Twain Harte Lake will end its 2014 season early because of a leak at the small dam that created the private swimming spot in 1928.
The leak, detected Sunday morning, will mean no more use during the current season, which was to run through Labor Day, according to the Twain Harte Lake Association.
The lake had opened on Memorial Day weekend for use by homeowners and their guests in the area known as the Twain Harte Tract.
Dam safety experts from the California Department of Water Resources decided to reduce the lake level by about 10 feet so the structure could be inspected. They have not reported their findings.
The leak prompted the National Weather Service to issue a flash flood warning Sunday, but it was quickly lifted. Officials said there was never a danger of dam failure.
The lake empties into Sullivan Creek, a tributary of the Tuolumne River. It does not store drinking water.
The concrete and metal dam is 36 feet high and 325 feet long, according to the state agency. It can hold up to 143 acre-feet of water. Don Pedro Reservoir on the Tuolumne, supplying the Modesto and Turlock irrigation districts, is about 14,000 times that size when full.
Twain Harte Lake was built a few years after the founding of the town, named for authors Mark Twain and Bret Harte. It serves what is believed to be the first recreational subdivision in the Sierra Nevada, according to the association website.