With a strong El Niño phenomenon increasing the risk of major storms this fall and winter, California is on alert for possible flooding. But while it packs a punch, it will also bring a benefit: a water boon.
How prepared is the state to take advantage of 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 it can still do more.
Los Angeles County uses a network of 27 leaching grounds, where artificial ponds fill when storms send torrents tumbling down the mountains into the San Fernando and San Gabriel valleys. The water sinks into the porous soil and replenishes the water table.
“It really makes a big difference in those wet years that we capture as much water as possible,” said Sterling Klippel, deputy assistant director of the Los Angeles County Department of Public Works. “Anytime we have a storm season with above-average precipitation, that means we capture a lot of water, and the water we capture during those wet storm seasons really helps fill the water supply gap.” »
During the 2025-2026 storm season, the Department of Public Works estimated the system captured as much water as 3.3 million Angelenos used in a year.
If El Niño causes major storms, the Los Angeles area could absorb even more water underground, allowing cities to pump it out later to deliver it to faucets.
As flood control system managers in Southern California prepare for an active storm season, some of the biggest efforts to capture more water are underway in the Central Valley.
Over the past several years, work crews have restored natural floodplains along rivers and streams, built recharge ponds and channeled floodwaters to agricultural fields where they can infiltrate the land.
“This year’s El Niño is a huge opportunity for our water system,” said Julie Rentner, president of the nonprofit group River Partners. “We know we can capture huge volumes of this water. »
Over the past decade, his group has helped repurpose 13,000 acres of farmland in the Central Valley, allowing water to spread, sink into the ground and replenish depleted groundwater.
Generations ago, the Central Valley was a vast expanse of lush prairies, wetlands and lakes fed by snowmelt from the Sierra Nevada. Then dams and expanding farmland dried it out and transformed it into a patchwork of fields, roads and towns. Rentner’s group is focused on restoring parts of natural floodplains so they absorb water again.
In one of these efforts Near Modesto, workers planted native trees on former agricultural fields and removed berms to create more space for water in a place called Dos Rios, where the San Joaquin and Tuolumne rivers meet.
A May 2024 image of the Dos Rios Ranch, a 2,100-acre floodplain aimed at replenishing groundwater near Modesto.
(Paul Kuroda / For Time)
In 2023, one of the wettest years in decades, the San Joaquin reached a width of four miles at the site. Rentner then led the visitors by boat, flying over the flooded land.
A year later, the restored Dos Rios floodplains have become California’s newest state park, and plans are underway, with support from Gov. Gavin Newsom’s administration and Rep. Adam Gray (D-Merced), to cut 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 most important step California can take to capture water during big storms.”
Julie Rentner, president of River Partners, stands on the edge of the Tuolumne River in a restored floodplain in Dos Rios State Park near Modesto in 2024.
(Brian van der Brug/Los Angeles Times)
Rentner’s Group plans additional project 6,000 acres along the rivers between Stockton and Bakersfield. He has a list of “shovel-ready” projects awaiting funding from the Proposition 4 climate bond, which voters approved in 2024.
“We’ve made progress,” said Ann Willis, California director of the American Rivers group. “We are better prepared to capture more of the snowmelt and precipitation runoff. There is a long way to go.”
In a 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 capture runoff and recharge groundwater.
During the 2023 floods, Newsom signed an executive order that encouraged groundwater recharge by suspending permit requirements, allowing irrigation districts and farms to pump floodwaters to fields and ponds where large amounts have seeped underground. The state also helped local agencies introduce diesel pumps and other equipment to draw water from rivers and into canals.
El Niño, The climate pattern of warming ocean waters in the central and eastern Pacific doesn’t guarantee devastating storms in California, but it tips the scales in their favor. And research shows that El Niño events have become more intense over the past half-century as global warming.
In anticipation of possible storms, farmers and irrigation district managers discuss where they will put all the water if it arrives. Some predict that a wet El Niño could bring back the long-dry Tulare Lake, which has resurfaced atop thousands of acres of farmland in 2023.
Don Cameron, a grower at Terranova Ranch in Helm, uses floodwaters from the Kings River to flood vineyards and walnut orchards and recharge groundwater.
(Tomas Ovalle / For time)
On a 5,500-acre farm near Fresno, grower Don Cameron prepares for a deluge.
He manages Terranova Ranch and is a pioneer in the practice of flooding agricultural land to replenish groundwater, which he has been doing every few years since 2011. We call him the godfather groundwater recharge of agricultural lands.
With a $5 million state grant a few years ago, he built 5 miles of canals to carry floodwaters to the fields. When the 2023 flood hit, his team rushed to install around 30 diesel pumps and sent water flowing over a vineyard and orchards of almonds, pistachios and olives. They also piped water to 350 acres of new earthen basins.
Don Cameron stands next to an irrigation canal where his farm draws water from the Kings River.
(Tomas Ovalle / For time)
The soil absorbed as much as a small town consumes in a year, and groundwater rose beneath the farm.
“We proved in ’23 that we could take a lot of water out of the Kings River when it was in flood,” Cameron said.
This time, he installed several large-capacity electric pumps to replace diesel ones, with the aim of harvesting even more floodwater.
“I hope we get some heavy rain,” he said. “We are better prepared if that happens this year, and we hope we can put more water in the ground.”
Producers to the south, in the Tulare Irrigation District, are also ready. During the latest floods in 2023, many siphoned water from overflowing canals into their fields.
“We acted like a big sponge,” said district general manager Aaron Fukuda. “The farmers came together. They understood what was needed and they did it.”
In March 2023, Tulare Lake reappeared on the farmlands of the San Joaquin Valley.
(Robert Gauthier/Los Angeles Times)
Statewide, so much water went into the ground by 2023, officials estimated that aquifers had gained 4.1 million acre-feet, more than the combined annual use of all Southern California cities, but still not enough to offset decades of declining groundwater.
To capture more water, state agencies are also taking other steps.
The Department of Water Resources has a program which provided funds to local agencies to purchase dozens of pumps, build 12 water collection ponds, and clear 600 acres of land to build more ponds.
It works 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 essential to the success of this work. »
California is also considering building new infrastructure to capture more water, such as the Site reservoir northwest of Sacramento.
Yet even without new reservoirs, experts say California could retain more water by asking dam operators to respond more flexibly to accurate weather forecasts, releasing more water to make way for deluges and retaining more water when no major storms occur.
Researchers at the Scripps Institution of Oceanography at UC San Diego demonstrated this approach on several dams and found in a recent study study that if dam managers adopted it in 20 reservoirs, the state would get enough additional water for more than a million homes each year.
Two reservoirs along the Russian River in Northern California – Lake Mendocino and Lake Sonoma – use this approach to hold more water from the October to April storm season for the summer.
“It worked very well over several years of testing,” said meteorologist Marty Ralph, who directs the Center for Western Weather and Water Extremes at Scripps. “And it looks like it will work well elsewhere. But we have to look at it very carefully because every reservoir is different.”
It’s not just a stormy winter linked to El Niño that California needs to prepare for. With global warming, not only will precipitation fall increasingly as rain and not snow, but atmospheric rivers should also become more powerful, bringing more intense showers. At the same time, droughts are prolonging and getting worse.
As climate change strains California’s water systems, it’s never been more important to know how to take advantage of big storms when they come.
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