Lake Mendocino would contain an additional 24,000 acre feet of water -#8212; about 7.8 billion gallons -#8212; had the U.S. Army Corps of Engineers held onto stormwater from January 2013, the last time there was a significant downpour, according to a local water agency.
Instead, lake levels have dropped to near record lows and Mendocino County officials are considering a water emergency declaration next week.
The water that was released downstream from the lake early last year is almost as much as the amount that now remains, just over 26,000 acre feet. It was enough to supply roughly 48,000 households for a year.
The water was discarded because the Army Corps is required to follow a rigid water-release schedule in winter.
"It's kind of crazy," said Sean White, manager of the Russian River Flood Control and Water Conservation Improvement District. The Russian River water district oversees the Ukiah Valley's 8,000 acre-foot right to water in Lake Mendocino.
"What we need are new rules that are reflective of modern technology," White said.
Army Corps officials said technology has yet to provide a foolproof mechanism for predicting storms that could cause severe flooding.
"The whole purpose of the graph is keeping the dam safe," said Mike Dillabough, chief of the Operations and Readiness Division for the Army Corps' San Francisco District.
The primary reason the dam at Lake Mendocino was built was to prevent flooding.
Under a worst case scenario that includes a complete dam failure, roughly 250,000 people between Lake Mendocino and Jenner could be adversely affected by flooding, Dillabough said.
"If you lived right below the dam, would you feel safe if we retained a whole lot of water and it was very early in the winter?" he said.
White contends Army Corps officials are overly cautious.
Forecasters may have difficulty predicting when a storm is coming, but they're quite successful at predicting when there won't be a storm for a week or more, White said. Knowing that it's not going to rain for at least a week should give the Army Corps time to evaluate whether or not to hold more water in the reservoir than the schedule currently allows, White said.
Water agencies in both Mendocino and Sonoma counties have been pushing for changes to the rules but the Army Corps resists change, White said.
"The Corps has a manual for everything except getting things done," he said.
Alterations would require lengthy studies and, most likely, an act of Congress. Dillabough said he's not certain who ultimately would make that call.
In an attempt to nudge the Army Corps to action, the Russian River water district is co-sponsoring a UC Davis study that will evaluate alternative water release plans. The study, begun last month, will be handed over to the Army Corps when it's completed, White said.
Dillabough said the Army Corps would have to study any alternatives before changes are made.
The Sonoma County Water Agency -#8212; which owns the lion's share of Lake Mendocino water -#8212; has offered to fund an Army Corps re-evaluation of the regulations but the Corps needs permission to move ahead before accepting the funding, White said.
The Russian River water agency also has launched lobbying efforts to convince legislators to make a change.