Eel River and the Potter Valley Project


On November 17, 2023, Pacific Gas and Electric Company (PG&E) released the initial draft license surrender application and conceptual decommissioning plan for the Potter Valley Project on the Eel River. PG&E has created a website for posting documents related to this proceeding. PG&E intends to restore a free-flowing Eel River and restore fish passage to important habitat by removing the two dams associated with the Potter Valley Project, which has been a long-standing goal of Humboldt County. PG&E is soliciting comments on the initial draft application through December 22, 2023. The next version of the application will be released in June 2024 and the final application will be submitted to the Federal Energy Regulatory Commission in January 2025.

PG&E’s initial draft application includes elements of a regional proposal for achieving the following co-equal goals:

  1. Improving fish migration and habitat on the Eel River with the objective of achieving naturally reproducing, self-sustaining, and harvestable native anadromous fish populations; and
  2. Maintaining material and continued water diversion from the Eel River through the existing tunnel to the Russian River to support water supply reliability, fisheries, and water quality in the Russian River basin.

This proposal provides a framework for continued discussions with a wide table of stakeholders to develop the content and terms of a License Surrender Agreement and Water Diversion Agreement that would be considered for approval sometime in 2024.

The Humboldt County Board of Supervisors adopted the following statement for the regional proposal:

  • The preferred position of Humboldt County is that Eel River water should stay within the Eel River watershed.
  • If water continues to be diverted out of the Eel River Basin into the Russian River Basin, (1) water diversions must be limited to the wet season and the amount and timing of diversions must be consistent with restoration of Eel River fisheries; and (2) an Eel River Restoration Fund must be established and supported in part by ongoing financial charges on water diversions. The Eel River Restoration Fund will need to be funded at a robust level that accounts for continued impacts and supports ecological recovery from historic impacts.
  • Humboldt County will continue to join proponents of the proposal in negotiating a fair and equitable outcome to fully implement the co-equal goals contingent upon no delay in PG&E’s timeline for dam removal. Humboldt County will remain committed to protecting the health and resilience of the Eel River and the interests of people and communities connected to the Eel River.


The Eel River is a major river on the North Coast of California with a biologically rich watershed that spans five counties and links Humboldt County to regional and statewide water resource and habitat management efforts. The Eel River watershed comprises 33% of Humboldt County, more than any other watershed, and the main stem Eel River flows through Humboldt County for 81 miles before entering the Pacific Ocean through the Eel River Delta near Loleta, Ferndale, and Fortuna. Major tributaries to the main stem Eel River include the Van Duzen River and the South Fork Eel River.

Eel River watershed map


The ecosystem services and beneficial uses of the Eel River are a vital part of Humboldt County’s core community values and identity. The Eel River is highly valued for providing fish and wildlife habitat, water supply, recreation opportunities, and scenic beauty. The Eel River is a sacred resource of the Wiyot Tribe which has deep cultural connections to the river and its fisheries. A total of 398 river miles within the Eel River watershed have been designated as recreational, scenic, or wild under the National Wild and Scenic Rivers System.  

Historically, the Eel River watershed supported some of the largest runs of salmon and steelhead on the North Coast. According to Yoshiyama and Moyle (2010), runs of Chinook salmon likely ranged between 100,000 and 800,000 fish per year in the 19th century, declining to between 50,000 and 1000,000 fish per year in the first half of the 20th century and significantly lower after the floods of 1955 and 1964. Recent monitoring by the Eel River Recovery Project has estimated annual Chinook runs of less than 10,000 to over 20,000 fish. The Eel River watershed also provides habitat for coho salmon, winter and summer steelhead, coastal cutthroat trout, lamprey, and green sturgeon.

Humboldt County envisions a healthy, resilient Eel River watershed with robust fisheries that support sustainable harvest opportunities. Eel River fisheries have been impacted by multiple factors which are analyzed in the Eel River Action Plan (2016). California Trout is currently leading the development of the Eel River Restoration and Conservation Program to provide a watershed-wide, process-based framework for prioritizing actions that benefit native anadromous fish and their habitats.

The Humboldt County Resource Conservation District is leading a major, multi-year restoration project on the Salt River and its primary tributaries, located near the Eel River estuary, to address severe sediment impairment and other factors. 

Humboldt County serves as the Groundwater Sustainability Agency for the Eel River Valley groundwater basin.

Potter Valley Project

The Eel River watershed exports water to the Russian River watershed through PG&E’s Potter Valley Project located in Lake and Mendocino Counties. The Potter Valley Project is a hydroelectric facility that includes Scott Dam, which forms the storage reservoir Lake Pillsbury, and Cape Horn Dam (located 12 river miles downstream from Scott Dam) which forms Van Arsdale reservoir, where flow is diverted through a mile-long tunnel into Potter Valley.  Water diversions began at Cape Horn Dam in 1908 and Scott Dam became operational in 1922.  Between the ocean and Cape Horn Dam, the Eel River passes through Humboldt County for 81 miles and Trinity and Mendocino Counties for 75 miles.  

Water diverted by the Potter Valley Project supplies the Potter Valley Irrigation District and then flows into Lake Mendocino near Ukiah to provide supplemental water for the Russian River system, serving water users in Mendocino, Sonoma, and Marin counties.  Prior to 2007, the average volume of diverted water was approximately 150,000 acre-feet per year.  Following implementation of conditions within the Biological Opinion for the Potter Valley Project from the National Marine Fisheries Service, the average diversions from 2007 through 2020 were 60,000 acre-feet per year.  In water year 2021-2022, a total of 40,000 acre-feet were diverted.

The Potter Valley Project has not produced power since July 2021 due to an equipment malfunction.  When the powerhouse was in service, production was relatively low, and the facility had been losing money for several years.  Since July 2021, the facility has continued to make water diversions to meet minimum flow requirements in the East Branch Russian River and to fulfill its contract with Potter Valley Irrigation District.

Scott Dam represents a full barrier to fish passage and blocks hundreds of miles of potential spawning and rearing habitat.  Cape Horn Dam has a fish ladder which periodically becomes impassable due to heavy sediment loading.  The two dams have caused significant downstream geomorphic effects on the Eel River by trapping sediment, and the dams release abnormally cold water in the spring which can alter environmental cues and delay juvenile outmigration.  The dams have enhanced conditions for the invasive Sacramento pikeminnow, a predator of native salmon, since their introduction to the Eel River basin around 1979.  Water diversions from the Potter Valley Project alter the natural flow regime in the Eel River which can impact fish passage and habitat availability especially during the fall and spring.  Water diversions may also affect geomorphic processes by reducing stream power and may reduce the recharge of interconnected alluvial aquifers.

In January 2019, PG&E announced that it would not seek re-licensing of the Potter Valley Project.  In July 2022, PG&E published its schedule for preparing a license surrender application and decommissioning plan for submittal to the Federal Energy Regulatory Commission.  PG&E intends to remove Scott Dam, Cape Horn Dam, and associated facilities so that a free-flowing river will be restored.

From 2019 through 2022, five parties (Sonoma Water, Mendocino Inland Water and Power Commission, Humboldt County, Round Valley Indian Tribes, California Trout) explored the feasibility of forming a partnership for regional ownership and operation of the facility.  Technical studies from this initiative are published at

In June 2018, the Humboldt County Board of Supervisors adopted Resolution 18-56 which stated the Board’s position on the Potter Valley Project. 

In December 2017, Congressman Jared Huffman initiated an ad hoc committee of agencies and organizations on the North Coast to address the future of PG&E’s Potter Valley Project based on a set of goals and principles for a Two-Basin Solution.