PG&E formalizes plan to eliminate Lake Pillsbury in Mendocino National Forest in landmark move
In a landmark moment, Pacific Gas & Electric Co. formalized its plans to tear down two more-than-a-century-old dams on the Eel River — removing the barrier that forms Lake Pillsbury, freeing the waters of the river and restoring the lake footprint to a more natural state.
The moves are part of a 94-page draft surrender application submitted to federal regulators and made public Friday as part of the utility’s plan to decommission its Potter Valley powerhouse and all the infrastructure that comes with it — including Scott and Cape Horn dams, sited slightly downstream.
PG&E has said it could get regulatory approval for deconstructing the dams as early as 2028, depending on environmental review of the plan. It is not clear when dam demolition might begin.
Scott Dam, built in 1921, would come down first, either in phases or all in one season.
Pacific Gas & Electric Co. initial draft plan
The plan fulfills long-held dreams of conservationists and fishery groups to see the cold, clear headwaters of the Eel River, part of the Mendocino National Forest, reopened to migrating fish and to restore natural river flows in hopes of reversing the decline of native fish stocks.
“Dam removal will make the Eel the longest free-flowing river in California and will open up hundreds of stream miles of prime habitat unavailable to native salmon and steelhead for over 100 years,” said Brian J. Johnson, California Director for Trout Unlimited. “This is the most important thing we can do for salmon and steelhead on the Eel River, and these fisheries cannot afford to wait.”
PG&E is still determining which of two approaches to take in removing Scott Dam, primarily related to how to handle sediment accumulated behind the dam and how best to release the stored water to limit its dispersal.
In a win for Sonoma Water and Russian River water users in Sonoma and Mendocino counties, PG&E also has agreed to evaluate a regional proposal to retain enough of smaller Cape Horn Dam, built in 1907, and a milelong diversion tunnel to allow continued, wintertime diversions from the Eel to the East Fork Russian River.
The idea is to draw off limited water when Eel River flows are high in order to top off Lake Mendocino and prevent the Russian River from running dry in summer, while still allowing salmon and steelhead trout to migrate up the Eel River to its headwaters unimpeded.
Local officials said they were excited to see the proposal included in PG&E’s draft, the first of two that will be circulated for public review over the coming months before a final surrender application is filed in January 2025. Two different approaches are being considered for diversions — one called a roughened channel and the other, a pumpback system involving embedded pumps, requiring less infrastructure in the water to move diversions toward the tunnel.
Sonoma County Supervisor James Gore called it ”big deal,“ saying PG&E ”could have taken the easy way out … and moved ahead with a less complex solution — one that doesn’t deal with multiple jurisdictions, partners, opinions, end goals.“
Members of the regional group, which includes the Round Valley Indian Tribes, are in the process of creating a joint power authority to establish the framework for governance and funding of the proposed diversion system, dubbed the new Eel-Russian Facility.
A tremendous amount of work still lies ahead to design, engineer, finance, establish operating protocols and arrange water rights in order to bring the diversion proposal to fruition.
But Gore, many of whose north county constituents depend on Russian River flows for municipal and agricultural use, as do thousands more in Mendocino County, said they knew what was coming and know what’s at stake in ensuring diversions continue, even if it comes at a cost.
“Everybody knows, unless they’ve been hiding under a rock, that the days of free water are gone,” Gore said.
The regional proposal comes with a pledge to move forward without delaying dam removals and promoting restoration of the fishery.
Proponents signed onto the regional proposal include the California Department of Fish and Wildlife, Humboldt County, Trout Unlimited and California Trout, whose focus is ensuring improved conditions in the Eel River. Many have long resented the abundance of water removed from the Eel, though diversions have lessened in recent years.
In many ways, the membership reflects the makeup and goals of the Two-Basin Solution Partnership, a stakeholder group brought together by North Coast Congressman Jared Huffman in 2019, after PG&E first announced it would not renew its federal license for the aging hydroelectric project.
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