Petition by Sonoma County Water Agency Requesting Approval of a Temporary Urgency Change in Permits 12947A, 12949, 12950 and 16596 in Mendocino and Sonoma Count

[PROJECT TITLE CONTINUED:] Counties (Applications 12919A, 15736, 15737, and 19351): 2026 Temporary Changes to Minimum lnstream Flow Requirements and Hydrologic Index of Decision 1610 The Sonoma County Water Agency (Sonoma Water) controls and coordinates water supply releases from the Coyote Valley Dam and Warm Springs Dam projects in accordance with the provisions of water rights Decision 1610, which the State Water Resources Control Board (State Water Board) adopted on April 17, 1986. Decision 1610 established Sonoma Water’s water right permits’ terms that specify the hydrologic index that determines the water supply conditions for the Russian River and the minimum instream flow requirements for the Upper Russian River, Dry Creek, and the Lower Russian River, which vary with water supply conditions based largely on cumulative inflow into Lake Pillsbury. Located in the Eel River watershed, Lake Pillsbury is a storage reservoir for Pacific Gas & Electric Company's (PG&E) Potter Valley Hydroelectric Project (PVP), which transfers water into the East Fork of the Russian River (East Fork). The PVP operated under a Federal Energy Regulatory Commission (FERC) license that expired on April 14, 2022, and now continues operations under an annual license while PG&E proceeds though a license surrender and decommissioning. PG&E filed a Final License Surrender Application and a Final Non-Project Use of Project Lands Application on July 29. 2025. The Surrender Application includes a decommissioning plan that requests approval to remove most of the PVP’s project facilities, including but not limited to, Scott Dam and Cape Horn Dam. The application for Non-Project Use of Project Land seeks FERC’s authorization for PG&E to allow the Eel-Russian Project Authority (ERPA) to construct a proposed New Eel-Russian Facility (NERF) for the purpose of future water diversion from the Eel River through the Project’s existing water diversion system to the Russian River watershed. FERC’s proceedings on PG&E’s applications will likely take many years, meaning that it will be years before PVP operations and long-term rules governing any Eel River imports to the Russian River watershed are resolved. Multiple changes to the PVP operations have reduced and could further reduce the transfers of Eel River water into the Russian River. Since 2021, a transformer bank failure at the PVP powerhouse has resulted in significant reductions in Eel River transfers into the Russian River. This failure caused PVP hydropower generation to cease and, with it, all associated discretionary transfers of Eel River water to the East Fork. PG&E also submitted a long-term flow regime request to amend flow requirements under the current FERC license on July 31, 2023. To reduce the potential seismic risk at Lake Pillsbury’s Scott Dam, PG&E made the decision to keep the spillway gates open atop Scott Dam indefinitely, reducing the water storage capacity in Lake Pillsbury by approximately 20,000 acre-feet. With hydropower operations no longer occurring at the project, PG&E has stated that transfers will be limited to the minimum releases to the East Fork required by its FERC license and water deliveries to the Potter Valley Irrigation District. As a result of the project no longer generating hydropower, the discontinuation of discretionary transfers of Eel River water to the East Fork have resulted in reduction of transfers by up to 456 acre-feet per day. To mitigate the reduced storage capacity at Lake Pillsbury, PG&E has been filing temporary flow variances with FERC requesting reduced minimum flow requirements in the Eel River and reduced minimum release requirements to the East Fork. Additionally, on July 23, 2023, and supplemented on January 30, 2025, and September 26, 2025, PG&E filed an application for a non-capacity license amendment for the PVP to formalize the flow changes it has been making under temporary variance requests. On December 29, 2025, PG&E notified FERC of its intent to supplement the license amendment application by June 30, 2026, to include revisions to the proposed flow requirements that would provide a more flexible release strategy. The deadline for submitting the supplemental application has since been extended to September 30, 2026. The non-capacity license amendment is currently under review by FERC and is anticipated to take several years before it is approved. While the license amendment application is under FERC review, PG&E is expected to continue with annual requests for a temporary variance of flow requirements due to the implications of its decision to no longer close the spillway gates on Scott Dam. On May 14, 2026, FERC issued an order approving PG&E’s January 30, 2026, temporary variance request. In the order, FERC approved changes to the minimum release flows in the Eel River and the East Fork that included: (1) a reduction in minimum release flow requirements for the Eel River below Scott Dam to the critical water year type requirement of 20 cubic feet per second (cfs); (2) a reduction in minimum release flow requirements for the East Fork triggered by the cessation of Lake Pillsbury spillway flows, to a range of 25 and 5 cfs based on a flexible management flow release strategy. After September 30th, the termination of the order will be dependent on when Lake Pillsbury storage exceeds 36,000 acre-feet. Sonoma Water is petitioning for temporary urgency changes to its four water-right permits used to provide wholesale water to cities and water districts in Sonoma and Marin counties. The historical link between the two watersheds upon which Decision 1610 is based is no longer applicable. The hydrologic index of Decision 1610 is not a reliable metric for Russian River water supply conditions without the historical large inter-basin transfer and will not function as intended. The request includes