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PG&E offers first look at surrender options for Potter Valley Project

A dam with a sluice.
Cape Horn Dam impounds the van Arsdale reservoir in Potter Valley, where proponents of a plan to continue the diversion once the dams are removed hope to build the seasonal diversion structure.

PG&E released an initial plan to surrender the Potter Valley Project on Friday morning.

There weren’t a lot of surprises in the 94-page document, which did include a proposalto continue diverting water from the Eel River into the Russian River. In August,a group of Russian River water users and the Round Valley Indian Tribes asked PG&E to consider presenting the plan to FERC, the Federal Energy Regulatory Commission. FERC will rule on the final decommissioning strategy after it’s submitted in 2025. The draft documents that were released Friday did not go to FERC, but are available for public review and comment until December 22. PG&E will submit the next draft to FERC in May of next year.

That gives the proponents of the continued diversion plan a tight timeline to round out their proposal. Without Cape Horn Dam, which impounds the van Arsdale Reservoir in Potter Valley, water could only be diverted during the rainy season. The two alternatives in the proposal are a 700-800 foot channel built of boulders, or a mechanical pumping method. There is still much to be learned about which approach would best serve the dual purposes of fish passage and water supply, how much they would cost, and how much water can legally be diverted. PG&E has three water rights for diversions at the project and two pre-1914 water rights, including one to directly divert 340 cubic feet per second from the Eel River.

The proponents of continuing some form of diversion will have to form a regional entity “with the legal and financial capacity to be responsible for ownership, construction and operation of the facility,” by the end of next month.

The original proponents, which are Sonoma Water, the Inland Mendocino County Water and Power Commission, and the Round Valley Indian Tribes, have been joined by California Fish and Wildlife, Humboldt County, and the conservation organizations California Trout and Trout Unlimited. Brian Johnson, the California Director for Trout Unlimited, noted that the proposal includes a commitment from all parties that the new diversion will not delay dam removal. In a statement, he said, “It represents a viable framework for a two-basin solution and we are committed to working with our partners to develop it further.” Congressman Jared Huffman weighed in with his support, saying that, “PG&E’s draft surrender application is a major step forward to achieving the Two-Basin Solution I’ve advocated for years…I’ll be working to ensure that both elements are completed in a way that best protects communities, tribes, and natural resources in the Eel and Russian river watersheds.”

But a joint statement from Friends of the Eel River and the Pacific Coast Federation of Fishermen’s Associations was skeptical, saying that, “Sonoma’s plan leaves some of the most difficult questions unanswered, such as who will pay how much for diverted Eel River water.”

Janet Pauli, chair of the Inland Mendocino County Water and Power Commission, one of the original proponents of the diversion, says the money will come from water sales and, she hopes, state and federal grants. “Owning, operating and funding the maintenance and actual functioning of the diversion works is going to be what, regionally, people that are dependent on this water supply are going to need to fund on an ongoing basis. We have yet to understand what kinds of costs we may incur.”

She added that consultants are studying water storage options for the new seasonal diversion, including, “potential storage sites for a lake or reservoir in the north ended of Potter Valley, (and) analyzing our groundwater storage potential, and we’ve been talking about this for a very long time, the potential to raise Coyote Valley Dam (which impounds Lake Mendocino) and increase storage.”

Pauli said she is “really pleased” that PG&E included the group’s proposal in its initial draft, though she freely acknowledged that a tremendous amount of work remains to be done, if proponents of the diversion want their plan to be considered by regulators.

Alicia Hamann, Executive Director of Friends of the Eel River, is also in an optimistic mood, if for a different reason. “Things are looking really, really hopeful for the Eel River right now,” she said. “Some people worked for their entire careers to get the Klamath Dams removed.And it’s going to happen so fast on the Eel, it will feel like the blink of an eye, compared to the Klamath.” She also feels like the initial draft “is kind of a win. FERC generally tends to do what utility companies ask for…I do think that this is a win for the Eel River, and it’s a potential win for the Russian RIver, too. We just need to see that water users can get their plan together in the short amount of time that we have” before the next draft, which is due in May.

The draft surrender plan also features a third option, which is capping or filling key components of the infrastructure that makes the diversion possible. That includes tunnels, shafts, penstocks and vents. If one of the alternatives in the proponents’ proposal is not implemented, the other equipment around the diversion will be removed, along with both dams.

One sticking point that hasn’t yet become a focus is what to do about the estimated 15 feet of sediment that’s accumulated in Lake Pillsbury. PG&E’s draft plan says that Scott Dam, which impounds the lake, will be removed before Cape Horn Dam . That process will take either two years, for a rapid removal, or three years, for a phased approach.

Approximately 12 million cubic yards of sediment will be flushed down the river, either in one fell swoop, or in increments, during the rainy season. More sediment will be scooped out of the lake and “placed on adjacent PG&E land for future disposal.” Those methods are not outlined in the draft plan.

The deadline to submit comments on the Initial Draft Surrender Application is December 22, 2023. Electronic submittal of comments is encouraged. Please submit comments to: 

Tony Gigliotti Senior Licensing Project Manager Power Generation 12840 Bill Clark Way Auburn, CA 95602 E-mail: PVSurrender@pge.com

You can view the surrender plan under the Documents tab here. The password is PV_Surrender.

Local News
Sarah Reith came to Mendocino County in 2008 and worked as a reporter and freelancer, joining KZYX as a community news reporter in 2017. She became the KZYX News Director in March, 2023.