photo credit: Sonoma Water
Map showing the location of the dams and diversion tunnel which make
up the Potter Valley Project on the Eel River in Lake County, as well as
various dam infrastructure downstream on the Russian River.

This week saw another milestone in the transformation of the Potter Valley Project in Lake County, as a new regional entity to take over the project was formed.

You’d think decisions about water flowing through Lake County would be made there. But the supervisors who voted on the Potter Valley Project’s future weren’t the ones in Lakeport.

On Tuesday, it was Sonoma County supervisors who unanimously approved a new joint powers agreement between the county, its water agency Sonoma Water, and the Mendocino County Inland Water and Power Commission, creating the Eel-Russian Project Authority.

Sonoma Water General Manager Grant Davis said the new authority will manage the transition of the Potter Valley Project from its current condition to a new smaller footprint, dubbed the new Eel-Russian Facility.

That's as PG&E prepares to relinquish control of the two dams and important diversion tunnel.

"It's a new facility that will be able to divert water from the Eel River in the winter months, the rest of the year, however, the other nine months, it will not be diverting water," Davis said. "So it's a limited authority and it's really exciting to see that we've found a solution at this point that will work for both the Eel and the Russian River watersheds."

County leaders had to form the new authority before the end of the year to make sure diversions of Eel River water into the Russian River continue. Sonoma Water’s Pam Jeane said stakes are high.

"Unless interventions are taken like drastic cuts to water use, it's anticipated that Lake Mendocino would go dry in about five of ten years," Jeane said.

Some 600,000 Sonoma Water customers, scores of agricultural producers, and the Russian River’s ecosystem and resident species have come to rely on diverted Eel River water. That water is stored in Lake Mendocino, and strategically released throughout the year.

As for the new joint powers agreement - called a JPA - between Sonoma County, Sonoma Water, and the Mendocino County Inland Water and Power Commission, Davis said a fourth group won’t be signing on, but will be a part of the new authority formed by the JPA.

"There is gonna be a seat available for the Round Valley Indian Tribes who've been our partners throughout this entire effort," Davis said.

Davis said that while the current makeup of the Eel-Russian Project Authority is set, it could change in the years to come.