With over 2 million acres of southern Idaho farm land receiving its irrigation water from snowmelt and reservoir storage, the University of Idaho has developed a statistical approach that projects the probability and severity of water shortages down to the irrigation-district level in the major potato-growing areas.
In the past, these surface-water irrigators have relied on basin-wide estimates to project their upcoming season's water supplies.
Now, U of I Agricultural Engineer Brad King, Ralph Oborn, senior scientific aide, and economist Chris McIntosh have developed a statistical approach to the problem.
Projections for 2005, which incorporate each district's water-rights priority dates along with each basin's hydrology, are now available. They may be obtained at: http://extension.ag.uidaho.edu/droughtpredict. January predictions will be updated for February, March and April.
While basin-wide water supply estimates are available from federal and state water resource agencies, an individual producer's water supply can be vastly different due to water-rights priority dates. This determines how water is distributed among users, says King.
"In order for producers to manage risk during drought conditions, they need to know the interaction between water rights and total water supply," he stated.
Also on the Web site, growers facing water shortages can find information developed by Stephen Love, Jeff Stark and other U of I potato scientists that will help them make water-stretching changes in their management and select less water-demand varieties.
Growers can click on UI field-trial results describing yields per inch of irrigation, evaluating different varieties for drought tolerance and comparing reduced-irrigation methods.