A unique spectacle key to Napa County’s water management could be drawing onlookers for weeks to come thanks to the string of atmospheric rivers continuing to hit Northern California.
Lake Berryessa’s famed “glory hole,” located about 80 miles north of San Francisco, experienced its first spillover in years after water levels on the man-made reservoir exceeded 440 feet, automatically triggering the use of the mid-lake pipe to keep the lake from flooding.
Technically called the Morning Glory Hole spillway, the drainage pipe has been used only 25 times in its nearly 70-year history, according to the Solano County Water Agency, which utilizes water from the reservoir.
“It started spilling at Feb. 4 at 6:15 p.m., and we’re going to see another atmospheric river hit us on Thursday, so it’s quite likely the lake will continue to spill for a few more weeks,” said Chris Lee, the general manager for the Solano County Water Agency.
The fascinating water management design, known as a passive spillway, was last used in 2019 and 2017. Before that it hadn’t been active since 2005, Lee said, a history that exemplifies California’s increasingly dramatic swings through wet and dry seasons amplified by human-caused climate change.
When the phenomenon occurs, the lake looks like it has a giant hole in it, where a ring of water is being pulled inward. The top of the pipe is 72 feet across and releases the water 200 feet down into Putah Creek.
“It’s definitely worth seeing,” Lee said. “I’ve been lucky enough to see it a few times. … It’s just not that common.”
Lee said he’s aware of only two other similarly passive spillways in California, one in Trinity Lake in Trinity County and one at Whiskeytown Lake in Shasta County, which also spilled over last week.
The New York Times first wrote about Lake Berryessa’s mesmerizing drain, interviewing Peter Kilkus, who was there hours after the spillway opened.
“People were taking pictures and videos and just standing in awe,” Kilkus, the editor of the Lake Berryessa News, told the paper.
Lake Berryessa is owned and operated by the U.S. Bureau of Reclamation, but it provides much of Sonoma County’s water for drinking and irrigation through the Sonoma County Water Agency, Lee said.
The reservoir was created after federal officials built the Monticello Dam on Putah Creek in the 1950s and has been providing water and hydroelectricity to the Greater Bay Area ever since, according to Visit Napa Valley. Because the dam was constructed in a canyon too narrow to support a typical spillway, officials erected the unique engineering feature to still allow for drainage — the Morning Glory Hole.
Though the section of the lake with the glory hole is marked off by buoys, it continues to draw in curious onlookers like gravity. Officials urge spectators and lake recreaters to be careful and not get close to the glory hole. A woman died in 1997 when she was sucked down into the pipe.
“We’re hoping that people use their best judgment,” Lee said.