changes to the hydrologic index as well as modifications to the minimum instream flow requirements. The hydrologic index changes are necessary to ensure that the designated water supply condition and corresponding minimum instream flow requirements in the Russian River watershed are aligned with actual watershed hydrologic conditions, which is essential to maintain sustainable reservoir and river operations protecting municipal water supply and listed salmon species. Additionally, changes to reduce the dry season minimum instream flow requirements are necessary under a designated Normal water supply condition to comply with the findings of the 2025 Russian River Biological Opinion issued by the National Marine Fisheries Service (NMFS) on April 29, 2025, (2025 Russian River Biological Opinion) and its predecessor issued on September 24, 2008 (2008 Russian River Biological Opinion). NMFS’ 2008 Russian River Biological Opinion required changes to the Decision 1610 minimum instream flow requirements to enable alternative flow management scenarios that will increase available rearing habitat in Dry Creek and the Upper Russian River, and provide a lower, closer-to-natural inflow to the estuary between late spring and early fall, thereby enhancing the potential for maintaining a seasonal freshwater lagoon that will likely support increased production of juvenile steelhead and salmon. As required by the 2008 Russian River Biological Opinion, in September 2009 Sonoma Water filed petitions with the State Water Board to make permanent changes to the Decision 1610 minimum instream flow requirements. These petitions were withdrawn and replaced with new petitions filed in August 2016, which are presently pending before the State Water Board. The State Water Board will not act on these petitions until the necessary environmental impact report is prepared and the water-rights issues associated with these petitions are resolved. The 2025 Russian River Biological Opinion has a 10-year term and covers the U.S. Army Corps of Engineers and Sonoma Water’s operations and maintenance activities, including water supply, flood control, channel maintenance and habitat restoration in the Russian River watershed. The 2025 Russian River Biological Opinion finds that continued restoration of freshwater habitats for listed salmon and steelhead is reliant on the adjustments to existing flow requirements of Decision 1610. It concludes that Sonoma Water should continue to petition the State Water Board for changes to Decision 1610 minimum flows during Normal hydrologic conditions in a manner consistent with the Reasonable and Prudent Alternative from the 2008 Russian River Biological Opinion. These changes were included in the Proposed Action to avoid potential take of listed salmonids. NMFS determined that these actions will improve water reliability and benefit salmon and steelhead through enhanced cold-water storage resulting in sustained cooler water temperatures during the summer and fall rearing season and greater flexibility to release water to facilitate fish migration. As with the previous NMFS’ 2008 Russian River Biological Opinion, the 2025 Russian River Biological Opinion requires petitions for temporary changes to minimum instream flows on the mainstem Russian River, and not on Dry Creek. These petitions do not seek any changes in the Dry Creek minimum-flow requirements adopted in Decision 1610. In accordance with the terms and conditions of the 2025 Russian River Biological Opinion and in response to changed watershed conditions due to recent operational changes of PG&E’s PVP, Sonoma Water is filing temporary urgency change petitions (TUCPs) with the SWRCB. The petitions request that the SWRCB make the following changes to Sonoma Water’s water rights permits. From November 16, 2026, for a period of 180 days, Sonoma Water requests the use of a hydrologic index based on storage thresholds in Lake Mendocino to establish water supply conditions as identified in the 2025 Russian River Biological Opinion. For the period from May 1, 2027, until the end of the order (or October 15, 2027, whichever is first)) under a Normal water supply condition, Sonoma Water requests to: (a) reduce the required minimum instream flow in the Russian River from the confluence of the East and West Forks to the river’s confluence with Dry Creek from 185 cfs to 125 cfs; and (b) reduce required minimum instream flow in the Russian River from its confluence with Dry Creek to the Pacific Ocean from 125 cfs to 70 cfs. Decision 1610 established the minimum instream flow requirements for Dry Creek and the Russian River (see Figure 1). These requirements vary based on defined hydrologic conditions. If approved, the requested reductions in Russian River instream flow requirements will be in effect starting May 1, 2027 under a Normal water supply condition. To improve its efforts at achieving the optimal habitat conditions in the Lower Russian River and to optimally manage flows in the entire river, Sonoma Water has requested in these TUCPs (as in previous ones) that these minimum instream flow requirements be implemented on a 5-day running average of average daily streamflow measurements with the condition that instantaneous flows on the Upper Russian River be no less than 110 cfs and on the Lower Russian River be no less than 60 cfs. No temporary change in the Dry Creek minimum instream flow requirements is proposed. The proposed temporary changes in Russian River minimum instream flow requirements will not result in any unusual circumstances, because the proposed minimum instream flow requirements are within the range of those that already occur during Dry and Critical water supply conditions under Decision 1610. During the period that the proposed temporary flow changes are in effect, Sonoma Water will also monitor water quality and fish and collect and report information and data related to monitoring activities, to be in accordance with NMFS’ 2025 Russian River Biological Opinion.