Rivers and pollutionGuide

Unmaking a lake to free a river: the Eel River dams, Lake Pillsbury and Sonoma County's water

By The Downspout · Updated Oct 18, 2026 · 12 min read Share

PG&E wants to take out Scott Dam, which makes Lake Pillsbury, and Cape Horn Dam on the Eel River. Salmon would get back a hundred miles or more of river. Lake Pillsbury would be gone, and Potter Valley and Lake Mendocino would lose much of the Eel water they still get. A compromise would keep a smaller winter diversion. Federal regulators haven't decided yet.

This fall, a barge sat on Lake Pillsbury, drilling into the bottom.

It was pulling up a century of mud. If Scott Dam comes out, that mud goes down the Eel River, and PG&E needs to know what's in it.^[1]

Forty miles south, the Eel water spilling into the Russian River's East Branch dropped to a trickle.^[1]

One dam made a lake people love, cut a river off from its salmon, and sent water to a valley and a river system that came to depend on it.

All three can't stay as they are.

How the Eel ended up in the Russian

In 1908, Cape Horn Dam and a mile-long tunnel began sending Eel River water over the ridge to a powerhouse in Potter Valley, then down the Russian River's East Branch.^[2]

In 1922, Scott Dam went in upstream to store more. Its lake is Lake Pillsbury. The dam has no fish ladder.^[2][3]

Map: USGS river and lake data, Census county lines. Dams and the tunnel are placed by hand.

Around that borrowed water grew Potter Valley's pears and vineyards, and later Lake Mendocino.

Most of that water has already stopped coming:

Source: Sonoma Water modeling for the Eel-Russian Project Authority, August 2026.^[4]

Fish protections cut it in the 2000s. The powerhouse broke down in 2021. In 2023, PG&E found Scott Dam's earthquake risk higher than it thought and lowered the lake 10 feet.^[4][5]

Why it matters in Sonoma County

Lake Mendocino, behind Coyote Valley Dam near Ukiah, is the Russian River's upper reservoir. It was designed when Eel water came by the hundred thousand acre-feet.^[6]

Its summer releases keep the river flowing past Hopland, Cloverdale and Healdsburg, for farms, towns and endangered salmon and steelhead.

Lake Sonoma, on Dry Creek, is the bigger reservoir. It gets no Eel water, and most of what Santa Rosa and Petaluma drink leans on it.

So losing the Eel hits the upper river hardest. Sonoma County feels it as more pressure on Lake Sonoma in dry years. With no diversion at all, Sonoma Water's modeling says, Lake Mendocino would run short eight years in ten and go dry two in ten.^[6]

Who has a stake

• PG&E, which owns the dams and wants out.
• Lake Pillsbury's cabin owners, campers and boaters, and Lake County.
• Potter Valley's farmers.
• Water agencies, from Sonoma Water and Ukiah to Marin.
• Tribes, above all the Round Valley Indian Tribes.
• Salmon advocates and fishers.
• Humboldt County and the lower Eel.
• Firefighters and the Mendocino National Forest, where the lake sits.
• The state and the federal government, which don't agree.
• PG&E's customers, who will likely pay for removal.

The lake

About 300 cabins, a campground, and families who've summered there for generations.^[7] Lake County's supervisors voted 5 to 0 against removing Scott Dam. They fear dry wells, lost taxes and a lakebed left as mud.^[7][8] Fire crews filled helicopters there during the 2020 August Complex fire.^[9]

The lake's defenders say it's more than stored water. It's where kids learn to sail, fish and camp, and where many people first come to love wild places.

The author of this story is one of them. He grew up sailing and camping on Lake Pillsbury and Lake Mendocino. He also lives in Sonoma County, drinks Russian River water and paddles the Russian. He has a stake on both sides.

