Mar 17, 2016

Bureau of Reclamation Releases Sacramento and San Joaquin Rivers Basin Study

Study finds climate change will cause earlier runoff, refill reservoirs earlier in year

sacramento, san joaquin river, basin study, bureau of reclamation

The Bureau of Reclamation has released the Sacramento and San Joaquin Rivers Basin Study, which found climate change will cause earlier runoff and refill reservoirs earlier in the year, potentially affecting reservoir operations and water storage.

This study, collaboratively developed by Reclamation, the State of California Department of Water Resources, El Dorado County Water Agency, Stockton East Water District, California Partnership for the San Joaquin Valley and Madera County Resource Management Agency, examines climate change impacts and adaptation actions for the Sacramento River Basin, San Joaquin River Basin and the Tulare Lake Basin.

Water from the Tulare Lake Basin reaches the San Joaquin River Basin only in wetter years. Because of the connection with the Central Valley Project, the upper Trinity River Basin was also included in this study. The basins flow into the Sacramento-San Joaquin Delta, which is the largest estuary on the west coast of the United States.

"These basins are at the center of discussions about the availability of water in California, not only for agriculture, but for municipal and environmental needs as well," Reclamation Commissioner Estevan López said. "Because of the collaborative efforts put forth in this basin study, we now have more information on how climate change will impact this region and a better understanding of what will be needed to ensure a sustainable water supply for today and for the future."

The study found that warming conditions will cause a median sea level rise of 36 in., which will increase the difficulty of conveying water through the Sacramento-San Joaquin Delta. Also, temperatures will most likely increase by 1.6 degrees Fahrenheit in the early 21st century to almost 4.8 degrees Fahrenheit by late in the 21st century; precipitation may increase in the areas north of the Sacramento-San Joaquin Delta, with very little change projected in the Tulare Lake Basin, where some of the greatest agricultural demands exist; evapotranspiration is expected to increase with warming temperatures; and snowpack will decline with warming temperatures, particularly in the lower elevations of the mountains surrounding California's Central Valley.

Reclamation, along with its partners and stakeholders, developed management actions to address these findings. The study revealed that conservation, groundwater and surface water augmentation projects and operational improvements may improve the reliability and sustainability of the Central Valley Project and State Water Project systems to meet current and future water needs.

The report also identified potential next steps to resolve current and future imbalances. These next steps were grouped into the following categories, Institutional Flexibility, Municipal and Industrial and Agricultural Water Use Efficiency, River Temperature Management, Forest Health, Groundwater and System Conveyance.

The Sacramento and San Joaquin Rivers Basin Study is a part of WaterSMART, the Department of the Interior's sustainable water initiative that uses the best available science to improve water conservation and help water resource managers identify strategies to narrow the gap between supply and demand. The report is available at For more information on the WaterSMART program, visit