Sonoma Water - Temporary Urgency Change Petitions

Water Resources / Water Supply / Temporary Urgency Change Petition

Temporary Urgency Change Petitions

April 2024 Temporary Urgency Change Petition

On April 19, 2024, Sonoma County Water Agency (Sonoma Water) filed temporary urgency change petitions 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 temporarily reduce the minimum instream flow requirements specified under the subject permits due constraints previously placed on Sonoma Water pursuant to the September 24, 2008, National Marine Fisheries Service (NMFS) Biological Opinion for Water Supply, Flood Control Operations, and Channel Maintenance conducted by the U.S. Army Corps of Engineers, Sonoma Water, and the Mendocino County Russian River Flood Control and Water Conservation Improvement District in the Russian River watershed (Biological Opinion).

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.

Weekly Hydrologic Reports

Summary reports of recent historical hydrologic conditions and forecasted rainfall for the Russian River watershed.

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.