Groveland was hit by flooding Thursday afternoon that caused a river of water to flow through the main part of town, while road closures due to a possible dam failure left some residents stranded for hours.
Moccasin Reservoir was being drained Thursday evening and expected to be empty by today for inspections of the earthen dam that was at one point believed to be at imminent risk of failing.
“There is no danger at this point for any excess water to come out of the reservoir or the dam, or to cause any damage,” said Todd Elmer, spokesman for San Francisco Public Utilities Commission, which operates the dam as part of its system that supplies water to 2.7 million residents in the Bay Area.
Steve Ritchie, assistant general manager of the SFPUC’s water enterprise, told reporters during a teleconference that started at 5:45 p.m. that water came within about two feet of flowing over the top of the dam.
The reservoir, one of the smallest in the SFPUC’s system, holds a maximum capacity of about 550 acre feet. Pinecrest Reservoir along Highway 108, which stores the water supply for 44,000 residents in Tuolumne County, has a total capacity of more than 18,000 acre feet.
An estimated 1,000 acre feet of water was released from Moccasin Reservoir’s spillways and foothills tunnel into Don Pedro Reservoir, which holds about 2 million acre feet, Thursday.
Ritchie said the Bay Area’s water supply was never at risk because the SFPUC had turned off the supply of water from Hetch Hetchy Reservoir to Moccasin for scheduled maintenance earlier that day.
The warnings of the dam’s potential “imminent failure” prompted the SFPUC to activate its emergency action plan and evacuate its 30 to 40 employees in the town of Moccasin at about 1:30 p.m.
People were unable to get into or out of Groveland via Highway 120 from about 2:30 p.m. to just before 4 p.m. when the warning about the dam was lifted. Old Priest Grade, which is maintained by the county, was also reopened Thursday evening.
Meanwhile, the main section of Groveland along Highway 120 was flooded as much as three to four feet deep in some places.
“It’s been the worst flooding we’ve ever seen,” said Jenn Edwards, co-owner of the Hotel Charlotte and Groveland Hotel in downtown Groveland.
She said the hotels didn’t sustain major damage except for some flooding in the basement, though the Groveland Hotel’s parking lot was “completely destroyed.”
Doug Edwards, Jenn Edwards’ husband and business partner, said he was behind the Hotel Charlotte checking on a Pacific Gas and Electric Co. pole that appeared to be at risk of coming down when he saw two 100 to 200 gallon propane tanks float by him.
“Literally the whole downtown was a ripper about three to four feet high,” said Doug Edwards. “It was apocalyptic.”
Chelsea Garcia, owner of Mountain Sage Coffee at 18653 Main Street in Groveland, said water came pouring into the back door of her business and she had to open the front door so it would stream out.
Garcia’s coffee shop is housed in a building that’s also home to a nursery, landscaping business, and art gallery. She estimated about six to eight inches of water was inside at one point.
“I’m going to have to be closed tomorrow for sure with the amount of clean up I’ll have to do because the floors are ruined and walls are possibly damaged,” she said. “I’m thinking at least a week, which is tough for us because that also means the loss of the weekend.”
The town’s economy relies heavily on visitors going to and from the northernmost entrance of Yosemite National Park, about 23 miles from downtown Groveland on Highway 120.
Garcia said she and others watched as vehicles along Main Street were pushed back by the amount of water surging down the street. She called it the most water she’s seen in the 33 years she’s lived in Groveland.
At a press conference Thursday evening, Tuolumne County Sheriff Jim Mele said there was minor property damage throughout the town.
Mele said students at Tenaya Elementary School and Tioga High School were sheltered in place until it was possible for school buses to navigate the flooded lots and nearly impassable roads.
The county was preparing to establish Red Cross evacuation areas in anticipation of the Moccasin Creek Dam’s failure, but that turned out to not be necessary.
Mele said the Tuolumne County Sheriff Search and Rescue team assisted with rescuing a senior couple who had taken refuge on top of a chicken coop after their home and driveway in Groveland were flooded.
County Supervisor John Gray, 69, who represents Groveland and other South County communities, has lived in the town nearly all of his life and called Thursday’s flooding the worst he’s ever seen.
Gray was in Modesto when he began getting calls and text messages as the water started coming. He was prevented from getting home due to the closure of Highway 120 and had to wait in Jamestown until the road was reopened.
“It’s unprecedented,” Gray said of the flooding. “This is worst than last year, and I thought last year was the worst.”
Contact Alex MacLean at firstname.lastname@example.org or (209) 588-4530.