and Soils Potentially Significant Impact Less than Significant with Mitigation Incorporated Less-than - Significant Impact No Impact Would the project: a. Directly or indirectly cause potential substantial adverse effects, including the risk of loss, injury, or death involving: 1. Rupture of a known earthquake fault, as delineated on the most recent Alquist-Priolo Earthquake Fault Zoning Map issued by the State Geologist for the area or based on other substantial evidence of a known fault? □ □ □ ■ 2. Strong seismic ground shaking? □ □ ■ □ 3. Seismic-related ground failure, including liquefaction? □ □ ■ □ 4. Landslides? □ □ □ ■ b. Result in substantial soil erosion or the loss of topsoil? □ □ ■ □ c. Be located 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- or off-site landslide, lateral spreading, subsidence, liquefaction, or collapse? □ □ ■ □ d. Be located on expansive soil, as defined in Table 18-1-B of the Uniform Building Code (1994), creating substantial direct or indirect risks to life or property? □ □ □ ■ e. Have soils incapable of adequately supporting the use of septic tanks or alternative wastewater disposal systems where sewers are not available for the disposal of wastewater? □ □ □ ■ f. Directly or indirectly destroy a unique paleontological resource or site or unique geologic feature? □ □ ■ □ City of Atascadero Community Development Department Atascadero Mutual Water Company Water Treatment Plant Project 50 The following analysis is based on the conclusions and recommendations of the project-specific Geotechnical Report prepared by Yeh & Associates in July 2023, and included as Appendix C. Existing Setting The project site is located in the Coast Ranges, one of the eleven geomorphic provinces in California, defined as a region of unique topography and geology that is distinguished from other regions based on its landforms and geologic history. The Coast Ranges extend along the majority of California’s coast from the California-Oregon border to Point Arguello in Santa Barbara County in the south and consist of northwest-trending mountain ranges and valleys. The Coast Ranges are composed of Mesozoic and Cenozoic sedimentary, igneous, and metamorphic strata. The eastern side is characterized by strike-ridges and valleys in the Upper Mesozoic strata. The coastline is primarily comprised of uplifted, wave-cut marine terraces. The Coast Ranges are generally often split into northern and southern portions divided by San Francisco Bay. The Coast Ranges province runs parallel to and overlaps the San Andreas Fault in some areas (California Geological Survey 2002). The project site is located in the Templeton, California USGS 7.5-minute topographic quadrangle(s). The geology of the region surrounding the project site was mapped by Dibblee and Minch (2004a) who identified two geologic units, Quaternary stream channel deposits and Quaternary alluvium within the project site. In addition, the project-specific Geotechnical Report identified artificial fill sediments within the project site (Appendix C). The project-specific Geotechnical Report represents a much more localized assessment of the project site compared to the regional scale of Dibblee and Minch (2004a); therefore, its assessment of the site geology is primarily relied on in this section. The project site is not located in an Alquist-Priolo Fault Zone or an earthquake-induced landslide hazard zone (DOC 2023; United States Geological Survey 2023). The United States Geological Survey defines active faults as those that have had surface displacement within the Holocene period (approximately the last 11,000 years). Potentially active faults are those that have had surface displacement during the last 1.6 million years, and inactive faults have not had surface displacement within that period. Like much of California, the project site is in a seismically active region, and the most recent significant earthquake was the 2003 San Simeon earthquake, a magnitude 6.5 event. The nearest known fault to the project site is the Rinconada Fault, an undifferentiated Quaternary fault located approximately 560 feet east of the project site (USGS 2024). Much of Atascadero is underlain by older alluvium, which is considered to have moderate liquefaction potential (City of Atascadero 2016), and the 2003 San Simeon earthquake resulted in liquefaction at the project site and adjacent areas, which caused structural damage to Atascadero City Hall. The presence of loose to medium dense sand at depths of 20 to 38 feet below ground surface and the presence of groundwater at 26 feet below the ground surface along with highly porous soil results in a high susceptibility to liquefaction at the project site (Appendix C). The project site has low potential for lateral spreading because it is relatively flat with relatively deep groundwater, and near-surface soils at the project site do not contain high concentrations of expansive clay minerals (Appendix C). Rincon requested a fossil locality search from the Natural History Museum of Los Angeles County on September 1, 2024, which indicated no known fossil localities are present within the project site (Bell 2024). The nearest known fossil localities come from Miocene-aged bedrock units - Santa Margarita and Vaqueros formations - which are not mapped within the project site. Initial Study Checklist Geology and Soils Initial Study – Mitigated Negative Declaration 51 a.1. Would the project directly or indirectly cause potential substantial adverse effects, including the risk of loss, injury, or death involving rupture of a known earthquake fault, as delineated on the most recent Alquist-Priolo Earthquake Fault Zoning Map issued by the State Geologist for the area or based on other substantial evidence of a known fault? The project site is not located in an Alquist-Priolo Fault Zone (DOC 2023). Therefore, the project would not directly or indirectly cause potential substantial adverse effects, including the risk of loss, injury, or death involving rupture of a known earthquake fault, and no impact would occur. NO IMPACT a.2. Would the project directly or indirectly cause potential substantial adverse effects, including the risk of loss, injury, or death involving strong seismic ground shaking? The project involves construction of water infrastructure and associated Operations Center. Because most of California is susceptible to strong ground shaking from severe earthquakes and the project site is located in close proximity to the Rinconada Fault, construction of the project could expose project structures and infrastructure to strong seismic ground shaking, and a large seismic event could result in damage to the proposed structure and infrastructure, which could lead to leakages of water and treatment chemicals. However, the project would be designed and constructed in accordance with the recommendations of the geotechnical report, state and local building codes (e.g., California Building Code), and current seismic design standards to reduce the potential for exposure of structures and infrastructure to seismic risks to the maximum extent feasible. Furthermore, the project would not increase or exacerbate seismic ground shaking hazards at adjacent properties. In the event fault rupture or seismic ground shaking compromises the proposed infrastructure during operation, AMWC would temporarily shut-off processes and conduct emergency repairs as soon as practicable. Therefore, the project would not cause substantial adverse effects including the risk of loss, injury, or death involving strong seismic ground shaking, and impacts would be less than significant. LESS-THAN-SIGNIFICANT IMPACT a.3. Would the project directly or indirectly cause potential substantial adverse effects, including the risk of loss, injury, or death involving seismic-related ground failure, including liquefaction? Liquefaction is the sudden loss of soil shear strength due to a rapid increase of soil pore water pressures caused by cyclic loading from a seismic event. This means a liquefied soil acts more like a fluid than a solid when shaken during an earthquake. The types of on-site soils (loose to medium dense sand at depths from approximately 20 to 38 feet below ground surface) and depth to groundwater (approximately 20 feet) result in vulnerability to liquefaction, and the project site has experienced liquefaction events in the past (e.g., during the 2003 San Simeon earthquake) (Appendix C). Seismically induced liquefaction at the project site could result in approximately 0.75 to 2.5 inches of seismic settlement at the ground surface, which would potentially damage the proposed structures and infrastructure in the event of an earthquake and result in leakages of water and treatment chemicals (Appendix C). However, the project would be designed and constructed in accordance with the recommendations of the geotechnical report, state and local building codes (e.g., California Building Code), and current seismic design standards to reduce the potential for exposure of structures and infrastructure to liquefaction risk to the maximum extent feasible. Incorporation of the ground improvement recommendations of the geotechnical report, which involve the use of rapid impact compaction, would densify the ground beneath the project site and minimize the potential for liquefaction within the alluvium by reducing the estimated seismic City of Atascadero Community Development Department Atascadero Mutual Water Company Water Treatment Plant Project 52 settlement to one inch or less during a design earthquake (Appendix C). Furthermore, the project would not involve groundwater injection that could exacerbate the existing liquefaction hazard. Therefore, the project would not directly or indirectly cause potential substantial adverse effects, including the risk of loss, injury, or death involving seismic-related ground failure, including liquefaction, and impacts would be less than significant. LESS-THAN-SIGNIFICANT IMPACT a.4. Would the project directly or indirectly cause potential substantial adverse effects, including the risk of loss, injury, or death involving landslides? The project site is relatively flat and is not susceptible to landslides. Therefore, the project would not directly or indirectly cause potential substantial adverse effects, including the risk of loss, injury, or death involving landslides. No impact would occur. NO IMPACT b. Would the project result in substantial soil erosion or the loss of topsoil? Soil erosion or the loss of topsoil may occur when soils are disturbed but not secured or restored, such that wind or rain events may mobilize disturbed soils, resulting in their transport off the project site. Project construction and grading would result in exposure and disturbance of soils that could be subject to erosion during wind and rain events. However, the project would be subject to compliance with the National Pollutant Discharge Elimination System (NPDES) Construction General Permit (Order No. 2022-0057-DWQ). The Construction General Permit requires the preparation and implementation of a Storm Water Pollution Prevention Plan (SWPPP) with project-specific Best Management Practices (BMPs) to control erosion and sediment release and otherwise reduce the potential for discharge of pollutants from construction into stormwater. Typical BMPs would include, but would not be limited to, use of silt fences, fiber rolls, stabilized construction entrances/exists, storm drain inlet protection, wind erosion control, stockpile management, and materials storage and vehicle and equipment cleaning, fueling, and maintenance procedures that minimize the discharge of spills and leaks. In addition, design and construction of the project would incorporate the erosion and drainage recommendations of the geotechnical report, which would minimize soil erosion through the placement of erosion control measures on finished slopes immediately following construction and providing drainage systems that avoid directing water over the tops of slopes and that include energy dissipation devices at the outlets of drainage pipes/ditches and along concentrated flows of runoff (Appendix C). Therefore, with adherence to the requirements of the Construction General Permit and the recommendations of the geotechnical report, the project would not result in substantial soil erosion or the loss of topsoil, and impacts would be less than significant. LESS-THAN-SIGNIFICANT IMPACT c. Would the project be located 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- or off-site landslide, lateral spreading, subsidence, liquefaction, or collapse? Lateral spreading on the ground surface during a seismic activity usually occurs along the weak shear zones within a liquefiable soil layer and has been observed to generally take place towards a free face (i.e., retaining wall, slope, or channel), and to lesser extent, on ground surfaces with a very gentle slope. The likelihood of lateral spreading at the project site is low due to its topography and Initial Study Checklist Geology and Soils Initial Study – Mitigated Negative Declaration 53 depth of groundwater (Appendix C). Subsidence occurs when a large portion of the land is displaced vertically, usually due to the withdrawal of groundwater, oil, or natural gas. The proposed project would not result in increased groundwater extraction from AMWC’s production wells adjacent to the Salinas River between SR 41 and Chico Road and would therefore have low potential to result in subsidence. As discussed under threshold 7(a.4), the project site is not susceptible to landslides. As discussed under threshold 7(a.3), liquefaction hazards at the project site would be addressed through implementation of the ground improvement strategies outlined in the geotechnical report (Appendix C), and the project does not include activities that could exacerbate liquefaction hazards, such as groundwater injection. Therefore, the project would not potentially result in on- or off-site landslide, lateral spreading, subsidence, liquefaction, or collapse due to unstable geologic units or soils, and impacts would be less than significant. LESS-THAN-SIGNIFICANT IMPACT d. Would the project be located on expansive soil, as defined in Table 18-1-B of the Uniform Building Code (1994), creating substantial direct or indirect risks to life or property? Expansive soils are highly compressible, clay-based soils that tend to expand as they absorb water and shrink as water is drawn away. Expansive soils can result in structural damage when foundations are not designed to account for soil expansion potential. Near-surface soils at the project site do not contain high concentrations of expansive clay minerals (Appendix C). Therefore, the project would not be located on expansive soil, creating substantial direct or indirect risks to life or property, and no impact would occur. NO IMPACT e. Would the project have soils incapable of adequately supporting the use of septic tanks or alternative wastewater disposal systems where sewers are not available for the disposal of wastewater? The proposed project includes installation of a new septic tank adjacent to the Operations Center building that would serve the new restroom in this building. Effluent from the tank would flow into an existing leach field within the AMWC’s existing Corporation Yard facility, which was installed in 2009 and has soils capable of adequately supporting the use of septic tanks, including the additional effluent that would be generated by the new restroom (Mid-Coast Geotechnical, Inc. 2008). The leach field was designed based on an anticipated total of up to 31 on-site employees at a time when AMWC anticipated moving their operational facilities to the project site. AMWC decided not to move forward with relocating its operational facilities to the Corporation Yard property; therefore, the leach field currently has excess capacity available to serve the new restroom in the proposed Operations Center building (Hollenbeck 2025). Therefore, no impact would occur. NO IMPACT f. Would the project directly or indirectly destroy a unique paleontological resource or site or unique geologic feature? Paleontological resources, or fossils, are the evidence of once-living organisms preserved in the rock record. They include both the fossilized remains of ancient plants and animals and the traces thereof (e.g., trackways, imprints, burrows, etc.). Paleontological resources are not found in “soil” but are contained within the geologic deposits or bedrock that underlies the soil layer. Typically, fossils are greater than 5,000 years old (i.e., older than middle Holocene in age) and are typically City of Atascadero Community Development Department Atascadero Mutual Water Company Water Treatment Plant Project 54 preserved in sedimentary rocks. Although rare, fossils can also be preserved in volcanic rocks and low-grade metamorphic rocks under certain conditions (Society of Vertebrate Paleontology [SVP] 2010). Fossils occur in a non-continuous and often unpredictable distribution within some sedimentary units, and the potential for fossils to occur within sedimentary units depends on several factors. It is possible to evaluate the potential for geologic units to contain scientifically important paleontological resources and therefore evaluate the potential for impacts to those resources. Rincon evaluated the paleontological sensitivity of the geologic units that underlie the project site to assess the project’s potential for significant impacts to scientifically important paleontological resources. The analysis was based on the results of a paleontological locality search and a review of existing information in the scientific literature regarding known fossils within geologic units mapped at the project site. According to the SVP (2010) classification system, geologic units can be assigned a high, low, undetermined, or no potential for containing scientifically significant nonrenewable paleontological resources. Following the literature review, a paleontological sensitivity classification was assigned to each geologic unit mapped within the project site. This criterion is based on rock units within which vertebrate or significant invertebrate fossils have been determined by previous studies to be present or likely to be present. The potential for impacts to significant paleontological resources is based on the potential for project-related ground disturbance to directly impact paleontologically-sensitive geologic units. Artificial fill underlies the entire project area to a depth of between 10 and 20 feet below the surface (Appendix C). This artificial fill generally consisted of unconsolidated, brown/black/green, clayey sand with gravel and occasional clay layers. Artificial fill represents sediment deposited by humans to change the grade and/or physical properties of the land. Therefore, it cannot preserve scientifically-significant paleontological resources and has no paleontological sensitivity. Quaternary stream channel deposits and Quaternary alluvium are mapped as distinct units by Dibblee and Minch (2004a), but Yeh and Associates (Appendix C) did not distinguish between them. The location of the surficial contact between these two geologic units as mapped by Dibblee and Minch (2004a) is provisional and likely varies within the subsurface. Therefore, this analysis follows the project-specific Geotechnical Report in analyzing these sediments together and will henceforth refer to them as “Holocene alluvial sediments.” These sediments were found underlying the surficial layer of artificial fill throughout the project site down to at least 51.5 feet, the maximum depth explored by the project-specific Geotechnical Report (Appendix C) The uppermost layers of these sediments are likely too young (i.e., less than 5,000 years old; SVP 2010) to preserve paleontological resources and should thus be considered to have low paleontological sensitivity. However, at some depth, Holocene alluvial sediments become early Holocene- or Pleistocene-aged sediments that are old enough (i.e., 5,000 years or older) to preserve paleontological resources. Early Holocene- and Pleistocene-aged alluvial sediments are known to preserve paleontological resources in San Luis Obispo County (Jefferson 2010; Paleobiology Database 2024) and are considered to have high paleontological sensitivity. The depth at which this transition to high-sensitivity sediments occurs is unknown. Geotechnical investigations (e.g., Appendix C) do not necessarily reveal this information because there is not necessarily an expected change in sediment type at the 5,000-year mark. Dibblee and Minch (2004b) and Wiegers and Holland (2012) mapped Pleistocene-aged alluvial sediments less than 500 and 200 feet south of the southern end of the project site, respectively, which suggests this transition depth could occur as little as 10 feet below the top of Holocene alluvial sediments. Therefore, Holocene alluvial sediments are assigned low paleontological Initial Study Checklist Geology and Soils Initial Study – Mitigated Negative Declaration 55 sensitivity in the uppermost 10 feet of this unit and assigned high paleontological sensitivity greater than 10 feet below the upper boundary of this unit. Ground-disturbing activities within previously undisturbed sediments with high paleontological sensitivity could result in significant impacts to paleontological resources. Impacts would be significant if construction activities result in the destruction, damage, or loss of scientifically important paleontological resources and associated stratigraphic and paleontological data. The project site contains 10 to 20 feet of artificial fill underlain by Holocene alluvial sediments, which have low sensitivity in their uppermost 10 feet and high sensitivity beyond this depth. Therefore, the minimum depth at which sediments with high paleontological sensitivity occur within the project site is 20 feet below the surface. Ground-disturbing activities for the proposed project are expected to include excavation to a depth of approximately 15 feet to remove buried debris from the undocumented fill zone; deep ground improvements using rapid impact compaction; restoration of the over-excavated zone using structural backfill techniques; excavations to install new infrastructure, such as tanks, treatment equipment, sumps, clearwells, and pipelines; trenching for utilities; and excavations for building pad foundations. Excavation and trenching are anticipated to reach a maximum depth of 15 feet below the surface, and rapid impact compaction would consolidate the Holocene alluvial sediments down to a depth of 20-feet but would not extend beyond this depth into the portion of Holocene alluvial sediments considered to have a high paleontological sensitivity. Given that ground disturbing activities would only disturb Holocene alluvial sediments with low paleontological sensitivity, the project would not directly or indirectly destroy a unique paleontological resource or site or unique geologic feature, and impacts would be less than significant. LESS-THAN-SIGNIFICANT IMPACT Mitigation/Conclusion No significant impacts are expected. No mitigation is required. City of Atascadero Community Development Department Atascadero Mutual Water Company Water Treatment Plant Project 56 This page intentionally left blank. Initial Study Checklist Greenhouse Gas Emissions Initial Study – Mitigated Negative Declaration 57 8 Greenhouse Gas Emissions Potentially Significant Impact Less than Significant with Mitigation Incorporated Less-than - Significant Impact No Impact Would the project: a. Generate greenhouse gas emissions, either directly or indirectly, that may have a significant impact on the environment? □ □ ■ □ b. Conflict with an applicable plan, policy, or regulation adopted for the purpose of reducing the emissions of greenhouse gases? □ □ □ ■ Existing Setting Climate change is the observed change in the average temperature of the Earth’s atmosphere and oceans along with other substantial changes in