Hetch Hetchy dam stable after risk of failure

A dam is stable following a warning Thursday afternoon that it was ready to fail and flood properties downstream of a reservoir that helps regulate the San Francisco Bay Area’s water supply, officials with the San Francisco Public Utilities Commission said.

As of about 7:30 p.m., the dam on the Moccasin Reservoir in Tuolumne County was stable.

It was in imminent danger of failing after heavy rain earlier in the day sent a surge of water and debris toward it.

Officials with the commission said the dam functioned properly. The officials said the San Francisco Bay Area’s water supply was never at risk.

The Moccasin Reservoir is one of the utility’s smallest reservoirs. It’s used to regulate the Hetch Hetchy water system, which provides water to about 2.7 million customers in the Bay Area.

The dam never overtopped but this afternoon crews saw water leaking on the downstream face of the dam.

According to the commission, water in the reservoir is now down and water from it is being drained into the larger Don Pedro Reservoir.

Crews are inspecting the Moccasin Reservoir dam for damage to it and its spillways.

Significant flooding had been reported. The Tuolumne County Sheriff’s Office dispatched a swift water rescue team to assist a couple who were caught on top of a chicken coop after their home and vehicles were submerged in water.

Sheriff’s officials said the couple’s neighbors were able to get the couple to safety.

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