Environmental Documents

    Below are recent Environmental Impact Reports, Notice of Availabilities, and Notices of Preparation of an Initial Study for Sonoma County Water Agency Projects. Learn more about regulatory compliance.

    Santa Rosa Aqueduct and Cotati Aqueduct Cathodic Protection Project

    The Proposed Project would allow the Water Agency to update the existing, aging cathodic protection system. The Water Agency’s aqueducts are currently protected by a galvanic cathodic protection system (galvanic system). The galvanic system includes buried anodes that are attached to the aqueduct. The anodes provide a material that corrodes more readily than the aqueduct, so the corrosive materials in the environment around the aqueduct degrade the anodes rather than the aqueduct. This system also includes cathodic test stations, which consist of a wire lead from the aqueduct up to a test station mounted above the ground surface that allows Water Agency staff to test the level of cathodic protection without excavating to the aqueduct. The anodes in the current galvanic cathodic protection system are aging and, therefore, depleted and no longer provide adequate protection against corrosion. Failing to replace the existing anodes could result in corrosion and failure of sections of the aqueducts in the future.

    The objective of the proposed project is to extend the service lives of the Santa Rosa and Cotati aqueducts by installing an updated cathodic protection system, which will protect the aqueducts from corrosion.

    Public Comment Period for this Notice of Preparation

    Due to the time limits mandated by State law, responses must be sent no later than 5:00 p.m. on August 10, 2018. Please include a name, address, and telephone number, and email address of a contact person for all future correspondence on this subject. Comments may be submitted electronically to Anne.Crealock@scwa.ca.gov or mailed to: 

    Sonoma County Water Agency
    Attn: Anne Crealock
    404 Aviation Boulevard
    Santa Rosa, CA 95403

    Documents or files related to the Proposed Project are available for review online at http://www.scwa.ca.gov/environmental-documents/ or at the Water Agency’s administrative office at 404 Aviation Boulevard, Santa Rosa, California, 95403.

    If you have any questions regarding this NOP, or if you wish to update information on our mailing list, please contact Anne Crealock at 707-547-1948 or Anne.Crealock@scwa.ca.gov


    Major Planned Deviation to the Coyote Valley Dam-Lake Mendocino Water Control Manual

    Members of the Lake Mendocino Forecast Informed Reservoir Operations (FIRO) Steering Committee have requested a major planned deviation to the Coyote Valley Dam – Lake Mendocino Water Control Manual (WCM). The FIRO effort is led by a steering committee formed in 2014 and consisting of representatives from the Sonoma County Water Agency (Water Agency), Scripps Institute of Oceanography (Scripps), U.S. Army Corps of Engineers (USACE), National Oceanic and Atmospheric Administration (NOAA), U.S. Geologic Survey (USGS), U.S. Bureau of Reclamation and the California Department of Water Resources (DWR).

    Lake Mendocino has experienced significantly reduced water supply reliability over the past several years due to a significant reduction of trans-basin transfers into the facility from the Eel River. The goal of FIRO is to help restore some of the diminished water supply reliability without reducing the existing flood protection capacity of Lake Mendocino. Members of the FIRO Steering Committee are requesting USACE approval of a planned major deviation to store additional water above the existing guide curve for the Coyote Valley Dam Lake Mendocino WCM. If approved, this deviation would allow the USACE to store an additional 11,650 acre-feet of water above the existing guide curve, stipulated in the Coyote Valley Dam - Lake Mendocino Water Control Manual, between November 1 and February 28, to restore some of the diminished water supply reliability without reducing the existing flood protection capacity of Lake Mendocino. The requested major deviation to the WCM represents the next phase of the FIRO viability assessment. It is important to emphasize that if water levels are within the storage space allowed by this deviation, the USACE will have the discretion to utilize the additional information provided to inform (but not control) reservoir operations. USACE reservoir operators will retain full operational control and authority, with the FIRO decision support model (DSM) providing an additional tool for operators.

    The draft Environmental Assessment (EA) is available for review on the US Army Corps of Engineers San Francisco District's website.

