Water-level changes in the High Plains aquifer -- Predevelopment to 1992

Changes in water levels in the High Plains aquifet underlying parts of Colorado, Kansas, Nebraska, New Mexico, Oklahoma, South Dakota, Texas, and Wyoming result from the variability of precipitation, land use, and ground-water withdrawals. From the beginning of development of the High Plains aquifer to 1980, water levels declined throughout much of the area; the declines exceeded 100 feet in parts of the central and southern High Plains. From 1980 to 1992, water levels continued to decline in these same areas, but at a slightly slower overall annual rate. This slower rate of decline was associated, in part, with a decrease in ground-water application for irrigated agriculture and above normal precipitation throughout the High Plains during 1980-91. Declines exceeding 20 feet were common from 1980 to 1992 in areas of intense irrigation development in Kansas, New Mexico, Oklahoma, and Texas. In the northern High Plains, declines of 10 to 20 feet from 1980 to 1992 were widespread in northeastern Colorado, southwestern Nebraska, and the Nebraska Panhandle. Water levels were generally stable from 1980 to 1992 in most other areas of the High Plains. In a large area in the southern High Plains of Texas, however, water-level rises exceeded 20 feet. Also, scattered rises of 5 to 10 feet occurred in eastern Nebraska. The estimated average area-weighted water-level change, from 1991 to 1992 was -0.55, even though precipitation was well-above normal in 1991 in the High Plains. Water- level declines of 3 to 5 feet were widespread in the intensively irrigated areas of southwestern Kansas and the northern part of the Southern High Plains of Texas. These large declines were not closely related to 1991 precipitation patterns in those areas. Declines of 1 to 3 feet were common throughout the intensively irrigated areas of the Northern High Plains and the less intensively irrigated areas of the Central and Southern High Plains. Water levels continued to rise, generally 1 to 3 feet in the extreme Southern High Plains of Texas. Rises of 1 to 3 feet also occurred in parts of northeastern and central Nebraska.