Public places like this take a fight to keep. In 2025, a Senate plan to sell millions of acres of federal land, national forest included, was dropped only after a public backlash.^[10]

"If we don't fight for these small rural communities, who will?"^[7]Bruno Sabatier, Lake County supervisor

The valley

Potter Valley has about 390 farmers on some 4,900 acres, almost no usable groundwater, and water at about $35 an acre-foot.^[11][12]

"If anybody had asked me ten years ago what would happen if [the Project] was gone I would have said it would be disastrous."^[12]Janet Pauli, Mendocino County Inland Water and Power Commission

Now she's working on ponds, groundwater and a bigger Lake Mendocino instead.^[12]

The tribes

Under the compromise deal, PG&E's Eel River water rights would go to the Round Valley Indian Tribes, whose water was taken a century ago without their consent.^[13][14] In June 2026, they were left out of a White House meeting about their own river.^[15]

The process "should be guided by the communities and Tribal Nations that live with its consequences, not by interests seeking to reshape it from outside the region."^[15]Joseph Parker, President, Round Valley Indian Tribes

The fish

The Eel once had some of California's biggest salmon and steelhead runs. Above Scott Dam lie roughly a hundred miles of Chinook habitat, and more for steelhead, depending on whose survey you read.^[3][16] Fishing groups see removal as the biggest single thing that could bring those runs back.^[3][17]

The federal wildcard

In December 2025, the US Department of Agriculture asked regulators to reject PG&E's plan,^[18] and later floated a Southern California water district as a buyer.^[19] Regulators turned the district away in July 2026. It's appealing.^[20][21]

"Water supply for farms and communities is not a secondary amenity of this proceeding."^[21]US Department of the Interior, September 2026

Rep. Jared Huffman, who helped build the compromise, called the federal intervention potentially "catastrophic" for North Coast water.^[22]

PG&E's part in this

PG&E said in 2019 that it wouldn't renew its license,^[23] the same year it filed for bankruptcy over wildfire claims.^[24] The powerhouse hasn't made power since July 2021.^[2]

PG&E says the project stopped paying and the earthquake risk came later. Lake County points to a state inspection that found the dam safe to keep using under limits.^[5][7]

Removal could cost $532 million, and customers will likely carry much of it.^[25]

Is this about safety and fish, or a utility walking away from a project it stopped keeping up? The record supports some of each.

What a lake gives, and what a dam takes

Lake Pillsbury, Lake Mendocino and Lake Sonoma are all made by dams. People love them anyway.

A reservoir gives camping, sailing and summers that become family memory. It gives eagles and ospreys open water, fire crews a place to fill up, and dry summers stored winter rain.

A dam also takes. It blocks salmon from cold spawning streams and traps the gravel rivers need. Its warm, slow water favors invaders: Sacramento pikeminnow, dumped into Lake Pillsbury in 1979, now hunt young salmon across the basin.^[26]

Lake Pillsbury has its own troubles. The state lists it for mercury in fish,^[27] and this September recommended its highest toxic algae warning there.^[28]

Removal costs something real too: the lake and its campground, a muddy few years as 20 million or more cubic yards of sediment move downstream, a bare lakebed, and less cold summer water in the upper Eel.^[26][16]

What happened on the Klamath

Want to know what happens when a dam comes out? Look north.

The last of four dams on the Klamath River came out in October 2024. It was the largest dam removal in US history, and the closest preview of what the Eel could go through.

About 7,700 Chinook passed the old Iron Gate Dam site in 2024, and about 13,300 in 2025. Within two seasons they were back in 88% of their old range above the dams.^[29]

"The biological response has been much faster than I, and most of us, expected."^[30]Damon Goodman, CalTrout

The drained reservoirs left about 2,200 acres of bare lake bottom. Crews, many of them Yurok tribal members, started seeding it before the water was even gone: about 15 billion seeds from roughly 100 native plants.^[31]

Two years later, poppies, lupines and native bunchgrasses cover the old lakebeds. Willows and cottonwoods came back on their own.^[32]

The land the power company left behind, about 8,000 acres, goes to California and Oregon. California has promised about 2,800 acres to the Shasta Indian Nation, whose land was taken to build the dams.^[33][34] Much of it is expected to stay open to the public.^[33]

It's no fairy tale. Heat and low snow still hit the Klamath hard in 2026,^[30] and no valley there leaned on a diversion the way Potter Valley does.

And Lake Pillsbury's land?

If Scott Dam comes out, the Eel would run through a valley again.

Most of that land is already protected. Since 2022, about 5,600 acres of PG&E's Eel River land have been under a permanent conservation easement held by the Mendocino Land Trust. It bars new development and protects public access.^[35] The national forest around it stays.

