Dam Removal

Since the early 20th century, two dams and a diversion tunnel known as the Potter Valley Hydroelectric Project have caused significant harm to Eel River fisheries. Removal of both dams, Scott and Cape Horn, and access for native fish to the high-quality cold water habitat in the upper basin is a top priority. The current diversion extracts a seasonally significant amount of water from the Eel. While we prefer to see an end to the diversion, we do believe an ecologically appropriate, wet-season only diversion is possible. Dam owners, PG&E are in the midst of the decommissioning process, with dam removal proposed to begin as early as 2028.

Potter Valley Project

The Potter Valley Project is a small hydropower project in the headwaters of the Eel River. It consists of two dams, a mile-long diversion tunnel, and a powerhouse with a 9.4 mw capacity. The project is located in the Eel River headwaters and diverts water out of the watershed into the Russian River. Removing this project is the necessary first step to fisheries recovery on the Eel River.

Eel Watershed Map
Map of Eel River dams, Potter Valley Project relicensing

The Potter Valley Project is a small hydropower project in the headwaters of the Eel River. It consists of two dams, a mile-long diversion tunnel, and a powerhouse with a 9.4 mw capacity. The project is located in the Eel River headwaters and diverts water out of the watershed into the Russian River. Removing this project is the necessary first step to fisheries recovery on the Eel River.

Scott Dam

Scott Dam impounds the river to form Lake Pillsbury Reservoir, all under the backdrop of Snow Mountain.

Scott Dam

Cape Horn Dam impounds the Eel River to form Van Arsdale Reservoir. There is a fish ladder here where the Department of Fish and Wildlife conducts fish counts.

The Latest Eel River Dams News

Critical Dam Safety Documents Need to Be Made Public
April 24, 2024

Friends of the Eel River has long been pursuing more clarity from PG&E on dam safety at the Potter Valley Project. The utility company has long made the choice to classify dam safety and emergency planning documents related to the …
Read More

Unmanageable with Alicia Bales: Eel River Deep Dive
April 18, 2024

Tune into this clip from Episode 8 of “Unmanageable with Alicia Bales” to hear Friends of the Eel River Conservation Director Scott Greacen break down dam removal at the Potter Valley Project and what a diversion means in the …
Read More

Comments on PG&E’s Flow Variance Request
April 15, 2024
The Potter Valley Project, which blocks access to pristine, cold water spawning habitat for Eel River salmonids, is no longer a functioning hydroelectric project. PG&E has announced plans to remove both Scott and Cape Horn dams as soon as possible …
Read More

KMUD Environment Show: Dam Removal, Groundwater, and the Great Redwood Trail
March 26, 2024
Tune into this recording from the KMUD Environment Show hosted by Tom Wheeler to hear our Executive Director Alicia Hamann discuss our most pressing initiatives at Friends of the Eel River: dam removal on the Eel River, protecting the public’s …
Read More

Save the Date: Eel River Dams Out in 2028!
November 21, 2023
We’re encouraged by the progress we are making toward Eel River dam removal. PG&E seems eager to rid themselves of this liability-ridden project. It’s our job to make sure dam removal comes in time to save the Eel’s native fish …
Read More

Submit Comments on PG&E’s Initial Draft Decommissioning Plan
November 17, 2023
PG&E has released their initial draft decommissioning plan for the Potter Valley Project. The plan calls for removal of both Scott and Cape Horn Dams, and provides a few options for consideration by stakeholders. This initial draft does not include …
Read More

Dam Removal Resources

DamNation

This film released in 2014 with support from Patagonia makes an excellent case in support of dam removal. Friends of the Eel River highly recommends DamNation as an educational and inspirational resource.

hydropowerRC

The Hydropower Reform Coalition

The Hydropower Reform Coalition has great resources on hydropower, the Federal Energy Regulatory Commission, and the effects of dams on river systems.

Articles on Dam Removal

What is FERC?