    The document is also available for review at:

    • Mendocino County Ukiah Branch Library, 105 N. Main St., Ukiah, CA 95482;
    • Sonoma County Library Central Library, 211 E. St., Santa Rosa, CA 95404;
    • US Army Corps of Engineers’ office at Lake Mendocino; and
    • Sonoma County Water Agency 404 Aviation Blvd. Santa Rosa, CA, 95403.

    The 30-day public review period for the draft EA extends from July 2, 2018, to July 31, 2018.

    All comments postmarked by July 31, 2018, will be considered and incorporated into the final EA, as appropriate. Specific responses will also be included in a comments and responses appendix to the final document.

    Please send any questions and comments to: Sonoma County Water Agency, c/o Connie Barton, 404 Aviation Blvd, Santa Rosa, CA 95403 or email at connie.barton@scwa.ca.gov


     Green Valley Creek High Flow Channel Project

    The Sonoma County Water Agency (Water Agency) has developed a proposal to reduce flooding on Green Valley Road west of Graton by removing sediment from the adjacent Green Valley Creek and restoring the creek banks with native vegetation. Pursuant to the California Environmental Quality Act, the Water Agency released a Draft Initial Study and Negative Declaration (IS/ND) for the project on June 22. The public is invited to provide comment on the project before July 24.

    Green Valley Creek experiences recurring flooding, leading to extended road closures or hazardous driving conditions on Green Valley Road, stranded fish and wildlife species, and damage to the roadway and adjacent farmland. In recent years, flooding has become worse, lasting longer, causing more damage, and occurring with greater frequency. The proposed project would excavate and maintain channels in the creek and install native plants along the banks to reduce flooding of Green Valley Road and nearby properties and improve aquatic habitat. The project is expected to be implemented in fall 2018. Annual dry season maintenance would occur as needed for five years.

    “Last year, Green Valley Road was closed for over three weeks due to flooding,” said Water Agency Director Lynda Hopkins. “The project would make Green Valley Road safer for the communities who rely on it, as well as the fish and wildlife who rely on the creek.”

    The project would involve clearing blackberry understory from the creek and an adjacent area in order to establish a temporary access road across a dry channel; excavating sediment from the existing creek and installing a high flow channel through a gravel bar; and planting native species along its banks. Although construction is likely to temporarily disturb fish and wildlife, over the long term the project would improve fish passage, reduce the number of fish stranded by receding floodwaters, improve habitats for other aquatic species, and support healthier habitats downstream by decreasing sediment flows from the area.

    An electronic copy of the Draft IS/ND is available at www.scwa.ca.gov/environmental-documents. Hard copies of the Draft IS/ND are available for purchase by request at 707-547-1900 or at the Water Agency’s administrative office (404 Aviation Boulevard, Santa Rosa). Hard copies are also available for public viewing at the following locations:

    • Sonoma County Water Agency: 404 Aviation Blvd Santa Rosa, CA 95403
    • Sebastopol Regional Library: 7140 Bodega Avenue, Sebastopol, CA 95472

    An Initial Study is a preliminary analysis of a project’s potential environmental impacts used to determine whether a Negative Declaration or an Environmental Impact Report will be prepared. The Initial Study is intended to provide a clear understanding of the environmental impacts associated with the construction and operation of the proposed project for decision-makers, responsible and trustee agencies under CEQA, and the public. If an Initial Study identifies potentially significant impacts but the project is modified or revised to clearly mitigate the impacts, a Mitigated Negative Declaration may be prepared. If an Initial Study concludes that a project may have a significant effect on the environment, an Environmental Impact Report should be prepared.

    There have been several previous studies in Green Valley Creek watershed by the Gold Ridge Resource Conservation District. These past studies include evaluating flooding along Green Valley Road. For more information, visit the Gold Ridge Resource Conservation District website.


    North Bay Water Reuse Program, Phase 2

    The Water Agency is a member of, and contract administrator for, the North Bay Water Reuse Authority (NBWRA). The NBWRA is a coordinated effort of three counties and 10 water and sanitation agencies, working together as one entity, to address water supply shortages from a watershed perspective. The member agencies are investing in a number of diverse recycled water projects to offset potable water demands throughout the North Bay region.

