Stronger water-saving efforts likely as Lake Mendocino drops to scary low

Lake Mendocino this week fell below 20,000 acre-feet (AF) of storage, the level officials say for adequate downstream flows for municipal service.

The Sonoma County Water Agency set a minimum goal of 20k AF (Sonoma Water) for October 1, a figure that would  provide an adequate carry-over water supply entering the 2021-22 fall-winter rainy season. But an August 26 reading showed that the reservoir’s storage level has already dropped below that number.

The storage drop spotlights the historic drought in the Russian River watershed. The slower flow also imperils fish and wildlife throughout the system, and may ultimately affect water quality for residential users.

Sonoma Water, which provides drinking water to more than 600,000 customers in the North Bay and Sonoma Valley, has reduced its diversions from the Russian River by more than 20% over 2020 levels in response to drought conditions.

Sonoma County Supervisor and Sonoma Water Board of Director Chair Lynda Hopkins said officials were initially hopeful that continued conservation could maintain the conservation goal for Lake Mendocino. “Unfortunately, the water-saving efforts in the Upper Russian River have not been enough, even with state action being taken to curtail water rights,” she said. “We really urge everyone to step up their water saving efforts. The only way we’re going to get through this drought is if we all do our part.”

Fourth District Supervisor and Sonoma Water Director James Gore stressed the need for a regional approach to the drought.

“Recognizing the limits of our water supply, we must work together to continue to reduce consumption along the entire Russian River,” Gore said. “Maintaining as much storage as possible in Lake Mendocino will keep enough water in the river for fisheries and  human health and safety. We can meet that goal if we all work together.”

Water managers fear that as water levels drop in Lake Mendocino, reservoir releases will insufficient for fisheries and to meet the human health and safety needs of downstream municipal users. In addition, there is concern that as the reservoir levels drop there may be a decline in water quality for downstream water users.

Learn more about the drought and ongoing water conservation efforts.