climate (such as wind patterns, precipitation, and storms) over an extended period. Climate change may be the result of numerous factors, including cumulative sources of GHG emissions contributing to the “greenhouse effect,” a natural occurrence which takes place in Earth’s atmosphere and helps regulate the temperature of the planet. Most radiation from the sun hits Earth’s surface and warms it. The surface, in turn, radiates heat back towards the atmosphere in the form of infrared radiation. Gases and clouds in the atmosphere trap and prevent some of this heat from escaping into space and re-radiate it in all directions. GHG emissions occur both naturally and as a result of human activities, such as fossil fuel burning, decomposition of landfill wastes, deforestation, and some agricultural practices. GHGs produced by human activities include CO2, methane, nitrous oxide, hydrofluorocarbons, perfluorocarbons, and sulfur hexafluoride. The project site is within AMWC’s existing Corporation Yard facility. There are no substantial sources of GHG emissions within the project site itself. Sources of existing GHG emissions associated with AMWC’s Corporation Yard facility as a whole generally consist of electricity used to power lighting in the existing buildings, natural gas used to power HVAC equipment in the existing buildings and Wells No. 1A, 3, 5, and 5A, vehicle trips to and from the facility, the use of heavy equipment (e.g., backhoes, front-end loaders, dump trucks) to load trucks and handle materials, and infrequent routine testing of existing emergency generators. Methodology Calculations of CO2, methane, and nitrous oxide emissions are estimated in CalEEMod to identify the magnitude of potential project GHG emissions effects. The analysis focuses on CO2, methane, and nitrous oxide because these make up 98 percent of all GHG emissions by volume and are the GHG emissions the project would emit in the largest quantities (IPCC 2014). Emissions of all GHGs are converted into their equivalent global warming potential in terms of CO2 (i.e., CO2e). Minimal City of Atascadero Community Development Department Atascadero Mutual Water Company Water Treatment Plant Project 58 amounts of other GHGs (such as chlorofluorocarbons) would be emitted; however, these other GHG emissions would not substantially add to the total GHG emissions. GHG emissions associated with project construction and operation were estimated using CalEEMod, version 2022.1, with the assumptions described under Section 3, Air Quality, in addition to the following: ▪ The model uses default CalEEMod assumptions for area and stationary sources, as well as natural gas consumption for the proposed project. ▪ The project would consume approximately 4,420 MWh of electricity annually, based on electrical service load data provided by the project engineer (Word 2024). ▪ 2022 PG&E CO2e intensity factors were used (PG&E 2024). ▪ The anticipated lifetime of the proposed project is 50 years. Significance Thresholds Based on Appendix G of the CEQA Guidelines, impacts related to GHG emissions from the project would be significant if the project would: ▪ Generate greenhouse gas emissions, either directly or indirectly, that may have a significant impact on the environment; and/or ▪ Conflict with an applicable plan, policy or regulation adopted for the purpose of reducing the emissions of greenhouse gases. The majority of individual projects do not generate sufficient GHG emissions to directly influence climate change. However, physical changes caused by a project can contribute incrementally to cumulative effects that are significant, even if individual changes resulting from a project are limited. The issue of climate change typically involves an analysis of whether a project’s contribution towards an impact would be cumulatively considerable. “Cumulatively considerable” means that the incremental effects of an individual project are significant when viewed in connection with the effects of past projects, other current projects, and probable future projects (CEQA Guidelines Section 15064[h][1]). In August 2023, SLOAPCD adopted updated CEQA thresholds for GHG emissions to achieve the State’s 2030 and 2045 GHG emissions reduction targets. Three thresholds were recommended for evaluating the level of significance of GHG emissions impacts for land use development projects (residential, commercial, and mixed-use). The SLOAPCD’s thresholds for the year 2027 (i.e., the first year of project operation) are 780 metric tons (MT) of CO2e per year for the bright-line threshold and 3.8 MT of CO2e per service person per year for the efficiency threshold. The SLOACPD guidance allows for choosing the bright-line or per-service-person thresholds and states that if a project’s emissions are at or below the applicable threshold for its operational year, then the project is considered to be contributing its fair share toward the State’s SB 32 GHG reduction target (SLOAPCD 2023). The City has determined the bright-line threshold of 780 MT of CO2e per year is appropriate to utilize for the purposes of evaluating the GHG emissions impacts of the proposed project because the project is a land use development project but is not a residential, commercial, or mixed-use project that would have a service population. Initial Study Checklist Greenhouse Gas Emissions Initial Study – Mitigated Negative Declaration 59 Proposed Project a. Would the project generate GHG emissions, either directly or indirectly, that may have a significant impact on the environment? Construction of the proposed project would generate temporary GHG emissions primarily as a result of operation of construction equipment on site, vehicles transporting construction workers to and from the project site, and haul trips. As shown in Table 7, construction of the proposed project would generate approximately 457 MT of CO2e. Amortized over the 50-year estimated project lifetime, construction of the proposed project would generate an estimated 9 MT of CO2e per year Table 7 Estimated Construction GHG Emissions Year Project Emissions (MT of CO2e) 2026 283 2027 174 Total 457 Total Amortized over 50 Years 9 MT = metric tons, CO2e = carbon dioxide equivalents See Appendix B for CalEEMod worksheets. Operation of the proposed project would generate GHG emissions associated with area sources, energy and water usage, vehicle trips, wastewater and solid waste generation, and periodic testing and maintenance of the emergency generator. As shown in Table 8, annual operational emissions generated by the proposed project combined with amortized construction emissions would total approximately 457 MT of CO2e per year, which would not exceed the SLOAPCD threshold of 780 MT of CO2e per year for year 2027 (i.e., the first year of project operation). Therefore, the project would not generate GHG emissions, either directly or indirectly, that may have a significant impact on the environment, and impacts would be less than significant. City of Atascadero Community Development Department Atascadero Mutual Water Company Water Treatment Plant Project 60 Table 8 Combined Annual Emissions of Greenhouse Gases Emission Source Annual Emissions (MT of CO2e) Construction 9 Operational Mobile 7 Area 1 Energy 149 Water 7 Waste 8 Refrigerant <1 Stationary 176 Total 357 SLOAPCD Bright Line Threshold for Year 2026 780 Exceed Threshold? No MT = metric tons; CO2e = carbon dioxide equivalents See Appendix B for CalEEMod worksheets. LESS-THAN-SIGNIFICANT IMPACT b. Would the project conflict with an applicable plan, policy, or regulation adopted for the purpose of reducing the emissions of greenhouse gases? The City adopted its Climate Action Plan in 2014, which is a long-range planning document to cost- effectively reduce GHG emissions from City government operations and community activities in Atascadero as well as to adapt to increase climate hazard risks. The majority of the measures in the Climate Action Plan are not applicable to the proposed project because they involve initiatives, programs, and actions to be implemented by the City rather than project applicants. Measure A-3: Infrastructure encourages improving the resilience of systems that provide the resources and services critical to community function (City of Atascadero 2014). The proposed project is intended to enhance the quality and resiliency of the water supply serving the City’s population. Therefore, the project would be consistent with the City’s Climate Action Plan. In addition, as discussed in Initial Study Checklist Section 2.6, Energy, the project would not conflict with the energy-related goals and policies of City’s General Plan, which would serve to reduce GHG emissions. Approximately two percent of total energy usage in California is used for the conveyance, treatment, and distribution of water. One of the goals of CARB’s 2022 Scoping Plan is to support climate adaptation and biodiversity that includes protection of the state’s water supply, water quality, and infrastructure to achieve carbon neutrality as soon as possible (CARB 2022). The project would provide treatment of an existing groundwater supply source; therefore, the project would improve the reliability and resiliency of the local water distribution network and preclude the need for energy- and GHG-emissions intensive imported water supplies to be purchased and conveyed to Atascadero to provide water supplies for the community. Thus, the project would not conflict with Initial Study Checklist Greenhouse Gas Emissions Initial Study – Mitigated Negative Declaration 61 applicable plans, policies, or regulations adopted for the purpose of reducing GHG emissions, and no impact would occur. NO IMPACT Mitigation/Conclusion No significant impacts are expected. No mitigation is required. City of Atascadero Community Development Department Atascadero Mutual Water Company Water Treatment Plant Project 62 This page intentionally left blank. Initial Study Checklist Hazards and Hazardous Materials Initial Study – Mitigated Negative Declaration 63 9 Hazards and Hazardous Materials Potentially Significant Impact Less than Significant with Mitigation Incorporated Less-than - Significant Impact No Impact Would the project: a. Create a significant hazard to the public or the environment through the routine transport, use, or disposal of hazardous materials? □ □ ■ □ b. Create a significant hazard to the public or the environment through reasonably foreseeable upset and accident conditions involving the release of hazardous materials into the environment? □ □ ■ □ c. Emit hazardous emissions or handle hazardous or acutely hazardous materials, substances, or waste within 0.25 mile of an existing or proposed school? □ □ □ ■ d. Be located on a site that is included on a list of hazardous material 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? □ □ □ ■ e. For a project located in 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? □ □ □ ■ f. Impair implementation of or physically interfere with an adopted emergency response plan or emergency evacuation plan? □ □ □ ■ g. Expose people or structures, either directly or indirectly, to a significant risk of loss, injury, or death involving wildland fires? □ □ ■ □ City of Atascadero Community Development Department Atascadero Mutual Water Company Water Treatment Plant Project 64 Existing Setting The project site is within AMWC’s existing Corporation Yard, and sodium hypochlorite and orthophosphate corrosion inhibitor are currently used and stored at the facility for use in water disinfection/treatment. The nearest school to the project site is Atascadero Middle School, located approximately 0.8 mile southwest of the project site. Based on a search of State Water Resources Control Board (2024) - GeoTracker, the California Department of Toxic Substances Control EnviroStor, the United States Environmental Protection Agency (2024) Superfund Enterprise Management System, and the Cortese List, the project site is not included on a list of hazardous material sites compiled pursuant to Government Code Section 65962.5 (California State Water Resources Control Board 2024; California Department of Toxic Substances Control 2024; California Environmental Protection Agency 2024b). The closest public or public use airport to the project site is the San Luis Obispo County Regional Airport, located approximately 18.5 miles to the southeast in San Luis Obispo. The applicable emergency response or emergency evacuation plan is the San Luis Obispo County Multi-Jurisdictional Hazard Mitigation Plan, which identifies potential hazards and vulnerabilities and outlines mitigation action plans. The County’s Multi-Jurisdictional Hazard Mitigation Plan incorporates specific information for Atascadero in Annex B (County of San Luis Obispo 2019). The project site is not within a State Responsibility Area or designated as a Very High Fire Hazard Severity Zone (VHFHSZ; California Department of Forestry and Fire Protection [CAL FIRE] 2024). The nearest VHFHSZ is approximately 0.1 mile southeast of the project site. Proposed Project a. Would the project create a significant hazard to the public or the environment through the routine transport, use, or disposal of hazardous materials? Construction of the proposed project would temporarily increase the transport and use of hazardous materials during the use of construction vehicles and equipment. Limited quantities of miscellaneous hazardous substances, such as diesel fuel, oil, solvents, and other similar materials, would be brought onto the project site, used, and stored during the construction period. The use, transport, and disposal of potentially hazardous materials during construction of the proposed project would be required to comply with all local, state, and federal regulations regarding the handling of hazardous materials, including the Hazardous Material Transportation Act, Resource Conservation and Recovery Act, the California Hazardous Materials Management Act, and CCR Title 22, Division 4.5, which would minimize the potential for the project to create a significant hazard to the public or the environment. During operation, sodium hypochlorite (chlorine) and orthophosphate corrosion inhibitor would be stored at the proposed WTP in a completely enclosed structure with proper containment and venting. Sodium hypochlorite is a liquid disinfection agent added to the water and is commonly referred to as “bleach.” Sodium hypochlorite is not the equivalent of chlorine gas, and chlorine gas would not be used or released during project operation. Chemical deliveries to the proposed facility would occur approximately one to two times a month, and these materials would be contained within vessels specifically engineered for safe storage. However, in accordance with standard operating practice, AMWC would submit an emergency response/contingency plan as part of a Hazardous Materials Business Plan to the California Environmental Reporting System for the proposed facility. Spent GAC media from the filtration vessels, which may be considered a hazardous waste depending on the concentration of PFAS, would be removed every six to nine months by the GAC supplier, who would be required to transport and dispose of or regenerate the Initial Study Checklist Hazards and Hazardous Materials Initial Study – Mitigated Negative Declaration 65 material in accordance with all applicable regulations, such as the Hazardous Materials Transportation Act, California Hazardous Material Management Act, and California Code of Regulations, Title 22. Compliance with existing local, state, and federal regulations regarding the handling of hazardous materials during construction and operation would not expose the public or the environment to a significant hazard through the routine transport, use, or disposal of hazardous materials. Impacts would be less than significant. LESS-THAN-SIGNIFICANT IMPACT b. Would the project create a significant hazard to the public or the environment through reasonably foreseeable upset and accident conditions involving the release of hazardous materials into the environment? Small quantities of hazardous materials used during project construction activities, including but not limited to ground-disturbing activities such as trenching, could result in an accidental upset or release of hazardous materials if they are not properly stored and secured. Hazardous materials used during project construction would be disposed of off-site in accordance with all applicable laws and regulations, including but not limited to the regulations of the federal and state Occupational Safety and Health Administrations. Additionally, project construction would require a SWPPP, which includes Good Housekeeping BMPs to reduce the risk of hazardous material spills or leaks. With adherence to the requirements of the SWPPP, project construction would not create a significant hazard to the public or the environment through reasonably foreseeable upset and accident conditions involving the release of hazardous materials into the environment, and impacts would be less than significant. The project includes installation of a new septic tank adjacent to the Operations Center building that would serve the new restroom within the Operations Center. Improper design or installation of the septic tank could result in leaks from the septic tank into on-site soils and groundwater. Pursuant to AMC Title 6, Chapter 5, the installation and operation of a septic tank is only permissible by obtaining a permit from the County of San Luis Obispo. In order to obtain a permit for the installation and operation of the septic tank, the septic tank must be designed in accordance with the requirements of the County of San Luis Obispo’s Local Agency Management Program (County of San Luis Obispo 2020), which sets forth local regulations for the design, siting, operation, and maintenance of septic tanks. The Local Agency Management Program requires a permit applicant to submit a percolation test of on-site soils and design plans, which must incorporate the results of the percolation test into septic tank design. Septic tank design must adhere to the minimum design specifications and requirements within the Local Agency Management Program, including ensuring the tank is watertight (County of San Luis Obispo 2020). The proposed septic tank would be required to be designed in accordance with the requirements of the Local Agency Management Program, which would minimize the potential for leaks. In addition, as discussed in Section 7, Geology and Soils, the existing leach field at the AMWC Corporation Yard facility has sufficient excess capacity to accommodate the additional wastewater flows generated by the new restroom. The existing leach field system is located approximately 350 feet from the nearest groundwater well, which is further than the 200-foot minimum setback distance mandated by the Local Agency Management Program and therefore protective of groundwater quality. The existing leach field system is also located approximately 175 feet from the bank of the Salinas River and approximately 475 feet from the bank of Atascadero Creek, which is further than the 100-foot minimum setback distance for flowing streams and creeks mandated by the Local Agency Management Program and therefore protective of surface water quality (County of San Luis Obispo 2020). Therefore, the proposed septic tank and additional use of the existing leach field would not create a significant hazard to the public or the City of Atascadero Community Development Department Atascadero Mutual Water Company Water Treatment Plant Project 66 environment through reasonably foreseeable upset and accident conditions involving the release of hazardous materials into the environment, and impacts would be less than significant. As discussed under threshold 9(a), operation and maintenance would involve the routine use and storage of sodium hypochlorite and orthophosphate corrosion inhibitor. Although greater volumes of these chemicals would be used and stored at the project site, these chemicals are already used and stored at AMWC’s Corporation Yard facility. Spent GAC media from filtration vessels, which may be considered a hazardous waste depending on the concentration of PFAS, would be removed every six to nine months by the GAC supplier who would be required to transport and dispose of or regenerate the material in accordance with all applicable regulations, such as the Hazardous Materials Transportation Act, California Hazardous Material Management Act, and California Code of Regulations, Title 22. Because of the static nature of the spent GAC, any accidents occurring during the removal, transport, and disposal of the GAC would be unlikely to create a significant hazard to the public or the environment. In addition, the project site is approximately 260 feet away from the nearest residence and approximately 370 feet away from the Salinas River. Given these distances, any potential spills or releases of materials are unlikely to create significant hazards to the public or the environment. Furthermore, in accordance with standard operating practice, AMWC would submit an emergency response/contingency plan as part of a Hazardous Materials Business Plan to the California Environmental Reporting System for the proposed facility, which would include provisions for appropriate handling and clean-up of any spills or releases of materials. Therefore, the project would not create a significant hazard to the public or the environment through reasonably foreseeable upset and accident conditions involving the release of hazardous materials into the environment, and impacts would be less than significant. LESS-THAN-SIGNIFICANT IMPACT c. Would the project emit hazardous emissions or handle hazardous or acutely hazardous materials, substances, or waste within 0.25 mile of an existing or proposed school? There are no existing or proposed schools within 0.25 mile of the project site. Therefore, the project would not emit hazardous emissions or handle hazardous or acutely hazardous materials, substances, or waste within 0.25 mile of an existing or proposed school, and no impact would occur. NO IMPACT d. Would the project be located on a site that is included on a list of hazardous material 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? The following databases and listings compiled pursuant to Government Code Section 65962.5 were reviewed on August 26, 2024, for known hazardous materials contamination at the project site: ▪ State Water Resources Control Board (2024) GeoTracker search for leaking underground storage tanks (LUST) and other cleanup sites; ▪ California Department of Toxic Substances Control (2024) EnviroStor database for hazardous waste facilities or known contamination sites; and ▪ List of solid waste disposal sites identified by the State Water Resources Control Board with waste constituents above hazardous waste levels outside the waste management unit (California Environmental Protection Agency 2025) ▪ List of active Cease and Desist Orders and Cleanup and Abatement Orders from the State Water Resources Control Board (California Environmental Protection Agency 2025) Initial Study Checklist Hazards and Hazardous Materials Initial Study – Mitigated Negative Declaration 67 ▪ List of hazardous waste facilities subject to corrective action pursuant to Section 25187.5 of the Health and Safety Code, identified by the California Department of Toxic Substances Control (California Environmental Protection Agency 2025) In addition, the United States Environmental Protection Agency (2024) Superfund Enterprise Management System was reviewed for the project site. The project site is not listed in the above databases, and no listed sites are present within 1,000 feet of the project site. Therefore, the project would not be located on a site that is included on a list of hazardous material sites compiled pursuant to Government Code Section 65962.5. No impact would occur. NO IMPACT e. 