Aerial photo of the Scott Dam and the high-elevation habitat it blocks. Photo courtesy of Friends of the Eel River.
|
The Eel River
The Eel River rises near Bald Mountain in the Northern California Coastal Range and flows roughly north to northwest for almost 200 miles through the Mendocino National Forest to its mouth just south of Humboldt Bay. Draining 3,684 square miles, its watershed is California’s third largest. 398 miles of the Eel and its major tributaries are designated Wild, Scenic or Recreational under the National Wild and Scenic River Act. Historically, the Eel supported some of the largest runs of salmon and steelhead on California’s North Coast. Before development in its watershed increased rapidly in the mid-19th century, returning spawners averaged more than one million per year. But today, the Eel’s salmon and steelhead teeter on the brink of extinction. Last year, American Rivers named the Eel one of America’s Ten Most Endangered Rivers™. This is the story of the past, present and emerging future of the Eel River. The Potter Valley Project The Eel’s flows are highly variable, with average flows in January and February more than 100 times greater than those in August and September. The flows of the Russian River system to the south of the Eel are highly variable as well. |
Map from PG&E.
|
The Potter Valley Project (PVP), conceived and developed in the early 20th century by the Eel River Power and Irrigation Company, was a complex of two dams, two reservoirs, and a diversion tunnel to bring water from the Eel to the upper Russian River. The PVP allowed development and farming to flourish in Potter Valley, which is normally starkly dry during the summer and fall. The initial Potter Valley project consisted of the 96-foot tall Cape Horn Dam on the Eel that was completed in 1908, a small (700 acre-foot) reservoir it impounded, and the diversion tunnel to the Russian River Basin. An ineffective fish ladder on the Cape Horn Dam blocked much upstream fish migration. The diversion tunnel included penstocks for electricity production.
In 1922, Scott Dam was completed 12 miles upstream of Cape Horn Dam. Standing 138 feet tall, it originally impounded 95,000 acre-feet of water in “Lake Pillsbury” (i.e. Pillsbury Reservoir) to augment PVP flows during dry months. Constructed with no fish ladder, Scott Dam blocks all upstream fish migration to this day. In 1930, the PVP was acquired by Pacific Gas and Electric Company (PG&E), which has operated it since.
In 1922, Scott Dam was completed 12 miles upstream of Cape Horn Dam. Standing 138 feet tall, it originally impounded 95,000 acre-feet of water in “Lake Pillsbury” (i.e. Pillsbury Reservoir) to augment PVP flows during dry months. Constructed with no fish ladder, Scott Dam blocks all upstream fish migration to this day. In 1930, the PVP was acquired by Pacific Gas and Electric Company (PG&E), which has operated it since.
The nearly 100-foot tall Cape Horn Dam. Photo by Kyle Schwartz.
|
Historic Impacts
Large canning operations along the Eel began in the 1850s. By their peak in 1877 they canned an unsustainable 600,000 salmon and steelhead in a single year. In the decades ahead, watershed impacts from activities including logging and grazing compounded those of the canneries on the river and its fish. They were compounded again with the development of the Potter Valley Project in the early 20th century. By 1922, Scott Dam completely blocked almost 300 miles of crucial high-elevation, cool-water spawning habitat upstream in the Eel’s watershed and altered the volume and quality of flows downstream. |
In the following decades there were fluctuations in fish returns from year to year, but the long-term trend was steadily down. By 2010, returning salmon and steelhead averaged only about 3,500 per year — well less than 1% of their historic abundance. Today, the Eel’s Chinook salmon, coho salmon, and steelhead are all listed under both the state and federal Endangered Species Acts.
Advocacy & Regulation
Concerned about the impacts of the PVP, the Round Valley Indian Tribes and area conservation groups worked for decades to bring public attention to the plight of the Eel. In time, they also challenged the relicensing of the PVP. In public and in court, they worked tirelessly to reduce the effects of the PVP on the Eel’s flows, fish and people.