    The NBWRA is proposing Phase 2 of the North Bay Water Reuse Program (Phase 2 Program). The NBWRA has prepared a joint Draft Environmental Impact Report / Environmental Impact Statement (EIR/EIS) pursuant to the California Environmental Quality Act (CEQA) and the National Environment Policy Act (NEPA) to assess potential environmental effects of their proposed North Bay Water Reuse Program Phase 2, or NBWRP Phase 2. The Sonoma County Water Agency (SCWA) will act as Lead Agency under CEQA and the Department of Interior, Bureau of Reclamation, will be the federal Lead Agency under NEPA.

    Pursuant to Section 15088 of the CEQA Guidelines, the Final EIR/EIS is being made available to the commenters for a minimum 10-day period prior to its consideration by the CEQA Lead Agency for certification. This review period will be from August 3 – 13, 2018. Following consideration of CEQA certification by SCWA, each Member Agency will consider approval of NBWRP Phase 2 under Proposed Action. Each Member Agency will consider approval of the projects identified under NBWRP Phase 2 that are within its jurisdiction.

    Project Website:

    For more information on this project, please visit: http://www.nbwra.org/project-descriptions/phase-2/public-participation/


    NBWRA Phase 2 - Notice of Preparation (PDF, 3MB)

    NBWRA Phase 2 - Notice of Availability of Draft Environmental Impact Report (PDF, 1MB)

    NBWRA Phase 2 - Draft Environmental Impact Report / Environmental Impact Statement (PDF, 33 MB)

    NBWRA Phase 2 - Notice of Availability of Final Environmental Impact Report / Environmental Impact Statement (PDF, .6MB)

    NBWRA Phase 2 - Final Environmental Impact Report / Environmental Impact Statement (PDF, 5 MB)



    Occidental Wastewater Transport Plan

    In December 2017, the Board of Directors of the Sonoma County Water Agency (Water Agency), which operates the Occidental County Sanitation District’s (District) Wastewater Treatment Facility, approved a project for transporting untreated wastewater from the OCSD to the Airport-Larkfield-Wikiup Sanitation Zone (ALWSZ) for treatment, storage, and reuse to avoid future discharges into Dutch Bill Creek and potential violations of the District’s operating permit.

    The Project, which is currently under construction, will allow the Occidental County Sanitation District (District) to comply with conditions set forth by the North Coast Regional Water Quality Control Board in Order No. R1-2012-0101 (Order). This order requires the OCSD to cease discharging secondary treated recycled water to Dutch Bill Creek by January 31, 2018. The Project includes transporting untreated wastewater to the ALWSZ wastewater treatment facility for treatment, storage, and disposal. The ALWSZ wastewater treatment facility currently treats wastewater to secondary and tertiary standards and utilizes irrigation of agricultural lands for disposal of secondary and tertiary-treated recycled water.



    Fish Habitat Flows and Water Rights Project - Draft EIR

    On August 19, 2016, the Water Agency released the Fish Habitat Flows and Water Rights Project (Fish Flow Project) Draft Environmental Impact Report (DEIR) for public review. The Fish Flow Project DEIR describes the Proposed Project, the purpose of the project, why it is necessary and the potential environmental impacts of the project.

    The Fish Flow Project has five purposes:

    1. Comply with National Marine Fisheries Service’s Russian River Biological Opinion, which requires the Water Agency to ask the State Water Board to lower minimum instream flow requirements in the Russian River and Dry Creek in order to improve conditions for coho and steelhead.
    2. Improve conditions for threatened Chinook salmon, by better preserving cold water in Lake Mendocino, which can be released for the fall Chinook migration.
    3. Replace a measuring requirement in the Water Agency’s water right permits, called the “hydrologic index,” to better reflect conditions in the Russian River watershed.
    4. Extend to 2040 the Water Agency’s right to divert and re-divert 75,000 acre feet of water annually, in order to ensure a reliable water supply for more than 600,000 people.
    5. Add existing points of diversion for Occidental Community Service District and the Town of Windsor as authorized points of diversion in the Water Agency’s water right permits. (The Water Agency has agreements with specific entities, including Occidental and Windsor, that authorize them to divert water from the Russian River under the Water Agency’s water right permits using their own facilities. The proposed change would allow these entities to report water diverted through these existing points of diversion under the Water Agency’s water right permits, and would not increase the total amount of diversions.)