The Federal Energy Regulatory Commission (FERC), is an independent agency within the US Department of Energy. The agency consists of five Commissioners who are nominated by the President and approved by the Senate to serve five-year terms. FERC is responsible for regulating the interstate transmission of electricity, natural gas, and oil. FERC also reviews proposals to build liquefied natural gas (LNG) terminals and interstate natural gas pipelines as well as licensing hydropower projects. FERC’s authority to license hydropower projects is balanced by state and federal agencies’ authority to recommend environmental conditions.

Hydropower licenses issued by FERC last for 50 years, which is why it is so important that interested parties engage with the licensing process and voice any concerns during these once-in-a-lifetime opportunities.

You can subscribe to FERC’s eLibrary to receive email notifications when documents pertaining to the Potter Valley Project are posted. Follow the on-screen instructions to register and use docket #P-77.

Additional resources:

Hydropower Licensing – Get Involved: A Guide for the Public

Department of Water Resources California Data Exchange Center PVP data set

FOER Comments on Potter Valley Project

FOER Comments on FERC Office of Public Participation
April 22, 2021

FOER Challenges FERC for Violations of the Endangered Species Act
February 26, 2021

FOER Comments on Initial Study Report: Study Plan Disagreements and Requests for Amendments
November 16, 2020

FOER Comments to FERC on Inadequacies of Cape Horn Dam Fish Ladder
March 7, 2019

FOER Submits Technical Memorandum Re: Geotechnical Concerns at Scott Dam
September 12, 2018

FOER and Conservation Partners Comments on Proposed Study Plans
December 10, 2017
Re: PG&E’s Proposed Study Plans for Potter Valley Project Relicensing

FOER and Conservation Partners Comments on Scoping Document 1 Exhibit 1 & 2 ; Appendix A
August 4, 2017
Re: FERC’s Scoping Document 1 for Potter Valley Project Relicensing

FOER Motion to Intervene; Comments
August 15, 2016
Re: Application for Temporary Variance of Minimum Flow Requirement

FOER Motion to Intervene; Comments
June 2, 2015
Re: Application for Temporary Variance of Minimum Flow Requirement

FOER Motion to Intervene
October 29, 2014
Re: Application for Temporary Variance of Minimum Flow Requirement in East Branch Russian River

FOER Motion to Intervene; Comments
January 15, 2014
Comments on Application for Temporary Variance of License Requirement and December 12, 2013 FERC Order Granting Temporary Variance of Minimum Flow Requirements

FOER Comments to DFW & NMFS
October 26, 2011
Urgent Request for Release of Water to Eel River Pursuant to Reasonable and Prudent Alternative, Biological Opinion for the Potter Valley Project

Potter Valley Project Relicensing

Eel River Dams License Surrender

Federal Energy Regulatory Commission
(Eel River Dams, called the Potter Valley Project is docket #P-77)

PG&E’s Potter Valley Project

Congressman Huffman’s Ad Hoc Committee.
Friends of the Eel River has been a participant in Congressman Huffman’s collaborative Ad Hoc process, helping develop locally supported recommendations for the Federal Energy Regulatory Commission.

Reasons to Remove the Eel River Dams

Ecological Health

The Eel River is home to many wonderful flora and fauna, including three salmonid species listed under the federal and state Endangered Species Acts; California Coastal Chinook, Southern Oregon Northern California Coho, and Northern California Steelhead.

  • Invasive species Sacramento pikeminnow predates on salmon and proliferates in the warm water conditions created by the dam

Geotechnical Concerns

UPDATE: Read Friends of the Eel River’s Sept 2018 press release about the results of geotechnical analysis conducted by Miller Pacific Engineering Group. Press release and accompanying technical memo here.

Miller Pacific engineers concluded “it is our professional opinion that the large landslide complex adjacent to, and possibly below, the left abutment presents a significant geological hazard to the dam that requires further investigation. Since the dam acts as a strut across the Eel River, the landslide mass may be applying a significant soil pressure to the dam. In addition, the preliminary calculated seismic displacements are enough to cause concern about uplift or damage to the dam from landslide movement during a strong seismic event.”


