CalTrout wants old Scott Dam on Eel River removed to help salmon and steelhead

Four aging hydropower dams on the Klamath River in Northern California and Southern Oregon are slated for removal in 2021 at a cost of up to $450 million and with support from more than 40 organizations. It would be the largest dam removal project in the world, restoring access to more than 300 miles of habitat for salmon and steelhead.

Located on Malibu Creek about 3 miles from the coast in Los Angeles County, 100-foot Rindge Dam was built in 1924 by the Rindge family and filled with sediment in less than 30 years. It was decommissioned in 1967 and subsequently approved for removal, but the cost of hauling away 276,000 cubic yards of impounded sediment remains an obstacle. The dam thwarts migration of endangered Southern California steelhead.

Built in 1892 on a creek near Stanford University in San Mateo County, 65-foot Searsville Dam blocks the spawning passage for Central California Coast steelhead, a threatened species. The dam’s reservoir is nearly filled with sediment, and the non-potable water is mainly used to irrigate the Stanford campus.

Completed in 1947 on a creek in the Ventura River watershed north of Ojai, 163-foot Matilija Dam impounds a reservoir almost completely filled with sediment. Targeted for removal in 1998 but with no funding approved, it remains a barrier for endangered Southern California steelhead, which number about 500 fish.

Built in 1922 on the Eel River in Lake County’s portion of the Mendocino National Forest, the 138-foot Scott Dam impounds Lake Pillsbury, a popular recreational area, and is part of a hydropower project that owner PG&E has abandoned, opening the door to removal as part of a decommissioning process. The dam blocks off the river’s upper watershed to threatened salmon and steelhead.

California Trout, a nearly 50-year-old environmental nonprofit, cites five of the state’s more than 1,400 sizable dams as “ripe for removal.”

A state environmental group is calling for the removal of an old dam on the Eel River, contending it threatens the future of protected salmon and steelhead while acknowledging it is a key part of the North Bay’s water supply.

Scott Dam, a 138-foot concrete dam erected in 1922, is one of five aging dams California Trout asserts are “ripe for removal” to benefit their natural surroundings and communities.

The nearly 50-year-old nonprofit known as CalTrout said in its report, “Top 5 California Dams Out,” the Eel River represents “perhaps the greatest opportunity in California to restore a watershed to its former abundance of wild salmonids.”

Scott Dam, located in Lake County’s portion of the Mendocino National Forest, has been a longstanding target of other groups, including Friends of the Eel River, who want steelhead, coho and chinook salmon to swim freely within the 288 miles of habitat in the Eel watershed blocked by the dam.

The environmentalists see a “unique opportunity” to achieve their goal, as California’s largest utility PG&E, which has owned the dam as part of a small hydropower project since 1930, has filed Chapter 11 bankruptcy and abandoned plans to sell or seek relicensing of the project that diverts 20 billion gallons of water a year from the Eel to the Russian River at Potter Valley.

Eel River interests have considered the diversion a form of theft, while the water is critical to towns and ranches on the upper Russian River from Potter Valley to Healdsburg and part of the water supply for 600,000 residents in Sonoma and Marin counties.

How the future of the Potter Valley Project will play out over the next 18 months to two years is unclear, but it appears likely to result in either decommissioning or relicensing of the project, which includes a small powerhouse and two Eel River dams.

The bottom line is either PG&E or a new owner of the project may face a choice between paying more than $90 million for a fish ladder at Scott Dam or about $70 million to remove it.

North Coast Rep. Jared Huffman, D-San Rafael, and CalTrout both say federal officials are likely to require “volitional fish passage” at Scott Dam, enabling the threatened salmon and steelhead adults to swim freely to their spawning grounds and juvenile fish to get out to the Pacific Ocean.

“There’s no way around it,” Huffman said.

The National Marine Fisheries Service, under federal law, has the authority to require fish passage at hydropower projects that are either changing hands or shutting down, said Josh Fuller, an agency biologist based in Santa Rosa.

Fuller, who is involved in process, declined to name a preferred fate for the dam but said it should ensure the dwindling number of Eel River fish are “on a recovery trajectory.”

“We’re going to have to have some sort of fish passage at the facility,” he said. There are numerous ways to accomplish it, including trapping fish and trucking them around the dam, but Marine Fisheries favors volitional passage because it involves “less human intervention” in the fish population. Fuller said.

“It’s fair to say the status quo will not work,” he said.

Darren Mierau, CalTrout’s Arcata-based North Coast director, said the cost difference supports removal of Scott Dam, noting an engineer’s report to PG&E last year that estimated the fish ladder cost at $55 million to $93 million.