With a strong El Niño increasing the odds of big storms this fall and winter, California is on alert for possible flooding. But if it delivers a wet punch, it will also bring an upside: a bonanza of water.
How prepared is the state to capitalize on El Niño? And what more can it do to take advantage of an extremely wet year?
Experts say California has made progress capturing more stormwater, but there is still more it can do.
Los Angeles County uses a network of 27 spreading grounds, where artificial basins fill up when storms send torrents cascading down from the mountains into the San Fernando and San Gabriel valleys. The water sinks into porous soil and replenishes the groundwater.
“It really makes a big difference during these wet years that we capture as much of that water as possible,” said Sterling Klippel, assistant deputy director of the L.A. County Public Works Department. “Whenever we have a storm season with above-average rainfall, that means we are capturing a lot of water, and the water that we capture during these wet storm seasons really helps to bridge the gap in water supply.”
During the 2025-26 storm season, the Public Works Department estimated the system captured as much water as 3.3 million Angelenos use in a year.
If this El Niño brings major storms, the L.A. area could take in even more water underground, enabling cities to pump it out later to deliver to taps.
While managers of Southern California’s flood control system are preparing for an active storm season, some of the biggest efforts to capture more water are underway in the Central Valley.
Over the last several years, work crews there have been restoring natural floodplains along rivers and creeks, building recharge basins, and routing floodwater to farm fields where it can soak into the land.
“This El Niño year is a huge opportunity for our water system,” said Julie Rentner, president of the nonprofit group River Partners. “We know that we can capture huge volumes of that water.”
Over the last decade, her group has helped repurpose 13,000 acres of farmland in the Central Valley, enabling water to spread out, sink into the soil and replenish depleted groundwater.
Generations ago, the Central Valley was a vast expanse of lush meadows, wetlands and lakes fed by melting Sierra Nevada snow. Then dams and expanding farmlands dried it up and turned it into a patchwork of fields, roads and towns. Rentner’s group focuses on restoring pieces of the natural floodplains to absorb water again.
In one of these efforts near Modesto, workers planted native trees on former farm fields and removed berms to create more space for water in a place called Dos Rios, where the San Joaquin and Tuolumne rivers meet.
In 2023, one of the wettest years in decades, the San Joaquin swelled to four miles wide at the site. Rentner led visitors around by boat then, skimming over the inundated land.
A year later, the restored floodplains at Dos Rios became California’s newest state park, and plans are in the works, with support from Gov. Gavin Newsom’s administration and Rep. Adam Gray (D-Merced), to cut into levees upstream and downstream of the park and open up more land to absorb pulses of water during floods.
This type of solution, Rentner said, is “by far the single most important step California can take to capture water during big storms.”
Rentner’s group has plans for an additional 6,000 acres along rivers between Stockton and Bakersfield. It has a list of “shovel-ready” projects awaiting funding from the Proposition 4 climate bond, which voters approved in 2024.
“We have been making progress,” said Ann Willis, California director for the group American Rivers. “We are better prepared to capture more of the snowmelt and the rainfall runoff. There is a long way to go.”
In one step that could help, Newsom declared a statewide emergency this week to prepare for an active El Niño storm season, mobilizing state agencies to prepare for possible flooding and also to support local efforts to catch runoff and recharge groundwater.
During the 2023 flooding, Newsom signed an executive order that encouraged groundwater recharge by suspending permit requirements, enabling irrigation districts and farms to pump floodwaters to fields and basins where vast amounts soaked underground. The state also helped local agencies bring in diesel-powered pumps and other equipment to suck water out of rivers and into canals.
El Niño, the climate pattern of ocean waters warming up in the central and eastern Pacific, does not guarantee drenching storms in California, but it tilts the chances in their favor. And research shows El Niños have gotten more intense in the last half-century with global warming.
Ahead of possible storms, farmers and managers of irrigation districts are discussing where they’ll put all the water if it comes. Some are predicting that a wet El Niño could bring back long-dry Tulare Lake, which reappeared atop thousands of acres of farmland in 2023.
On a 5,500-acre farm near Fresno, grower Don Cameron is prepared for a deluge.
He manages Terranova Ranch and is a pioneer of the practice of flooding farmland to replenish groundwater, which he’s done every few years since 2011. He’s been called the godfather of farmland groundwater recharge.
With a $5-million state grant years ago, he built 5 miles of canals to route floodwaters to fields. When the 2023 flood came, his crew scrambled to set up about 30 diesel pumps and sent water flowing onto a vineyard and orchards of almonds, pistachios and olives. They also routed water to 350 acres of new earthen basins.
The ground soaked up as much as a small city uses in a year, and the groundwater rose beneath the farm.
“We proved in ’23 we could take a lot of water off the Kings River when it flooded,” Cameron said.
This time, he has installed several high-capacity electric pumps to replace the diesel ones, aiming to grab even more floodwater.
“Hopefully, we get some serious rains,” he said. “We’re better prepared if it does come this year, and hopefully we can put more water in the ground.”
Growers to the south in Tulare Irrigation District are also prepared. During the last floods in 2023, many siphoned water from the brimming canals to their fields.
“We acted like one big sponge,” district Chief Executive Aaron Fukuda said. “Farmers came together. They understood what was needed and they got it done.”
Across the state, so much water went into the ground in 2023 that officials estimated aquifers gained 4.1 million acre-feet — more than the combined annual usage of all the cities in Southern California, though still not enough to make up for decades of groundwater declines.
To capture more water, state agencies are also taking other steps.
The Department of Water Resources has a program that has provided funding for local agencies to buy dozens of pumps, build 12 water-catching basins and clear 600 acres of land for more basins.
It is working with local agencies to “streamline efforts to capture as much water as possible,” said Paul Gosselin, deputy director of sustainable water management. “Continued coordination will be critical to the success of this work.”
California also has plans to build new infrastructure to capture more water, such as the proposed Sites Reservoir northwest of Sacramento.
Yet even without new reservoirs, experts say California could hold on to more water by having dam operators respond more flexibly to precise weather forecasts, releasing more water to make room for deluges, and holding extra water when no major storm is coming.
Researchers at UC San Diego’s Scripps Institution of Oceanography have demonstrated this approach at several dams, and found in a recent study that if dam managers adopted it at 20 reservoirs, the state would get enough extra water for more than 1 million households each year.
Two reservoirs along the Russian River in Northern California — Lake Mendocino and Lake Sonoma — are using the approach to hold more water from the October-April storm season for summer.
“It’s worked really well during several years of testing,” said meteorologist Marty Ralph, who leads the Center for Western Weather and Water Extremes at Scripps. “And it looks like it’s going to work well elsewhere. But we’ve got to look very carefully because every reservoir is different.”
It’s not just a stormy El Niño winter that California needs to prepare for. With global warming, not only will precipitation increasingly fall as rain and not snow, but atmospheric rivers are also predicted to grow more potent, bringing more intense downpours. At the same time, droughts are getting longer and more severe.
As climate change stresses California’s water systems, figuring out how to take advantage of big storms when they come has never been so important.
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