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? The project site is not located in an area covered by an airport land use plan or within two miles of a public or public use airport. Therefore, no impact would occur. NO IMPACT f. Would the project impair implementation of or physically interfere with an adopted emergency response plan or emergency evacuation plan? The project site is located within AMWC’s existing Corporation Yard facility and a portion of the Sycamore Road right-of-way. The proposed project would not require any temporary lane or road closures that could impede emergency response or evacuation during construction. In addition, the project includes construction of an improved driveway on Sycamore Road, which would enhance ingress/egress to the facility in the event of emergency response or evacuation. During project operation, daily AMWC operator visits and periodic chemical deliveries would not substantially increase congestion on Sycamore Road in the event of emergency evacuations. Therefore, the project would not impair implementation of or physically interfere with the San Luis Obispo County Multi-Jurisdictional Hazard Mitigation Plan, and no impact would occur. NO IMPACT g. Would the project expose people or structures, either directly or indirectly, to a significant risk of loss, injury, or death involving wildland fires? As discussed in detail in Initial Study Checklist Section 20, Wildfire, the project site is not located within a State Responsibility Area nor designated as a Very High Fire Hazard Severity Zone (California Department of Forestry and Fire Protection (California Department of Forestry and Fire Protection [CAL FIRE] 2024). The nearest VHFHSZ is approximately 0.1 mile southeast of the project site, immediately southeast of the SR 41 overcrossing of Sycamore Road, and is associated with wooded open space areas, including Stadium Park. The project site is within the AMWC Corporation Yard and is immediately surrounded by other portions of the facility to the north, west, and east and Sycamore Road to the south. Beyond the Corporation Yard boundaries, surrounding land uses include SR 41 to the east, the Salinas River to the north, Atascadero Creek and single-family residences to the west, and the Union Pacific Railroad and single-family residences to the south. Construction personnel would be required to adhere to City of Atascadero Community Development Department Atascadero Mutual Water Company Water Treatment Plant Project 68 applicable provisions of the PRC to minimize fire risk. These regulations include PRC Section 4442, which requires earth-moving and portable construction equipment with internal combustion engines to use spark arrestors when operating on any forest-covered, brush-covered, or grass- covered land; and PRC Section 4428, which requires construction contractors to maintain fire suppression equipment during the highest fire danger period (April 1 to December 1) when operating on or near any forest-covered, brush-covered, or grass-covered land. In addition, the project does not include components that would present the risk of wildland fire ignition, such as aboveground power lines. Therefore, the project would not expose people or structures, either directly or indirectly, to a significant risk of loss, injury, or death involving wildland fires, and impacts would be less than significant. LESS-THAN-SIGNIFICANT IMPACT Mitigation/Conclusion No significant impacts are expected. No mitigation is required. Initial Study Checklist Hydrology and Water Quality Initial Study – Mitigated Negative Declaration 69 10 Hydrology and Water Quality Potentially Significant Impact Less than Significant with Mitigation Incorporated Less-than - Significant Impact No Impact Would the project: a. Violate any water quality standards or waste discharge requirements or otherwise substantially degrade surface or ground water quality? □ □ ■ □ b. Substantially decrease groundwater supplies or interfere substantially with groundwater recharge such that the project may impede sustainable groundwater management of the basin? □ □ ■ □ c. Substantially alter the existing drainage pattern of the site or area, including through the alteration of the course of a stream or river or through the addition of impervious surfaces, in a manner which would: (i) Result in substantial erosion or siltation on- or off-site; □ □ ■ □ (ii) Substantially increase the rate or amount of surface runoff in a manner which would result in flooding on- or off-site; □ □ ■ □ (iii) Create or contribute runoff water which would exceed the capacity of existing or planned stormwater drainage systems or provide substantial additional sources of polluted runoff; or □ □ ■ □ (iv) Impede or redirect flood flows? □ □ ■ □ d. In flood hazard, tsunami, or seiche zones, risk release of pollutants due to project inundation? □ □ ■ □ e. Conflict with or obstruct implementation of a water quality control plan or sustainable groundwater management plan? □ □ ■ □ City of Atascadero Community Development Department Atascadero Mutual Water Company Water Treatment Plant Project 70 Existing Setting The project site in Atascadero is located within the Salinas River watershed, an area influenced by seasonal rainfall and surface water flows. The Salinas River and its tributaries, such as Atascadero and Graves Creeks, are key hydrological features that contribute to local water supply and groundwater recharge (San Luis Obispo County Public Works Department 2024). The applicable water quality control plan is the Water Quality Control Plan for the Central Coast Basin (Basin Plan) adopted by the Central Coast Regional Water Quality Control Board. The project site overlies the Atascadero Subbasin of the Salinas Valley Groundwater Basin (referred to as “Atascadero Basin”), which is managed under the Atascadero Basin Groundwater Sustainability Plan (GSP) to ensure long- term sustainability and address concerns such as nitrate contamination from agricultural activities (Atascadero Basin Groundwater Sustainability Agency 2022). The Atascadero Basin consists of an alluvial aquifer comprised of alluvial sediments that underlie the Salinas River and the Paso Robles Formation Aquifer, which is comprised of sand and gravel in the Paso Robles Formation (Atascadero Basin Groundwater Sustainability Agency 2022). The Rinconada Fault zone restricts flow from the Atascadero Basin to the Paso Robles Basin; however, the alluvial deposits along the Salinas River that overlie the Paso Robles Formation are able to recharge the Atascadero Basin and Paso Robles Basin (Atascadero Basin Groundwater Sustainability Agency 2016). The City implements stormwater management practices and water quality regulations to protect both surface and groundwater resources from potential pollutants, ensuring compliance with state and federal water quality standards (City of Atascadero 2023). The project site is located within a 0.2 percent annual chance flood hazard zone, indicating a moderate risk of flooding (Federal Emergency Management Agency [FEMA] 2024). Proposed Project a. Would the project violate any water quality standards or waste discharge requirements or otherwise substantially degrade surface or ground water quality? Construction Excavation, grading, and construction activities associated with project construction would result in soil disturbance. As stormwater flows over a construction site, it can pick up sediment, debris, and chemicals, and transport them to receiving water bodies. Construction activities could also affect water quality in the event of an accidental fuel or hazardous materials leak or spill. Receiving water bodies in the vicinity of the project site including the Salinas River to the north. As previously discussed in Initial Study Checklist Section 7, Geology and Soils, construction activities would be required to comply with the requirements of the NPDES Construction General Permit (Order No. 022-0057-DWQ, as amended) because project construction would disturb more than one acre of land. The NPDES Construction General Permit requires preparation and implementation of a project-specific SWPPP to reduce erosion during construction activities. Compliance with the requirements set forth in this permit would require the construction contractor(s) to implement BMPs for erosion control during construction. With adherence to the requirements of the Construction General Permit, polluted stormwater runoff would be minimized to the extent feasible. If groundwater is encountered during project construction, produced groundwater would be discharged to the existing on-site well flushing/sedimentation basins, where it would percolate back into the underlying groundwater basin. The quality of groundwater produced during dewatering Initial Study Checklist Hydrology and Water Quality Initial Study – Mitigated Negative Declaration 71 would be the same as that of the existing shallow aquifer such that no impacts to groundwater quality would occur. Upset or accident conditions could result in the unanticipated spill or release of hazardous materials such as vehicle and equipment fuels during project construction. However, the project-specific SWPPP would include BMPs that would reduce the risk of hazardous material spills or leaks. With adherence to the required SWPPP, impacts related to substantial degradation of surface or ground water quality during construction would be less than significant. Operation Following completion of project construction, the new infrastructure would be flushed and disinfected with potable water that would be dechlorinated prior to discharge to the existing on-site well flushing/sedimentation basins. With adherence to these regulatory requirements, the discharge of water used for flushing the new infrastructure would not result in substantial degradation of surface water or groundwater quality. As described in Section 9, Hazards and Hazardous Materials, the project includes installation of a new septic tank. The septic tank would be required to be designed in accordance with the requirements of the County of San Luis Obispo’s Local Agency Management Program, which governs septic tank design, permitting, construction, and operation. Design specifications included within the Local Agency Management Program include the required use of watertight tanks, which would minimize the potential for leaks. In addition, the existing leach field system at the AMWC Corporation Yard facility that would accommodate the additional effluent from the proposed septic tank is located approximately 350 feet from the nearest groundwater well, which is further than the 200-foot minimum setback distance mandated by the Local Agency Management Program and therefore protective of groundwater quality. The existing leach field system is also located approximately 175 feet from the bank of the Salinas River and approximately 475 feet from the bank of Atascadero Creek, which is further than the 100-foot minimum setback distance for flowing streams and creeks mandated by the Local Agency Management Program and therefore protective of surface water quality (County of San Luis Obispo 2020). Accordingly, the design and siting of the proposed septic tank and existing leach field would minimize potential for the release of pollutants that could otherwise substantially degrade groundwater quality. The remainder of project operation and maintenance would consist of treating groundwater through the proposed WTP, and no discharges would otherwise occur. Therefore, project operation would not result in substantial degradation of surface water or groundwater quality, and impacts would be less than significant. LESS-THAN-SIGNIFICANT IMPACT b. Would the project substantially decrease groundwater supplies or interfere substantially with groundwater recharge such that the project may impede sustainable groundwater management of the basin? The Atascadero Basin is defined in Bulletin 118 as Subbasin No. 3-004.11, as outlined in the Atascadero Basin Groundwater Sustainability Plan (GSP), is currently designated by the Department of Water Resources as a very-low-priority basin and is not required to comply with the Sustainable Groundwater Management Act (SGMA) mandate. Nevertheless, local agencies have proactively formed a Groundwater Sustainability Agency (GSA) to manage the basin's groundwater resources and have developed a GSP to ensure long-term sustainability (Atascadero Basin Groundwater Sustainability Agency 2022). The goal of the Atascadero Basin GSP is to manage groundwater City of Atascadero Community Development Department Atascadero Mutual Water Company Water Treatment Plant Project 72 resources sustainably for the benefit of all stakeholders, balancing water supply needs while avoiding undesirable results over the 20-year SGMA implementation horizon and beyond. The project consists of a groundwater treatment facility that would provide treatment for an existing groundwater supply source, rather than introduce a new water supply. The project would not result in increased groundwater extraction by AMWC. The proposed project would introduce approximately 3.5 acres of new impervious surfaces to the project. Post-construction stormwater runoff from the project site would be directed to the existing on-site well flushing/stormwater detention basins, where it would be allowed to percolate back into the alluvial subsurface aquifer and recharge the Atascadero Basin and Paso Robles Basin, thereby not reducing overall groundwater recharge potential on the project site. Therefore, the project would not interfere substantially with groundwater recharge such that the project may impede sustainable groundwater management of the basin, and the impacts would be less than significant. LESS-THAN-SIGNIFICANT IMPACT c.(i) Would the project substantially alter the existing drainage pattern of the site or area, including through the alteration of the course of a stream or river or through the addition of impervious surfaces, in a manner which would result in substantial erosion or siltation on- or off-site? c.(ii) Would the project substantially alter the existing drainage pattern of the site or area, including through the alteration of the course of a stream or river or through the addition of impervious surfaces, in a manner which would substantially increase the rate or amount of surface runoff in a manner which would result in flooding on- or off-site? c.(iii) Would the project substantially alter the existing drainage pattern of the site or area, including through the alteration of the course of a stream or river or through the addition of impervious surfaces, in a manner that would create or contribute runoff water which would exceed the capacity of existing or planned stormwater drainage systems or provide substantial additional sources of polluted runoff? The project site does not include alteration of any streams or rivers. Under existing conditions, stormwater currently sheet flows from the project site to the Salinas River. The proposed project would introduce approximately 3.5 acres of new impervious surfaces to the project site. As part of the project, grading would be conducted to direct stormwater runoff away from the Salinas River to minimize potential impacts. Post-construction stormwater runoff from the project site would be directed to the existing on-site well flushing/stormwater detention basins, where it would be allowed to percolate back into the alluvial subsurface aquifer. Because the project involves disturbance of greater than 22,500 square feet (approximately 0.5 acre) and is in Watershed Management Zones 1 and 4, AMWC would be subject to the requirements of the City’s Stormwater Control Plan for Post Construction Requirements (2014), specifically Requirements 1, 2, and 3, which require implementation of site design strategies for runoff reduction, water quality treatment measures, runoff retention measures, and peak management strategies. Together, these requirements mandate retention of the 95th percentile storm event for Zone 1 and the 85th percent storm event for Zone 4 via infiltration overlying the groundwater basin as well as post-development peak flows in Zone 1 to not exceed pre-project peak flows for the two-year through 10-year storm events. In addition, AMC Section 7.13.025 requires preparation and implementation of a drainage plan that meets the City Council’s adopted Storm Drainage Standards and that includes construction-phase and long-term BMPs to manage stormwater runoff. Given these requirements, Initial Study Checklist Hydrology and Water Quality Initial Study – Mitigated Negative Declaration 73 the net change in surface runoff to the Salinas River would be minimal. Consequently, the increase in impervious surfaces under the proposed project would not result in substantial erosion or siltation on- or off-site, substantially increase the rate or amount of surface runoff in a manner which would result in flooding on- or off-site, or create or contribute runoff water that would exceed the capacity of existing or planned stormwater drainage systems or provide additional sources of polluted runoff. Therefore, with compliance with the City’s stormwater control requirements, impacts would be less than significant. LESS-THAN-SIGNIFICANT IMPACT c.(iv) Would the project substantially alter the existing drainage pattern of the site or area, including through the alteration of the course of a stream or river or through the addition of impervious surfaces, in a manner which would impede or redirect flood flows? Based on the Flood Insurance Rate Map (FIRM) prepared by FEMA, a portion of the project site is located within the mapped boundaries of the 100-year floodplain associated with the Salinas River, the Salinas River floodway, and the remainder of the project site is located within the mapped boundaries of the 500-year floodplain associated with the Salinas River and Atascadero Creek, which is not considered a special flood hazard zone (FEMA 2024). The portion of the project site mapped within the 100-year floodplain and floodway is also considered a special flood hazard area pursuant to AMC Section 7-11.008. However, FEMA mapping of floodplain boundaries is based on broad interpolation of base flood elevation9 contours using representative cross-sections and is not always reflective of site-specific topography. FEMA’s (2005) National Flood Insurance Program (NFIP) Floodplain Management Requirements: A Study Guide and Desk Reference for Local Officials guidance document acknowledges that “due to the limited detail and large scale of the base maps used for most FIRMs, much interpolation between contour lines is done in mapping the floodplain boundaries. This is why you may find discrepancies when actual ground elevations are surveyed: the maps are just the best available graphic representations of the base flood elevations.” The document also indicates the most accurate base flood elevations for a riverine floodplain are found in the Floodway Data Table and that the least accurate source of elevation data for a riverine floodplain is the FIRM (FEMA 2005). According to the Floodway Data Table for the Salinas River (see cross-section AR), the boundary of the Salinas River floodway is determined using a base flood elevation of 821.4 feet above mean sea level in the vicinity of the project site (FEMA 2012 and 2024). At this location, site-specific topographic survey data indicates the ground surface elevation rises to 825 feet above mean sea level between the Salinas River and the northern boundary of AMWC’s Corporation Yard facility and that elevations within the project site range from approximately 824 to 834 feet above mean sea level. Based on the difference between the actual ground surface elevation and the base flood elevation, the project site is elevated above the base flood elevation and is therefore not within the 100-year floodplain of the Salinas River. Similarly, according to the Floodway Data Table for Atascadero Creek (see cross-section A), the boundary of the 100-year floodplain is determined using a base flood elevation of 827.5 feet above mean sea level in the vicinity of the project site (FEMA 2012 and 2024). At this location, site-specific topographic survey data indicates the ground surface elevation rises to 830 feet above mean sea level along the western boundary of AMWC’s Corporation Yard facility, west of the project site. This intervening topographic feature forms a barrier between Atascadero Creek and the project site that would preclude flooding during the 100- 9 The base flood elevation is the elevation to which floodwater is anticipated to rise during the base flood, also known as the 100-year flood (FEMA 2005). City of Atascadero Community Development Department Atascadero Mutual Water Company Water Treatment Plant Project 74 year flood event, even though elevations at the project site itself range from 824 to 834 feet above mean sea level. Therefore, the proposed project would not substantially alter the existing drainage pattern of the project site or area in a manner that would impede or redirect flood flows, and impacts would be less than significant. LESS-THAN-SIGNIFICANT IMPACT d. In flood hazard, tsunami, or seiche zones, would the project risk release of pollutants due to project inundation? The project site is not within a seiche or tsunami zone. A portion of the project site is located within the mapped boundaries of the 100-year floodplain and regulatory floodway associated with the Salinas River, and the remainder of the project site is located within the mapped boundaries of the 500-year floodplain for the Salinas River and Atascadero Creek, which is not considered a special flood hazard zone (FEMA 2024). As detailed under threshold 10(c), although the FIRM prepared by FEMA shows the project site as within the 100-year floodplain associated with the Salinas River, site- specific topographic survey data indicates the project site is elevated above the base flood elevation and therefore not expected to be inundated during a 100-year flood event along the Salinas River. In addition, due to intervening topography, the project site is not expected to be inundated during a 100-year flood event along Atascadero Creek. Furthermore, the risk of pollutant release due to project inundation is considered low. As mentioned in Initial Study Checklist Section 9, Hazards and Hazardous Materials, during operation, the project would involve the use of sodium hypochlorite (chlorine) and orthophosphate corrosion inhibitor. These materials would be stored in a completely enclosed structures with proper containment and venting. Specifically, they would be housed in secondary containment vessels, which would minimize the potential for pollutant release in the unlikely event of inundation. Therefore, the project would not risk release of pollutants due to project inundation, and impacts would be less than significant. LESS-THAN-SIGNIFICANT IMPACT e. Would the project conflict with or obstruct implementation of a water quality control plan or sustainable groundwater management plan? The project site is within an area subject to the Basin Plan, which designates beneficial uses for water bodies in the Central Coast Region and establishes water quality objectives and implementation plans to protect those beneficial uses (Central Coast Regional Water Quality Control Board 2019). As discussed under threshold (a) of this section, during construction, project activities would be subject to compliance with the Construction General Permit, which requires development of a SWPPP and implementation of BMPs to reduce erosion and topsoil loss from stormwater runoff during construction activities. If groundwater is encountered during project construction, produced groundwater would be discharged to the existing on-site well flushing basins, where it would percolate back into the alluvial subsurface aquifer. The quality of groundwater produced during dewatering would be the same as that of the existing shallow aquifer. Following completion of project construction, the new infrastructure would be flushed and