Temporary changes to water rights for the Russian River proposed by Sonoma Water.

NOTICE OF TEMPORARY URGENCY CHANGE PETITIONS FOR PERMITS 12947A, 12949, 12950, AND 16596 (APPLICATIONS 12919A, 15736, 15737, AND 19351) OF SONOMA COUNTY WATER AGENCY On March 20, 2026, Sonoma County Water Agency (Sonoma Water) filed temporary urgency change petitions (TUCPs) with the State Water Resources Control Board (State Water Board), Division of Water Rights (Division) requesting approval of temporary changes to water right Permits 12947A, 12949, 12950, and 16596 (Applications 12919A, 15736, 15737, and 19351) pursuant to California Water Code section 1435. The petitions seek authorization to implement minimum instream flow requirements for the Russian River that will be established using an alternate hydrologic index based on water storage in Lake Mendocino, rather than the current hydrologic index based on cumulative inflow into Lake Pillsbury from May 1 through October 27, 2026, and to temporarily reduce the minimum instream flow requirements specified under the subject permits due to constraints placed on Sonoma Water pursuant to the April 29, 2025, National Marine Fisheries Service (NMFS) Endangered Species Act Section 7(a)(2) Biological Opinion and MagnusonStevens Fishery Conservation and Management Act Essential Fish Habitat Response for the Russian River Watershed Water Supply and Channel Maintenance Project (Biological Opinion). The requested changes to the instream flow requirements are as follows: From May 1 through October 15, 2026, reduce the minimum instream flow requirements for the upper Russian River (from its confluence with the East Fork of the Russian River to its confluence with Dry Creek) from 185 cubic feet per second (cfs) to 125 cfs; and, From May 1 through October 15, 2025, reduce the minimum instream flow requirements for the lower Russian River (from its confluence with Dry Creek to the Pacific Ocean) from 125 cfs to 70 cfs. Sonoma Water proposes to implement the minimum instream flow requirement for the upper Russian River as a 5-day running average of average daily stream flow measurements, with the stipulation that instantaneous stream flows on the upper Russian River would be no less than 110 cfs and on the lower Russian River no less than 60 cfs. This would allow Sonoma Water to manage stream flows with a smaller operational buffer, thereby facilitating the attainment of the flow conditions that the Biological Opinion has concluded are conducive to the enhancement of salmonid habitat. More information regarding the TUCPs, including copies of the petitions, is available at: https://www.sonomawater.org/tucp Pursuant to Water Code section 1438, subdivision (d), any interested person may file an objection to the temporary change. Objections filed in response to this notice should be submitted to the persons listed below by 4:30 p.m. on April 27, 2026. Please be advised the State Water Board may issue an order approving or denying the TUCPs before the end of the noticing period. All objections received will be considered promptly, and an amended order may be issued if necessary to address objections. State Water Resources Control Board Division of Water Rights Attn: Ken Emanuel P.O. Box 2000 Sacramento, CA 95812-2000 Kenneth.Emanuel@waterboards.ca.gov Sonoma County Water Agency Attn: Grant Davis, General Manager 404 Aviation Boulevard Santa Rosa, CA 95403-9019 Grant.Davis@scwa.ca.gov For more information regarding this matter please contact Ken Emanuel at Kenneth.Emanuel@ waterboards.ca.gov. DATE OF NOTICE: March 26, 2026 Publish: 3/29/2026