Climate change is rewriting the rules of our environment, and California is feeling the heat—literally. With temperatures climbing to record-breaking levels both statewide and globally, the impacts are impossible to ignore. At the tail end of the 2020-2022 drought, the Department of Water Resources projected that by 2040, California’s water supply could shrink by 10% due to a thirstier atmosphere, parched landscapes, and a phenomenon known as the “evaporative gap,” where rising temperatures accelerate water loss through evaporation, leaving less to sustain ecosystems, agriculture, and communities. In 2022, the Newsom Administration released the Water Supply Strategy, which focuses on ways to increase water supply and adapt to the more extreme weather patterns caused by climate change.
At the June California Water Commission meeting, Anthony Navasero, Drought Coordinator for the Department of Water Resources, and Annalisa Kihara, Assistant Deputy Director of Division of Water Quality at the State Water Board, shared updates on implementing the Water Supply Strategy, highlighting progress in brackish and seawater desalination, advancing groundwater recharge projects, and improving information systems like stream gauges and a new water rights system.
THE WATER SUPPLY STRATEGY
The Water Supply Strategy proposes a multi-prong approach to address the problem and is centered around four initiatives:
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- Develop new water through recycling and desalination,
- Reduce the use of water in cities and on farms through more efficient water use and conservation,
- Improve all water management actions with better data, forecasting, conveyance, and administration of water rights, and
- Capture and save more stormwater above and below ground.
The Strategy establishes new statewide goals for 2030 and 2040 for municipal recycled water, desalination, stormwater capture, water conservation, and increasing water storage capacity to address the anticipated 10% gap in our water supply by 2040. 
Implementation actions include conservation regulations, stormwater capture and use, recycled water projects, seawater and brackish desalination, groundwater recharge, and improving data collection & forecasting.
The Delta Conveyance Project is a key action item, said Mr. Navasero. Based on future projections for declines of water supply under climate change, the Delta Conveyance Project is an infrastructure solution to help ameliorate these water losses and protect future water supplies while addressing a system built for climate and weather patterns that no longer exist.
BRACKISH GROUNDWATER DESALINATION
The Water Supply Strategy tasked the State Water Board with estimating groundwater availability for brackish desalination. Released in December 2023, the report, Projected Brackish Water Desalination Projects in California, focused on groundwater with salinity levels lower than seawater but still requiring desalination to be suitable for human use.
“This report concluded, not too surprising, that the highest potential for brackish groundwater desalination exists in coastal groundwater basins with access to existing infrastructure for brine disposal for the high saline brine, and where extraction is consistent with a local groundwater sustainability plan,” said Ms. Kihara.
The Strategy also directed DWR and the State Water Board to identify brackish desalination projects that could be operational by 2030. The 2023 report, Water Available for Brackish Groundwater Desalination, identified nine planned brackish groundwater desalination facilities that could provide an estimated 20,000 acre feet of potable water by 2040. In addition, the report identified areas in California with the highest potential for future brackish groundwater desalination projects.
To support this action, the Department has awarded $123 million in grant funding for various desalination projects. Those projects are at various stages, ranging from research and planning to design and construction. Many local, regional partners will continue to propose and construct new desalination projects.
After surveying and interviewing project proponents throughout the state, the report concluded that brackish desalination is projected to yield approximately 39,600 acre-feet per year by 2030, exceeding the goal of 28,000 acre-feet per year set in the Water Supply Strategy for 2030.
“Unfortunately, we cannot project that we will meet the strategy’s 2040 goal of 84,000 acre feet per year,” said Mr. Navasero. “Hopefully, the success of identified brackish desalination projects when built will spur other projects beyond 2030 to meet that goal in 2040.”
SEAWATER DESALINATION
The State Water Board, Coastal Commission, DWR, and other State entities were tasked with developing criteria for the siting of desalination facilities along the coast and recommending new standards to facilitate approval. The State Water Board is to consider amendments to the Desalination Policy in its Ocean Plan to streamline permits that meet the recommended siting and design standards for projects located in the identified priority areas.
The State Water Board released its report, Seawater Desalination Siting and Streamlining Report to Expedite Permitting, in December 2023. The overall goal of the report is to provide additional clarity on the local, state, and federal requirements for seawater desalination projects, as well as how California agencies involved in permitting implement these requirements. The water boards worked with the Coastal Commission, State Lands Commission, Department of Fish and Wildlife, National Marine Fisheries Service, Ocean Protection Council, Coastal Conservancy, as well as the Department of Water Resources.
