Potential dam failure in Tuolumne County won't affect Bay Area water supply

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A dam at risk of failure in Tuolumne County does not pose a threat to the Bay Area's water supply, according to a spokesman for the San Francisco Public Utilities Commission. 

The utility agency dispatched a team to monitor the dam after heavy rainflow caused a surge of water and debris into the Moccasin Reservoir, which is more than 100 miles east of San Francisco.

They observed water leaking from the downstream face of the dam and around 1:30 p.m. an evacuation was ordered for the Moccasin Fish Hatchery and Moccasin Marina, according to a statement issued by utilities commission spokesman Tyler Gamble.

Significant flooding has been reported, and the Tuolumne County Sheriff's Department dispatched a swift water rescue team to assist a couple that had gotten caught on top of a chicken coop after their home and vehicles were submerged in water.

As of 4:45 p.m. no injuries had been reported, according to sheriff's officials and the risk of dam failure had been downgraded from "imminent" to "potential."


This comes after heavy rain pelted the area. 

The emergency action plan was enacted due to large amounts of rain. San Francisco Public Utilities Commission noticed a large increase in flow to the dam as well as a lot of debris.

Officials said in a conference call that all individuals in harm's way were have been evacuated. As many as 30 to 40 people were affected. 

The waters will flow into the Don Pedro Reservoir, which is about one mile downstream.

Moccasin Dam is one of the smallest reservoirs in the system. Officials say a "huge amount" of water came in today. There is some damage around the spillways. The dam is being emptied to give it a full and thorough inspection. 

As many as 2.7 million people rely on the system. Officials said there was no disturbance to the water supply. 

According to the National Weather Service, flash flooding is limited to Moccasin Creek between Moccasin Dam and Don Pedro Reservoir. 

Impacted locations include Highway 49, Highway 120, Moccasin Creek to Don Pedro Reservoir and Moccasin Fish Hatchery. 

KTVU's Mark Tamayo says this could impact travel to Yosemite.