The U.S. Geological Survey, in cooperation with the Bent County Board of County Commissioners, began a study to evaluate irrigation water use quanti- tatively for about 91,630 acres of farmland irrigated from the 103.7-mile-long Fort Lyon Main Canal in the Arkansas River Valley of southeastern Colorado. This report provides information from 1980 and 1990 for four hydrologic components of irrigation water use: Surface-water withdrawals, conveyance losses, ground-water withdrawals, and estimates of threretical crop consumptive use. Surface-water withdrawals for the Fort Lyon Canal were 211,150 acre-feet (about 2.3 acre-feet per acre) during 1989 and 202,000 acre-feet (about 2.2 acre-feet per acre) during 1990. Conveyance losses occurred during the transport of water in the unlined Fort Lyon Canal. Conveyance losses were as much as 72 (acre-feet per day) per mile in the first division of the canal and generally decreased in the downstream canal divisions. Ground-water withdrawals for the Fort Lyon Canal were estimated to be 38,890 acre-feet (about 0.8 acre-foot per acre irrigated ground water) during 1989 and 33,970 acre-feet (about 0.7 acre-foot per acre irrigated by ground water) during 1990. Theoretical crop consumptive use was estimated to be 227,530 acre-feet (about 2.7 acre-feet per acre of cropland) during 1989 and 251, 130 acre-feet (about 2.9 acre-feet per acre of cropland) during 1990. The total crop irrigation requirement needed from irrigation withdrawals was 172,100 acre-feet (about 2.0 acre-feet per acre of cropland) during ` 1989 and 190,050 acre-feet (about 2.2 acre-feet per acre of cropland) during 1990. Crops cultivted in the five divisions of the canal were alfalfa, sorghum, corn, wheat, pasture, and spring grains.
Additional Publication Details
USGS Numbered Series
Irrigation water use for the Fort Lyon Canal, southeastern Colorado, 1989-90
Water-Resources Investigations Report
U.S. Geological Survey :
USGS Earth Science Information Center, Open-File Reports Section [distributor],