Besides the Water Supply Strategy, the Board’s triannual review of the Ocean Plan in 2019 also recommended updates to the seawater desalination provisions.
The State Water Board last amended the seawater desalination provisions in the Ocean Plan in May of 2015. The provisions called for the regional water board to conduct an analysis to determine the best available site design technology and mitigation measures for the facility to minimize intake and mortality of all forms of marine life. These impacts can result from the size and location of a facility, the actual technology used for seawater intake, or the technology employed to discharge the high-saline brine back into the ocean.
Water Board staff conducted interested party workshops last fall in 2024 to gather additional recommendations for potential desalination amendments. Some of the input received included applying an integrated water resource management approach, recognizing that many communities consider desalinated water alongside increased conservation and wastewater recycling. This approach ensures that all voices and perspectives are heard throughout the planning and permitting process, allowing desalination pilot projects to be implemented in a safe and streamlined manner.
“In the last 10 years, we have identified areas where we can provide some additional clarity and information to project proponents as well as our permitting teams,” said Ms. Kihara. “We do plan to do some additional interested party outreach this year before officially kicking off an amendment process.”
NEW WATER RIGHTS SYSTEM
The State Water Board is actively modernizing its water rights system, as called for in the Strategy. The new system, called the California Water Accounting, Tracking, and Reporting System (CalWATRS), is intended to make reporting water rights easier and more efficient, and help the state manage water data more effectively. The system will also make it easier for the public to access information on water rights. The system will go live later this summer, with water right holders to begin submitting water usage reports in October of this year.
PERMITTING GROUNDWATER RECHARGE
To boost the amount of water being recharged to groundwater aquifers, the Water Board has three types of permits for groundwater recharge:
- The standard permitting process, which establishes the permanent water right with a priority date through a somewhat lengthy process;
- A 180-day temporary permit, which is intended for short-term use, such as a pilot project, but does not establish a permanent water right; and
- A five-year temporary permit which is intended to allow for diversions while a standard application is being processed. It avoids the need for repeated 180-day permits, but does not establish a permanent right itself.
Much of the permitting for groundwater recharge has been achieved through the authorization of temporary permits, which have enabled the recharge of over 800,000 acre-feet of water since 2022.
Because California’s climate swings between times of drought to times of high precipitation and flooding, Governor Newsom issued two executive orders, N-4-23 and N-4-27, that authorized water users to divert surface water for groundwater recharge during significant storm events without a water right, and to simultaneously manage flood waters and replenish groundwater supplies.
The executive orders did require reporting and other conditions to prevent impacts to sensitive infrastructure ecosystems, as well as to other water right holders. The Executive Orders are codified in California Water Code 124.2.1 and only allow for diversions if a local agency determines that there is an imminent risk of flooding and that the agency has adopted a flood control plan or has considered flood risk as part of its general plan.
However, Ms. Kihara noted that many communities were unable to take advantage of the executive orders because they were unable to establish a local flood plan in time. This led to Executive Order N-16-25, which waived the flood planning requirements for counties that were part of the drought proclamation. There are 39 counties, including those in the Sacramento and San Joaquin basins, the Tulare Lake Basin, the Scott, Shasta, and Klamath river watersheds, and the Clear Lake Watershed.
The current floodwater recharge reporting requirements include notification to the State Water Board and submission of a preliminary report, followed by a final report.
- Note: The State Water Board held a workshop in June of 2025 for parties interested in acquiring a permit for groundwater recharge. A recording of that workshop is available here.
EXPANDING GROUNDWATER RECHARGE
Another action called for in the Water Supply Strategy is to expand watershed modeling tools to better assess water available for recharge. The Department has been working with local and regional partners on watershed studies in the San Joaquin basin. Known as the San Joaquin Basin Flood MAR watershed studies, this series of studies examines the Calaveras, Stanislaus, Tuolumne, Merced, and upper San Joaquin watersheds to assess water management sectors within those areas.
The study uses an integrated analytic toolset to assess climate change vulnerability and adaptation performance for flood control, water supply, and ecosystems. By leveraging information from the Department’s airborne electromagnetic surveys, climate change analytics, and land-use data, the studies provide a multi-sector understanding of vulnerability to climate change within each basin.
