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Western States Water Council Full Council Minutes Boise, Idaho April 22, 2005 . Beginning in the 1950-60s, sprinkler irrigation systems began to spread, primarily to save labor. Today, nearly 75 % of all irrigation is with sprinklers. Now farmers can run,their sprinklers through laptops from sailboats in Hawaii! Teton Dam was the last remaining large gravity irrigation system, which w~s destroyed by failure of the dam. We now divert 1 Maf less annually, which was once incidental recharge, but which is now mostly stored in reservoirs. That water, except in times of drought, must sometimes be evacuated for flood storage. A number of entrepreneurs appropriated much of the water from many of the springs in the 1960s for fish propagation. Critics say that the state has over appropriated its water resources, but that is not true. The Appropriation Doctrine assumes there will be shortages at times and regulates use with priority dates. However, we did fail to recognize the impact of surface irrigation practices on spring discharges. You can't compel a farmer to divert and over apply water to his fields. Generally, an appropriator's use is limited to diverting the minimum amount necessary for beneficial use. Often, the usual practice is to divert the entire paper right, which may be more than is needed. In Idaho, there has been massive land development for irrigation. About one million acres are irrigated from ground water, using sprinklers and deep wells. Karl added that then you throw in the worst drought of record in the upper Snake Plain. It is worse than the 1930s. No single year has been asbad .as 1977, but close. Since 2000, it is the worst . back-to-back drought years ofrecord. The statistical probability seems to be one in 500 years f9r such a drought. He observed, "So we had the perfect storm, and nobody saw it coming." Today, there is not enough water to satisfy all the water rights issued over the years, and administration by priority has had to take place. In 1992, Keith Higginson, then Idaho's Department of Water Resources Director, set a moratorium on new water rights, unless there is mitigation. Idaho barley malt is produced in Idaho Falls, and trucked to Mexico to brew Corona beer. Such commerce has developed with water mitigation. Karl described the effects of ground water depletions on the Snake River. He showed a chart of spring discharges. He compared the Snake River to the South Platte River and ground water's alluvial connection to that river. Generally, ground water impacts are seen in the month, season or year of the withdrawal. However, on the Snake Plain, ground water depletions are not expressed for years or decade. The challenge then is how to administer rights that are not causing injury for 10-20 years. It is much more difficult to administer. Karl's Tuesday decision involving water rights administration addresses injury from 10-20 years ago. Typically, we do not shut off junior water users if there is a "futile call," one that won't 4 .