The petition was submitted due to drought conditions, severely low storage levels in Lake Mendocino, and a hydrologic index for establishing minimum flows not aligning with the watershed conditions. On January 1, 2021, the water supply condition for the Russian River was reclassified as 'Normal' from 'Dry' based on the cumulative inflow into Lake Pillsbury for the water year. The calculated cumulative inflow of 9,539 acre-feet exceeded the threshold criterion of 8,000 acre-feet between the two classifications. This designation of 'Normal' water supply conditions does not accurately reflect the current watershed conditions and the lack of rainfall experienced in 2020 in the Upper Russian River. As measured at Ukiah, recorded rainfall for 2020 was 11.32 inches, which amounts to 31% of the average rainfall (37.01 inches). This was the second lowest rainfall recorded since 1893.
In response to the third driest year on record in our region and water supply projections that show the potential for Lake Mendocino to decline to critically low water storage levels, the State Water Resources Control Board on July 29, 2020 approved Sonoma Water’s request to provide flexibility in how water releases are made from Lake Mendocino and flows are managed in the Russian River. The Temporary Urgency Change Order (Order) allows Sonoma Water the flexibility of reducing Russian River flows to 50 cubic-feet-per-second (CFS) in the upper Russian River and 60 CFS in the lower Russian River. If water storage in Lake Mendocino drops more than one percent below the target water supply storage levels, the Order authorizes Sonoma Water to reduce flows to 40 CFS in the upper Russian River and 50 CFS in the lower Russian River. Lake Mendocino is currently about 2,000 acre-feet above target water supply storage levels. If water levels continue to remain above the target water supply storage by a similar buffer, flows in the upper Russian River would be managed near 70-75 cfs and near 80-85 cfs in the lower Russian River.
In June, Sonoma Water filed a Temporary Urgency Change Petition (TUCP) with the State Water Resources Control Board to reduce Russian River minimum in-stream flows this summer. With the Ukiah region facing its third driest water year on record, Lake Mendocino’s water supply is projected to reach critically low levels due to dry conditions and reduced water transfers from the Potter Valley Project. The reduced Potter Valley Project water transfer is forecasted to put Lake Mendocino’s water supply levels into a critical condition. This critical condition is concerning for communities and agriculture that rely on Lake Mendocino for water their supply and could threaten water quality conditions for endangered fish species migrating in the fall up the Russian River. Minimum in-stream flows requested in the TUCP would help preserve water supplies in Lake Mendocino and protect the fall migration of endangered fish.
Sonoma Water Director James Gore said, “Sonoma Water needs every tool in its toolbox to ensure our regional water supply system has sufficient supplies to both meet urban water demand but also protect endangered fish species in the Russian River. The requested reduction in minimum flows is one tool that will help us meet our goals of balancing water for people and fish this year. Another important tool is water conservation. Our community has done a great job saving water and we encourage everyone to continue with their water saving efforts.”
Sonoma Water has launched a public awareness effort to increase community education on how the Russian River water supply system operates and the importance of saving water and its impact on the water supply system. A special E-News has also been created to help educate the community regarding the Order.
In addition, the Sonoma-Marin Saving Water Partnership, a coalition of Sonoma Water’s retail water contractors, have launched an annual saving water public education campaign. The campaign includes radio and newspaper public service announcements educating the community about water saving best practices. Our region continues to meet state conservation goals and has lowered water use from 130 gallons per capita per day (GPCD) in 2013, to 107 GPCD in 2019. That is well below the state’s 2020 conservation target of 129 GPCD for our region. Learn more about the Sonoma-Marin Saving Water Partnership and how to save water at www.savingwaterpartnership.org.
Sonoma Water General Manager Grant Davis said, “The Temporary Urgency Change Order will preserve water storage in Lake Mendocino. By preserving storage, we can better maintain the cold-water pool at Lake Mendocino to improve water quality conditions for migrating endangered fish from the ocean into the Russian River. We will also have more flexibility to manage our regional water supply system.”
Public comments on the TUCP were managed by the State Water Resources Control Board.
Minimum in-stream flow background:
Sonoma Water controls and coordinates water supply releases from Lake Mendocino and Lake Sonoma to implement the minimum instream flow requirements in water rights Decision 1610, which the State Water Resources Control Board adopted in 1986. Decision 1610 specifies minimum flow requirements for the Upper Russian River, Dry Creek, and the Lower Russian River. These minimum flow requirements vary based on water supply conditions, which are also specified in Decision 1610. The Decision 1610 requirements for the Upper Russian River and Lower Russian River are contained in term 20 of the Water Agency’s water-right Permit 12947A (Application 12919A). The Decision 1610 requirements for the Lower Russian River are contained in term 17 of the Water Agency’s water-right Permit 12949 (Application 15736) and term 17 of the Water Agency’s water-right Permit 12950 (Application 15737). The Decision 1610 requirements for Dry Creek and the Lower Russian River are contained in term 13 of the Water Agency’s water-right Permit 16596 (Application 19351).
Sonoma Water’s operations are also subject to the Russian River Biological Opinion issued by the National Marine Fisheries Service on September 24, 2008.