California's Biggest Reservoir Loses 265 Billion Gallons of Water

Lake Shasta has lost over 265 billion gallons of water in one month.

After years of drought, several reservoirs in California reached concerningly low water levels in the summer of 2022. However, an abnormally wet winter last year alleviated much of the state's drought and replenished the lakes. Lake Shasta, the state's largest reservoir, neared capacity last year.

The lake has dropped eight feet over the past week, but officials aren't concerned. In fact, they're voluntarily releasing the water through Shasta Dam because the lake's levels were too high for February.

Releases from the dam, also known as "flood operations, started January 31. Officials began the releases after a series of atmospheric rivers brought excessive precipitation to the Golden State throughout January and February. Another moisture-laden storm hit California over the weekend.

The last time officials had to conduct flood operations at the lake was in 2019, Dan Bader, U.S. Bureau of Reclamation area manager in Northern California, told Newsweek.

In the month since the releases began this year, more than 265 billion gallons of water have been released from the reservoir. Before the flood operations, water officials were releasing slightly over 3 million gallons per day for normal wintertime releases, Bader said.

Since flood operations began, enough water has been released from the lake to fill 540,000 Olympic-sized swimming pools.

"Last winter, we stored everything that came in," Bader said, adding that typically flood operations occur at Lake Shasta once every five years.

Release flows were reduced last week, he said.

However, there's a chance that flood operations could resume if more storms hit California this month. The most recent storm pummeled California with heavy snow and was expected to vastly improve California's snowpack levels, which were below normal before the storm. California relies on snowmelt through the spring to supplement as much as a third of the state's water supply.

Despite the releases, Lake Shasta is still in a much-improved state compared with last year. As of Monday morning, its water levels were at 1,038 feet—where it has remained since last Friday. This time last year, the lake was at 997 feet, and in February 2022 it was at 938 feet.

Water officials have conducted flood operations at other reservoirs throughout the state as well.

In February, the California Department of Water Resources opened the spillway at Oroville Dam at Lake Oroville to release water ahead of moisture-laden winter storms. The water was recaptured downstream, and the release provided flood mitigation for downstream communities.