disinfected with potable water that would be dechlorinated prior to discharge to the on-site well flushing basins. Project operation and maintenance would consist of treating groundwater through the proposed WTP, and no discharges would occur. Accordingly, the project would not conflict with or obstruct implementation of the Basin Plan, and no impact would occur. As discussed under threshold (b) of this section, the project consists of a groundwater treatment facility that would provide treatment for AMWC’s existing groundwater supply and would not result Initial Study Checklist Hydrology and Water Quality Initial Study – Mitigated Negative Declaration 75 in increased groundwater extraction by AMWC. Therefore, the proposed project would not conflict with or obstruct implementation of the Atascadero Basin GSP, and no impact would occur. NO IMPACT Mitigation/Conclusion No significant impacts are expected. No mitigation is required. City of Atascadero Community Development Department Atascadero Mutual Water Company Water Treatment Plant Project 76 This page intentionally left blank. Initial Study Checklist Land Use and Planning Initial Study – Mitigated Negative Declaration 77 11 Land Use and Planning Potentially Significant Impact Less than Significant with Mitigation Incorporated Less-than - Significant Impact No Impact Would the project: a. Physically divide an established community? □ □ □ ■ b. Cause a significant environmental impact due to a conflict with any land use plan, policy, or regulation adopted for the purpose of avoiding or mitigating an environmental effect? □ ■ □ □ Existing Setting The project site is located within AMWC’s existing Corporation yard facility that has been previously disturbed. The project site has a land use designation of Industrial and zoning designations of Industrial and Industrial Park (City of Atascadero 2011). The project site is immediately surrounded by other portions of the AMWC Corporation Yard facility to the north, west, and east and Sycamore Road to the south. Beyond the Corporation Yard boundaries, surrounding land uses include SR 41 to the east, the Salinas River to the north, Atascadero Creek and single-family residences to the west, and the Union Pacific Railroad and single-family residences to the south. Proposed Project a. Would the project physically divide an established community? The project site is located within AMWC’s existing Corporation Yard facility and would not introduce new barriers or structures that would impede access or connectivity within the surrounding community. Therefore, the project not physically divide an established community, and no impact would occur. NO IMPACT b. Would the project cause a significant environmental impact due to a conflict with any land use plan, policy, or regulation adopted for the purpose of avoiding or mitigating an environmental effect? Applicable land use plans, policies, and regulations include the City’s General Plan and AMC. The project site has a land use designation of Industrial, which provides for a range of uses, from intensive individual operations such as auto body shops, contractor staging areas, outdoor storage facilities, and manufacturing plants, to lower-intensity businesses in light industrial park developments master planned on large parcels. The project site is zoned Industrial and Industrial Park. The Industrial zone is established to provide suitable locations for heavy manufacturing and industrial uses within the city, and the Industrial Park zone is established to provide for the light manufacturing and large lot service commercial needs of the residents of the city and surrounding areas (City of Atascadero 2020). As a groundwater treatment facility, the proposed project would be consistent with the purpose of the underlying land use and zoning designations. City of Atascadero Community Development Department Atascadero Mutual Water Company Water Treatment Plant Project 78 The following development standards outlined in the AMC are applicable to development in the Industrial and Industrial Park zones: ▪ Front, side, and rear setbacks: none ▪ Minimum lot size: two acres ▪ Maximum height: 45 feet for structures; 60 feet for industrial towers, nonportable equipment, and other uninhabited structures; and no limit for public utility poles and structures for providing electrical and communications services ▪ Fencing and screening: minimum six-foot-tall fencing and screening required for mechanical support equipment located outside of a building (e.g., HVAC equipment), outdoor storage, public utility substations, and side and rear property lines when adjacent to a residential use or zone The project would be located across two parcels, each with a lot size greater than two acres. The proposed equipment would be up to approximately 26 feet in height, and the proposed Operations Center building would be approximately 20 feet in height. The proposed self-supporting tower assembly used for SCADA communications, which would range in height between 50 and 60 feet. Accordingly, the project would not exceed the maximum height limitations outlined in the AMC. Furthermore, the project includes planting of native plants along the Sycamore Road. Therefore, the project would be consistent with applicable zoning regulations adopted for the purpose of avoiding or mitigating environmental effects pertaining to aesthetics. The project’s consistency with zoning regulations pertaining to the City of Atascadero’s Native Tree Regulations is discussed in Initial Study Checklist Section 4, Biological Resources. In addition, the project’s consistency with zoning regulations pertaining to noise are discussed in Initial Study Checklist Section 13, Noise, and implementation of Mitigation Measures NOI-1 and NOI-2 are required to achieve compliance with the City’s nighttime exterior noise limits during occasional nighttime construction activities and operational activities. Table 9 outlines the project’s consistency with applicable goals and policies of the City’s General Plan adopted for the purpose of avoiding or mitigating an environmental effect. The project’s consistency with goals and policies pertaining to energy and transportation are discussed in Initial Study Checklist Section 6, Energy, Section 12, Mineral Resources, and Section 17, Transportation. Table 9 Project Consistency with the Land Use Policies of the City’s General Plan City of Atascadero General Plan Goals and Policies Project Consistency Land Use, Open Space, and Conservation Element Goal LOC 1: Protect and preserve the rural atmosphere of the community by assuring “elbow room” for residents by means of maintenance of large lot sizes which increase in proportion to distance beyond the Urban Core. ▪ Policy 1.3: Enhance the rural character and appearance of the City, including commercial corridors, gateways and public facilities. ▪ Policy 1.4: Ensure that “darkness” remain a rural characteristic by requiring that all exterior lighting does not result in significant off-site spillage or glare. Consistent. The proposed project involves development of a groundwater treatment facility within AMWC’s existing Corporation Yard facility. As discussed in Initial Study Checklist Section 1, Aesthetics, the proposed facility would be shielded with native plants that would be planted to be consistent in visual character along the Sycamore Road frontage of AMWC’s Corporation Yard. In addition, the proposed new outdoor lighting systems would be designed to minimize light spillover to adjacent properties. The nearest residence is approximately 260 feet south of the project site boundary, across the railroad and is shielded from the project site by existing mature trees and other vegetation, which would further block the transmission of light off site. Initial Study Checklist Land Use and Planning Initial Study – Mitigated Negative Declaration 79 City of Atascadero General Plan Goals and Policies Project Consistency Goal LOC 6: Preserve natural flora and fauna and protect scenic lands, sensitive natural areas, historic buildings and cultural resources. ▪ Policy 6.1: Ensure that development does not degrade scenic and sensitive areas, including historic sites, creeks, riparian corridors, wetlands, woodlands, hillsides and other valuable habitats. ▪ Policy 6.2: Protect prehistoric cultural resources from disturbance associated with development. Consistent. As discussed in Initial Study Environmental Checklist Section 1, Aesthetics, the proposed project would not result in significant impacts to scenic vistas in the project site vicinity. In addition, the project would preserve existing on-site trees and would not result in significant impacts to biological resources, including creeks, riparian corridors, wetlands, woodlands, or other sensitive natural communities, as detailed in Initial Study Checklist Section 4, Biological Resources. Furthermore, as discussed in Initial Study Checklist Section 5, Cultural Resources, there are no historic buildings within or adjacent to the project site, and the project would not result in significant impacts to cultural resources with implementation of Mitigation Measures CR-1 and CR-2. Goal LOC 8: Watershed areas of Atascadero shall be protected. ▪ Policy 8.1: Ensure that development along Atascadero Creek, Graves Creeks, the Salinas River, blue line creeks, and natural springs, lakes, or other riparian areas does not interrupt natural flows or adversely impact riparian ecosystems and water quality. Consistent. As detailed in Section 10, Hydrology and Water Quality, the proposed project would introduce approximately 3.5 acres of new impervious surfaces to the project site. As part of the project, grading would be conducted to direct stormwater runoff away from the Salinas River to minimize potential impacts. Post-construction stormwater runoff from the project site would be directed to the existing on-site stormwater detention basins, where it would be allowed to percolate back into the underlying alluvial groundwater. Because the project involves disturbance of greater than 22,500 square feet (approximately 0.5 acre) and is in Watershed Management Zones 1 and 4, AMWC would be subject to the requirements of the City’s Stormwater Control Plan for Post Construction Requirements (2014). Given these requirements, the net change in surface runoff volumes and water quality to the Salinas River would be minimal. Goal LOC 10: Conserve energy and resources by preventing or correcting degradation of the environment. ▪ Policy 10.3: Support regional efforts to maintain clean air. ▪ Policy 10.4: Ensure that development in mineral resource areas is appropriate and compatible with existing uses. ▪ Policy 10.5: Encourage soil conservation by minimizing grading and preventing erosion. Consistent. As discussed in Initial Study Checklist Section 3, Air Quality, Section 7, Geology and Soils, and Section 12, Mineral Resources, the proposed project would not result in significant impacts related to air quality, mineral resource areas, or soil erosion. Safety and Noise Element Goal SFN 2. Reduce damage to structures and danger to life caused by flooding and dam inundation. ▪ Policy 2.1: Enforce federal regulations regarding placement of structures in floodplains, and maintain appropriate standards for development in flood-prone and poorly drained areas (refer to Figure II-8). Not Applicable. As discussed in Initial Study Checklist Section 10, Hydrology and Water Quality, a portion of the project site is located within the mapped boundaries of the 100-year floodplain and regulatory floodway associated with the Salinas River, and the remainder of the project site is located within the mapped boundaries of the 500-year floodplain for the Salinas River and Atascadero Creek. Project survey data indicates the project site is elevated above the base flood elevation and therefore not expected to be inundated during a 100-year flood event along the Salinas River. In addition, due to intervening topography, the project site is not expected to be inundated during a 100-year flood event along Atascadero Creek. City of Atascadero Community Development Department Atascadero Mutual Water Company Water Treatment Plant Project 80 City of Atascadero General Plan Goals and Policies Project Consistency Goal SFN 3: Reduce the threat to life, structures, and the environment caused by fire. ▪ Policy 3.1: Carefully site and configure new development in higher fire risk areas Consistent. The project site is located in an area of moderate fire hazard risk, as shown on Figure IV-3 of the City’s General Plan. As discussed in Section 20, Wildfire, the project does not include components that would present the risk of wildland fire ignition, such as aboveground power lines. Furthermore, the proposed project would only require approximately one new AMWC operator to be present at the AMWC Corporation yard facility, which would be a minimal change as compared to baseline conditions. Goal SFN 4: Minimize the potential for loss of life and property resulting from geologic and seismic hazards. ▪ Policy 4.1: Ensure that developments, structures, and public facilities adequately address geologic and seismic hazards. ▪ Policy 4.2: Ensure that structures are designed and located to withstand strong groundshaking, liquefaction, and seismic settlement. Consistent. As discussed in Initial Study Checklist Section 7, Geology and Soils, the types of on-site soils (loose to medium dense sand at depths from approximately 20 to 38 feet below ground surface) and depth to groundwater (approximately 20 feet) result in vulnerability to liquefaction, and the project site has experienced liquefaction events in the past. However, the project would be designed and constructed in accordance with the recommendations of the geotechnical report, state and local building codes (e.g., California Building Code), and current seismic design standards to reduce the potential for exposure of structures and infrastructure to liquefaction risk to the maximum extent feasible. Incorporation of the ground improvement recommendations of the geotechnical report would densify the ground beneath the project site and minimize the potential for liquefaction within the alluvium by reducing the estimated seismic settlement to one inch or less during a design earthquake (Appendix C). Goal SFN 5. Reduce the potential for harm to individuals and damage to the environment from hazardous materials, radiation, electromagnetic fields, radon, and unsafe trees and structures. ▪ Policy 5.1: Reduce the potential for exposure to humans and the environment from hazardous substances. Consistent. As discussed in Initial Study Checklist Section 9, Hazards and Hazardous Materials, sodium hypochlorite (chlorine) and orthophosphate corrosion inhibitor would be stored at the proposed WTP in a completely enclosed structure with proper containment and venting. Chemical deliveries to the proposed facility would occur approximately one to two times a month, and these materials would be contained within vessels specifically engineered for safe storage. In accordance with standard operating practice, AMWC would submit an emergency response/contingency plan as part of a Hazardous Materials Business Plan to the California Environmental Reporting System for the proposed facility. Spent GAC cartridge filters, which may be considered a hazardous waste depending on the concentration of PFAS, would be removed every six to nine months by the cartridge filter supplier, who would be required to transport and dispose of the material in accordance with all applicable regulations, such as the Hazardous Materials Transportation Act, California Hazardous Material Management Act, and California Code of Regulations, Title 22. Initial Study Checklist Land Use and Planning Initial Study – Mitigated Negative Declaration 81 City of Atascadero General Plan Goals and Policies Project Consistency Goal SFN 6: Protect the citizens of Atascadero from the harmful and annoying effects of exposure to excessive noise. Goal SFN 8: Preserve the tranquility of residential areas by preventing the encroachment of noise- producing uses. Goal SFN 10: Avoid or reduce noise impacts through site planning and project design, giving second preference to the use of noise barriers and/or structural modifications to buildings containing noise- sensitive land uses. ▪ Policy 1: The noise standards in this chapter represent maximum acceptable noise levels. New development should minimize noise exposure and noise generation. ▪ Policy 5: Noise created by new proposed stationary noise sources or existing stationary noise sources which undergo modifications that may increase noise levels shall be mitigated so as not to exceed the noise level standards of Table IV-4 on lands designated for noise-sensitive uses. This policy does not apply to noise levels associated with agricultural operations. Consistent. The noise level standards provided in Table IV-4 of the Noise Element are the same as the noise limits outlined in AMC Section 9-14.05. As detailed in Initial Study Environmental Checklist Section 13, Noise, noise levels generated by the proposed stationary noise sources included in the project (e.g., pumps, HVAC equipment) would not exceed the noise limits established in the AMC and therefore would not exceed those in Table IV of the Noise Element. Source: City of Atascadero 2016 In light of the above discussion, with implementation of Mitigation Measures CR-1, CR-2, NOI-1, and NOI-2 to address impacts pertaining to cultural resources and nighttime construction noise, the project would not cause a significant environmental impact due to a conflict with the land use plans, policies, and regulations of the City adopted for the purpose of avoiding or mitigating an environmental effect. Impacts would be less than significant with mitigation incorporated. LESS THAN SIGNIFICANT WITH MITIGATION INCORPORATED Mitigation/Conclusion Implementation of Mitigation Measures CR-1 and CR-2, outlined in Initial Study Checklist Section 5, Cultural Resources, as well as Mitigation Measures NOI-1 and NOI-2, outlined in Initial Study Checklist Section 13, Noise, would be required to reduce impacts to land use and planning to less than significant. City of Atascadero Community Development Department Atascadero Mutual Water Company Water Treatment Plant Project 82 This page intentionally left blank. Initial Study Checklist Mineral Resources Initial Study – Mitigated Negative Declaration 83 12 Mineral Resources Potentially Significant Impact Less than Significant with Mitigation Incorporated Less-than - Significant Impact No Impact Would the project: a. Result in the loss of availability of a known mineral resource that would be of value to the region and the residents of the state? □ □ ■ □ b. Result in the loss of availability of a locally important mineral resource recovery site delineated on a local general plan, specific plan, or other land use plan? □ □ ■ □ Existing Setting The project site is located adjacent to the Salinas River, an area known for its abundant sand and gravel deposits, which are valuable for extraction (California Department of Conservation, Division of Mines and Geology 1989). The project site is not designated or zoned for mineral extraction, and the project site is not currently used for mineral extraction (City of Atascadero 2016). The project site is located in an area classified as Mineral Resource Zone 2 (MRZ-2) by the DOC (2023b).10 MRZ-2 areas are defined as lands where adequate information indicates that significant mineral deposits are present, or there is a high likelihood for their presence. These deposits, particularly for concrete- grade aggregate, are considered important for local and regional construction and infrastructure development. Proposed Project a. Would the project result in the loss of availability of a known mineral resource that would be of value to the region and the residents of the state? Although the project site is designated MRZ-2, the proposed project would not involve mineral extraction activities, and it would not preclude future mineral extraction within the designated MRZ- 2 area. In addition, the project would be developed within AMWC’s existing Corporation Yard facility and does not propose rezoning or changes in land use that would conflict with existing policies aimed at preserving access to mineral resources. Mineral resources on or adjacent to the project site would remain undisturbed and available for potential future extraction. Therefore, the project would not result in the loss of availability of a known mineral resource of value to the region or the state, and impacts would be less than significant. LESS-THAN-SIGNIFICANT IMPACT 10 Due to the scale of the maps, it is not feasible to precisely determine whether the project site is in MRZ-2. Therefore, to be conservative, this analysis assumes the project site is classified as MRZ-2. City of Atascadero Community Development Department Atascadero Mutual Water Company Water Treatment Plant Project 84 b. Would the project result in the loss of availability of a locally important mineral resource recovery site delineated on a local general plan, specific plan, or other land use plan? The project site is located within an area designated as Mineral Resource Zone 2 (MRZ-2), which indicates the presence of valuable mineral resources. As noted under threshold (a) of this section, the proposed project would not involve mineral extraction activities, and it would not preclude future mineral extraction within the designated MRZ-2 area. In addition, the project would be developed within AMWC’s existing Corporation Yard facility and does not propose rezoning or changes in land use that would conflict with existing policies aimed at preserving access to mineral resources. Mineral resources on or adjacent to the project site would remain undisturbed and available for potential future extraction. Therefore, the project would not result in the loss of availability of a locally important mineral resource recovery site as delineated in any local general plan, specific plan, or other land use plans, and impacts would be less than significant. LESS-THAN-SIGNIFICANT IMPACT Mitigation/Conclusion No significant impacts are expected. No mitigation is required. Initial Study Checklist Noise Initial Study – Mitigated Negative Declaration 85 13 Noise Potentially Significant Impact Less than Significant with Mitigation Incorporated Less-than - Significant Impact No Impact Would the project result in: a. Generation of a substantial temporary or permanent increase in ambient noise levels in the vicinity of the project in excess of standards established in the local general plan or noise ordinance, or applicable standards of other agencies? □ ■ □ □ b. Generation of excessive groundborne vibration or groundborne noise levels? □ □ ■ □ c. For a project located within the vicinity of a private airstrip or 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 expose people residing or working in the project area to excessive noise levels? □ □ □ ■ Existing Setting Sound is a vibratory disturbance created by a moving or vibrating source, which is capable of being detected by the hearing organs. Noise is defined as sound that is loud, unpleasant, unexpected, or undesired and may therefore be classified as a more specific group of sounds. Noise levels are commonly measured in decibels (dB) using the A-weighted sound pressure level (dBA). The A- weighting scale is an adjustment to the actual sound pressure levels so that they are consistent with the human hearing response. Decibels are measured on a logarithmic scale that quantifies sound intensity. A doubling of the energy of a noise source, such as doubling of traffic volume, would increase the noise level by 3 dB; dividing the energy in half would result in a 3 dB decrease (Crocker 2007). Human perception of noise has no simple correlation with sound energy: the perception of sound is not linear in terms of dBA or in terms of sound energy. Two sources do not “sound twice as