Scott Dam from the Potter Valley Project (Photo by Mike Wier)

This article was originally published by the Public Policy Institute of California on July 16th, 2019 as part of their California River Series.

The Eel River—once home to the state’s third-largest salmon and steelhead runs, all of which are now listed as threatened―may see the return of healthy fisheries in coming years. A unique opportunity to remove a dam that blocks fish from reaching spawning habitat has arisen. We talked to Curtis Knight, executive director of CalTrout, about the situation.

PPIC:  Why is the Eel River important for California fisheries?

Curtis Knight: This a complex system that involves two of the biggest coastal watersheds in the state—the Russian River and the Eel River. The Eel presents the best opportunity to restore historic fish abundance in California. The river is blocked by two aging dams—Cape Horn Dam, which diverts water from the Eel to the Russian River for hydropower and other uses and has limited fish passage, and Scott Dam, which has no fish passage and blocks important upper watershed fish habitat. Scott Dam is owned by PG&E, which is attempting to divest itself of the project. This presents an opportunity to reestablish fish into the upper Eel basin.

On the Russian River side, irrigators and others benefit from the water diversions. This water is used to grow crops like wine grapes and keep the river flowing for endangered species and recreation.

On the Eel River side, it’s all about wild fish. Getting fish into the upper watershed above the dam is a top priority for local tribes, NGOs, and others. We did an assessment with Humboldt State University that found more than 150 miles of quality habitat for salmon and steelhead above Scott Dam. This stretch includes high elevation habitat that is rare in the coastal range. Getting salmon and steelhead into this cold-water region will be increasingly important for these fish in a warming climate.

Congressman Jared Huffman has formed a committee to develop recommendations as part of the Federal Energy Regulatory Commission’s (FERC) dam relicensing process for this project. The committee’s goals are to improve fish passage and habitat on the Eel to support naturally reproducing and harvestable native fish populations and to minimize impacts to water supply reliability, fisheries, water quality, and recreation in both basins.

The committee is looking at various fish passage alternatives, but Scott Dam is tall, which makes fish ladders—step-like pools to enable fish to cross the dam—really expensive and not very effective. Trucking fish around the dam, as is done in some watersheds, is also being explored, but in my opinion is not sustainable and won’t lead to fish abundance. Removing Scott Dam would clearly be the best way to restore fish abundance in the Eel River.

PPIC: Is there concern about losing both the water and the energy?

CK: The project doesn’t produce much power. The real value is the water. PG&E is walking away from the project in part because they lose roughly $5 million per year operating it.

On July 1, Humboldt County, Sonoma Water, the Mendocino Inland Water and Power Commission, and California Trout applied to take over the dam relicensing process from PG&E. The purpose is to work toward the two-basin solution and ensure the future of the project is determined locally.

Congressman Huffman’s committee will play a central role in determining what the project will ultimately look like. But one idea is to remove Scott Dam while still diverting water to the Russian River during the winter via Cape Horn Dam. Fish passage would have to be improved at Cape Horn and there are Russian River interests that would need to be met. The loss of water storage from Scott Dam can potentially be offset by storing Eel River water in Lake Mendocino. This would certainly be a good scenario for Eel River fish, but there are still some challenges to overcome.

So while there is still a long way to go, we are confident we will come up with a locally derived solution that meets the needs of fish and people in both the Russian and Eel Rivers.

Photo credit: Mike Wier, California Trout