Mr. Navasero said thus far, the studies have shown strong indications that integrated managed aquifer recharge from high flood flows, implementing Forecast Informed Reservoir Operations to maximize storage, and providing ecosystem management releases would maximize benefits for all three water management sectors. The completed studies and their conclusions are expected to be available to the public later this fall.
STREAM GAUGING
With climate change driving the need to improve our forecasts and capabilities, there is also a need for more data, and thus more stream gauges. The Strategy calls for advancing a multi-agency effort to install 430 new stream gauges and upgrade or reactivate 200 more across the state. These gauges provide real-time surface water data for enhanced drought management and flood response.
In 2019, Senate Bill 19 charged the Department and the Water Board to develop a plan to address stream gauge information gaps and to prioritize actions to improve the stream gauge network and data collection. In 2022, the California stream gauging prioritization plan was developed, and subsequent funding of $20 million was allocated to support its implementation.
The program has funded gauging and data needs for both internal stream gauging and external partner requirements with public agencies, which will also benefit the statewide gaging network and data collection efforts. The program aims to fund 139 new or reactivated gauging sites and 198 upgraded sites, while also allocating funding to 38 external partners for 100% of the project cost. The gauging stations are located throughout the state, both north and south, as well as in the middle. The program is in the final stages of awarding and finalizing contracts and MOUs, of which the funding will sunset in June 2027
Mr. Navasero noted that there is no long-term funding for operations and maintenance (O&M) or management costs. However, the new and upgraded stream gauges will support the improvement of modeling and forecasting, helping to manage our resources in the face of climate change.
INNOVATIONS AND INVESTMENTS
The Department of Water Resources has several initiatives aimed at helping achieve the goals of the Water Supply Strategy.
The LandFlex program is an initiative designed to provide an immediate response to drought conditions, while also assisting in the transition of land use in overdrafted basins to support the implementation of the Sustainable Groundwater Management Act requirements.
“By limiting the use of groundwater in areas near vulnerable communities and reducing agricultural water use to only their sustainable yield allocations, the program was able to enroll 4474 acres of land, mostly in the San Joaquin Valley,” said Mr. Navasero. “It permanently retired groundwater overdraft of 66,993 acre feet, provided a water recharge of 22,471 acre feet, while saving evaporation of 14,178 feet, for a total of 103,642 acre feet of saved water.”
Unfortunately, the program funding has run out and is currently closed; however, some similar innovative programs may be funded through Prop 4.
Another innovative action to support new water sources is the state’s investment in the National Alliance for Water Innovation, or NAWI. Run by the Lawrence Berkeley National Laboratory and funded by the US Department of Energy, with $16 million of state investment leveraged into $100 million in federal funding, the partnership supports the research and development of new technologies that reduce the financial and environmental costs of desalination by improving efficiency, reducing energy consumption and improving brine management options.
An additional benefit is that pilot projects generate a range of data sets that are usable by other researchers to advance further research and development, said Mr. Navasero. In some cases, pilot projects will partner directly with historically disadvantaged communities and groups who have been historically underserved.
IN CONCLUSION
“We have highlighted a handful of actions that are helping the state meet near and short-term goals, which are projected to meet many of the strategies’ goals by 2030, but note, at this time we cannot project the same success of meeting the 2040 goals,” said Mr. Navasero. “It will take a combination the success of meeting the 2030 goals, local and regional partner implementing more projects and programs, state and federal support in the form of funding, technical assistance and regulatory support, and ultimately the focus of the people of the state to prioritize the completion of the strategy’s actions.”
Commissioner Curtin said he finds the 10% water reduction due to evaporation changes to be relatively modest. “I think it’s going to be a lot worse than that. The premise here is that the greatest reservoir we have is the snowpack, and that is changing dramatically … How do we do what we know how to do as cost-effectively as possible? I think we’re going to have to start reconsidering what cost-effective means. We’ve lived in a water bubble for a long time. People actually think water is cheap, and it’s not. And $2,500 an acre-foot is probably not even the value of water, and it certainly won’t be in the next few years. So, how are we adapting to climate change for losing the reservoir that we’ve relied on in modern times? That means to me much, much more infrastructure.”