The original plan called for Scott Dam to be constructed in a straight line across the Eel River canyon, and to attach to a substantial rock outcropping on the south side of the canyon, originally believed to be bedrock. During construction, however, this feature, now called ‘the Knocker,’ began to move, revealing that it is in fact a very large boulder, and not bedrock at all (see these photos from 1920 that show ‘the knocker’ before and after it slid down). The design of the dam was changed to run in front of ‘the Knocker,’ as it does today. In the photo below, the ‘the Knocker’ is the purple blob directly behind the dam.

The Knocker
Many dams are built on or nearly on fault lines because that’s where a river channel is naturally most narrow. Scott dam is no exception. The image below is a geologic map of Gravelly Valley, where Scott Dam is located.

Geologic Map Gravelly Valley

Local Economy

While there is no longer commercial fishing on the Eel River, salmon and steelhead from the Eel are a part of the commercial ocean fishery. Protecting these fish protects local economy.

Click here to read the Center for Environmental Economic Development’s 2004 study, Economic Benefits to Mendocino and Lake Counties from Removing the Dams on the Eel River. Study authors Dr. Ihara and Marshall conclude that “nature-based tourism benefits to Mendocino and Lake Counties, counting both rafting and increased fishing, are estimated to exceed $2,000,000 annually”.

Energy Production

The Eel River Dams generate very little energy. Their maximum generating capacity is 9.4 megawatts, but according to analysis by Dr. Rosenblum, the hydropower facility has operated at a maximum of 50% capacity over the last decade.

Click here to see Dr. Rosenblum’s presentation that includes analysis of hydropower generation at the Eel River Dams (Potter Valley Project) and Coyote Dam in Mendocino, as well as analysis of replacing that energy with solar power. A five acre solar array would more than replace the energy generated by the Eel River Dams.

Potter Valley Project Studies

Physical and Biological Constraints on the Capacity for Life-History Expression of Anadromous Salmonids: An Eel River, California, Case Study - FitzGerald 2021

This paper by Alyssa FitzGerald, et al from National Marine Fisheries Service confirms previous research and traditional ecological knowledge that the upper basin habitat behind Scott dam is some of the best in the entire watershed. The habitat is notable for its cold water availability, even in the summer months of a dry year, and the physical characteristics that make it especially productive spawning and rearing habitat.

Click here to read the full paper.

On the Ecology and Distribution of Steelhead in California's Eel River - Kannry 2020

This paper by Samantha Kannry, et al from UC Davis presents evidence that alleles for both anadromy and pre-mature migration (summer-run timing) are present in rainbow trout trapped in the upper basin behind Scott dam. It also documents the populations of Northern California summer steelhead elsewhere in the Eel watershed, in the north and middle forks, as well as the Van Duzen river.

Click here to read the full paper.

Phase 2 Feasibility Studies Completed for the Two Basin Partnership, 2021

 

Sediment Investigation Conducted by Geosyntec, 2020

Geosyntec conducted an assessment of sediments in Van Arsdale and Lake Pillsbury Reservoirs on behalf of the California State Coastal Commission.

Studies Completed by the Ad Hoc Committee

    An Estimation of Potential Salmonid Habitat Capacity in the Upper Mainstem Eel River, California - Cooper, 2017

    This research by Emily Cooper from Humboldt State University presents estimates for potential habitat for both Chinook Salmon and steelhead trout.

    “Using three fish passage scenarios, potential Chinook Salmon habitat was estimated between 89-127 km (55-79 mi) for spawning and rearing; potential steelhead trout habitat was estimated between 318-463 km (198-288 mi) for spawning and between 179-291 km (111-181 mi) for rearing.”

    Click here to read the paper

    Click here for an interactive map of steelhead populations

    Dam Safety and Reliability

    The Potter Valley Project (PVP) presents a range of potentially serious issues related to safety and reliability.

    The failure of the Federal Energy Regulatory Commission (FERC) to address dam safety issues as part of the PVP relicensing process has deprived stakeholders and the public of information and analysis critical to assessing the potential utility, and liabilities, of Scott Dam and the Potter Valley Project as a whole.

    FERC claims that its dam safety program assures the safety of Scott Dam and other federally licensed hydropower projects. However, the Oroville Dam crisis has raised grave questions about the adequacy of FERC’s dam safety inspection and review program.

