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Surface Water Supply Index (SWSI)


A Surface Water Supply Index (SWSI) is a predictive indicator of the surface water available in a basin compared to historic supply. The SWSI is calculated by summing the two major sources of irrigation water supply; reservoir carryover and spring and summer streamflow runoff. These two sources are analyzed together when determining the total surface water supply available for the season.

Monthly SWSI Products

Statewide Summary Table:     

Individual Basin Tables:

        Select Month   Select Basin   

 

1981 to Present Streamflow and Reservoir Graphs:

        Select Month   Select Basin   

 

Period of Record Streamflow and Reservoir Graphs:

        Select Month   Select Basin   


Flow Trend Graphs

Individual Flow Trend Graphs:     

 

Surface Water Irrigation Outlook

Drought Related Links