California Water Outlook Remains Strong Despite Reservoir Setback

Water Supply Picture Looks Good for Next Few Years, Even If We Have Below-Normal Rainfall and Snowpack

With the third good precipitation year in a row behind us, California is in a good position to meet water demands for the next few years even if those years have lower-than-average precipitation. With one significant exception, our reservoirs are full well above average for this time of year, and some are near full capacity.

The exception is San Luis Reservoir, located near Los Banos on the west side of the Central Valley. This is the first big reservoir on the State Water Project south of the Sacramento River Delta. When pumping from the Sacramento Delta is restricted, this is the first reservoir to begin to be depleted. Recently, the presence of a federally protected fish near the intake for the pumps has required a reduction in pumping into the State Water Project, and San Luis Reservoir is at only a little over 40% of its capacity. For reference, San Luis Reservoir has a capacity of about two and one-half Diamond Valley Lakes.

This illustrates the value of the Delta Conveyance Project, which would allow diversion of water from the Sacramento River into the State Water Project above the Delta when there is adequate flow in the river for environmental and other needs. That is certainly the case today. Water that could be moved to and through San Luis Reservoir is flowing through San Francisco Bay and into the Pacific Ocean because of pumping restrictions.

Both Governor Newsom and the Department of Water Resources recognize this problem and support construction of the Delta Conveyance Project as soon as possible. The governor took the unusual step of including some streamlining of the permitting process and a financing method in language in budget trailer bills that flesh out the state budget. The Legislature did not include this language in the budget it adopted last month, but additional budget trailer bills will be introduced next month, and it appears the expediting measures will be included in them.

Legislation to Improve California’s Water Planning Advances

Senate Bill 72 by Sen. Anna Caballero would require the Department of Water Resources to identify nine million acre-feet of new water supply by 2040. The bill has passed the Senate and the policy committee on the Assembly side. It will be heard in the Assembly fiscal committee next month, and if it passes, will go to the Assembly floor for a final vote. A similar bill passed the Legislature without a single negative vote last year but was vetoed by the governor due to concerns over cost. Most of the cost issues have been addressed in the current bill, and it looks to have a strong chance of being signed into law. This is important because California’s state-level water infrastructure has not been updated in more than 50 years.

Santa Ana Watershed Project Authority Ends Cloud Seeding Demonstration Project

The Santa Ana Watershed Project Authority, or SAWPA, has ended what was planned to be a four-year cloud seeding project designed to show whether cloud seeding in our area could significantly increase rain and snowfall. The project was suspended in the winter of 2023–24 after significant wildfires burned in some of the precipitation target areas of the San Bernardino, San Gabriel and Santa Ana Mountains, to avoid any possibility of contributing to mudflows and flooding.

Over the past year, analytical studies were performed by an independent third party to try to document how effective the first year of cloud seeding had been in increasing precipitation. These studies did not show any conclusive increase in precipitation related to the cloud seeding that was completed.

After reviewing the validation study and consulting with the flood control agencies responsible for the target areas, the SAWPA Commission voted unanimously to end the program.