Use of Landsat Imagery to Estimate Ground-Water Pumpage for Irrigation on the Columbia Plateau in Eastern Washington, 1985

摘要

The report presents a method for estimating ground-water pumpage for irrigation on the Columbia Plateau in eastern Washington. The method combines annual water-application rates estimated from pumpage data with acreage of irrigated crops that was mapped using Landsat imagery. The area chosen for the study includes Grant, Lincoln, Adams, and Franklin Counties. Pumpage data were obtained from private owners and were collected by U.S. Geological Survey personnel for the 1982 through 1985 growing seasons over the four-county area. Ground-water pumpage for irrigation was estimated for 1985 by using the Landsat mapping results and a regression equation developed from pumpage data. The regression equation was used to estimate the annual depth of water applied to irrigated lands on the basis of crop type, available water capacity of the soil, annual precipitation, and irrigation system type; an assessment of accuracy of the estimates also was made.