Sonoma Water has asked the state to let it hold the lower Russian River to 70 cubic feet per second next summer, down from the 125 cfs its water rights require in a normal year.
The request covers the river from Dry Creek to the ocean at Jenner, past Forestville, Guerneville, Monte Rio and Duncans Mills. According to the State Water Resources Control Board’s notice, flow would be measured as a five-day average and could never dip below 60 cfs. Upstream, from the forks above Ukiah to Dry Creek, the floor would drop from 185 cfs to 125.
The petitions also ask to keep rating the Russian’s water supply by storage in Lake Mendocino, not by inflow to Lake Pillsbury on the Eel, for 180 days starting Nov. 16, when the current order runs out. The state posted notice Sept. 17. Objections are due by 4:30 p.m. Monday, Oct. 19.
Why Lake Pillsbury stopped working
The minimum flows come from Decision 1610, which the state board adopted in 1986. It sorts each year into Normal, Dry or Critical by how much water flows into Lake Pillsbury, because PG&E’s Potter Valley Project then piped a big share of the Eel into the East Fork of the Russian.
Sonoma Water’s petition says a transformer bank failed at the Potter Valley powerhouse in 2021, and PG&E said in March 2023 it would not replace it, ending the power generation and the water transfers that went with it. PG&E has since applied to surrender the project’s federal license. According to the state’s May order, Sonoma Water told the board that transfers now average less than 40,000 acre-feet a year, against about 150,000 when Decision 1610 was written. It also said about 62% of the water entering the lower river from June through September 2025 came from upstream, mostly Lake Mendocino releases.
What happened this summer
The state approved the same 70 cfs floor May 21, but it applies only in a Normal year, and this summer wasn’t one. Sonoma Water’s weekly reports from June through late September list a Dry condition and an 85 cfs minimum for the lower river.
On Oct. 1, Lake Mendocino held 58,901 acre-feet, just over the 58,000 acre-foot line for a Dry rating on that date. The rating switched to Normal and the lower-river floor fell to 70 cfs. The petition says that lasts only through Oct. 15, when Decision 1610’s standard minimums return.
The next check comes Nov. 1, when less than 51,000 acre-feet in the lake means Dry. It held 55,956 acre-feet on Oct. 10, according to the California Data Exchange Center. That day the river at Hacienda Bridge ran 132 cfs, according to provisional U.S. Geological Survey data. The 87-year median for the date is 182 cfs.
Fish, swimmers and the sandbar
Sonoma Water says the summer cut follows the National Marine Fisheries Service’s April 2025 biological opinion on the Russian, written to protect threatened and endangered salmon and steelhead. The petition says slower water makes better habitat for young fish and lower releases save cold water in Lake Mendocino for fall. It also cites the service’s 2008 finding that Decision 1610’s summer flows push extra water into the estuary at Jenner, forcing the sandbar at the river mouth to be breached to prevent flooding.
The permit terms say the flows are kept for fish and wildlife “and for the maintenance of recreation in the Russian River.” The petition says lower flows “may impair some instream beneficial uses, principally recreational uses.” In its May order, the state board wrote that recreation “may be minimally affected.”
The spring round drew a letter of support from Mendocino County’s Russian River flood control district and two sets of comments. Barbara Delonno wrote that flows of 125 to 140 cfs on the lower river did more for water quality and recreation than 70. Russian Riverkeeper argued that rewriting Decision 1610 through temporary orders, year after year, sidesteps full environmental review. The board replied that Sonoma Water is preparing an environmental report for permanent changes, work it said the Potter Valley decommissioning has complicated.
Conflicting dates
Sonoma Water’s cover letter and petition forms are dated Friday, Aug. 28. The state notice says the agency filed them Monday, Aug. 31.
The forms ask for an order running Nov. 16 to May 14, 2027. The notice says the flow cut would start May 1, 2027, and last “through the end of this Order (or October 15, 2027, whichever is first),” and that the order expires “in approximately mid-May 2027.” Sonoma Water’s website says the cut would run May 1 to Oct. 15, 2027. As filed, the order would cover about two weeks of it. This year’s summer rules came from a separate petition filed in March.
How to object
According to the notice, anyone may object. Send objections to both:
- Ken Emanuel, State Water Resources Control Board, Division of Water Rights, P.O. Box 2000, Sacramento, CA 95812-2000, Kenneth.Emanuel@waterboards.ca.gov
- Grant Davis, general manager, Sonoma County Water Agency, 404 Aviation Blvd., Santa Rosa, CA 95403-9019, Grant.Davis@scwa.ca.gov
The notice says the board may rule before the deadline and can amend an order later to address objections. As of Oct. 11, Sonoma Water’s petition page listed no order on the August filing.