Russian River Weekly Update 5/18/26

East Fork Russian River in Potter Valley, April 2026 by E Salomone

Reservoir Storage & Operations:

Water supply information provided by Sonoma Water (find more water storage info here).

Lake Mendocino, Pillsbury, and Sonoma current storage data as of May 2023, with changes over the past week noted.

The graph shows Lake Mendocino's water storage levels (in acre-feet) from 2019 to 2026, with projected data for 2026.

The image shows Lake Pillsbury's storage levels and target scenarios from 2019 to 2026, with various target lines plotted over time.

The chart shows Lake Sonoma's water storage levels from 2019 to 2026, with projections indicating 261,969 acre-feet by May 2026.

FERC Approves Potter Valley Project Flow Variance, Effective Friday, May 15th

On May 14, 2026, FERC issued an order approving the 2026 temporary flow variance for the Potter Valley Project flows from the Eel to the Russian River. This means that starting May 15th, flows to the Russian River will remain at 25 cfs (rather than increasing to 75 cfs) and will fluctuate between a range of 5-25 cfs based on Lake Pillsbury storage forecasts and water temperature data. This will directly impact water availability for water rights along the Russian River. To establish the impact to your water right(s), review your water right documentation carefully and use the State Water Resources Control Board Supply and Demand Assessment tool for the Russian River. An instructional video is posted on this same website.

PG&E will utilize a flexible flow release approach to reservoir releases to provide adequate flows and cooler water temperatures in the Eel River. PG&E states that the variance is necessary due to the reduced water capacity in Lake Pillsbury as a result of its seismic-risk-related storage restriction, which has reduced the available water stores by approximately 18,200 acre-feet. PG&E has an objective of maintaining 25,000 acre-feet in Lake Pillsbury on October 1, 2026, which it calculates will allow it to meet its dam safety obligations and to preserve the cold water pool to ensure cooler water release temperatures. The initial flow release into the East Branch Russian River will remain at the current 25 cfs. PG&E will then adjust releases to the East Branch Russian River between 5 and 25 cfs based on Lake Pillsbury storage forecasts using available hydrologic forecasting tools and runoff forecasts, historical water temperature data and water temperature modeling, and other flexible water management criteria. Adjustments made to the East Branch Russian River releases will be made in consultation with the PG&E Drought Working Group. If Lake Pillsbury storage is below the 36,000 acre-feet after September 30, releases to the East Branch Russian River will be limited to 5 cfs. When Lake Pillsbury storage gets above 36,000 acre-feet after September 30, the variance will end and PG&E will release flows as required under its license.

Visit the RRFC Webpage for more information.

2026, 1-31 PG&E 2026 Flow Variance Request to FERC (77-334 ).pdf

Future of the Eel River to Russian River Trans Basin Diversion (Potter Valley Project)

RRFC webpage on the Future of the Eel River to Russian River Diversion

SWRCB Potter Valley Hydroelectric Project webpage

Recent comments and articles:

Notice of Availability of the Scoping Report for the Potter Valley Hydroelectric Project Surrender and Decommissioning Project

On May 12, 2026, the State Water Resources Control Board (State Water Board or SWRCB) posted the Scoping Report for the Potter Valley Hydroelectric Project Surrender and Decommissioning Project (Scoping Report). The Scoping Report summarizes comments received during the State Water Board’s Notice of Preparation of an Environmental Impact Report for the Potter Valley Hydroelectric Project Surrender and Decommissioning Project public comment period, which closed on November 3, 2025.

Link to the Scoping Report on Maven's Notebook website

Additional information related to the Potter Valley Hydroelectric Project can be found on the State Water Board’s Potter Valley Hydroelectric Project webpage: SWRCB Potter Valley Hydroelectric Project webpage

Questions regarding the Scoping Report or Potter Valley Hydroelectric Project: please contact Wilhelmina Chon, Project Manager by email at: Wilhelmina.Chon@waterboards.ca.gov.

Webinar Series: voices form the Field, Wednesday May 27 11- noon

Sustainable conservation is holding the third webinar in its Spring 2026 Voices from the Field webinar series, From Field to Policy: Scaling Sustainable Agriculture. Together with panelists from General Mills, East Turlock Subbasin Groundwater Sustainability Agency, and EcoThrive Farm Management, they will explore how farmer engagement, science, and policy can work together to advance and expand sustainable agriculture across California. The conversation will examine how growers, researchers, water managers, and industry partners are finding common ground to support soil health and groundwater sustainability under the Sustainable Groundwater Management Act (SGMA). Link to registration

Webinar Series: Ecological Drought: Drought Dashboards to Improve Drought Monitoring, Inform Tribal Resilience, and Preserve Ecological and Cultural Resources, May 26 11 AM

This webinar will focus on recently developed drought dashboards and tools to improve drought monitoring, inform tribal drought resilience, and preserve ecological and cultural resources. Presenters will share research findings from the Fiscal Year 2022 Coping with Drought competitions on Ecological Drought and Building Tribal Drought Resilience. More information and registration.