Climate Modification of Dry Desert Air by a Large Irrigation Project

Climatic changes caused by the evapotranspiration of large amounts of irrigation water may be important in irrigation scheduling, weather forecasting and the management of irrigated farmland. Results from previous studies are often in disagreement as to the magnitude of climatic modification by irrigation. Some studies show only minimal changes (Fritschen and Nixon, 1967, Fowler and Helvey, 1974) and others show sizeable modifications (Davenport and Hudson, 1967). Beebe (1974) reports that severe storms as indicated by tornado's are more prevalent over irrigated land in Texas. A recent statistical report (Schickendanz, 1976) shows rainfall increases, temperature anomalities, and hail increases, all caused by irrigation. Schickendanz work covered a very large area in the Great Plains of the United States. Previously reported studies differ greatly in size of area involved and objectives. The studies reported here had the objective of showing the possible climate modification caused by a large irrigation project in Idaho surrounded by a nonirrigated sagebrush grass desert