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Irrigation is required for profitable commercial potato production in the western U.S. Potatoes have a relatively shallow root zone and a lower tolerance for water stress than most other crops grown in Idaho. The preference for producing this drought sensitive crop in coarse-textured soils with limited water holding capacity makes precise irrigation management a necessity to obtain optimum yield and quality. When restricted water availability reduces potato production potential, options for increasing water use efficiency need to be considered.

Idaho growers that depend on canal irrigation water are always keeping an eye on the weather during the early part of the water year (starting in October).

Will there be enough water in the hills, mountains, reservoirs and streams for next years crops?

Here are some predictions for each canal user based on streamflow estimates and historical allocations of water.

How to Use this Site

Select the Predictions Link. (Here)
Select the current year.
Find your canal.
Determine the shortage risk and severity.
Compare with previous years predictions and results.
If the risk is serious enough consider altering farm practices.
Check out the Mitigation Strategies. (Here)
Continue checking as the season progresses.

Predictions HERE

Background Information HERE

Funding for this project was provided by USDA Risk Management Agency

Link to USDA RMA

Questions or comments about this site: DroughtWeb

Background Information

Idaho Water Users Association has a detailed history of Idaho Irrigation HERE.

Water is necessary for crop production in Idaho. Early pioneers hurriedly bypassed the barren sagebrush deserts of Idaho to get to the more hospitable Oregon and California coasts. In the 1870's early farmers started diverting Idaho river water for irrigation. Reclamation projects starting in 1902 greatly increased the availability of a consistent supply. Many thousands of acres then became profitable crop land.

In wet years the large dams control flood waters. In more normal years they stretch out the water so it will last the season. In dry years the storage from previous years ensures adequate supply. but in extremely dry years, or multiple dry years the supply can run short.

The series of canals that form a network across the Snake River plain distribute the water according to the Doctrine of Prior Appropriation: "First in Time, First in Right". Those that put the water to beneficial use first have first claim for as long as there is available water. All of the available water is claimed by growers, canal companies, municipalities or industry. Usually the amount of demand on the river exceeds the "natural flow" by July. So storage water makes up the difference.

Depending on the demands and flow, water rights after a certain time are cut off or shifted to storage. Any water rights after 1900 are always at risk. On more severe years rights may be cut as far back as 1884.

When growers are planning their cropping systems they need an estimate of their available water for the season. A preliminary estimate available in January, updated monthly until April would help growers optimize their operations. If water supply is likely to be normal or above, then standard production practices should be used. If water supplies are likely to be low, then decisions need to be made for allocating this valuable resource. The earlier the growers have information about the likelihood of shortages, the better the decisions.

This website is the result of a joint project with the University of Idaho Center for Potato Research and Education and the Risk Management Association of the USDA.

Sections of the website are devoted to water availability predictions for individual canal companies, field trial results from University of Idaho studies evaluating various production methods, links to areas with more information, and some suggestions for loss mitigation techniques.

To use: start with predictions

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