California turns winter season rain into future water supply

Last month, thanks to years of planning and investment, local stormwater-capture projects turned a downpour into a valuable boost to the water supply. In Los Angeles alone, those November storms generated billions of gallons of captured water — enough to supply tens of thousands of households — with the potential for even more as new projects come online.

Building water storage for a more resilient California

Building on the success of flood diversion efforts in 2023, the state has partnered with 14 local agencies in the Sacramento and San Joaquin regions to divert flood flows and prepare land for groundwater recharge.  These preparations include pre-deploying 20 large-capacity pumps and clearing more than 650 acres of land. These efforts aim to reduce flood risk and enhance groundwater supplies by helping local agencies safely divert flows from swollen streams into underground aquifers for storage. This builds upon an executive order from Governor Newsom in 2023 that authorized the diversion of flood flows for flood risk reduction and recharge benefits.   

Along the Sacramento River Basin, the Big Notch fish passage project is now in action to both modernize and improve California’s water system while also protecting juvenile endangered winter-run Chinook salmon. The Big Notch is a key State Water Project infrastructure investment, improving conditions for migratory fish while supporting the water supply depended upon by tens of millions of Californians. It’s part of the State Water Project’s ongoing efforts to balance water supply and environmental protection.   

In August, California committed an additional $219 million to the Sites Reservoir project. Sites Reservoir is a key component of Governor Newsom’s water strategy—capturing water from the Sacramento River during wet seasons and storing it for use during drier seasons. These efforts will hold up to 1.5 million acre-feet of water, which is enough to supply over 4.5 million homes for a year. The project will help California maintain a resilient water supply in the face of climate change, weather extremes, and water scarcity. 

Local agencies turn storms into supply

In addition to surface water storage, the Newsom administration is working to improve California’s underground water storage through groundwater recharge efforts. Data from the California Department of Water Resources confirms that the state’s aquifers are improving year after year thanks to abundant precipitation and efforts by the state and its regional partners to capture and store more high flows during winter storms in groundwater basins, expand recharge basins, improve groundwater monitoring, and better coordinate among local agencies to reduce groundwater pumping.  

These investments ensure that when water does arrive, we can store it, use it wisely, and build long-term resilience for the entire state.