Guy Kovner, THE PRESS DEMOCRAT
PG&E intends to sell a remote Mendocino County hydropower project at an auction this fall, a decision that means little in terms of its meager electrical output but sends a ripple through the water system that supplies cities, residents and ranchers from Ukiah south through much of Sonoma County and into northern Marin County.
Many of the more than 600,000 customers and residents who get their water from the Russian River have no idea how much of it flows from the Potter Valley Project’s two dams on the Eel River and through an aging powerhouse in the out-of-the-way valley about 20 miles north of Ukiah.
There’s no indication yet that PG&E’s divestiture from the 110-year-old project — or the alternative of transferring it to local control — would jeopardize the annual diversion of more than 20 billion gallons of Eel River water into the Russian River. But the utility’s announcement opens the door to changes water experts have anticipated and unsettles communities across two counties that rely on it.
“The water supply needs to be protected,” said Janet Pauli, a longtime Potter Valley rancher and irrigation district official. “It’s very serious. There’s no way around it.”
Lake Mendocino, the reservoir near Ukiah, depends on the Potter Valley diversion to supply dry-season Russian River flows down to Healdsburg and supplement the supply the Sonoma County Water Agency delivers to customers in Sonoma and Marin counties. Most is taken from water stored in Lake Sonoma, the region’s largest reservoir.
But without the diversion, Lake Mendocino would shrivel in size in the driest years ahead, diminishing flows in the upper Russian River, a local government study found.