Russian River Weekly Update 10/27/25

A group of people is standing outdoors by a lake, displaying a sign about reservoir operations at Lake Mendocino.

Reservoir Storage & Operations:

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

Lake storage data: Mendocino (61,075), Pillsbury (27,191), Sonoma (223,968) acre-feet with respective changes and storage curves.

Graph showing Lake Mendocino Storage from 2018-2025 in acre-feet, highlighting October 27, 2025, with 61,075 acre-feet.

Graph showing Lake Pillsbury storage and target scenarios from 2018-2025, measured in acre-feet.

Graph of Lake Sonoma storage levels from 2018 to 2025 (projected), showing variations and comparisons over time in acre-feet.

Updates on PG&E 2025 Flow Variance, Reducing Water Diversions to the Russian River

No new information this week.

Background & more information:

On August 4, 2025, FERC approved the PG&E 2025 Flow Variance, reducing water diversions to the Russian River basin. More information here.

The State Water Resources Control Board has developed a tool for water right holders, linked below. At the September 3, 2025 State Water Board meeting, staff provided an update on the Water Supply and Demand Assessment Program in which the Russian River was discussed throughout.

State Water Resources Control Board Supply and Demand Assessment tool for the Russian River

PG&E’s Final Surrender Application for Potter Valley Project

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

SWRCB Potter Valley Hydroelectric Project webpage

PVP related articles:

Lake Mendocino FIRO Water Control Manual Signing

Representatives gathered on Wednesday, October 22nd to celebrate the signing of the water management strategy known as FIRO – the Forecast Informed Reservoir Operations. The Water Control Manual (WCM) update represents over a decade of collaborative work across multiple agencies. In addition to Sonoma Water and the Corps, this coordinated effort included the National Oceanic and Atmospheric Administration, Scripps Institute of Oceanography Center for Western Weather and Water Extremes, U.S. Bureau of Reclamation, California Department of Water Resource, local partners and the community. Lake Mendocino will be the first reservoir to have an updated WCM that implements FIRO. The efforts at Lake Mendocino have now led to the evaluation of FIRO at multiple reservoirs throughout the West.

“Before this update, we would inevitably be required to release water to give airspace to the dam for the next storm regardless of the upcoming weather,” said Nick Malasavage, Operations & Readiness Division chief for the USACE San Francisco District. “FIRO allows us to be informed by the forecast and make better decisions.”

Fishermen at a depleted Lake Mendocino, Ukiah. Hilly landscape and cloudy sky in the background.

PPIC 2025 Annual Water Conference, Nov. 13, in Sacramento

The Public Policy Institute of California (PPIC) will host its 2025 Annual Water Conference in Sacramento on Thursday, Nov. 13. “California Water and a Changing Federal Partnership” will explore how California must adapt to its evolving relationship with the new federal administration. For decades, the federal government has been a key partner in California’s water management efforts. The nature and tone of the federal role, however, fluctuate significantly between administrations, with the current administration pursuing a strategy different than its predecessor’s. Join DWR Lead Deputy Director Thomas Gibson and other water experts as they share their thoughts to envision a way forward. This in-person event is free to attend and will be livestreamed. To attend in person, registration is required as space is limited.

Updates from Dept of Water Resources

📢 UPDATED - State Water Board Announces New Water Rights Reporting System

CalWATRS on agenda for State Water Board meeting, Oct. 21- Recording Available

CalWATRS, short for California Water Accounting, Tracking, and Reporting System, is the State's new-and-improved water rights data system, replacing the legacy eWRIMS platform. With CalWATRS, water right holders will have a streamlined way to view all their water right records, file annual reports, and request water rights services. In addition to the CalWATRS informational item at the public meeting on Oct. 21, upcoming CalWATRS events will be posted on the CalWATRS webpage as they are scheduled. CalWATRS successfully launched on Oct. 7, as planned. Learn more about CalWATRS at the CalWATRS Virtual Public Workshop, Tuesday, Oct. 28 - Meeting Recording on YouTube.