In a blow to boaters that underscores the growing extent of California's water squeeze, the level of Diamond Valley Lake is falling so low it will have to be closed to recreational uses on April 15, the Metropolitan Water District (MWD) announced Tuesday.
Water is receding so far that ramps in the Diamond Valley Marina are being left high and dry, said MWD spokesman Bob Muir.
It would be the first recreation closure forced by low water since the 2009 drought, but the second time for the reservoir since it opened to the public in 2003. The lake's ramp was shuttered from October 2008 to December 2009 because of low lake levels.
"This action speaks volumes about the seriousness of the water-supply situation Southern California faces now and next year. That's why continued conservation is essential," MWD General Manager Jeffrey Kightlinger said.
The largest reservoir in Southern California, Diamond Valley was built a generation ago to provide a buffer against drought.
During the suspension, the lake will remain open to the public with three miles of shoreline for public fishing. Kayaks and canoes "that meet guidelines" will be allowed as long as the boarding docks are serviceable.
Drawing on its reserves the past three years has so far enabled the Southland to avoid impacts already being felt in other parts of the state.
But now the insurance account is running low.
Diamond Valley is now down to 48 percent of capacity, Muir said, especially significant because this is the end of the winter season when California banks water reserves for hot, dry season. Barring a miraculous series of storms, by fall, it is expected that Diamond Valley could be drawn down to only a quarter of capacity, the lowest it has been since first filled in 2002.
"Diamond Valley Lake's exposed shoreline and dry boat ramp serve as a stark reminder to Southland consumers about the importance of saving water during this drought," Kightlinger said.
For more than a century, since Los Angeles built an aqueduct from the Owens Valley, semiarid Southern California has relied on imported water to augment its own natural supplies. Metropolitan is the largest wholesale supplier to Southern California, serving 26 member agencies, including the Los Angeles Department of Water and Power.
MWD imports water from the Colorado River and from Northern California via the State Water Project, the major source for Diamond Valley. However, in this statewide drought, precipitation is down throughout the state, and the Sierra snowpack is far below historic normal. California's Department of Water Resources has projected it will be able to deliver only 20 percent of its usual allocations. That may be revised upward, but MWD is not expecting it to go above 25 percent.
Construction of the reservoir took three years, and nearly doubled the Southland's surface water storage capacity. At full capacity, Diamond Valley holds 800,000 acre-feet of water, or 860 billion gallons, six times the capacity of nearby Lake Perris.
Next month, the MWD board is expected to reduce allocations to its member agencies on the order of 10 to 20 percent, Chairman Randy Record said Friday. Member retailers who go over will face surcharges.