    View the Fish Flow Project Page for more information


    Mark West Creek Crossing Project: Russian River-Cotati Intertie Pipeline Seismic Hazard Mitigation

    The purpose of the Project is to reduce potential pipe failure and loss of water supply service resulting from permanent ground deformation caused by a moderate or severe earthquake along the Rodger’s Creek Fault. To maintain safe and reliable water service during a seismic  event, the Project would modify the Russian River-Cotati Intertie to improve its ability to withstand the effects of ground deformation,
    liquefaction, and lateral spread hazards. The project consists of installation, operation, and maintenance of approximately 767 linear feet of a 48-inch diameter steel pipeline segment across the Mark West Creek channel (Figure 2). The new pipeline segment would replace the existing pipeline segment beneath the creek channel and would be installed parallel to (and within 25 feet of) the existing pipeline and buried 6 to 8 feet deeper than the existing pipeline. The existing pipeline segment would be disconnected, filled with a low strength concrete mixture, and abandoned in place. The new pipeline segment would tie into the existing 48-inch diameter Russian River-Cotati Intertie pipeline.


    Russian River Crossing Project: Russian River - Cotati Intertie Pipeline Seismic Hazard Mitigation

    The Water Agency owns, operates, and maintains a 48-inch diameter steel water supply pipeline (referred to as the Russian River-Cotati Intertie) that crosses the southern and eastern aqueduct transmission lines and crosses the Russian River in Sonoma County. The pipeline is buried at a relatively shallow depth (approximately 7 feet below ground surface) across the Russian River channel and stream banks, and crosses seismically unstable terrain.

    The Local Hazard Mitigation Plan (LHMP) identifies the Russian River-Cotati Intertie Intertie crossing of the Russian River as vulnerable to potential ground deformation, liquefaction, and lateral spread resulting from strong ground shaking in the soil at or below the elevation of the pipeline. The LHMP states that pipeline failure from an earthquake would isolate the Mirabel collector wells from the Russian River-Cotati Intertie Intertie Pipeline.

    The proposed project is needed to address seismic concerns related to reliable delivery of water to the Water Agency’s service area and prevent the loss of an essential water service due to a moderate or severe earthquake along the Rodger's Creek/Hayward Fault.


    Dry Creek Habitat Enhancement Project, Miles 2-6 - Draft Environmental Impact Report

    The Sonoma County Water Agency (Water Agency), as Lead Agency, has prepared this Draft Environmental Impact Report (EIR) for Dry Creek Habitat Enhancement Project, Miles 2–6 (proposed project) to provide the public and responsible and trustee agencies reviewing the Dry Creek Habitat Enhancement Project an analysis of the potential effects, both beneficial and adverse, on the environment.1 This project is intended to fulfill federal mandates to implement habitat enhancement within Dry Creek to create both winter and summer rearing habitats for juvenile steelhead and coho salmon, with an emphasis on improving habitats for the survival of juvenile coho salmon while allowing the Water Agency to maintain the existing flow range in Dry Creek for water supply purposes.


    Occidental Wastewater Treatment Facility Recycled Water Project

    The Occidental County Sanitation District is preparing an Initial Study for the Occidental Wastewater Treatment Facility Recycled Water Project to upgrade the treatment plant and change how the recycled water is managed.


    Mirabel Fish Screen and Fish Ladder Replacement Project

    Notice of Availability (PDF, 1MB)

    Initial Study and Mitigated Negative Declaration – Appendices Included (PDF, 13MB)

    Initial Study and Mitigated Negative Declaration – No Appendices (PDF, 3MB)

    Learn more about the Mirabel Seismic and Fish Passage Improvement Project


    Russian River Estuary Management Project

    View Project Page for more information


    North Sonoma County Agricultural Reuse Project


    Stream Maintenance Program Manual and EIR