loud” as one source. It is widely accepted that the average healthy ear can barely perceive changes of 3 dBA, increase or decrease (i.e., twice the sound energy); that a change of 5 dBA is readily perceptible (8 times the sound energy); and that an increase (or decrease) of 10 dBA sounds twice (half) as loud as what is readily perceptible (Crocker 2007). Sound changes occur in both level and frequency spectrum as it travels from the source to the receptor. The most obvious change is the decrease in level as the distance from the source increases. The manner by which noise reduces with distance depends on factors such as the type of sources (e.g., point or line, the path the sound will travel, site conditions, and obstructions). Noise City of Atascadero Community Development Department Atascadero Mutual Water Company Water Treatment Plant Project 86 levels from a point source typically attenuate, or drop off, at a rate of 6 dBA per doubling of distance (e.g., construction, industrial machinery, ventilation units). Noise from a line source (e.g., roadway, pipeline, railroad) typically attenuates at about 3 dBA per doubling of distance (Caltrans 2013). Noise levels may also be reduced by intervening structures; the amount of attenuation provided by this “shielding” depends on the size of the object and the frequencies of the noise levels. The impact of noise is not a function of loudness alone. The time of day when noise occurs, and the duration of the noise are also important factors of project noise impact. Most noise that lasts for more than a few seconds is variable in its intensity. Consequently, a variety of noise descriptors have been developed by academics and industry professionals. One of the most frequently used noise metrics is the equivalent noise level (Leq); it considers both duration and sound power level. Leq is defined as the single steady A-weighted level equivalent to the same amount of energy as that contained in the actual fluctuating levels over time. Noise that occurs at night tends to be more disturbing than that occurring during the day. The project site is within AMWC’s existing Corporation Yard facility. There are no substantial sources of noise within the project site itself. Existing sources of noise associated with AMWC’s Corporation Yard facility as a whole generally consist of HVAC equipment for the existing buildings, electrical motor noise from one or more of the four groundwater wells in the area, vehicle trips to and from the facility, the use of heavy equipment (e.g., backhoes, front-end loaders, dump trucks) to load trucks and handle materials, fabricating activities (e.g., welding, grinding) and handling of pipes and fittings, and infrequent routine testing of existing emergency generators. The existing ambient noise environment near the project site vicinity is comprised primarily of residential and commercial vehicle traffic, including trucks, buses, and autos traveling on local roadways. Motor vehicle noise is characterized by a high number of individual events that can create a sustained noise level in proximity to noise-sensitive uses. Roadways with the highest traffic volumes and speeds produce the highest noise levels. Near the project site, the main thoroughfare road and primary source of vehicular traffic noise is SR 41. Noise is also generated from vehicle traffic on Sycamore Road and Mercedes Avenue as well as railroad traffic on the adjacent railroad track. Noise- and vibration-sensitive land uses are locations where people reside or where the presence of unwanted sound and vibration could adversely affect the use of the land. The closest noise-sensitive receptors to the project site are residences located approximately 250 feet to the south and 300 feet to the west. Noise Standards The City’s Noise Ordinance is contained in AMC Chapter 14. AMC Section 9-14.03 states that noise created by construction activities are exempt from the provisions of the Noise Ordinance as long as the activities occur between 7:00 a.m. and 9:00 p.m. This section also exempts noise sources associated with work performed by private or public utilities in the maintenance or modification of its facilities. In addition, any mechanical device, apparatus or equipment used in relation to or connection with emergency activities or emergency work is exempt from the Noise Ordinance. AMC Section 9-14.05 establishes allowable exterior noise levels at noise-sensitive receptors (i.e., single- or multi-family residences, schools, hospitals, churches, and public libraries) in the city, which are shown in Table 10. These limits are used in the analysis to evaluate project impacts pertaining to construction noise generated between the hours of 9:00 p.m. and 7:00 a.m. (which is not exempt from compliance with the Noise Ordinance) and operational noise. Initial Study Checklist Noise Initial Study – Mitigated Negative Declaration 87 Table 10 Exterior Noise Limits Daytime (7:00 a.m. to 9:00 p.m.) Nighttime (9:00 p.m. to 7:00 a.m.) dB Leq (1-hour) 50 45 dB Lmax 70 65 dB = decibel; Leq = average noise level equivalent; Lmax = maximum instantaneous noise level Source: AMC Section 9-14.05 AMC Section 9-14.11 outlines procedures for obtaining an exception to the noise standards. The owner or operator of a noise source which the City’s Compliance Official has determined violates any of the provisions of this chapter may file an application with the Compliance Official for an exception from strict compliance with any particular provisions of this chapter where such an exception would not result in a hazardous condition or a nuisance and strict compliance would be unreasonable in view of all circumstances. The owner or operator would set forth all actions taken to comply with such provisions, and the reasons why immediate compliance cannot be achieved. Because the City does not have a daytime construction noise limit, the Federal Transit Administration’s (FTA) 2018 Transit Noise and Vibration Impact Assessment guidance document was used to evaluate construction noise levels. The guidance provides reasonable criteria for assessing construction noise impacts based on the potential for adverse community reaction, which are presented in Table 11. Table 11 FTA Daytime Construction Noise Criteria Receiving Land Use Noise Criterion (dBA Leq [8-hour]) Residential 80 Commercial 85 Industrial 90 dBA = A-weighted decibel; Leq = average noise level equivalent Source: FTA 2018 The City has not adopted vibration limits in the AMC or the City’s General Plan Noise Element. Therefore, FTA criteria for evaluating the potential for architectural damage to buildings, which are summarized in Table 12, are used in this analysis. Table 12 FTA Groundborne Vibration Criteria – Architectural Damage Building Category PPV (in/sec) I. Reinforced-concrete, steel, or timber (no plaster) 0.5 II. Engineered concrete and masonry (no plaster) 0.3 III. Non-engineered timber and masonry buildings 0.2 IV. Buildings extremely susceptible to vibration damage 0.12 PPV = peak particle velocity; in/sec = inches per second Source: FTA 2018 City of Atascadero Community Development Department Atascadero Mutual Water Company Water Treatment Plant Project 88 Proposed Project a. Would the project result in generation of a substantial temporary or permanent increase in ambient noise levels in the vicinity of the project in excess of standards established in the local general plan or noise ordinance, or applicable standards of other agencies? Construction Temporary noise levels caused by construction activity would be a function of the noise generated by construction equipment, the location and sensitivity of nearby land uses, and the timing and duration of noise-generating activities. Construction noise was estimated using the Federal Highway Administration (FHWA) Roadway Construction Noise Model Version 1.1. Construction equipment used in modeling was taken from the CalEEMod outputs, described further in Initial Study Checklist Section 3, Air Quality. Construction equipment would not all operate at the same time or location, and construction equipment would not be in constant use during the eight-hour operating day. It is assumed diesel engines would power all construction equipment. For a conservative analysis, construction noise was modeled from the closest portion of the project site boundary to the nearest residential property lines. DAYTIME CONSTRUCTION NOISE Table 13 presents estimated combined noise level from pieces of equipment assumed to generate the highest noise levels during daytime construction activities. As shown therein, daytime construction noise levels would reach up to 72 dBA Leq (8-hour), which would not exceed the FTA’s daytime construction noise limit of 80 dBA Leq (8-hour). Therefore, daytime construction activities would not generate a substantial temporary increase in ambient noise levels in the vicinity of the project site, and impacts would be less than significant. Table 13 Estimated Daytime Construction Noise Levels Construction Phase Estimated Noise Levels (dBA Leq [8-hour]) Residences to the West (300 feet) Residences to the South (250 feet) Residence to the Northeast (800 feet) Site Preparation2 70 72 61 Grading 70 71 61 Building Construction 70 71 61 Paving 69 71 60 Architectural Coating 58 60 50 Threshold1 80 80 80 Threshold Exceeded? No No No dBA = A-weighted decibel; Leq = average noise level equivalent 1 Source: FTA 2018 2 Rapid impact compaction activities conducted for geotechnical stabilization would generate similar noise levels as other site preparation activities (Rush Contractors Group 2025) and would occur as part of the site preparation phase but not concurrently with other site preparation activities (e.g., tree removal, site leveling). Therefore, it is not shown as a separate construction phase in the table. Roadway Construction Noise Model data sheets and assumptions are included in Appendix F. Initial Study Checklist Noise Initial Study – Mitigated Negative Declaration 89 NIGHTTIME CONSTRUCTION NOISE Occasional nighttime construction activities may be required between the hours of 9:00 p.m. and 7:00 a.m. for temperature-sensitive activities such as coating/painting and concrete placement events. It is conservatively assumed that a ready-mix concrete truck, generator, and excavator would be used simultaneously during nighttime construction activities. The exact location of nighttime construction activities within the project site is not known at this time; therefore, it was conservatively assumed to occur at the closest distance analyzed in Table 13 for each residence. Estimated nighttime construction noise levels are presented in Table 14; as shown therein, noise levels would reach up to 67 dBA Leq at the nearest residence to the south. Nighttime construction noise levels at the nearest residences would exceed the City’s nighttime exterior noise limit of 45 dBA Leq; therefore, nighttime construction noise impacts would be potentially significant. Implementation of Mitigation Measure NOI-1 would be required to reduce impacts related to nighttime construction noise to less than significant. Table 14 Estimated Nighttime Construction Noise Levels Construction Phase Estimated Noise Levels (dBA Leq) Residences to the West (300 feet) Residences to the South (250 feet) Residence to the Northeast (800 feet) Nighttime Activities (cement truck, generator, and excavator) 66 67 57 Threshold1 45 45 45 Threshold Exceeded? Yes Yes Yes dBA = A-weighted decibel; Leq = average noise level equivalent 1 Source: AMC Section 9-14.05 Roadway Construction Noise Model data sheets and assumptions are included in Appendix F. Operation On-site noise sources associated with the proposed project would include mechanical equipment operated by electric motors, specifically the pump station equipment and HVAC units. Distances were estimated using the location of the equipment on the preliminary site plan layout relative to nearby residences to the west, south, and northeast. HVAC noise levels were assumed to be generated from the center of the Operations Center building. To analyze noise impacts from the pump station and accompanying mechanical components, a reference noise level measured for a 100-horsepower pump at a water treatment plant was used (Padre Dam Municipal Water District 2015). This 100-horsepower pump had a sound power level of 93.2 dBA, which is equivalent to a sound pressure level (SPL) of 85.2 dBA Leq at a distance of three feet. This noise level was assumed for both the transfer pump station and the high-service pump station. To provide a conservative estimate of impacts, this analysis assumes the pumps would be operational 24 hours per day, 365 days per year. The size and type of HVAC unit is currently unknown at this stage of planning. Potential HVAC units used for the project could include a Carrier 50HCQA06, which generates a sound power level of 79 dBA, which is equivalent to 68.8 dBA Leq at three feet (detailed specifications are included in Appendix F). City of Atascadero Community Development Department Atascadero Mutual Water Company Water Treatment Plant Project 90 Estimated operational noise levels from the pump stations and HVAC units are presented in Table 15. As shown therein, combined operational noise levels would reach up to approximately 48 dBA Leq at the nearest residences, which would not exceed the City’s daytime exterior noise limit of 50 dBA Leq. However, the high service pump station would generate a noise level of 47 dBA Leq, and the cumulative operation of the transfer pump station, high service pump station, and HVAC units would exceed the City’s nighttime exterior noise limit of 45 dBA Leq at residences 250 feet south of the project site. Therefore, operation of the pump stations and HVAC equipment would generate a substantial permanent increase in ambient noise levels in the vicinity of the project site and impacts would be potentially significant. Implementation of Mitigation Measure NOI-2 would be required. Table 15 Estimated Operational Noise Levels Noise Source Distance to Receiver (feet) Residences to the West (dBA Leq) Distance to Receiver (feet) Residences to the South (dBA Leq) Distance to Receiver (feet) Residence to the Northeast (dBA Leq) Transfer Pump Station 435 42 500 41 1,080 <1 High Service Pump Station 715 38 250 47 1,030 <1 HVAC Units 400 26 420 26 1,200 17 Combined Noise Levels - 43 - 48 - 18 Thresholds (Daytime/ Nighttime)1 - 50/45 - 50/45 - 50/45 Thresholds Exceeded? (Daytime/ Nighttime) - No/No - No/Yes - No/No dBA = A-weighted decibel; Leq = average noise level equivalent 1 Source: AMC Section 9-14.05 Project operation would also include emergency generators that could operate at any time during a loss of electrical service from PG&E and would be tested as part of routine maintenance activities during normal business hours. Because AMWC is considered a private water utility, their maintenance activities are exempt from noise standards pursuant to AMC Section 9-14.03(g). In addition, the emergency generators would only be used outside of testing for emergency activities, which are also exempt from noise standards pursuant to AMC Section 9-14.03(b). Therefore, operation of the emergency generators would not generate a substantial permanent increase in ambient noise levels in the vicinity of the project site, and impacts would be less than significant. Furthermore, each emergency generator would be furnished with noise-attenuating devices such as silencer exhaust systems and noise dampening enclosures surrounding the natural gas-powered engine. Off-site Roadway Noise During project operation, AMWC staff, who are already stationed at the Corporation Yard, would visit the site approximately once per day for maintenance and operation activities. In addition, there Initial Study Checklist Noise Initial Study – Mitigated Negative Declaration 91 would be approximately two roundtrip delivery truck trips to the project site per month and one roundtrip truck trip per six months to remove spent cartridge filters. This minor amount of additional vehicle trips on nearby roadways would result in a negligible addition of roadway traffic noise. Therefore, the project would not generate a substantial permanent increase in ambient off- site roadway noise levels at the nearest sensitive receptors, and impacts would be less than significant. LESS THAN SIGNIFICANT WITH MITIGATION INCORPORATED b. Would the project result in generation of excessive groundborne vibration or groundborne noise levels? Construction activities at the project site have the potential to generate low levels of groundborne vibration because the operation of heavy equipment (e.g., dozers, rollers, loaded trucks) generates vibrations that propagate though the ground and diminish in intensity with distance from the source. The greatest anticipated sources of vibration during project construction would be a vibratory roller used for consolidating structural backfill and the rapid impact compaction equipment11 for performing deep ground improvements. This equipment may be used within 250 feet of the nearest residential structure to the west. A vibratory roller would generate a vibration level of 0.21 peak particle velocity (PPV) inches per second (in/sec) at a distance of 25 feet; vibration from the roller would attenuate to 0.007 PPV in/sec at a distance of 250 feet. This level of vibration would be well below the FTA’s vibration damage potential threshold for non-engineered timber and masonry building structures of 0.2 PPV in/sec (see Table 12). Therefore, project construction would not generate excessive groundborne vibration or groundborne noise levels, and impacts would be less than significant. The proposed project does not include any substantial vibration sources associated with operation, such as railroad or subway lines. As a result, project operation would not generate excessive groundborne vibration or groundborne noise levels, and no impact would occur. LESS-THAN-SIGNIFICANT IMPACT c. For a project located within the vicinity of a private airstrip or 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 expose people residing or working in the project area to excessive noise levels? The airstrip/airport nearest to the project site is the Santa Margarita Ranch Airport, a private airstrip located approximately seven miles to the south of the project site. Given the small size of the airstrip and the large distance between the project site and the airstrip, the project would not expose people residing or working in the project area to excessive noise levels associated with this airport. No impact would occur. NO IMPACT 11 Rapid impact compaction activities conducted for geotechnical stabilization would generate a vibration level of approximately 0.05 to 0.2 inches per second at a distance of 100 feet, which would be less than that of a vibratory roller (Rush Contractors Group 2025). City of Atascadero Community Development Department Atascadero Mutual Water Company Water Treatment Plant Project 92 Mitigation/Conclusion Mitigation Measures NOI-1 AMWC shall require its construction contractor(s) to reduce construction noise levels to at or below 45 dBA Leq (1-hour) at the nearest residences during any construction activities occurring between 9:00 p.m. and 7:00 a.m. (i.e., during necessary nighttime construction operations). Strategies to achieve this may include, but are not limited to, the following noise reduction measures: ▪ Staging and delivery areas shall be located as far as feasible from residences. ▪ Material hauling and deliveries shall be coordinated by the construction contractor to reduce the potential for nighttime truck trips. ▪ Whenever feasible, nighttime construction activities should be scheduled to avoid operating several pieces of heavy equipment simultaneously. ▪ Temporary sound barriers/blankets shall be installed between heavy construction equipment used during the nighttime hours and the residences to the east, south, and northwest. The barriers shall be at least 1.5 pounds per square foot with no gaps from the ground to the top of the barrier. As an alternative, if sound blankets are preferred, barriers shall be constructed with solid material with a density of at least 1 pound per square foot with no gaps from the ground to the top of the barrier and be lined on the construction side with acoustical blanket, curtain or equivalent absorptive material rated sound transmission class (STC) 32 or higher. ▪ To the extent consistent with applicable safety regulations, trucks operating at nighttime with reverse motions alarms shall be outfitted with SAE J994 Class D or equivalent alarms (ambient- adjusting, or “smart alarms” that automatically adjust the alarm to 5 dBA above the ambient noise level near the operating equipment), or back-up alarms shall be switched off and replaced with human spotters in compliance with all safety requirements and laws. Documentation of the noise control strategies implemented to reduce construction noise levels to at or below 45 dBA Leq (1-hour) at the nearest residences shall be provided to the City prior to initiating nighttime construction activities. In addition, AMWC shall implement the following measures: ▪ At least 21 days prior to the start of nighttime construction activities, off-site residents within 1,000 feet of the proposed night work shall be notified of the planned construction activities. The written notification shall include a brief description of the project, the nighttime activities that would occur, the hours when nighttime construction would occur, and the nighttime construction period’s overall duration. The notification shall include the telephone numbers of AMWC’s and the contractor’s authorized representatives that are assigned to respond in the event of a noise complaint. In addition, a construction notification sign shall be posted at the job site, clearly visible to the public, that includes telephone numbers of AMWC’s and the contractor’s authorized representatives that are assigned to respond in the event of a noise complaint. Documentation of the resident notification and the construction notification sign shall be provided to the City prior to the start of nighttime construction activities. ▪ If a noise complaint(s) is registered regarding nighttime construction, the contractor shall retain a qualified noise consultant to conduct noise measurements at the properties that registered the complaint. The noise measurements shall be conducted for a minimum of one hour during nighttime construction. The consultant shall prepare a letter report for AMWC and the City Initial Study Checklist Noise Initial Study – Mitigated Negative Declaration 93 summarizing the measurement results and potential measures to reduce nighttime noise to 45 dBA Leq (1-hour) at residences. AMWC and its contractor(s) shall implement the measure(s) identified in the letter report as necessary to reduce nighttime noise to 45 dBA Leq (1-hour) at residences through the duration of nighttime construction. Following the installation of the noise reduction measure(s), the City shall visit the project site to confirm the noise reduction measure(s) identified in the letter report have been properly implemented. Documentation of the measures implemented shall be provided to the City prior to resuming nighttime construction activities. ▪ A request for extended construction hours shall be obtained at least 3 days prior to early/late construction activities, in accordance with AMC Section 9-14.11. NOI-2 Upon the completion of construction but prior to the City’s final inspection, AMWC shall retain a qualified noise consultant to conduct noise measurements generated during full WTP operations at the nearest residential properties during nighttime hours (9:00 p.m. to 7:00 a.m.). If noise levels exceed the City’s nighttime exterior noise limit of 45 dBA Leq, AMWC shall install a solid barrier around the southern portion of the high service pump station, tall enough to break the line of sight between the noise-generating equipment and the closest residences, prior