Water-Level Changes, 1980 to 1997, and Saturated Thickness, 1996-97, In the High Plains Aquifer

The High Plains aquifer underlies one of the major agricultural regions in the world, including parts of eight States Colorado, Kansas, Nebraska, New Mexico, Oklahoma, South Dakota, Texas, and Wyoming. In the area underlain by the High Plains aquifer (called the High Plains region in this report), the total number of acres irrigated with ground water expanded rapidly after 1940: 1949 2.1 million acres; 1959 6.1 million acres; 1969 9.0 million acres; and 1980 13.7 million acres (Gutentag and others, 1984; Thelin and Heimes, 1987). In 1990, about 95 percent of the water withdrawn from the High Plains aquifer (about 15.7 million acre-feet) was used for irrigation (Marilee Horn, U.S. Geological Survey, written commun., 1996).