    The classification of most dam safety-related information as closely restricted Critical Energy Infrastructure Information (CEII) has contributed to the difficulty of holding PG&E and FERC accountable for their failures to fully address dam safety issues, at Scott Dam and elsewhere. CEII information restrictions also make it more difficult to show that Scott Dam can, in fact, be safely left in place.

    FOER has been hammering for years on the many reasons why Scott Dam is not only unsafe, but also unreliable. From its unstable foundation to the active landslides adjacent to the southern side, our confidence in the structure is shaky at best. Plans for failure of various parts of the aging infrastructure are unavailable to the public at best, non-existent at worst. See below for links to our series of short articles which detail the range of dam safety issues at the Potter Valley Project, complete of course with links to all the evidence we can get our hands on.

    Dam Safety Blog Posts

    Critical Dam Safety Documents Need to Be Made Public
    April 24, 2024
    Friends of the Eel River has long been pursuing more clarity from PG&E on dam safety at the Potter Valley Project. The utility company has long made the choice to classify dam safety and emergency planning documents related to the …

    Read More

    Unmanageable with Alicia Bales: Eel River Deep Dive

    April 18, 2024
    Tune into this clip from Episode 8 of “Unmanageable with Alicia Bales” to hear Friends of the Eel River Conservation Director Scott Greacen break down dam removal at the Potter Valley Project and what a diversion means in the …

    Read More

    Comments on PG&E’s Flow Variance Request

    April 15, 2024
    Tune into this clip from Episode 8 of “Unmanageable with Alicia Bales” to hear Friends of the Eel River Conservation Director Scott Greacen break down dam removal at the Potter Valley Project and what a diversion means in the …

    Read More

    Dangerous Dams in Our Backyard

    October 7, 2023
    On this week’s episode of the EcoNews Report we reflect on the tragic dam failure in Libya last month and discuss why Scott Dam on the Eel River poses similar risks. The PG&E owned dam sits right on a significant …

    Read More

    Bigger Storms, Poor Oversight Put Dams at Risk
    October 5, 2023
    ​On Sept. 12, storm Daniel overwhelmed two neglected dams in Libya. The flood washed away entire neighborhoods in the coastal city of Derna, killing thousands. Experts warned just last year that lack of maintenance risked failure of the dams, built …
    Read More

    PG&E Tells FERC “Seismic Risk of Eel River Dams Greater Than Previously Understood”
    October 3, 2023
    PG&E TELLS FERC “SEISMIC RISK OF EEL RIVER DAMS GREATER THAN PREVIOUSLY UNDERSTOOD” -FERC Approves Changes to Dam Operations to Mitigate Earthquake Risks -Four Months After Request, Approval Comes Too Late to Stop Fish Kill Washington, DC – Yesterday, the Federal …
    Read More

    Keep Us On The Fast Track to Dam Removal
    June 20, 2023
    Dear Friends, For the last several years, I’ve been optimistically sharing that if everything fell perfectly into place, the Eel River Dams could be out of the river by 2030. We’ve just learned that my optimistic timeline may turn out …
    Read More

    PG&E Admits Scott Dam Faces Serious Seismic Risks
    March 17, 2023
    PG&E Admits Scott Dam Faces Serious Seismic Risks In a March 16, 2023 press release, PG&E has admitted that Scott Dam faces previously unacknowledged risks from seismic activity. Those risks are so great that the utility has announced that it …
    Read More

    Dam Safety Series: Faults
    December 14, 2021
    Hold PG&E At Fault Underlying issues threatening Scott Dam Scott Dam’s proximity to the Bartlett Springs Fault is a major safety concern. The Bartlett Springs fault was not identified by geologists as “a regionally significant seismic source” until the 1980s, …
    Read More

    Letter to California Public Utilities Commission Regarding PVP Equipment Failure
    October 27, 2021
    Wednesday, October 27, 2021 President Marybel Batjer California Public Utilities Commission 505 Van Ness Avenue San Francisco, CA 94102 via electronic mail as feasible RE: Potter Valley Project Equipment Failure Dear President Batjer, This letter is meant to apprise you …
    Read More

