Russian River crisis

Will dismantling a dam for one California river doom another?

PG&E's Potter Valley plan fuels clash between Eel River restoration and Russian River crisis

By Matt LaFever

In the past week, Northern California’s century-old Potter Valley Project crossed a major threshold toward dismantling. On July 25, PG&E submitted its formal plan to federal regulators to tear down the two-dam system that has rerouted Eel River water into the Russian River for over a century. Just days earlier, the Humboldt County Board of Supervisors became one of seven required signatories to a water diversion agreement, paving the way for a replacement system called the New Eel-Russian Facility, or NERF.

Together, the two developments mark a historic shift: The original infrastructure is on its way out, and the future of interbasin water sharing is up for grabs.

For more than 100 years, the Potter Valley Project has diverted Eel River water through a milelong tunnel blasted through a Mendocino County mountain, supporting agriculture, drinking water and firefighting from Potter Valley to Marin. Scott Dam, completed in 1922, created Lake Pillsbury to store the diverted water. 

PG&E now says the project is outdated, seismically vulnerable and economically unsustainable. Its decommissioning plan calls for removing both Scott and Cape Horn dams, eliminating the hydroelectric plant and draining Lake Pillsbury — triggering sharp debate across both river basins.

NERF, the proposed replacement, would divert water only during high winter and early spring flows, a major shift from the summer diversions that Russian River communities have long relied on. Eel River advocates say the timing is designed to protect salmon and restore ecological balance, but in the Russian River watershed, where steady summer water is critical for farming, tourism and recreating, concerns are mounting.

At the Humboldt County Board of Supervisors meeting in Eureka, Eel River advocates voiced support for the new deal. Brian Johnson, senior policy adviser for Trout Unlimited, called the agreement “affirmatively good for the Eel River,” noting it’s packed with scientific safeguards.

“The agreement can only be renewed if it’s doing what it’s intended to do,” he said, meaning diversions could be scaled back even further if they harm conditions on the Eel River. In essence, the agreement prioritizes the health of the Eel River’s flows over guaranteed water deliveries to the Russian.

Charlie Schneider, California Trout’s Lost Coast Project manager, framed NERF as a major ecological win. The proposed system is “supportive of volitional fish passage,” he said, and would ensure salmon and steelhead have clean, connected habitat after the dams come down.

“Fish need a place to live. They need a healthy ecosystem. They need food resources,” he said.

Alicia Hamann, executive director of Friends of the Eel River, said the moment was deeply personal.

“Friends of the Eel River was founded for this very purpose,” she told the board, “so this is a really exciting time for us.”

Though her organization isn’t a signatory, she strongly supports the agreement, calling it a turning point: “This agreement is really important because it commits those former opponents of dam removal to supporting dam removal, and in exchange, Eel River stakeholders are supporting an ecologically appropriate diversion.”

Hamann warned, however, that some Russian River stakeholders have shown signs of backpedaling. “We have continued to hear some rhetoric from some of those signatories in the Russian River indicating a lack of support for dam removal,” she said, urging the board and other parties to “hold those parties to this agreement … to support dam removal.”

In a follow-up interview with SFGATE, Hamann clarified her meaning. “I don’t think it’s unreasonable that people are upset, afraid even, of big changes coming,” she said, but she cautioned that open skepticism from signatories could compromise “timely dam removal.”

Meanwhile, PG&E’s own documents submitted last week to the Federal Energy Regulatory Commission make clear just how disruptive dam removal will be for the Russian River watershed. The utility’s decommissioning plan warns of “unavoidable adverse effects” that would follow the end of water diversions. “Flows would return to natural flow conditions,” PG&E writes, meaning less water for farmers, ranchers and rural communities in the Russian River Valley, especially in summer. 

Wildlife would feel the impact, too, PG&E outlines: The disappearance of Lake Pillsbury would erase a key hunting ground for ospreys and bald eagles. Tule elk might become stranded in sediment. Northern spotted owls could abandon nesting sites near the construction zone. 

In its decommissioning application, PG&E acknowledges that life in the Scott Dam region will never be the same. The utility says the area will shift “from a lacustrine to riverine environment” — in other words, the calm lake will vanish, replaced by a raw, re-formed river. That transformation could have “unavoidable effects on recreation value, community way of life, and population and housing in the Scott Dam area,” PG&E writes.

Lake County Treasurer Patrick Sullivan warned that dam removal could carry serious economic consequences for the region. Sullivan estimated the resulting loss in property tax revenue alone could top $1 million annually. “That can hardly be characterized as a negligible impact to Lake County,” he wrote in a statement to SFGATE.

The divide between the two watersheds isn’t just bureaucratic — it’s personal for the communities who live there. During public comment, Humboldt County resident Kent Sawatzky gave voice to those tensions, warning that the “negative karma incurred by the people in the Russian River Basin is something they may regret having to deal with.” In his view, the decadeslong manipulation of the Eel River has provoked something elemental. 

“Mother Nature bats last,” he said. “When you try and push Mother Nature around, she usually has ways of responding — whether it be for fires, floods, earthquakes.”