to the City’s final inspection. The barrier/enclosure shall be constructed of a material with a minimum weight of four pounds per square foot with no gaps or perforations to the south. The barrier may be constructed of, but is not limited to, masonry block, concrete panels, 1/8-inch-thick steel sheets, 1-1/2 inch-thick wood fencing, or 1/4-inch-thick glass panels. If wood is used as the primary barrier component, the fence boards shall overlap or be of “tongue and groove” construction with a joining compound between the boards, battens, or require the use of sealant to ensure there are no gaps or holes in the fence. Annual inspection and maintenance shall be conducted for the life of the project to ensure the barrier continues to perform to the minimum requirements. Significance After Mitigation Implementation of Mitigation Measure NOI-1 would require the use of several noise reduction measures for nighttime construction noise, including resident notification, a noise complaint hotline, and noise attenuation measures, which would reduce construction noise at nearby residences to at or below the City’s nighttime exterior noise limit of 45 dBA Leq (1-hour) at the nearest residences. Implementation of Mitigation Measure NOI-1 would reduce project impacts related to nighttime construction noise to a less-than-significant level. Implementation of Mitigation Measure NOI-2 would require installation of a barrier to reduce noise generated by the high service pump station should measured operational noise levels exceed the City’s nighttime exterior noise limit. Table 16 presents the reduction in operational noise levels that would occur from implementation of Mitigation Measure NOI-2. City of Atascadero Community Development Department Atascadero Mutual Water Company Water Treatment Plant Project 94 Table 16 Estimated Operational Noise Levels - Mitigated Noise Level at Residences to the South (dBA Leq) Noise Reduction Measure Transfer Pump Station High Service Pump Station (Mitigated) HVAC Units Combined Construction of a solid barrier around the southern portion of the high service pump station 41 12 26 41 Thresholds (Daytime/ Nighttime)1 -- -- -- 50/45 Thresholds Exceeded? (Daytime/ Nighttime) -- -- -- No dBA = A-weighted decibel; Leq = average noise level equivalent 1 Source: AMC Section 9-14.05 Source: Appendix F; FHWA 2011 As shown in Table 16, with implementation of Mitigation Measure NOI-2, combined operational noise levels would be reduced such that they would not exceed the City’s nighttime exterior noise limit of 45 dBA Leq at residences 250 feet south of the project site. Therefore, implementation of Mitigation Measure NOI-2 would reduce operational noise impacts to a less-than-significant level. Initial Study Checklist Population and Housing Initial Study – Mitigated Negative Declaration 95 14 Population and Housing Potentially Significant Impact Less than Significant with Mitigation Incorporated Less-than - Significant Impact No Impact Would the project: a. Induce substantial unplanned population growth in an area, either directly (e.g., by proposing new homes and businesses) or indirectly (e.g., through extension of roads or other infrastructure)? □ □ □ ■ b. Displace substantial numbers of existing people or housing, necessitating the construction of replacement housing elsewhere? □ □ □ ■ Existing Setting The project site is located in Atascadero adjacent to a residential area characterized by a mix of single-family homes and multi-family dwellings. There are no residences within the project site. The city has experienced modest population growth in recent years, maintaining a balance between preserving its small-town charm and accommodating new residents. Atascadero’s current population is approximately 29,773, which is expected to increase to 32,907 residents in 2050 (San Luis Obispo Council of Governments 2017; United States Census Bureau 2024). Atascadero's General Plan emphasizes sustainable growth and development that aligns with the community's character (City of Atascadero 2016). Proposed Project a. Would the project induce substantial unplanned population growth in an area, either directly (for example, by proposing new homes and businesses) or indirectly (for example, through extension of roads or other infrastructure)? The proposed project would not result in the construction of new homes and therefore would not directly induce substantial unplanned population growth. The project consists of a groundwater treatment facility and would not represent a new water supply source but would rather provide treatment of an existing groundwater supply source. The proposed project would not be utilized to increase the amount of water currently being supplied to existing customers or to provide water to areas currently not serviced by AMWC. Rather, the project would enable AMWC to continue providing water supplies to its existing customers and supplying water to future development in Atascadero as anticipated by the City’s General Plan (2016) and AMWC’s 2020 Urban Water Management Plan (2021). As such, the proposed project would not increase water supply such that it would facilitate the development of land that previously could not be developed due to water service constraints. In addition, project operation would only require approximately one new AMWC employee, who would likely be sourced from the existing local or regional workforce. Therefore, the City of Atascadero Community Development Department Atascadero Mutual Water Company Water Treatment Plant Project 96 project would not induce substantial unplanned population growth in the area, either directly or indirectly, and no impact would occur. NO IMPACT b. Would the project displace substantial numbers of existing people or housing, necessitating the construction of replacement housing elsewhere? The project site is located on previously disturbed land within AMWC’s Corporation Yard facility and does not contain existing housing or residential units. In addition, the project site is designated for industrial use, and the proposed project would not result in any changes to housing availability or create a demand for additional housing elsewhere. Therefore, the project would not displace substantial numbers of existing people or housing, necessitating the construction of replacement housing elsewhere, and no impact would occur. NO IMPACT Mitigation/Conclusion No impacts are expected. No mitigation is required. Initial Study Checklist Public Services Initial Study – Mitigated Negative Declaration 97 15 Public Services Potentially Significant Impact Less than Significant with Mitigation Incorporated Less-than - Significant Impact No Impact a. Would the project result in substantial adverse physical impacts associated with the provision of new or physically altered governmental facilities, or the need for new or physically altered governmental facilities, the construction of which could cause significant environmental impacts, in order to maintain acceptable service ratios, response times or other performance objectives for any of the public services: 1 Fire protection? □ □ □ ■ 2 Police protection? □ □ □ ■ 3 Schools? □ □ □ ■ 4 Parks? □ □ □ ■ 5 Other public facilities? □ □ □ ■ Existing Setting Fire protection and emergency services in the project site vicinity are provided by the Atascadero Fire & Emergency Services Department, with the nearest fire station located approximately 0.8 mile southwest of the project site. Law enforcement is provided by the Atascadero Police Department, which operates from a central station about 1.0 mile to the southwest. Atascadero Unified School District is the local school district, and the nearest schools are Atascadero Middle School/Atascadero Adult School and Atascadero Fine Arts Academy, both located approximately 0.8 mile southwest of the project site. Nearby parks include Atascadero Lake Park and Paloma Creek Park, which provide various of for community recreation, and the Atascadero Public Library is located about 0.8 mile south of the project site. Proposed Project a.1. Would the project result in substantial adverse physical impacts associated with the provision of new or physically altered fire protection facilities, or the need for new or physically altered fire protection facilities, the construction of which could cause significant environmental impacts, in order to maintain acceptable service ratios, response times or other performance objectives? City of Atascadero Community Development Department Atascadero Mutual Water Company Water Treatment Plant Project 98 a.2. Would the project result in substantial adverse physical impacts associated with the provision of new or physically altered police protection facilities, or the need for new or physically altered police protection facilities, the construction of which could cause significant environmental impacts, in order to maintain acceptable service ratios, response times or other performance objectives? a.3. Would the project result in substantial adverse physical impacts associated with the provision of new or physically altered schools, or the need for new or physically altered schools, the construction of which could cause significant environmental impacts, in order to maintain acceptable service ratios or other performance objectives? a.4. Would the project result in substantial adverse physical impacts associated with the provision of new or physically altered parks, or the need for new or physically altered parks, the construction of which could cause significant environmental impacts, in order to maintain acceptable service ratios or other performance objectives? a.5. Would the project result in substantial adverse physical impacts associated with the provision of other new or physically altered public facilities, or the need for other new or physically altered public facilities, the construction of which could cause significant environmental impacts, in order to maintain acceptable service ratios, response times or other performance objectives? As discussed in Initial Study Checklist Section 14, Population and Housing, the proposed project would not directly or indirectly induce population growth that may increase demand for fire protection services, police protection services, schools, parks, or other public facilities. The proposed project would not include features or facilities requiring additional or unusual fire protection resources during operation. In addition, the project would include security measures that would minimize the need for additional police protection services, such as perimeter fencing and access gates as well as security cameras. Therefore, no impact to public services would occur. NO IMPACT Mitigation/Conclusion No impacts are expected. No mitigation is required. Initial Study Checklist Recreation Initial Study – Mitigated Negative Declaration 99 16 Recreation Potentially Significant Impact Less than Significant with Mitigation Incorporated Less-than - Significant Impact No Impact a. Would the project increase the use of existing neighborhood and regional parks or other recreational facilities such that substantial physical deterioration of the facility would occur or be accelerated? □ □ □ ■ b. Does the project include recreational facilities or require the construction or expansion of recreational facilities which might have an adverse physical effect on the environment? □ □ □ ■ Existing Setting Atascadero is home to a variety of parks, open spaces, and recreational facilities that cater to a wide range of outdoor activities. The project site does not contain parks or recreational facilities, and the nearest park or recreational facility is the Traffic Way Park, located approximately 0.6 miles southwest of the project site. Proposed Project a. Would the project increase the use of existing neighborhood and regional parks or other recreational facilities such that substantial physical deterioration of the facility would occur or be accelerated? b. Does the project include recreational facilities or require the construction or expansion of recreational facilities which might have an adverse physical effect on the environment? As discussed in Initial Study Checklist Section 14, Population and Housing, the proposed project would neither directly nor indirectly induce population growth that would increase demand for parks and recreational facilities. In addition, the proposed project does not include recreational facilities, and it does not require the construction or expansion of recreational facilities. Therefore, the project would not increase the use of existing neighborhood and regional parks or other recreational facilities such that substantial physical deterioration of the facility would occur or be accelerated or include recreational facilities or require the construction or expansion of recreational facilities which might have an adverse physical effect on the environment. No impacts would occur. NO IMPACT Mitigation/Conclusion No impacts are expected. No mitigation is required. City of Atascadero Community Development Department Atascadero Mutual Water Company Water Treatment Plant Project 100 This page intentionally left blank. Initial Study Checklist Transportation Initial Study – Mitigated Negative Declaration 101 17 Transportation Potentially Significant Impact Less than Significant with Mitigation Incorporated Less-than - Significant Impact No Impact Would the project: a. Conflict with a program, plan, ordinance or policy addressing the circulation system, including transit, roadway, bicycle and pedestrian facilities? □ □ ■ □ b. Conflict or be inconsistent with CEQA Guidelines section 15064.3, subdivision (b)? □ □ □ ■ c. Substantially increase hazards due to a geometric design feature (e.g., sharp curves or dangerous intersections) or incompatible use (e.g., farm equipment)? □ □ □ ■ d. Result in inadequate emergency access? □ □ □ ■ Existing Setting The project site is accessible via Sycamore Road, and other nearby roadways include Capistrano Road and SR 41, which provides regional connectivity. The project site is located on a local, two-lane road with no bicycle, pedestrian, or transit facilities along the project site frontage. The Union Pacific Railroad runs parallel to Sycamore Road south of the project site. Proposed Project a. Would the project conflict with a program, plan, ordinance or policy addressing the circulation system, including transit, roadway, bicycle and pedestrian facilities? Regional and local plans and policies addressing the circulation system include the San Luis Obispo Council of Governments’ 2023 Regional Transportation Plan and the City of Atascadero’s General Plan Circulation Element. Access to the project site during construction would be provided by Sycamore Road. Project construction would require construction-related vehicle trips including construction workers traveling to and from the project site, haul trucks (including for export of demolished and excavated materials), and other trucks associated with equipment, material, and concrete deliveries. Construction-related traffic would be short-term and would cease upon completion of construction activities. In addition, no lane or road closures would be required during project construction. Project operation would require a daily visit for an AMWC operator as part of existing rounds in the area and chemical deliveries to the WTP via 45-foot semi-trailers approximately one to two times each month. Furthermore, the project does not propose significant changes to the existing roadway infrastructure. As such, the project would not interfere with the policies of the City of Atascadero’s General Plan Circulation Element, including Policy 1.2, which aims to minimize through-traffic on local streets by maintaining regional connections, such as SR 41, City of Atascadero Community Development Department Atascadero Mutual Water Company Water Treatment Plant Project 102 for higher traffic volumes, and Policy 2.1, which calls for a comprehensive system of trails, pathways, and bikeways to connect neighborhoods, schools, commercial, and recreational areas (City of Atascadero 2016). Given the minimal number of trips generated, project construction and operation would not conflict with a program, plan, ordinance or policy addressing the circulation system, and impacts would be less than significant. LESS-THAN-SIGNIFICANT IMPACT b. Would the project conflict or be inconsistent with CEQA Guidelines section 15064.3, subdivision (b)? CEQA Guidelines Section 15064.3(b) identifies criteria for evaluating transportation impacts. Specifically, the guidelines state vehicle miles traveled (VMT) exceeding an applicable threshold of significance may indicate a significant impact. According to CEQA Guidelines Section 15064.3(b)(3), a lead agency may include a qualitative analysis of operational and construction traffic if existing models or methods are not available to estimate the VMT for the particular project being considered. A VMT calculation is typically conducted on a daily or annual basis to determine operational usage of a project. Such a qualitative analysis would evaluate factors such as the availability of transit, proximity to other destinations, etc. Neither the City of Atascadero nor SLOCOG has adopted VMT thresholds. A VMT calculation is typically conducted on a daily or annual basis for long-range planning purposes. Construction of the proposed project would result in a minimal, short-term increase in local VMT as a result of construction-related worker traffic, material and equipment deliveries, and hauling of demolished material and soil. However, increases in VMT from construction would be short-term, minimal, and temporary. The Governor’s Office of Planning and Research Technical Advisory on Evaluating Transportation Impacts in CEQA (2018) states, “Projects that generate or attract fewer than 110 trips per day generally may be assumed to cause a less-than-significant VMT impact.”. As discussed under threshold 17(a), the project would require one daily AMWC operator visit as part of existing staff rounds as well as chemical deliveries approximately one to two times each month, which would result in a minimal increase in VMT in the area. Given the limited scope of these activities, the project would not exceed the VMT screening level of 110 trips per day. Therefore, the project would not conflict or be inconsistent with CEQA Guidelines Section 15064.39b), and no impact would occur. NO IMPACT c. Would the project substantially increase hazards due to a geometric design feature (e.g., sharp curves or dangerous intersections) or incompatible use (e.g., farm equipment)? The proposed project would involve the construction of an improved facility driveway along Sycamore Road. The turn onto the driveway would have a slight curve, and design would be required to comply with the City’s safety standards, including AT-414 for minimum sight distances and AT-423 for driveway approaches (City of Atascadero 2024). These standards ensure safe access and egress, reducing potential hazards associated with geometric design features. The driveway would be utilized by AMWC staff and delivery vehicles and would not be open to the public. In addition, daily AMWC operator visits and periodic chemical deliveries would not be incompatible Initial Study Checklist Transportation Initial Study – Mitigated Negative Declaration 103 uses of Sycamore Road. Therefore, the project would not substantially increase hazards due to a geometric design feature or incompatible use, and no impact would occur. NO IMPACT d. Would the project result in inadequate emergency access? The proposed project would not require any temporary lane or road closures that could impede emergency access during construction. In addition, the project includes construction of an improved driveway on Sycamore Road, which would enhance ingress/egress to the facility in the event of an emergency. Therefore, the project would not result in inadequate emergency access, and no impact would occur. NO IMPACT Mitigation/Conclusion No impacts are expected. No mitigation is required. City of Atascadero Community Development Department Atascadero Mutual Water Company Water Treatment Plant Project 104 This page intentionally left blank. Initial Study Checklist Tribal Cultural Resources Initial Study – Mitigated Negative Declaration 105 18 Tribal Cultural Resources Potentially Significant Impact Less than Significant with Mitigation Incorporated Less-than - Significant Impact No Impact Would the project cause a substantial adverse change in the significance of a tribal cultural resource, defined in a Public Resources Code Section 21074 as either a site, feature, place, or 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: a. 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)? □ ■ □ □ b. 