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California 'miracle' water year: Rain, snow has state's reservoirs at 128% of historical average

Echowater Project: The future of water in California?
Echowater Project: The future of water in California? 02:40

California ended its "miracle" water year on Saturday with enough rain and snow to fill the state's reservoirs to 128% of their historical average, making it among the wettest years in recorded state history.

That's a welcome boon to a state that has spent much of the past dozen years in a deep drought, forcing state leaders to grapple with how the state should share and manage its water in the future. A series of winter storms in early 2023 busted the state's most recent dry spell.

State officials measured 33.56 inches (85.2 centimeters) of precipitation through the end of September. California's "water year" begins annually on Oct. 1 so it can include all of the fall and winter months when California gets the bulk of its rain and snow. The state depends on those wet months to fill its reservoirs that supply water for drinking, farming and environmental uses throughout the state.

Those reservoirs dipped to dangerously low levels in in recent years because of an extreme drought. That prompted water restrictions on homes and businesses and curtailed deliveries to farmers. It also threatened already endangered species of fish, including salmon, that need cold water in the rivers to survive.

Statewide, reservoirs held 27.4 million acre-feet of stored water as September ended. One acre-foot of water is enough to supply two families of four for a year. Of that, about 4.5 million acre-feet are held in the State Water Project, a network of 30 reservoirs and storage facilities that provides water to 27 million people.

"This was as close to a miracle year as you can get," said Karla Nemeth, director of the California Department of Water Resources.

The reservoirs were helped by a series of nine strong storms that hit California over the winter. Those storms carried so much rain and snow they were known as "atmospheric rivers." They caused widespread flooding throughout the state and were blamed for multiple deaths.

The storms also dumped tons of snow on the mountains. The state snowpack on April 1 was 237% above its historical average. It's just the fourth time since 1950 that the state's snowpack exceeded 200% of average, according to Michael Anderson, the state's climatologist.

All of that snow melted in the spring and summer, filling rushing rivers and reservoirs. Water levels at Lake Oroville rose 240 feet (73 meters) between Dec. 1, 2022, and the end of the snowmelt period. That's the largest increase in storage in one season since the reservoir opened in 1968, according to Ted Craddock, deputy director for the State Water Project.

State and federal officials will have to drain some of the reservoirs to make room for more water that's expected to come this year. The state's rainy season could be complicated by El Nino — the natural, temporary and occasional warming of part of the Pacific Ocean. El Nino affects weather patterns around the world. California typically gets more rain and snow during El Nino year. This year's El Nino has a 56% chance to be considered strong and a 25% chance to reach supersized levels, according to the National Oceanic and Atmospheric Administration.

The potential for more strong storms this year, particularly along the coast, "keeps me awake a little bit at night," said Gary Lippner, deputy director for flood management and dam safety with the California Department of Water Resources.

"We just do not have extensive flood systems on the coast of California," he said. "That's an area we're paying particular attention to."

All of the rain and snow this year could have played a part in what has so far been a smaller wildfire season. Wildfires exploded in size during the drought in part because of the super dry conditions. So far this year, just over 476 square miles (1,234 square kilometers) have burned in California. That's well below the five-year average of 2,031 square miles (5,260 square kilometers), according to the California Department of Forestry and Fire Protection.

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This story has been updated to correct the amount of acre-feet of storage the reservoirs in the State Water Project finished the year with. It was 4.5 million acre-feet, not 27.4 million.

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