The Moccasin Dam was expected to fail Thursday afternoon after heavy rain in the area brought a surge of water to the Moccasin Reservoir. The National Weather Service issued a flash flood warning through 2:15 p.m. Friday for south-central Tuolumne County. Flood waters were expected to move down Moccasin Creek into the Don Pedro Reservoir.
"Very stressful because we felt that they were going to lose that dam. It would've eroded a lot of the roadway and Highway 120," said Tuolumne County Sheriff Jim Mele.
The threat later was downgraded to a "potential failure" after the rain let up and officials were able to divert the water...
"We do tabletop excessive on these types of events," Mele said. "Even though stress levels were very high they followed their procedures."
Fish hatchery employees and their families who live there were evacuated from their homes. The hatchery, where there are 1.5 million trout in every stage of development, completely flooded. A total loss of fish is anticipated.
"Almost shocking to lose that many fish in the whole area that fast," said resident Tommy Thomason.
Still, a sense of relief hung over the county. The damage could've been much worse had the dam failed.
"If it went over the dam, well you can see how much water was there and you see today what happened," Thomason said.
The Moccasin Reservoir has a storage capacity of 554 acre-feet. The reservoir, its dam and power plant are part of the Hetch Hetchy Project, which provides water and power to San Francisco.
The dam was last inspected on May 4 of last year.
County residents aren't out of the woods just yet. The sheriff warns people to be vigilant and prepared for the next storm.