Water is an important topic here in Mendocino County for farmers, ranchers, wildlife, residents and businesses. Farmers and ranchers in Mendocino County are very aware of the importance of a long-term, reliable water supply and good water quality for everyone. Mendocino County Farm Bureau works directly with farmers and ranchers in the various watersheds to consider critically important water issues. Farm Bureau’s Water Committee reaches out to collaborate with multiple stakeholder groups and seeks to build partnerships that allow us to do even more for our members.
Water Committee News
Submitted by Frost Pauli, Water Committee Chair
Potter Valley Project Variance
On May 13, PG&E submitted a flow variance request for the Potter Valley Hydroelectric Project (Project) requesting a license diversion variance from the Federal Energy Regulatory Commission (FERC). The reason for the variance was stated to protect storage and to preserve the cold-water pool in Lake Pillsbury for fishery needs. The variance was approved on July 27th which immediately reduced the flow diverted into the East Fork of the Russian River from 75 CFS to 5 CFS. From the discussions with the PG&E drought working group since July, there has not been a willingness to look at increasing these flow allocations even thought the variance allowed for flow increase considerations based on storage levels at Lake Pillsbury. The variance could have been terminated by October 1st, if storage in Lake Pillsbury remained at or above 36,000 AF. However, the fisheries agencies made the determination to start using the first 2,500 acre-feet of block water (water allocations retained in Lake Pillsbury to be used by the fisheries agencies as determined to assist with fishery needs such as migration) on September 20th. With this additional water release Lake Pillsbury fell below the 36,000-acre foot threshold at the end of September. The fisheries agencies may decide to use the additional 2,500 acre-feet of block water in November or December. So, Mother Nature will have to bring some precipitation in the coming months to increase the storage at Lake Pillsbury above the 36,000-acre-foot threshold to terminate the variance. However, since the failed transformer bank at the powerhouse has not been remedied, the Russian River will not be seeing any degree of “normal” diversions from the Project this winter.
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Water Diversion and Use Reporting
If you divert and use water from a surface water source such as a lake, creek, stream, or river, or you divert water from a subterranean stream that flows in a known and definite channel, California law requires you to report your diversion and use to the State Water Board, Division of Water Rights.
On September 23, 2021, Governor Gavin Newsom signed Senate Bill (SB) 155 which modifies the reporting deadline and reporting period for annual water use to the Division of Water Rights. Provisions in SB 155 consolidate all water use reporting periods, for all types of water rights, to the standard Water Year (October 1 through September 30). Further, the new law consolidates the due dates for all water use reports to February 1 of the ensuing year.
All water right holders who have previously diverted or intend to divert more than 10 acre-feet per year (riparian and pre-1914 ), or are authorized to divert more than 10 acre-feet per year under a permit, license, or registration, are required to measure the water they divert.
State Water Board Reports and Measurement Website
State Water Board Report Management System (for annual reporting) Website
The Sustainable Groundwater Management Act (SGMA)

In December 2014, the Department of Water Resources (DWR) released the ground water basin classifications to determine coverage under SGMA. For Mendocino County, the upper Russian River from the Tomki Road area in Redwood Valley to Knight Hill (north of Hopland) was classified as a medium priority ground water basin, the Ukiah Valley ground water basin # 1-52, and is subject to SGMA compliance. From July of 2016 until July of 2017, the Mendocino County Water Agency hosted public meetings to assist in the formation of the Groundwater Sustainability Agency (GSA) and Farm Bureau was at the table to ensure that agriculture was represented in the process. The GSA formation was the first step to work toward compliance and this was completed in June of 2017. The Ukiah Valley Basin Groundwater Sustainability Agency (UVBGSA) was created by a Joint Powers Agreement (JPA) and have been meeting regularly since 2017. The Groundwater Sustainability Plan (GSP) was finalized and submitted to DWR in 2022. The GSP is pending final approval from DWR. For additional information, please see the links below.
Ukiah Valley Groundwater Basin: Groundwater Sustainability Agency (GSA)
Department of Water Resources SGMA Website
Other Water Related Resources
North Coast Regional Water Quality Control Board (Water Quality Programs)
CA Department of Fish and Wildlife Lake and Streambed Alteration Program (1600 Permits)
Russian River Flood Control and Water Conservation Improvement District
Lake Mendocino Water Supply Information
CDEC Lake Mendocino Reservoir Data
Sonoma Water Russian River Gauges
USGS Russian River Gauge at Calpella
USGS West Fork Russian River Gauge
USGS Russian River Gauge at Talmage
USGS Russian River Gauge at Hopland
USGS Russian River Gauge Near Cloverdale