Petitions Requesting Approval of Temporary Urgency Changes in Water Right Permits 12947A, 12949, 12950, and 16596 in Mendocino and Sonoma Counties

Summary

SCH Number
2023100350
Public Agency
Sonoma County Water Agency
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
10/13/2023
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 (TUCP) 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 that 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
Connie Barton
Agency Name
Sonoma County Water Agency
Job Title
Senior Environmental Specialist
Contact Types
Lead/Public Agency / Project Applicant

Location

Counties
Mendocino, Sonoma
Regions
Citywide, Countywide, Northern California, Unincorporated
Other Location Info
The proposed action would 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. Figure 1 shows the minimum instream flow requirements for the Russian River system. 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
Section 21080(b)(4), State CEQA Guidelines 15269(c), 15307, 15308.
Reasons for Exemption
A. Actions to Prevent or Mitigate an Emergency California Public Resources Code, Division 13, Section 21080(b)(4) provides that specific actions necessary to prevent or mitigate an emergency are exempt from CEQA. The emergency conditions are due to an urgent need to implement the proposed changes as a result of the drastic reduction of potential Eel River water imports through the PVP resulting from the inoperability of the powerhouse for the foreseeable future and PG&E’s decision to keep the spillway gates open atop Scott Dam indefinitely, consequently revising the operations at Lake Pillsbury, and filing a long-term flow regime request to modify flow requirements. The volume of Eel River water that can be transferred to the Russian River is no longer correlated to cumulative inflow into Lake Pillsbury. An evaluation of the hydrologic condition in the Russian River is more appropriately established by conditions in its watershed. 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 in storage could cause serious impacts to human health and welfare and reduce water supplies needed for fishery protection. The required change is urgent, and cannot be accomplished within the timeframe required for completion of the Environmental Impact Report (already in process) that evaluates broader proposed changes to Decision 1610. B. 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 prevent Lake Mendocino from declining to a storage level at which the reservoir may no longer be functional. Approval of the TUCP 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 more likely can be sustained with releases from Lake Mendocino and Lake Sonoma without the risk of severely depleting storage and exacerbating a water shortage condition and harm to natural resources and the environment.
County Clerks
Mendocino, Sonoma

Attachments

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