Land Use Related Adjustments to Aquifer Depletion in Southwestern Kansas

From prairie to wheat field, the historical transformation of the Kansas landscape has been dramatic. The contributions to this transformation have been based on many factors including new grain varieties, irrigation technology, and other resource converting-space adjusting techniques. In Western Kansas in particular, with inadequate precipitation (14 to 16 inches average from AprilSeptember) for high yield intensive cropland agriculture, the structure of land transformation has been strongly influenced by the availability of water for irrigation. Since surface sources are negligible, groundwater from the Ogallala Aquifer is the critical source for irrigation water. With the dramatic increase in land area irrigated in Western Kansas, water for irrigation now accounts for 80 percent of the total groundwater use (Figure 1). Associated with the increased demand for groundwater has been a decline in groundwater levels. Western Kansas is essentially "mining" its groundwater resource since water is being pumped from the Ogallala faster than the formation is recharging. Water is currently being pumped from the Ogallala formation at an estimated forty to fifty times the rate of replenishment. The result has been a drop in the water table of one to five feet per year in the last twenty years.'