Federal water decision that could affect Russian River flows imminent

Federal approval of a drought-related request to reduce flows from Lake Pillsbury could come Friday or early next week, relieving concerns shared by PG&E, North Bay water managers and ranchers in Potter Valley.

If the remote reservoir on the Eel River in Lake County falls too low this summer, it could trigger a dramatic cutback in water to Potter Valley, with repercussions down the Russian River from Ukiah to Healdsburg and potentially into the rest of Sonoma County and Marin County.

PG&E, which operates a small powerhouse in Potter Valley, filed an urgent request Wednesday with the Federal Energy Regulatory Commission seeking permission to curtail releases from Lake Pillsbury, which already has dropped to 52 percent of capacity.

The utility asked if the reduced water flow plan - backed by the Sonoma County Water Agency, state and federal fish biologists and other groups - could be implemented “on or before” Friday.

A spokeswoman for the federal agency said Thursday in an email that PG&E’s request is “under review and we will act as quickly as possible.” Celeste Miller said she had no further information on the timing of the agency’s decision.

Paul Moreno, a PG&E spokesman, said the utility was expecting to get approval of its request early next week, “if not sooner,” possibly on Friday.

Janet Pauli, a grape grower and Potter Valley Irrigation District board member, said last week she hoped the water cutback could start immediately.

If approved, PG&E’s request would allow a minimum release from Lake Pillsbury of 40 cubic feet per second, with an anticipated actual flow of 70 to 90 cfs, said Michelle Lent, a PG&E hydro-scheduler. Flows down the East Fork of the Russian River would be cut from 75 to 25 cfs, she said.

That water winds up in Lake Mendocino, a critical summertime water source for communities from Ukiah to Healdsburg and a contributor to the Sonoma County Water Agency’s supply for 660,000 customers in Sonoma and Marin counties.

Releases from Lake Pillsbury go down the Eel River and are partially diverted through a milelong tunnel to the Potter Valley powerhouse and then divided again between the Potter Valley Irrigation District, which serves 300 ranchers, and the East Fork of the Russian River.

If Lake Pillsbury, which currently holds about 38,800 acre-feet of water, drops below targeted levels for every month from July through November, more drastic flow reductions would be triggered. Flows on the East Fork of the Russian River could go as low as 5 cfs, meaning Lake Mendocino would probably get no Eel River water.

You can reach Staff Writer Guy Kovner at 521-5457 or guy.kovner@pressdemocrat.com. On Twitter @guykovner.