    Article Archive

    2022

    New Twist For Potter Valley Project
    Redheaded Blackbelt, December 29, 2022

    Environmental groups intend to sue PG&E over Potter Valley Project
    Jefferson Public Radio, April 20 2022

    An Expired License, A Mysterious Applicant, And a Threat to Sue: What Else Can We Expect as the Fight to Control the Waters of the Eel River Continues?
    Redheaded Blackbelt, April 19 2022

    Environmental, Fishing Groups Submit Notice of Intent to Sue PG&E for Violating Endangered Species Act With Potter Valley Project on the Eel River
    Lost Coast Outpost, April 18 2022

    Environmentalists, fishermen threaten to sue PG&E over Potter Valley Project
    Times-Standard, April 18 2022

    Fishery groups plan to sue PG&E over Potter Valley plant and related Scott, Cape Horn dams
    The Press Democrat, April 18 2022

    Eel River Dam Removal is Moving Forward. It Will Create California’s Longest Free-Flowing River
    Active NorCal, April 17 2022

    ‘Beginning of the end’: Potter Valley Project license expires
    Times Standard, April 14 2022

    The Potter Valley Project’s License Expires Today
    Lost Coast Outpost, April 14 2022

    Letters: Salmon, not grapes, are at risk
    The Ukiah Daily Journal, April 2 2022

    Catching Even Insiders ‘Off Guard’, PG&E Decides to Return to the Potter Valley Project, which diverts water from the Eel River, to Full Operational Status
    Redheaded Blackbelt, February 4 2022

    PG&E to bring Potter Valley Project back online as license takeover unravels
    Times-Standard, February 3 2022

    Plan to acquire Mendocino County power plant unravels
    The Press Democrat, February 1 2022

    2021

    Potter Valley Project relicensing effort facing costly hurdles
    Sarah Reith, KZYX News – Mendocino County’s Public and Community Radio, October 18 2021

    More time sought for Potter Valley Project license takeover
    Times-Standards, September 9 2021

    2018

    Diverted California River Sustains California Wine Industry, but It’s Killing Salmon
    Water Deeply, January 29 2018
    Friends of the Eel River thinks it is a stretch to claim diversions from the Eel River “sustain” the California wine industry, but it is certainly killing salmon.

    PG&E Tells Regional Commission It’s Thinking about Selling or Abandoning Potter Valley Dams, Which Take Water Out of the Eel and Send it South
    Lost Coast Outpost, February 23 2018

    The Water, Not the Power
    Anderson Valley Advertiser, March 7 2018

    New Earthquake Hazards App Shows Fault Line at Scott Dam Location
    Friends of the Eel River, April 5 2018

    PG&E to Sell Off Potter Valley Project, Which Diverts Eel River Water South, Friends of the Eel Vows to Keep Up Fight
    Lost Coast Outpost, May 11 2018

    Friends of the Eel Decries ‘Secret Plans’ for Future of River-Draining Potter Valley Dams; Board of Supes Meets on Issue Tomorrow
    Lost Coast Outpost, May 14 2018

    FOER Comments to Humboldt County on Eel River Fisheries Restoration and Dam Removal
    Friends of the Eel River, May 31 2018

    Supervisors Call for Removal of Scott Dam, Solidify Stance on Potter Valley Project
    Eureka Times Standard, June 5 2018

    Mendo County Stakeholders Want to Take Over the Potter Valley Project, Which Diverts Water From the Eel; Local Enviros Say That Spells Trouble
    Lost Coast Outpost, August 16 2018

    PG&E Moves to Auction Off Eel River Dams Amid Growing Seismic Safety Concerns
    Friends of the Eel River, September 6 2018

    PG&E Has Put the Potter Valley Project up for Auction and Who Buys it Could Reshape Water Policy for Decades
    The Mendocino Voice, September 9 2018

    Will a Landslide on the Eel River Cause California’s Next Dam Disaster?
    Water Deeply, October 3, 2018

    2016

    Balancing the Russian River on the Back of the Eel River
    Friends of the Eel River, July 21, 2016

    What is Decision 1610?
    Friends of the Eel River, July 21, 2016

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    Email: foer(at)eelriver.org

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