Potential Impacts of Past Land Use and Recharge Rates on the Ogallala Aquifer: Water Quality Issues in Kansas By

Quantification of available water and the rate of recharge to the High Plains aquifer in western Kansas are much discussed but little agreed upon topics. The usable lifetime of the aquifer is under investigation, but thus far studies have focused largely on the quantity of water and ignored the quality. The quality of the remaining water for agricultural and water supply uses is an issue that deserves attention and further research. Land use in the High Plains aquifer area is dominated by irrigated agriculture. Water levels and water quality in the Ogallala portion of the High Plains aquifer continue to be impacted by past land uses. KGS site studies and USGS National Water Quality Assessment (NAWQA) program regional studies show that irrigation recharge enhances the movement of contaminants to the water table. Overall increase of nitrate-N (20 %- 80%), specific conductance (3 %- 30%), chloride (11 %-50%), and sulfate (4 %- 90%) concentrations measured at the same irrigation wells in the 1970’s and 1990’s indicate movement of contaminants to the water table. The USGS NAWQA study has observed atrazine and its metabolites in soil water and at the water table at monitoring sites