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. □ ■ □ □ Existing Setting Tribal cultural resources are defined in Public Resources Section 21074(a)(1)(A-B) as sites, features, places, cultural landscapes, sacred places, and objects with cultural value to a California Native American tribe that are either: ▪ Included or determined to be eligible for inclusion in the California Register of Historical Resources; and/or ▪ Included in a local register of historical resources as defined in Public Resources Section 5020.1(k). AB 52 establishes a formal consultation process for California tribes regarding those resources. The consultation process must be completed before a CEQA document can be adopted or certified. Under AB 52, lead agencies are required to “begin consultation with a California Native American tribe that is traditionally and culturally affiliated with the geographic area of the proposed project,” City of Atascadero Community Development Department Atascadero Mutual Water Company Water Treatment Plant Project 106 specifically with those Native American tribes that have requested notice of projects proposed within the jurisdiction of the lead agency. Consultation begins with a written notification that must include a brief description of the proposed project, the project location, the CEQA lead agency contact information, and notification that the California Native American Tribe has 30 days to request consultation. Upon receipt of a written response from a California Native American Tribe requesting consultation, the CEQA lead agency and the California Native American Tribe requesting consultation shall begin the AB 52 process. The City circulated AB 52 consultation letters for the proposed project, including project information, map, and contact information, to the following Native American tribes on September 25, 2024: ▪ Barbareño/Ventureño Band of Mission Indians ▪ Chumash Council of Bakersfield ▪ Coastal Band of the Chumash Nation ▪ Northern Chumash Tribal Council ▪ Salinan Tribe of Monterey, San Luis Obispo Counties ▪ Santa Ynez Band of Chumash Indians ▪ Tule River Indian Tribe ▪ Xolon-Salinan Tribe ▪ yak tityu tityu yak tiłhini – Northern Chumash Tribe The Santa Ynez Band of Chumash Indians responded via email with a letter dated October 15, 2024, stating the Tribe would not request consultation, requesting to be notified if supplementary literature reveals additional information or if the scope of the project changes, and requesting to be contacted if the City decides to have a Native American monitor in place during ground disturbance. The Salinan Tribe of Monterey, San Luis Obispo Counties responded via email on November 1, 2024, requesting to participate in cultural resource monitoring for the project. The City did not receive any requests for consultation. Proposed Project a. Would the project cause a substantial adverse change in the significance of a tribal cultural resource as defined in Public Resources Code Section 21074 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)? b. Would the project cause a substantial adverse change in the significance of a tribal cultural resource as defined in Public Resources Code 21074 that is 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? No Tribes requested consultation in response to the City’s AB 52 consultation letters, and no tribal cultural resources listed or eligible for listing in the California Register of Historical Resources, listed or eligible for listing in a local register of historical resources as defined in Public Resources Code Section 5020.1(k), or determined significant by the City as lead agency were identified. However, as discussed in Initial Study Checklist Section 5, Cultural Resources, there remains a possibility that unanticipated Native American cultural materials could be encountered during ground-disturbing Initial Study Checklist Tribal Cultural Resources Initial Study – Mitigated Negative Declaration 107 activities (Rincon 2024). Therefore, impacts to tribal cultural resources would be potentially significant, and implementation of Mitigation Measures CR-1 and CR-2 would be required to reduce impacts to a less-than-significant level. LESS THAN SIGNIFICANT WITH MITIGATION INCORPORATED Mitigation/Conclusion Mitigation Measures Implementation of Mitigation Measures CR-1 and CR-2, outlined in Initial Study Checklist Section 5, Cultural Resources would be required to reduce impacts to tribal cultural resources to less than significant. Significance after Mitigation Implementation of Mitigation Measures CR-1 and CR-2 would minimize potential impacts to unanticipated discoveries of tribal cultural resources by requiring Native American monitoring of ground disturbing activities, and implementation of appropriate procedures for evaluation and treatment of any unanticipated discoveries of cultural resources made during construction. Therefore, implementation of Mitigation Measures CR-1 and CR-2 would reduce potential impacts to tribal cultural resources to a less-than-significant level. City of Atascadero Community Development Department Atascadero Mutual Water Company Water Treatment Plant Project 108 This page intentionally left blank. Initial Study Checklist Utilities and Service Systems Initial Study – Mitigated Negative Declaration 109 19 Utilities and Service Systems Potentially Significant Impact Less than Significant with Mitigation Incorporated Less-than - Significant Impact No Impact Would the project: a. Require or result in the relocation or construction of new or expanded water, wastewater treatment or storm water drainage, electric power, natural gas, or telecommunications facilities, the construction or relocation of which could cause significant environmental effects? □ □ ■ □ b. Have sufficient water supplies available to serve the project and reasonably foreseeable future development during normal, dry and multiple dry years? □ □ □ ■ c. Result in a determination by the wastewater treatment provider which serves or may serve the project that it has adequate capacity to serve the project’s projected demand in addition to the provider’s existing commitments? □ □ ■ □ d. Generate solid waste in excess of State or local standards, or in excess of the capacity of local infrastructure, or otherwise impair the attainment of solid waste reduction goals? □ □ ■ □ e. Comply with federal, state, and local management and reduction statutes and regulations related to solid waste? □ □ ■ □ Existing Setting The project site is supported by a variety of utility and service systems, including water supply, wastewater treatment, stormwater management, solid waste collection, electricity, and natural gas. Water service is provided by AMWC, which draws from local groundwater wells. The project site itself is within AMWC’s Corporation Yard facility, which contains AMWC’s production wells adjacent to the Salinas River between SR 41 and Chico Road. Wastewater generated by AMWC’s Corporation Yard facility is discharged to an existing leach field within the property that was installed in 2009. Stormwater is managed through a combination of natural drainage features and a constructed stormwater infrastructure network. Solid waste and recycling collection and disposal services are provided by WM (formerly known as Waste Management), with materials taken to the Chicago Grade Landfill, east of Atascadero. Electricity service is supplied by Pacific Gas and Electric (PG&E), City of Atascadero Community Development Department Atascadero Mutual Water Company Water Treatment Plant Project 110 natural gas service is supplied by Southern California Gas Company, and Spectrum/Charter Communications provides telecommunications services (e.g., internet, televisions, and phone). Proposed Project a. Would the project require or result in the relocation or construction of new or expanded water, wastewater treatment or storm water drainage, electric power, natural gas, or telecommunications facilities, the construction or relocation of which could cause significant environmental effects? Water The project consists of the construction of groundwater treatment infrastructure, the environmental effects of which are analyzed throughout this document. No additional impacts related to water facilities would occur beyond the impacts identified herein. Therefore, the project would not result in the construction or relocation of additional new or expanded water facilities. No impact would occur. Wastewater Treatment The project includes the construction of a restroom within the proposed Operations Center building, which would connect to a new septic tank adjacent to the Operation Center building, and septic tank effluent would flow into an existing leach field within the AMWC Corporation Yard facility. The environmental effects of this project component are analyzed throughout this document, and no additional impacts related to wastewater facilities would occur beyond the impacts identified herein. Therefore, the project would not result in the construction or relocation of additional new or expanded wastewater facilities. No impact would occur. Stormwater Drainage As discussed in Initial Study Checklist Section 10, Hydrology and Water Quality, the proposed project would introduce approximately 3.5 acres of new impervious surfaces to the project site. Post- construction stormwater runoff from the project site would be directed to the existing on-site stormwater detention basins, where it would be allowed to percolate back into the underlying groundwater. The project would also be required to comply with the requirements of the City’s Stormwater Control Plan for Post Construction Requirements (2014), which would minimize the net increase in stormwater runoff from the project site. As such, the project would not result in the construction or relocation of new or expanded stormwater drainage facilities, and impacts would be less than significant. Electric Power As discussed in Initial Study Checklist Section 6, Energy, project operation would increase annual electricity consumption at the project site by approximately 4,420 MWh. However, no new or expanded electric power facilities beyond what is currently installed at the project site would be required. Therefore, impacts would be less than significant. Natural Gas The project would involve the periodic use of emergency generators powered by natural gas, which would require a new natural gas connection, and the use of natural gas to power HVAC equipment Initial Study Checklist Utilities and Service Systems Initial Study – Mitigated Negative Declaration 111 in the Operations Center building. However, no new or expanded natural gas facilities beyond what is currently installed at the project site would be required. Therefore, impacts would be less than significant. Telecommunications The project would involve the installation of a self-supporting tower assembly to support SCADA communications. The environmental impacts of this infrastructure have been evaluated throughout this document, and no additional environmental impacts would occur. Therefore, the project would not result in the construction or relocation of additional new or expanded telecommunications facilities. No impact would occur. LESS-THAN-SIGNIFICANT IMPACT b. Would the project have sufficient water supplies available to serve the project and reasonably foreseeable future development during normal, dry and multiple dry years? AMWC has a diverse water supply portfolio, as outlined in its Urban Water Management Plan (2021), which includes a combination of groundwater, imported water, and recycled water sources to ensure a reliable supply for its customers. The proposed project consists of a groundwater treatment facility and would not represent a new water supply source but would rather provide treatment of an existing groundwater supply source. The proposed project would not be utilized to increase the amount of water currently being supplied to existing customers or to provide water to areas currently not serviced by AMWC. The project would enable AMWC to continue providing drinking water supplies to Atascadero during normal, dry, and multiple dry years. Therefore, no impacts would occur. NO IMPACT c. Would the project result in a determination by the wastewater treatment provider which serves or may serve the project that it has adequate capacity to serve the project’s projected demand in addition to the provider’s existing commitments? Wastewater generated by the new restroom in the proposed Operations Center Building during project operation would be conveyed to the proposed septic tank, then discharged to the existing leach field within the AMWC Corporation Yard facility. As discussed in Section 7, Geology and Soils, the existing leach field has sufficient excess capacity to accommodate the additional wastewater flows generated by the new restroom. Therefore, the project would not require a connection to the City’s wastewater conveyance and treatment system, and the project would not have the potential to cause an exceedance of the capacity of the City’s Wastewater Treatment Plant. Therefore, no impact would occur. NO IMPACT d. Would the project generate solid waste in excess of State or local standards, or in excess of the capacity of local infrastructure, or otherwise impair the attainment of solid waste reduction goals? e. Would the project comply with federal, state, and local management and reduction statutes and regulations related to solid waste? The Chicago Grade Landfill is located approximately 1.7 miles northwest of the project site and has a permitted capacity of 10.5 million cubic yards. As of July 2022, the remaining capacity at the landfill City of Atascadero Community Development Department Atascadero Mutual Water Company Water Treatment Plant Project 112 was approximately 4.2 million cubic yards. Chicago Grade Landfill accepts a variety of waste, including inert, industrial, construction/ demolition, green materials, and mixed municipal waste (California Department of Resources Recycling and Recovery 2024). Project construction would temporarily generate solid waste, including soil spoils or other construction waste, which would be disposed of in accordance with all applicable federal, state, and local statutes and regulations at the Chicago Grade Landfill. Due to the temporary nature of construction and minimal amount of construction waste anticipated to require disposal, the project would not generate quantities of solid waste that would account for a substantial percentage of the total daily regional permitted capacity available at the Chicago Grade Landfill. In addition, any hazardous materials would be disposed of at a licensed hazardous waste disposal facility. The project would be required to comply with all applicable laws and regulations related to solid waste generation, collection, and disposal. Therefore, the project would not generate solid waste in excess of state or local standards, or in excess of the capacity of local infrastructure, or otherwise impair the attainment of solid waste reduction goals and would comply with federal, state, and local management and reduction statutes and regulations related to solid waste. Therefore, impacts to solid waste would be less than significant. LESS-THAN-SIGNIFICANT IMPACT Mitigation/Conclusion No significant impacts are expected. No mitigation is required. Initial Study Checklist Wildfire Initial Study – Mitigated Negative Declaration 113 20 Wildfire Potentially Significant Impact Less than Significant with Mitigation Incorporated Less-than - Significant Impact No Impact If located in or near state responsibility areas or lands classified as very high fire hazard severity zones, would the project: a. Substantially impair an adopted emergency response plan or emergency evacuation plan? □ □ □ ■ b. Due to slope, prevailing winds, and other factors, exacerbate wildfire risks and thereby expose project occupants to pollutant concentrations from a wildfire or the uncontrolled spread of a wildfire? □ □ ■ □ c. Require the installation or maintenance of associated infrastructure (such as roads, fuel breaks, emergency water sources, power lines or other utilities) that may exacerbate fire risk or that may result in temporary or ongoing impacts to the environment? □ □ □ ■ d. Expose people or structures to significant risks, including downslopes or downstream flooding or landslides, as a result of runoff, post-fire slope instability, or drainage changes? □ □ ■ □ Existing Setting The project site not within a State Responsibility Area or designated as a Very High Fire Hazard Severity Zone (VHFHSZ; CAL FIRE 2024). The nearest VHFHSZ is approximately 0.1 mile southeast of the project site, immediately southeast of the intersection of SR 41 and Sycamore Road, and is associated with wooded open space areas, including Stadium Park. Proposed Project a. If located in or near state responsibility areas or lands classified as very high fire hazard severity zones, would the project substantially impair an adopted emergency response plan or emergency evacuation plan? The applicable emergency response or emergency evacuation plan is the San Luis Obispo County Multi-Jurisdictional Hazard Mitigation Plan, which identifies potential hazards and vulnerabilities and outlines mitigation action plans. The County’s Multi-Jurisdictional Hazard Mitigation Plan City of Atascadero Community Development Department Atascadero Mutual Water Company Water Treatment Plant Project 114 incorporates specific information for Atascadero in Annex B (County of San Luis Obispo 2019). As discussed in Initial Study Checklist Section 9, Hazards and Hazardous Materials, the project site is located within AMWC’s existing Corporation Yard facility and a portion of the Sycamore Road right- of-way. The proposed project would not require any temporary lane or road closures that could impede emergency response or evacuation during construction. In addition, the project includes construction of an improved driveway on Sycamore Road, which would enhance ingress/egress to the facility in the event of emergency response or evacuation. During project operation, daily AMWC operator visits and periodic chemical deliveries would not substantially increase congestion on Sycamore Road in the event of emergency evacuations. Therefore, the project would not substantially impair an adopted emergency response or evacuation plan, and no impact would occur. NO IMPACT b. If located in or near state responsibility areas or lands classified as very high fire hazard severity zones, would the project, due to slope, prevailing winds, and other factors, exacerbate wildfire risks and thereby expose project occupants to pollutant concentrations from a wildfire or the uncontrolled spread of a wildfire? The project site is relatively flat and is immediately surrounded by other portions of the facility to the north, west, and east and Sycamore Road to the south. Beyond the Corporation Yard boundaries, surrounding land uses include SR 41 to the east, the Salinas River to the north, Atascadero Creek and single-family residences to the west, and the Union Pacific Railroad and single-family residences to the south. Construction personnel would be required to adhere to applicable provisions of the PRC to minimize fire risk. These regulations include PRC Section 4442, which requires earth-moving and portable construction equipment with internal combustion engines to use spark arrestors when operating on any forest-covered, brush-covered, or grass- covered land; and PRC Section 4428, which requires construction contractors to maintain fire suppression equipment during the highest fire danger period (April 1 to December 1) when operating on or near any forest-covered, brush-covered, or grass-covered land. In addition, the project does not include components that would present the risk of wildland fire ignition, such as aboveground power lines. Therefore, the project would not exacerbate wildfire risks or expose occupants to significant pollutant concentrations from wildfires or the uncontrolled spread of a wildfire, and impacts would be less than significant. LESS-THAN-SIGNIFICANT IMPACT c. If located in or near state responsibility areas or lands classified as very high fire hazard severity zones, would the project require the installation or maintenance of associated infrastructure (such as roads, fuel breaks, emergency water sources, power lines or other utilities) that may exacerbate fire risk or that may result in temporary or ongoing impacts to the environment? The project does not include components that would present the risk of wildfire ignition, such as aboveground power lines. The project would not include roads, fuel breaks, emergency water sources, or other infrastructure that would exacerbate fire risk or result in temporary or ongoing impacts to the environment. Therefore, no impact would occur. NO IMPACT Initial Study Checklist Wildfire Initial Study – Mitigated Negative Declaration 115 d. If located in or near state responsibility areas or lands classified as very high fire hazard severity zones, would the project expose people or structures to significant risks, including downslopes or downstream flooding or landslides, as a result of runoff, post-fire slope instability, or drainage changes? As discussed in Initial Study Checklist Section 10, Hydrology and Water Quality, the project would not result in substantial changes to the drainage patterns on the project site. Although the FIRM prepared by FEMA shows the project site as within the 100-year floodplain associated with the Salinas River, site-specific topographic survey data indicates the project site is outside the boundaries of the base flood elevation and therefore not expected to be inundated during a 100- year flood event along the Salinas River. In addition, due to intervening topography, the project site is not expected to be inundated during a 100-year flood event along Atascadero Creek. Furthermore, as discussed in Initial Study Checklist Section 7, Geology and Soils, the project site is relatively flat and is not susceptible to landslides. The proposed project would require approximately one new AMWC operator to be present at the AMWC Corporation Yard facility, which would be a minimal change as compared to baseline conditions. Therefore, the project would not expose people or structures to significant risks, including downslopes or downstream flooding or landslides, as a result of runoff, post-fire slope instability, or drainage changes, and impacts would be less than significant. LESS-THAN-SIGNIFICANT IMPACT Mitigation/Conclusion No significant impacts are expected. No mitigation is required. City of Atascadero Community Development Department Atascadero Mutual Water Company Water Treatment Plant Project 116 This page intentionally left blank. Initial Study Checklist Mandatory Findings of Significance Initial Study – Mitigated Negative Declaration 117 21 Mandatory Findings of Significance Potentially Significant Impact Less than Significant with Mitigation Incorporated Less-than - Significant Impact No Impact Does the project: a. Have the potential to substantially degrade the quality of the environment, substantially reduce the habitat of a fish or wildlife species, cause a fish or wildlife population to drop below self-sustaining levels, threaten to eliminate a plant or animal community, substantially reduce the number or restrict the range of a rare or endangered plant or animal or eliminate important examples of the major periods of California history or prehistory? □ □ □ ■ b. Have impacts that are individually limited, but cumulatively considerable? (“Cumulatively considerable” means that the incremental effects of a project are considerable when viewed in connection with the effects of past projects, the effects of other current projects, and the effects of probable future projects)? □ ■ □ □ c. Have environmental effects which will cause substantial adverse effects on human beings, either directly or indirectly? □ ■ □ □ Existing Setting As discussed in Initial Study Checklist Section 4, Biological Resources, the project site does not have moderate or high potential to support special status plant and wildlife species (Appendix A). In addition, as discussed in Initial Study Checklist Section 5, Cultural Resources, no important examples of the major periods of California history or prehistory are known to be present within the project site. The project site is within AMWC’s existing Corporation Yard facility, which has minor ongoing impacts to human beings related to air quality, hazards and hazardous materials, and noise associated with AMWC’s operation and maintenance activities (e.g., operating equipment and vehicles, using and storing hazardous materials used in the water treatment process). City of Atascadero Community Development Department Atascadero Mutual Water Company Water Treatment Plant Project 118 Proposed Project a. Does the project have the potential to substantially degrade the quality of the environment, substantially reduce the habitat of a fish or wildlife species, cause a fish or wildlife population to drop below self-sustaining levels, threaten to eliminate a plant or animal community, substantially reduce the number or restrict the range of a rare or endangered plant or animal or eliminate important examples of the major periods of California history or prehistory? As discussed in Initial Study Checklist Section 4, Biological Resources, the proposed project would not substantially reduce the habitat of fish and wildlife species, cause a fish or wildlife population to drop below self-sustaining levels, eliminate a plant or animal community, or substantially reduce the number or restrict the range of a rare or endangered plant or animal. In addition, as discussed in Initial Study Checklist Section 5, Cultural Resources, the project would not eliminate important examples of the major periods of California history or prehistory. Therefore, no impact would occur. NO IMPACT b. Does the project have impacts that are individually limited, but cumulatively considerable? (“Cumulatively considerable” means that the incremental effects of a project are considerable when viewed in connection with the effects of past projects, the effects of other current projects, and the effects of probable future projects)? As described in Initial Study Checklist Sections 1 through 20, with respect to all environmental issues, the proposed project would not result in significant and unmitigable impacts to the environment. All anticipated impacts associated with project construction and operation would be either less than significant or less than significant with mitigation incorporated. This is largely because project construction activities would be temporary, and project operational activities would result in generally minimal alterations to the environmental baseline condition. As discussed throughout this IS-MND, the project would result in no impacts to agriculture and forestry resources, energy, population and housing, public services, and recreation, and therefore the project would not contribute to cumulative impacts to these resources. Cumulative impacts could occur if the construction of other projects occurs at the same time