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

2023100350

Sonoma County Water Agency

NOE - Notice of Exemption

10/13/2023

10/13/2023

Connie Barton

Sonoma County Water Agency

Senior Environmental Specialist

Lead/Public Agency / Project Applicant

404 Aviation Blvd.
Santa Rosa, CA 95403

(707) 547-1905

connie.barton@scwa.ca.gov

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.

Categorical Exemption

Section 21080(b)(4), State CEQA Guidelines 15269(c), 15307, 15308.

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.