California’s reservoirs swell in the wake of winter storms

Water levels fell so much in major reservoirs during California’s drought that boat docks were on dry, cracked land and cars were driven into the middle of what should have been Folsom Lake.

The scene no longer exists after a series of powerful storms dumped large amounts of rain and snow on California, filling reservoirs and ending – usually – the state’s three-year drought.

Currently, 12 of California’s 17 major reservoirs are filled above the historical average for the start of spring. These include Folsom Lake, which controls the flow of water along the American River, as well as Lake Oroville, the nation’s second largest reservoir and home to the nation’s tallest dam.

This is a surprising change in water availability in the country’s most populous state. Late last year, almost all of California experienced drought, including at extreme and exceptional levels. Wells went dry, farmers watered their fields and cities cut down on grass.

The picture of water changed dramatically since December, when the first twelve “atmospheric rivers” hit, causing widespread flooding and destroying homes and infrastructure, and throwing close to 18 meters of snow in the Sierra Nevada mountains.

“California went from the driest three years on record to the wettest three weeks as we launched into the rainy season in January,” said Karla Nemeth, director of the California Department of Water Resources. “So, hydrologically, California is no longer in a drought, except for a small portion of the state.”

However, all the rain and snow can bring new challenges. Some reservoirs are so full that water is being released to make room for storm runoff and snowmelt that could cause flooding this spring and summer, a new problem for exhausted water managers and emergency responders.

Flooding is expected

The storm has created one of the largest snowpacks on record in the Sierra Nevada mountains. Snowpack water content is 239 percent of normal and nearly triple that in the southern Sierra, according to state data.

As the weather warms, water managers prepare for all the snow to melt, releasing a flood of water that will cause flooding in the foothills of the Sierra and the Central Valley.

“We knew there was going to be flooding because of the snow,” Nemeth said. “There’s just too much snow to hold in the creeks and channels and keep things between the levees.”

Managers are now releasing water from the Oroville Dam spillway, which was rebuilt after it burst during heavy rains in February 2017, forcing the evacuation of more than 180,000 people downstream of the Feather River.

The reservoir is 16 percent above its historical average. This compares to 2021, when water levels drop so much that hydroelectric dams stop generating power.

That year, Bidwell Canyon and Lime Saddle marinas had to pull many recreational boats out of Lake Oroville and close their boat rental businesses because the water level was low and it was too difficult to get to the marina, said Jared Rael, who manages it. marinas.

By the end of March, the water in Lake Oroville had risen to 262 meters above sea level, about 70 meters higher than the low point in 2021, according to state data.

“The community will benefit with higher water. Everything is easier to reach. They can just jump in the lake and have fun,” said Rael. “We have tons of water right now. We have high lakes with a lot of snowpack. We’re going to have a great year.”

The heavy precipitation prompted Gov. Gavin Newsom to lift some of the state’s water restrictions and stop asking people to voluntarily reduce their water use by 15 percent.

Some shortcomings remain

Newsom has yet to declare a drought, as there are still water shortages along the California-Oregon border and parts of southern California that depend on the struggling Colorado River.

Cities and irrigation districts that provide water for farms will get their water supplies from the State Water Project and the Central Valley Project, a network of reservoirs and canals that supply California’s water. Some farmers use stormwater to recharge underground aquifers that have been depleted after years of pumping and droughts have left wells dry.

State officials are warning residents not to let the current abundance go to waste. In the era of climate change, one very rainy year can be followed by several dry years, returning the country to drought conditions.

“Given the weather whiplash, we know the return of the drought and the intensity of the drought that is likely to return means that we need to use water more sparingly,” said Nemeth. “We must embrace conservation as a way of life.”