The Potter Valley Project, which dams Northern California’s Eel River, isn’t doing very much right now. Its reservoir is clogged with sediment, and drought often empties it out. The project once supported a hydroelectric power plant that could produce about 9 megawatts of electricity, which is about 1 percent of a typical fossil-fuel-fired plant, but it has not worked in years. Plus, some of its infrastructure may be at risk of collapsing during an earthquake.
Like thousands of other small dams across the U.S., it is now more trouble than it’s worth. That’s why the utility that owns the project, Pacific Gas and Electric, moved last year to demolish it and undam the river. PG&E has wanted to abandon the project for decades, but a final removal agreement required years of careful negotiation. The dam project currently supplies water to vineyards and cities in Sonoma County, and it’s the sole water source for the rural farm community of Potter Valley.
The final agreement was a delicate compromise: The Round Valley Indian Tribe, which has senior rights to water from the Eel, agreed to let some water flow from the river to farmers through a diversion tunnel, and the farmers agreed to accept about half the water they had received in past years when the reservoir was full. Supporters say that dam removal will restore natural water flow for vulnerable fish that have long inhabited the river.
