California’s natural resources agencies are beginning to move ahead with an updated state water plan in response to climate warming that threatens an estimated 10% reduction in the state’s available water by 2040. Late last year, Newsom signed SB 72 into law, giving state agencies the go-ahead for a broad-based water supply plan with conservation, new storage facilities and local projects at its core. A panel of state leaders recently discussed the importance of the plan for the state’s future.
California’s water supply plan for a hotter, drier climate came in the shadow of prolonged drought. In 2022, Newsom ordered a series of actions to build water resilience for the near future in the face of recurring climate whiplash. That strategy is being updated with a data-driven and science-based approach to calculating how much water, in any given year, will be available and how it will be stored and delivered. Those issues were unpacked by a panel of state leaders. Wade Crowfoot, heading the California Natural Resources Agency, outlined the challenge.
“If you grew up in California, you knew drought and challenges with this swinging drought and flood as part of our natural environment. We’re in a Mediterranean climate. So like other parts of the world that share this climate, we do have episodic swings of water from drought to flood. But we also know that climate change is sort of stacking the deck and creating more intense volatility.”
March 2026 provided a stunning example of the challenge facing the state’s water and wildlife agencies. Following February’s atmospheric rivers of rain and snow, it was the hottest and driest March on record. The Sierra Nevada snowpack almost disappeared, yet reservoirs in the state average 122% above normal. Karla Nemeth, director of the Department of Water Resources, said it could become the new climate pattern.
“What’s really interesting is this juxtaposition of our precipitation being at about average, our major reservoirs being above average for this time, but our snowpack being dismal. And what you see in that 18% of average peak snowpack is how singularly awful March was.”
California’s water plan is ambitious. Its goal is to increase water supplies statewide by nine million acre-feet. That’s roughly equal to the volume of water currently delivered by the state and federal water projects combined. The strategy includes building storage facilities above and below ground to capture floodwaters, recycling and reusing wastewater, collecting stormwater and desalinating ocean water. Local supply projects are also in the plan. Some $8 billion in funding is being allocated toward projects. Nemeth explained that the state is updating the way it manages water year by year.
“One is after 2021 we put a lot of time and attention into like a dryness model, a soil moisture model, which incidentally is not only important for our water resource management, but it’s also important for our colleagues at Cal Fire to really start to understand how does this really translate into potential wildfire risk.”
Nemeth explained that in addition to expanded aerial snow surveys, which measure water content of snow periodically throughout the year, the state is looking at individual watershed characteristics. That data will be important for local water agencies as they try to supply sufficient and affordable water to customers.
Craig Miller manages the Western Metropolitan Water District serving six million people in Riverside County. The key, he said, was to develop local sources and coordinate with the state and other water agencies on an overall plan going forward. He observed that large projects like desalination are too expensive for locals, so they must rely on their own watersheds for capturing rain and snowmelt.
Miller calculated that desalination could cost up to $8,500 per acre-foot compared to $400 an acre-foot cost of delivering surface water. “That really pushes this group of water managers to say, the, the brighter thing to do is to maximize the water that Mother Nature is putting on this state. And we have to figure out how to catch it and move it and not just move it for water users. This is for the environment, and this is for recovery of species building habitat, agricultural needs and north and south urban needs.”
Most of the water consumed by cities, farms and the environment is born in the Sierra Nevada. Sandi Matsumoto is director of the Nature Conservancy’s California water program and a member of the California Water Commission. She described the process by which it gets to the valley in a usable form. “It really moves through our ecosystems, and it’s sitting up in the forests and those forests store that water that we have. Meadows are incredibly important as water storage. And when they’re in good condition, they’re storing the water so that it can melt over the summer months and slowly deliver water down to the valley. In order to do that, we rely on our rivers. We have rivers, we have wetlands, and these are the mechanisms that actually move that water from the Sierra down into the valley floor.”
Climate warming is changing the dynamics of mountain snowmelt and runoff. Warmer winters produce less snow and more rain. And, as we experienced in March, extreme temperatures can melt what snow does exist. Water managers can no longer count on snowbound water in the mountains to melt slowly into waiting reservoirs. While much attention is focused on the gray infrastructure of dams and canals, Matsumoto emphasized the importance of the green infrastructure for long-term water security.
“One important way is forest health. If we have healthy forests reducing fire risk, we’re reducing the risk of mega fires and problems for air quality. And we’re improving the ability to store water, to improve the water quality and to address flood risk. Similarly, if we can restore habitat and restore flows to our rivers, then we’re facilitating groundwater recharge and really getting our aquifers pumping.”
Matsumoto emphasized the important connection between our rivers and groundwater basins. “Take care of our groundwater basins and bring them into a sustainable place so people can use them during droughts. Groundwater actually helps water stay in the rivers because it’s not percolating automatically into a depleted groundwater basin. There are these relationships like the mountain meadow relationship, a groundwater and surface water relationship, that I think are going to point the way toward some pretty interesting solutions.”
The California water plan pledges an open process with outreach across the state. It will include clear targets to align state, regional and local actions. The California Water Commission will hold an advisory meeting on the 2028 water plan update on May 13 and 14 in Sacramento. Information is available from the Department of Water Resources website.