PG&E's plan is to return the lake's footprint to a more natural state. Its 2023 plan would also close the campgrounds it runs at the lake.^[36]

What no one has laid out yet is what the valley becomes for people: trails, river camps, swimming holes. The Klamath's wildflowers and Lake County's mud flat are both possible. Which one happens depends on whether someone plans for it.

Can we keep the lake and free the river?

On paper, maybe. In practice, it's hard.

In 2018, engineers studied a fish ladder over Scott Dam for PG&E. They priced it at $55 to $93 million and concluded:

"The most feasible and cost-effective fish ladder design would be challenging to build, complicated to operate, very costly, and would have uncertain effectiveness."^[37]Mead & Hunt, for PG&E, 2018

Lake County argues cheaper options were overlooked, like trapping fish and trucking them around the dam.^[38] Even then, someone would have to own the dam, fix its earthquake problem and win a new license. No buyer has made PG&E a real offer.^[20]

Three possible futures

Future 2 is the Two-Basin Solution. A fish-screened pump station would replace Cape Horn Dam and take Eel water only in the wet months, and only when the river runs high.^[13][39] It would cost about $50 million, not yet raised.^[39] And winter water only helps if there's somewhere to keep it until summer.^[4]

If not Eel water, then what?

• Store more winter water. A raised Coyote Valley Dam would let Lake Mendocino hold much more. The House voted 415 to 9 in September 2026 to speed up the study, but with no money.^[40]
• Run reservoirs smarter. Since October 2025, Lake Mendocino can hold up to 11,650 extra acre-feet when forecasts show no storm coming.^[41]
• Ponds and recharge. Potter Valley needs at least 5,000 acre-feet of new storage.^[12] Winter water spread on fields can refill groundwater. See can your yard recharge groundwater?
• Use less. Every gallon saved in summer is one Lake Mendocino doesn't have to release. See water rebates in Sonoma County.
• Borrow from another river? It would face the same objections. As one public comment to the state put it, a diversion like this "would not be approved today."^[42]

Storage, recharge and using less help in every future, even if the dams stay. The hard part is paying for them in time.

How it gets decided

• Federal regulators (FERC) closed early public input on September 18, 2026. Next is a draft environmental review, open for comment, then a decision.^[43]
• The State Water Board runs its own review and must certify water quality.^[44]
• The pump station needs its own review, expected to open for comment this fall.^[45]
• Removal could start in 2028 at the earliest. That's PG&E's goal, not an approved date.^[46] Appeals and lawsuits could slow it.

How to weigh in

• Get an email when it's your turn. Sign up for FERC's free eSubscription and enter docket P-77. You'll hear when the draft review opens for comment.^[47]
• Comment to FERC. When the review opens, use the eComment form at ferc.gov. Name the docket, P-77, and say what you value and why.
• Comment to the state. The State Water Board posts its comment periods on its Potter Valley page.^[44]
• Weigh in on the pump station. The Eel-Russian Project Authority posts its review and meetings at eelrussianauthority.org.^[45]
• Show up locally. Lake County supervisors, the Sonoma Water board and Mendocino County's Inland Water and Power Commission all take public comment at meetings.

Questions worth sitting with

We don't pick a side here. There's a real case for the lake and a real case for the river, and you may feel both.

The author does. He'd love to keep Lake Pillsbury. He also believes the tribes whose river this is should have a strong voice, maybe the final one. He's still making up his mind.

If you are too, these are the questions that matter most:

• Who should decide? Regulators in Washington, the people at the lake, the farms that use the water, or the tribes who were here first?
• What is a lake worth? It's made by a dam, but it's where people learn to love the outdoors. How does that weigh against a hundred miles of salmon river?
• Who pays? Keeping the dams safe and fish-friendly costs a lot. So does taking them out. Either way, it lands on someone.
• Can we get ready in time? The water is already fading. Storage, ponds and recharge take years to build.

What a fair ending needs

Whichever way it goes, a fair ending would:

• Replace the fire crews' water.
• Protect the wells around the lake.
• Invest in Lake County.
• Build storage before the Eel water ends.
• Keep the land public, lake or valley.

The real question isn't only dam or no dam. It's whether we build the storage, the recharge and the habits that let us lean less on any one river.

Photos by Devan Hemmings unless noted.

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