as the proposed project and in the same geographic scope, such that the effects of similar impacts of multiple projects combine to create greater levels of impact than would occur at the project-level. For example, if the construction of other projects in the area occurs at the same time as construction of the proposed project, combined noise and transportation impacts may be greater than at the project-level. However, there are currently no planned development projects in the vicinity of the project site (Gleason 2024). Atascadero would continue to generally develop over time in accordance with the City’s General Plan. The potential for the project to contribute to cumulative impacts in conjunction with existing and future development would be limited to the following specific issue areas, for which the project is anticipated to have less than significant impacts (with or without mitigation): ▪ Aesthetics: Cumulative development in the region could continue to change the existing visual landscape. However, there are no cumulative projects in the vicinity of the project site, and the surrounding areas to the west, southwest, and northwest are built out with residential neighborhoods. The project would result in a minor change to the current visual character of the project site, and cumulative development would be subject to existing regulations governing Initial Study Checklist Mandatory Findings of Significance Initial Study – Mitigated Negative Declaration 119 scenic character, including the City’s General Plan. Therefore, cumulative impacts related to aesthetics would not be significant. ▪ Air Quality: Because western San Luis Obispo County is designated nonattainment for the ozone and PM10 CAAQS, significant cumulative air quality impacts currently exist for these pollutants. As discussed in Initial Study Checklist Section 3, Air Quality, the proposed project would not generate emissions of ozone precursors (ROG and NOX) or dust (PM10) that exceed the SLOAPCD significance thresholds, which are intended to assess whether a project’s contribution to existing cumulative air quality impacts is considerable. Therefore, the project’s contribution to significant cumulative air quality impacts would not be cumulatively considerable. ▪ Biological Resources: Cumulative development in the region would continue to disturb areas with the potential to contain or provide habitat for biological resources. Cumulative development projects have undergone or would be required to undergo CEQA review, which would determine the extent of potential biological resources impacts and mitigate those impacts appropriately. If these cumulative projects would result in impacts to biological resources, impacts to such resources would be addressed on a case-by-case basis. Given the uncertainty in the extent of impacts associated with these projects, this analysis conservatively assumes a significant cumulative impact to biological resources would occur. However, the proposed project would be required to implement Mitigation Measure BIO-1 to reduce its impacts to biological resources to a less-than-significant level such that project-level impacts would not result in a cumulatively considerable contribution to this cumulative impact. ▪ Cultural and Tribal Cultural Resources: Cumulative development in the region would continue to disturb areas with the potential to contain cultural and tribal cultural resources. As mentioned above, cumulative development projects have undergone or would be required to undergo CEQA review, which would determine the extent of potential cultural and tribal cultural resources impacts and mitigate those impacts appropriately. If cumulative projects would result in impacts to known or unknown cultural and tribal cultural resources, impacts to such resources would be addressed on a case-by-case basis. Given the uncertainty in the extent of impacts associated with these projects, this analysis conservatively assumes a significant cumulative impact to cultural resources would occur. Nevertheless, the proposed project would be required to implement Mitigation Measures CR-1 and CR-2 to reduce its impacts to cultural resources to a less-than-significant level such that project-level impacts would not result in a cumulatively considerable contribution to this cumulative impact. In addition, as discussed in Section 18, Tribal Cultural Resources, no tribal cultural resources were identified within the project site during the AB 52 consultation process. ▪ Energy: Cumulative development in the region would use energy resources during both construction and operation. Similar to the proposed project, cumulative project construction would be subject to existing regulations that would minimize inefficient, wasteful, or unnecessary fuel consumption. Furthermore, in the interest of cost-efficiency, cumulative project construction contractors would not be anticipated to utilize fuel in a manner that is wasteful or unnecessary. Cumulative project operations would largely consist of a continuation of existing uses and would not substantially increase energy usage. Therefore, cumulative impacts related to energy would not be significant. ▪ Geology and Soils: Cumulative development in the region would continue to disturb areas with the potential to contain paleontological resources. As discussed above, cumulative development projects have undergone or would be required to undergo CEQA review, which would determine the extent of potential paleontological resources impacts and mitigate those impacts appropriately. This analysis conservatively assumes a significant cumulative impact to City of Atascadero Community Development Department Atascadero Mutual Water Company Water Treatment Plant Project 120 paleontological resources would occur. Nevertheless, the proposed project would only disturb geologic units with a low paleontological sensitivity and therefore would not result in a cumulatively considerable contribution to this cumulative impact. ▪ Greenhouse Gas Emissions: GHG emissions and climate change are, by definition, cumulative impacts. As discussed in Initial Study Checklist Section 8, Greenhouse Gas Emissions, the adverse environmental impacts of cumulative GHG emissions, including increased average temperatures, more drought years, and more frequent large wildfires, are already occurring. As a result, cumulative impacts related to GHG emissions are significant. Thus, the issue of climate change involves an analysis of whether a project’s contribution towards an impact is cumulatively considerable. As discussed in Initial Study Checklist Section 8, Greenhouse Gas Emissions, project emissions would be consistent with adopted plans and would therefore not be cumulatively considerable. ▪ Hazards and Hazardous Materials: Similar to the proposed project, cumulative projects would be required to comply with regulations applicable to the use, disposal, and transportation of hazardous materials during construction activities, and compliance with applicable regulations would reduce potential cumulative impacts to less-than-significant levels. With respect to the use and accidental release of hazardous materials in the environment during construction, effects are generally limited to site-specific conditions. Therefore, cumulative impacts related to accidental release of hazardous materials would less than significant. ▪ Hydrology and Water Quality: As discussed in Initial Study Checklist Section 10, Hydrology and Water Quality, the project’s construction-related water quality impacts would be less than significant with SWPPP implementation and regulatory compliance. Cumulative projects in the area would have less-than-significant impacts related to hydrology and water quality because they would be required to comply with existing NPDES regulations to ensure they do not result in substantial erosion or stormwater discharges that would substantially affect water quality in the area and existing City and FEMA regulations related to floodplain development. Implementation of these regulations minimizes and avoids the potential for cumulative impacts to occur. Therefore, cumulative impacts related to hydrology and water quality would not be significant. ▪ Mineral Resources: Cumulative development in the region would continue to affect areas with the potential to contain mineral resources. As mentioned above, cumulative development projects have undergone or would be required to undergo CEQA review, which would determine the extent of potential mineral resources impacts and mitigate those impacts appropriately. If cumulative projects would result in impacts to mineral resources, impacts to such resources would be addressed on a case-by-case basis. Given the uncertainty in the extent of impacts associated with these projects, this analysis conservatively assumes a significant cumulative impact to mineral resources would occur. Nevertheless, the proposed project does not involve mineral resource extraction, and mineral resources on or adjacent to the project site would remain undisturbed and available for potential future extraction. Therefore, project-level impacts would not result in a cumulatively considerable contribution to this cumulative impact. ▪ Noise: There are no planned cumulative development projects in the vicinity of the project site that would combine with the proposed project to create cumulative impacts related to construction noise and vibration. In addition, both the proposed project and existing cumulative development are required to adhere to the City’s noise level limits outlined in AMC Section 9- 14.05. Therefore, cumulative impacts related to operational noise would not be significant. Initial Study Checklist Mandatory Findings of Significance Initial Study – Mitigated Negative Declaration 121 ▪ Transportation: There are currently no planned cumulative development projects in the vicinity of the project site that may be constructed at the same time as the proposed project such that cumulative construction transportation impacts could occur. Cumulative development in the region would potentially result in long-term increases in VMT over time. Given the uncertainty in the extent of impacts associated with these projects, this analysis conservatively assumes a significant cumulative impact to VMT would occur. However, the proposed project would result in a negligible increase in long-term traffic volumes and VMT because the project would require one daily AMWC operator visit as part of existing staff rounds as well as chemical deliveries approximately one to two times each month. Therefore, project-level impacts would not result in a cumulatively considerable contribution to this cumulative impact. ▪ Utilities and Service Systems: The project itself consists of groundwater treatment infrastructure, and would therefore not result in a cumulatively considerable contribution to adverse impacts on water supply. The project would generate minimal wastewater and solid waste and would not require new or relocated utilities. Therefore, the project’s contribution to cumulative impacts related to utilities and service systems would not be considerable. ▪ Wildfire: As described in Initial Study Checklist Section 20, Wildfire, potential wildfire impacts associated with the project would be limited to heavy-duty construction equipment possibly producing sparks to ignite vegetation, which would be less than significant with compliance with applicable laws and regulation. Project operation would not involve potentially flammable activities. There are currently no planned development projects in the vicinity of the project site that could contribute to increasing wildfire risks over time. Because there would be no long- term project operational wildfire impacts and potential construction-related wildfire impacts would be limited, the project’s contribution to cumulative impact wildfire impacts would not be considerable. Given the above discussion, the proposed project would not result in a cumulatively considerable contribution to a significant cumulative impact with mitigation incorporated. LESS THAN SIGNIFICANT WITH MITIGATION INCORPORATED c. Does the project have environmental effects which will cause substantial adverse effects on human beings, either directly or indirectly? In general, impacts to human beings are associated with air quality, hazards and hazardous materials, noise, and wildfire impacts. As detailed under Environment Checklist Section 3, Air Quality, Section 9, Hazards and Hazardous Materials, Section 13, Noise, and Section 20, Wildfire, the proposed project would not result, either directly or indirectly, in substantial adverse effects related to air quality, hazardous materials, and noise with implementation of Mitigation Measures NOI-1 and NOI-2. Therefore, impacts to human beings would be less than significant with mitigation incorporated. LESS THAN SIGNIFICANT WITH MITIGATION INCORPORATED Mitigation/Conclusion Implementation of Mitigation Measures BIO-1, outlined in Initial Study Checklist Section 4, Biological Resources, Mitigation Measures CR-1 and CR-2, outlined in Initial Study Checklist Section 5, Cultural Resources, and Mitigation Measures NOI-1 and NOI-2, outlined in Initial Study Checklist Section 13, Noise, would be required to reduce impacts to less than significant. City of Atascadero Community Development Department Atascadero Mutual Water Company Water Treatment Plant Project 122 For further information on California Environmental Quality Act (CEQA) or the City’s environmental review process, please visit the City’s website at www.atascadero.org under the Community Development Department or the California Environmental Resources Evaluation System at: http://resources.ca.gov/ceqa/ for additional information on CEQA. Initial Study References and Outside Agency Contacts Initial Study – Mitigated Negative Declaration 123 Initial Study References and Outside Agency Contacts Bibliography Atascadero Basin Groundwater Sustainability Agency. 2016. Technical Report Salinas Valley – Atascadero Area Subbasin Basin Boundary Modification Application. https://www.atascaderobasin.com/wp-content/uploads/2016/03/Atascadero-Basin- Boundary-Modification-Technical-Report.pdf (accessed June 2025). ______. 2022. Atascadero Basin Groundwater Sustainability Plan. https://atascaderobasin.com/ (accessed October 2024). Atascadero, City of. 2011. City of Atascadero Figure 11-2 General Plan Land Use Diagram. Adopted June 25, 2002. Last updated January 25, 2011. https://www.atascadero.org/sites/default/files/2023-06/Landuse.pdf (accessed October 2024). ______. 2014a. City of Atascadero Climate Action Plan. January 28, 2014. ______. 2014b. Atascadero Storm Water Control Plan Template. https://www.atascadero.org/sites/default/files/2023- 06/Atascadero%20Storm%20Water%20Control%20Plan%20Template.pdf (accessed October 2024). ______. 2016. Atascadero General Plan 2025. https://www.atascadero.org/sites/default/files/2023- 06/Atascadero%20GP%202025.pdf (accessed August 2024). ______. 2020. City of Atascadero Zoning Handbook. https://www.atascadero.org/sites/default/files/2023- 06/Zoning%20Handbook%20Update%202020_No%20ADU%20Section.pdf (accessed October 2024). ______. 2022. City of Atascadero Zoning Diagram. Adopted June 25, 2002. Last updated September 14, 2022. https://www.atascadero.org/sites/default/files/2023-06/Zoning%20%282%29.pdf (accessed October 2024). ______. 2023. 2045 General Plan Update Existing Conditions Report: Chapter 9 Infrastructure. https://www.atascadero2045.org/files/managed/Document/98/AGPU_ECR_CH9%20Infrast ructure_Public%20Draft_09182023.pdf (accessed October 2024). ______. 2024. “Engineering Standards.” https://www.atascadero.org/engineering-standards (accessed October 2024). Atascadero Mutual Water Company (AMWC). 2021. Urban Water Management Plan. https://web.amwc.us/resources/AMWC%20UWMP.pdf (accessed August 2024). Bell, A. 2024. Collections search of the Natural History Museum of Los Angeles County for the AMWC WTP Project (#21-11135), dated September 1, 2024. City of Atascadero Community Development Department Atascadero Mutual Water Company Water Treatment Plant Project 124 California Air Resources Board (CARB). 2005. Air Quality and Land Use Handbook: A Community Health Perspective. April 2005. https://files.ceqanet.opr.ca.gov/221458-6/attachment/UNr- g159CW-r0G4DR8q6daNdAKT3RJTd8gGQCfz4wqFfl- eNdZNQEqjf8tfls1x6Gsae7YqpXwtFIZBd0 (accessed October 2024). ______. 2022. 2022 Scoping Plan for Achieving Carbon Neutrality. November 16, 2022. https://ww2.arb.ca.gov/sites/default/files/2023-04/2022-sp.pdf (accessed September 2024). ______. 2024. “Overview: Diesel Exhaust & Health”. https://ww2.arb.ca.gov/resources/overview- diesel-exhaust-and-health (accessed September 2024). California Department of Conservation (DOC). 2011. Updated Mineral Land Classification Map for Concrete-Grade Aggregates in the San Luis Obispo-Santa Barbara Production-Consumption Region, California - North Half. ______. 2023. Earthquake Zones of Required Investigation. https://maps.conservation.ca.gov/cgs/EQZApp/app/ (accessed September 2024). ______. 2025a. California Important Farmland Finder. https://maps.conservation.ca.gov/DLRP/CIFF/ (accessed May 2025). ______. 2025b. California Williamson Act Enrollment Finder. https://maps.conservation.ca.gov/dlrp/WilliamsonAct/App/index.html (accessed May 2025). California Department of Conservation, Division of Mines and Geology. 1989. Mineral Land Classification: Portland Cement Concrete Aggregate and Active Mines of All Other Mineral Commodities in the San Luis Obispo-Santa Barbara Production-Consumption Region. Special Report 162. https://maps.conservation.ca.gov/cgs/informationwarehouse/index.html?map=mlc (accessed October 2024). California Department of Forestry and Fire Protection (CAL FIRE). (2024). Fire Hazard Severity Zone Viewer [map]. https://experience.arcgis.com/experience/03beab8511814e79a0e4eabf0d3e7247/ (accessed October 2024) California Department of Resources Recycling and Recovery. 2024. 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Available: https://water.ca.gov/-/media/DWR-Website/Web- Pages/Programs/Groundwater-Management/Bulletin-118/Files/2003-Basin- Descriptions/3_004_01_180-400FootAquiferSubbasin.pdf (accessed October 2024). California Environmental Protection Agency. 2025. Cortese List: Section 65962.5(a). https://calepa.ca.gov/sitecleanup/corteselist/ (accessed May 2025). California Geological Survey. 2002. California Geomorphic Provinces. Note 36. https://www.conservation.ca.gov/cgs/Documents/Publications/CGS-Notes/CGS-Note- 36.pdf (accessed October 2024). California Governor’s Office of Planning and Research. 2018. Technical Advisory on Evaluating Transportation Impacts in CEQA. https://opr.ca.gov/docs/20190122- 743_Technical_Advisory.pdf (accessed October 2024). California Natural Resources Agency. 2019. California’s Fourth Climate Change Assessment Statewide Summary Report. January 2019. http://www.climateassessment.ca.gov/state/ (accessed October 2024). California State Water Resources Control Board. 2024. GeoTracker. https://geotracker.waterboards.ca.gov (accessed October 2024). Central Coast Regional Water Quality Control Board. 2019. Water Quality Control Plan for the Central Coast Basin. https://www.waterboards.ca.gov/centralcoast/publications_forms/publications/basin_plan / (accessed October 2024). Crocker, Malcolm J. Crocker (Editor). 2007. Handbook of Noise and Vibration Control Book, ISBN: 978-0-471-39599-7, Wiley-VCH, October. Dibblee, T.W. and H.E. Ehrenspeck. 2004a. Geologic map of the Templeton quadrangle, San Luis Obispo County, California. [map]. Dibblee Geologic Foundation, Dibblee Foundation Map DF-135, scale 1:24,000. ______. 2004b. Geologic map of the Atascadero quadrangle, San Luis Obispo County, California. [map]. Dibblee Geologic Foundation, Dibblee Foundation Map DF-132, scale 1:24,000. Federal Emergency Management Agency. 2005. 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Outside Agency Contacts The Community Development Department of the City of Atascadero has contacted various agencies for their comments on the proposed project. With respect to the proposed project, the following outside agencies have been contacted (marked with an ☒) with a notice of intent to adopt a proposed negative / mitigated negative declaration. ☒ AB 52 – Barbareño/Ventureño Band of Mission Indians ☐ Charter Communications ☒ AB 52 – Chumash Council of Bakersfield ☐ HEAL SLO – Healthy Communities Workgroup ☒ AB 52 – Coastal Band of the Chumash Nation ☐ LAFCO ☒ AB 52 – Northern Chumash Tribe ☒ Native American Heritage Commission ☒ AB 52 – Salinan Tribe of Monterey, San Luis Obispo Counties ☒ Office of Historic Preservation ☒ AB 52 – Santa Ynez Band of Chumash Indians ☒ Pacific Gas & Electric ☒ AB 52 – Tule River Indian Tribe ☒ Regional Water Quality Control Board Region 3 ☒ AB 52 – Xolon Salinan Tribe ☒ San Luis Obispo Air Pollution Control District ☒ AB 52 – yak tityu tityu yak tiłhini – Northern Chumash Tribe ☐ San Luis Obispo Council of Governments ☐ Address Management Service ☐ San Luis Obispo County Assessor ☒ Atascadero Mutual Water Company ☒ San Luis Obispo County Environmental Health Department Initial Study References and Outside Agency Contacts Initial Study – Mitigated Negative Declaration 129 ☐ Atascadero Unified School District ☐ San Luis Obispo County Planning & Building ☐ Atascadero Waste Alternatives ☐ San Luis Obispo Integrated Waste Management Board ☒ CA Air Resources Board ☒ Southern California Gas Co. (SoCal Gas) ☐ CA Department of Conservation ☐ Upper Salians – Las Tablas RCD ☐ CA Department of Food & Agriculture ☐ US Army Corps of Engineers ☒ CA Department of Toxic Substances Control ☐ US Postal Service ☐ CA Housing & Community Development ☐ Other: ☒ California Department of Fish and Wildlife (Region 4) ☐ Other: ☒ California Department of Transportation (District 5) ☐ Other: ☐ California Highway Patrol ☐ Other: ☐ Central Coast Information Center (CA. Historical Resources Information System) ☐ Other: Reference Materials The following checked (“☒”) reference materials have been used in the environmental review for the proposed project and are hereby incorporated by reference into the Initial Study. The following information is available at the Community Development Department and requested copies of information may be viewed by requesting an appointment with the project planner at (805) 461-5000. ☒ Project File / Application / Exhibits / Studies ☐ Adopted Atascadero Capital Facilities Fee Ordinance ☒ Atascadero General Plan 2025 / Final EIR ☐ Atascadero Inclusionary Housing Policy ☒ Atascadero Municipal Code ☒ SLO APCD Handbook ☐ Atascadero Appearance Review Manual ☒ Regional Transportation Plan ☒ Atascadero Urban Stormwater Management Plan ☒ Flood Hazard Maps ☐ Atascadero Hillside Grading Guidelines ☒ CDFW / USFW Mapping ☒ Atascadero Native Tree Ordinance & Guidelines ☒ CA Natural Species Diversity Data Base City of Atascadero Community Development Department Atascadero Mutual Water Company Water Treatment Plant Project 130 ☐ Atascadero Climate Action Plan (CAP) ☒ Archeological Resources Map ☐ Atascadero Downtown Revitalization Plan ☐ Atascadero Mutual Water Company Urban Water Management Plan ☐ Atascadero Bicycle Transportation Plan ☐ CalEnviroScreen ☒ Atascadero GIS mapping layers ☐ Other _______________ ☐ Other _______________ ☐ Other _______________ List of Preparers The City of Atascadero prepared this IS-MND with support from Rincon Consultants, Inc. Persons involved in data gathering analysis, project management, and quality control are listed below. City of Atascadero Kelly Gleason, Planning Manager Rincon Consultants, Inc. Jennifer Jacobus, PhD, Principal Margo Nayyar, Cultural Resources Principal Annaliese Torres, Supervising Environmental Planner William Vosti, Program Manager – Air Quality, GHG Emissions, and Noise Harvey Williams, Environmental Planner Ethan Knox, Environmental Planner Aaron Rojas Jr., Environmental Planner Andrew McGrath, PhD, Paleontologist Zachary Lema, Paleontologist