Advocacy & Regulation
Concerned about the impacts of the PVP, the Round Valley Indian Tribes and area conservation groups worked for decades to bring public attention to the plight of the Eel. In time, they also challenged the relicensing of the PVP. In public and in court, they worked tirelessly to reduce the effects of the PVP on the Eel’s flows, fish and people.
|
In the 1980s, courts mandated that more water be released into the Eel system during drier months to support decimated fish stocks. In 2004, the Federal Energy Regulatory Commission (FERC) placed further limits on the amount of water the PVP could divert.
Further Complications for the PVP Problems regarding the PVP continued to accumulate. PG&E acknowledged that the Scott Dam poses a serious seismic risk and therefore decided never again to raise “Lake” Pillsbury to full pool. That commitment decreased its storage capacity by about 20,000 acre-feet. (A century’s worth of accumulated sediment had already decreased its capacity by that much or more, leaving its current capacity only about half its original.) Costs for PG&E to maintain the PVP’s aging power generation facility continued to increase. When a transformer failed in 2021, it was shut down. It has generated no power since. |
The ladderless Scott Dam blocks nearly 300 river miles of upstream cool-water spawning habitat. Photo courtesy of PG&E.
|
Recent Events & Decisions
In 2019, PG&E decided not to pursue FERC relicensing further because by that time operating and modernizing the PVP had clearly become prohibitively expensive. What was unclear at the time was whether another entity would step forward to take responsibility for the project. (None has.) When its license with FERC expired in April of 2022, PG&E began to prepare for decommissioning.
Meanwhile in 2022, conservation and fishing groups filed a lawsuit against FERC for Endangered Species Act violations, stating that the PVP limits salmon and steelhead access to critical portions of their habitat, closes fishways at key moments in their life cycle due to reduced water flows, encourages predation by virtue of fishway design, and facilitates inhospitable temperatures for salmonids.
In November, 2023, PG&E announced and invited public comment on an initial draft plan for removing the two Eel River dams and surrendering its FERC permit. A final draft must be submitted to FERC in June of this year. FERC expects PGE’s final surrender application to be complete by January 2025.
PG&E now wants to be free of the Eel River dams as soon as possible. Both the Cape Horn Dam and the Scott Dam will likely be removed beginning in 2028.
Removing the dams is just one component of the path to a healthier Eel watershed — but it is a vital one for the river to reconnect and recover. Pacific Rivers strongly supports the removal of both the Cape Horn Dam and the Scott Dam. We applaud the work of all the parties that led to this moment of promise. In light of the continued decline of salmon populations and the complete collapse of salmon fishing in California, dam removal remains one of the most important ways to help our endangered fish populations recover in the Eel and other rivers.
In 2019, PG&E decided not to pursue FERC relicensing further because by that time operating and modernizing the PVP had clearly become prohibitively expensive. What was unclear at the time was whether another entity would step forward to take responsibility for the project. (None has.) When its license with FERC expired in April of 2022, PG&E began to prepare for decommissioning.
Meanwhile in 2022, conservation and fishing groups filed a lawsuit against FERC for Endangered Species Act violations, stating that the PVP limits salmon and steelhead access to critical portions of their habitat, closes fishways at key moments in their life cycle due to reduced water flows, encourages predation by virtue of fishway design, and facilitates inhospitable temperatures for salmonids.
In November, 2023, PG&E announced and invited public comment on an initial draft plan for removing the two Eel River dams and surrendering its FERC permit. A final draft must be submitted to FERC in June of this year. FERC expects PGE’s final surrender application to be complete by January 2025.
PG&E now wants to be free of the Eel River dams as soon as possible. Both the Cape Horn Dam and the Scott Dam will likely be removed beginning in 2028.
Removing the dams is just one component of the path to a healthier Eel watershed — but it is a vital one for the river to reconnect and recover. Pacific Rivers strongly supports the removal of both the Cape Horn Dam and the Scott Dam. We applaud the work of all the parties that led to this moment of promise. In light of the continued decline of salmon populations and the complete collapse of salmon fishing in California, dam removal remains one of the most important ways to help our endangered fish populations recover in the Eel and other rivers.
To learn more about the Eel River and influences on its wellbeing, we recommend “Seasons of the Eel” by Jason Hartwick and Shane Anderson, available to purchase in our online store.
