Now we’re worrying about whether we have too much water in some places.
California, always a state of extremes, rarely faces one quite like this. After three years of drought, the state’s snowpack is suddenly the deepest it’s been on record for mid-January. Most spots in the Sierra already have far more snow today than is usually measured on April 1, the date the snowpack typically peaks. In the central Sierra. The snowpack is 255% of normal for Jan. 17.
“You always have to be prepared for surprises in California,” said Jay Lund, director of the Center for Watershed Sciences at UC Davis.
Among the biggest surprises: after years of paltry water levels? The state’s reservoirs are filling up, including some that are well above their average depth for this time of year. Lake Oroville, the second-largest reservoir in the state, is at 105% of normal for this time of year. Several smaller reservoirs are also filling up, including Folsom, New Bullards Bar and Camanche.
Since its low point on Dec. 1, Lake Oroville has risen more than 120 feet, or about 1 million acre feet (an acre foot is equal to about 326,000 gallons), state water officials said.
Memories are still fresh of Oroville’s near disaster in 2017, when heavy rains damaged the reservoir dam’s main and emergency spillways, forcing the evacuations of more than 180,000 people in communities along the Feather River. State water officials are not expressing concern with the lake or its repaired spillway today, saying they have 600,000 acre feet of capacity in Oroville before they will need to increase water releases for flood control purposes.
“Based upon the current conditions and the dry and cold forecast (over the next two weeks), we do have ample storage to still be able to conserve (water in the lake),” said Molly White, a water operations manager with the California Department of Water Resources.
The concern might increase in April, when the snowpack typically begins to melt, sending water flowing from the mountains and into rivers, streams and reservoirs. Lake Oroville is at just 58% of total capacity, but already has more water than it had in either 2021 or 2022.
Lund said “in theory,” Lake Oroville should be fine.
“They spent a billion dollars on that spillway and they tried to grab the best people in the world to work on that thing,” he said. “In principle, it should be just fine. But, still, it could be the first major test of that spillway.”
Other major reservoirs have even more room. Shasta, the state’s largest reservoir, is at 84% of its historical average. Trinity and New Melones, two other large lakes, are well below their average depths.
Where might it flood?
Spring flooding is far more likely in rivers and small tributaries flowing from the mountains and foothills. With the snowpack at “epic levels,” snow melt issues will be worth watching beginning in April — or when sunny, warm days arrive in the mountains, said state Department of Water Resources climatologist Mike Anderson.
The robust snowpack, Anderson said, “does set the stage for potentially dealing with flood issues as we do move through the snow melt season.”
Lund said significant amounts of water may also need to be released from some of the state’s mid-sized reservoirs, particularly those on the eastern side of the Central Valley and in the San Joaquin River watershed, where many rivers used to control reservoir levels have less capacity than outlets such as the American River below Folsom Lake.
“The latest storms hit when the reservoirs were quite empty,” he said. “If we have another sequence (of storms) when the reservoirs are full and spilling, it will be a little more interesting.”
As for the drought, state water officials are still urging residents to conserve water and it’s likely too early in the winter for local agencies to begin relaxing restrictions. Still, the state’s water outlook has seen a dramatic turn.
“We are about at the halfway point of the snow season and the combination of an exceptional Sierra snowpack and rapid recovery of our reservoir systems are providing an elixir for drought recovery,” said John Abatzoglou, a climate and weather expert at the University of California, Merced. “There is no guarantee that we’ll continue to significantly add to snowpack totals over the second half of winter, but even modest contributions will help.
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