New Report Highlights Key Factors Affecting State Water Project Deliveries
Thermalito Afterbay, an off-stream reservoir for the State Water Project, provides storage and produces controlled flows in the Feather River downstream from the Oroville-Thermalito facilities.
As California enters a possible fourth dry year, the Department of Water Resources (DWR) has released its biennial report to help water managers better understand how key factors, like climate change and regulatory and operational considerations, affect the operation of the State Water Project (SWP) under historical and future scenarios.
The State Water Project provides water to 27 million Californians and 750,000 acres of farmland throughout the state. In the State Water Project Final Delivery Capability Report 2021, there are estimates on the SWP’s water delivery capability for current and future conditions based on three major factors:
- The effects of population growth on California’s balance of water supply and demand
- State legislation intended to help maintain a reliable water supply
- Impact of potential climate change-driven shifts in hydrologic conditions.
“The delivery capability of the SWP system is an important component in water supply planning and ultimately affects the amount of water available for use in California,” said Erik Reyes, Manager of DWR’s Modeling Support Office. “The availability of these water supplies may be highly variable from year to year, especially in the face of climate change and drought. Having estimates on how much water the public water agencies could receive in a given year from the SWP — whether they be wet, dry, or somewhere in between — gives these agencies information they need to make decisions about increased conservation measures, plans for new facilities, or additional water supply sources to meet local needs.”
While many of the assumptions of SWP operations described in the 2019 Report remain the same in this 2021 update, the most significant changes are due to the water resources model’s improvements that include water supply estimates with updated hydrology and more geographic and operational detail.
As California experiences a rapidly changing climate, the next report in 2023 will expand on the potential impacts of a shift to a hotter, drier future. This new modeling will be critical to helping the public water agencies that receive water from the SWP prepare for ongoing impacts to our water supply from climate change.
The report is provided to the SWP’s 29 water agencies located statewide and is released every two years.
For more information and to access the report, visit website.