Water Resources of Idaho
Water Resources of Idaho |
By Molly A. Maupin ¹
As part of the U.S. Geological Survey's National Water Quality Assessment Program in the Upper Snake River Basin study unit, land- and water-use data were used to describe activities that have potential effects on water quality and biological conditions in the basin. Land-use maps and estimates of water use by irrigated agriculture were needed for Gooding, Jerome, Lincoln, and Minidoka Counties (south-central Idaho), four of the most intensively irrigated counties in the study unit. Land-use in the four counties was mapped from Landsat Thematic Mapper imagery data for 1992 water year using the SPECTRUM computer program. Land-use data were field verified in 108 randomly selected sections (640 acres each); results compared favorably with land-use data from other sources. Water used for irrigation during the 1992 water year was estimated using land-use and ancillary data. In 1992, a drought year, estimated irrigation withdrawals in the four counties were about 2.9 million acre-feet of water. Of the 2.9 million acre-feet, an estimated 2.1 million acre-feet of water was withdrawn from surface-water, mainly the Snake River, and nearly 776,000 acre-feet was withdrawn from ground-water. One-half of the 2.9 million acre-ft of water withdrawn for irrigation was considered to be lost during conveyance; the remainder was consumptively used by crops during the growing season.
¹ U.S. Geological Survey, 230 Collins Rd. Boise, Idaho 83702-4520
U.S. Department of the Interior | U.S. Geological Survey
URL: id.water.usgs.gov/nawqa/reports/MAUPIN.4115.html
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Page Last Modified: Wednesday, 22-Apr-2009 14:12:47 EDT