On February 14, 2025, PG&E submitted a temporary license flow amendment (previously referred to as a temporary flow variance) to the Federal Energy Regulatory Commission (FERC) for the Potter Valley Project 2025 operations.

 See 2025, 2-14 PG&E 2025 Flow Variance Request to FERC.pdf at top of page. 

PG&E requests a temporary variance of its minimum flow requirements at two project locations.  Due to seismic risk at Scott Dam, PG&E has elected to leave the spillway gates at Scott Dam open indefinitely, thereby reducing the storage capacity in Lake Pillsbury by approximately 20,000 acre-feet to 56,000 acre-feet water storage.  PG&E also states that there is a high potential for bank sloughing and ensuing dam safety and operational constraints should the reservoir recede to a pool level of between 5,000 and 12,000 acre-feet, with 12,000 acre-feet becoming the planning minimum for water management. 

To preserve water storage in Lake Pillsbury and conserve cold water for downstream aquatic resources, PG&E proposes to release flows below Scott Dam (as measured at gage E-2) to be consistent with a critical water year type minimum flow of 20 cubic feet per second (cfs).  However, actual releases would be closer to the minimum facility limitation of 35 cfs from the low-level outlet.  In addition, PG&E would reduce minimum flows in the East Branch Russian River (as measured at gage E-16) to match the dry water year minimum flow requirement of 25 cfs with the flexibility to further reduce flows to the critical water year requirement of 5 cfs, depending on water availability, safety concerns, and water temperature conditions in the Eel River.  After September 30, 2025, PG&E would resume the dry water year flow release of 25 cfs.  In addition, PG&E requests that compliance with the minimum flow requirement in the Eel River below Cape Horn Dam (as measured at gage E-11) be modified to a 24-hour average instead of an instantaneous requirement to allow for a tighter compliance buffer. 

PG&E's request also includes provisions for water temperature and biological monitoring, environmental mitigation, and monthly consultation throughout implementation of the proposed variance.  PG&E requests that the variance begin immediately upon FERC approval and conclude when Lake Pillsbury storage exceeds 36,000 acre‑feet following October 1, 2025, or is superseded by another variance or license amendment.

On April 16, 2025, FERC opened the comment period on PG&E’s Application for Temporary Variance of Flow Requirements. With this notice, FERC is inviting federal, state, local, and Tribal agencies with jurisdiction and/or special expertise with respect to environmental issues affected by the proposal, that wish to cooperate in the preparation of any environmental document, if applicable, to follow the instructions for filing such requests.  Cooperating agencies should note the Commission's policy that agencies that cooperate in the preparation of any environmental document cannot also intervene. Deadline for filing comments, motions to intervene, and protests is May 16, 2025. More information on how to file comment can be found in the document linked below:

 See 2025, 4-16 FERC notice of comment period on flow variance.pdf at top of page.

Comments submitted to FERC on the Flow Variance request:

PG&E filed a request in February 2025 for a temporary variance of the flow release requirements for the Potter Valley Project. FERC states it found that approval of PG&E’s temporary variance request would help ensure that it has adequate water storage capacity in Lake Pillsbury to provide flows and temperatures necessary for the protection of threatened species.  The proposed variance conserves limited water resources, minimizes the risk of bank sloughing, which would result in impaired outlet operation and could affect the stability of the dam abutments at Lake Pillsbury, and maintains flows within the bounds of Article 52 of the license. 

FERC States that while the Russian River watershed would receive reduced flow allocations, the proposed variance would appropriately balance competing interests by only further reducing flows to the Russian River below 25 cfs as necessary for the protection of Eel River salmonids or the project outlet works.  In addition, the proposed variance would avoid additional effects to Eel River environmental resources while minimizing any effects to aquatic resources in the East Branch Russian River.  Finally, approval of the proposed variance would allow additional time for the Commission to review and complete its analysis of the July 31, 2023 PG&E license amendment request.

See 2025, 8-4 FERC approval of PG&E 2025 flow variance.pdf at top of page.