Petitions Requesting Approval of Temporary Urgency Changes in Water Right Permits 12947A, 12949, 12950, and 16596 in Mendocino and Sonoma Counties
2 Documents in Project
Summary
SCH Number
2025100171
Public Agency
State Water Resources Control Board
Document Title
Petitions Requesting Approval of Temporary Urgency Changes in Water Right Permits 12947A, 12949, 12950, and 16596 in Mendocino and Sonoma Counties
Document Type
NOE - Notice of Exemption
Received
Posted
12/24/2025
Document Description
The Sonoma County Water Agency (Sonoma Water) controls and coordinates water supply releases from the Coyote Valley Dam and Warm Springs Dam projects in accordance with the provisions of water rights Decision 1610, which the State Water Resources Control Board (State Water Board) adopted on April 17, 1986. Decision 1610 specifies the water supply conditions for the Russian River and the minimum instream flow requirements for the Upper Russian River, Dry Creek, and the Lower Russian River, which vary based on hydrological conditions and cumulative inflow into Lake Pillsbury as the hydrologic index.
Sonoma Water is filing temporary urgency change petitions (TUCPs) requesting that storage thresholds in Lake Mendocino be used as the hydrologic index to determine the water supply condition in the Russian River watershed. An urgent need exists to implement the proposed changes due to the drastic reduction of potential Eel River water imports through Pacific Gas and Electric’s (PG&E) Potter Valley Hydroelectric Project (PVP). Without the proposed changes, the applicable minimum instream flow requirements may require releases of water from Lake Mendocino and Lake Sonoma at levels that would risk significant depletions of storage levels. Such depletions could cause serious impacts to human health and welfare and reduce water supplies needed for protection of listed salmon species in the Russian River. These changes are necessary to ensure that the water supply condition and corresponding minimum instream flow requirements in the Russian River watershed are aligned with actual watershed hydrologic conditions. This is essential to maintain sustainable reservoir/river operations to protect municipal water supply and listed salmon species in the Russian River.
Contact Information
Name
Ken Emanuel
Agency Name
State Water Resources Control Board
Job Title
Environmental Scientist
Contact Types
Responsible Agency
Phone
Name
Connie Barton
Agency Name
Sonoma County Water Agency
Job Title
Senior Environmental Specialist
Contact Types
Lead/Public Agency / Parties Undertaking Project
Phone
Location
Cities
Unincorporated
Counties
Mendocino, Sonoma
Regions
Unincorporated
Other Location Info
The proposed project will occur in Mendocino and Sonoma counties at Lake Mendocino, in the Upper Russian River from Coyote Valley Dam/Lake Mendocino to the confluence with Dry Creek, Dry Creek downstream of Warm Springs Dam/Lake Sonoma, and in the Lower Russian River from the confluence with Dry Creek to the Pacific Ocean. Communities and cities along the Russian River include Ukiah, Hopland, Cloverdale, Geyserville, Healdsburg, Forestville, Mirabel Park, Rio Nido, Guerneville, Monte Rio, Duncans Mills, and Jenner.
Notice of Exemption
Exempt Status
Categorical Exemption
Type, Section or Code
15307, 15308
Reasons for Exemption
Actions by Regulatory Agencies for Protection of Natural Resources and the Environment CEQA Guidelines Sections 15307 and 15308 provide that actions taken by regulatory agencies to assure the maintenance, restoration or enhancement of a natural resource and the environment are categorically exempt. Sonoma Water is proposing temporary urgency changes to its water right Permits 12947A, 12949, 12950, and 16596 that the State Water Resources Control Board, as the regulatory agency, will consider and potentially approve. Those changes are necessary to ensure an accurate evaluation of water supply conditions that would maintain viable operations to support municipal use, protect listed salmon species, address water supply conditions at Lake Mendocino and Lake Sonoma, and best prevent Lake Mendocino from declining to a storage level at which the reservoir may no longer be functional. Approval of the TUCPs would provide alternative storage thresholds and criteria for determining minimum instream flow requirements for the Russian River that would be based on a more accurate assessment of water supply conditions in the Russian River watershed. This would result in minimum instream flow requirements that could more likely be sustained with releases from Lake Mendocino and Lake Sonoma without the risk of severely depleting storage and exacerbating a water shortage condition and harming natural resources and the environment.
County Clerks
Mendocino, Sonoma
Attachments
Notice of Exemption
Disclaimer: The Governor’s Office of Land Use and Climate Innovation (LCI) accepts no responsibility for the content or accessibility of these documents. To obtain an attachment in a different format, please contact the lead agency at the contact information listed above. For more information, please visit LCI’s Accessibility Site.