The two largest reservoirs in California are already at ‘critically low levels’ and the dry season is just starting

“We anticipate that in the Sacramento Valley alone, over 350,000 acres of farmland will be fallowed,” Mary Lee Knecht, public affairs officer for the Bureau’s California-Great Basin Region, told CNN. For perspective, it’s an area larger than Los Angeles. “Cities and towns that receive [Central Valley Project] water supply, including Silicon Valley communities, have been reduced to health and safety needs only.”

“Communities across California are going to suffer this year during the drought, and it’s just a question of how much more they suffer,” Gable told CNN. “It’s usually the most vulnerable communities who are going to suffer the worst, so usually the Central Valley comes to mind because this is an already arid part of the state with most of the state’s agriculture and most of the state’s energy development, which are both water-intensive industries.”

‘Only 5%’ of water to be supplied

Lake Oroville is the largest reservoir in California’s State Water Project system, which is separate from the Central Valley Project, operated by the California Department of Water Resources (DWR). It provides water to 27 million Californians and 750,000 acres of farmland.

Although heavy storms toward the end of 2021 alleviated the lake’s record-low levels, resuming the power plant’s operations, state water officials are wary of another dire situation as the drought worsens this summer.

“The fact that this facility shut down last August; that never happened before, and the prospects that it will happen again are very real,” California Gov. Gavin Newsom said at a news conference in April while touring the Oroville Dam, noting the climate crisis is changing the way water is being delivered across the region.

According to the DWR, Oroville’s low reservoir levels are pushing water agencies relying on the state project to “only receive 5% of their requested supplies in 2022,” Ryan Endean, spokesperson for the DWR, told CNN. “Those water agencies are being urged to enact mandatory water use restrictions in order to stretch their available supplies through the summer and fall.”

The Bureau of Reclamation and the DWR, in concert with federal and state agencies, are also taking unprecedented measures to protect endangered winter-run Chinook salmon for the third drought year in a row. Reclamation officials are in the process of securing temporary chilling units to cool water down at one of their fish hatcheries.

Both reservoirs are a vital part of the state’s larger water system, interconnected by canals and rivers. So even if the smaller reservoirs have been replenished by winter precipitation, the plunging water levels in Shasta and Oroville could still affect and drain the rest of the water system.

The water level on Folsom Lake, for instance, reached nearly 450 feet above sea level this week, which is 108% of its historical average around this time of year. But with Shasta and Oroville’s low water levels, annual water releases from Folsom Lake this summer may need to be bigger than normal to make up for the other reservoirs’ significant shortages.

California depends on storms and wintertime precipitation to build up snowpack in the Sierra Nevada, which then gradually melts during the spring and replenishes reservoirs.

Gable said as California enters a future much hotter and drier than anyone has experienced before, officials and residents need to rethink the way water is managed across the board, otherwise the state will continue to be unprepared.

“Water is supposed to be a human right,” Gable said. “But we are not thinking that, and I think until that changes, then unfortunately, water scarcity is going to continue to be a symptom of the worsening climate crisis.”