Percentage of Probability of Nonpoint-Source Nitrate Contamination of Recently Recharged Ground Water in the High Plains Aquifer

This raster data set represents the percentage of probability of nonpoint-source nitrate contamination (greater than the proposed background concentration of 4 milligrams per liter (mg/L) as N) of recently (defined as less than 50 years) recharged ground water in the High Plains aquifer of the United States. The High Plains aquifer covers approximately 175,000 square miles in eight States; Colorado, Kansas, Nebraska, New Mexico, Oklahoma, South Dakota, Texas, and Wyoming. Elevated nitrate concentrations above the background concentration have been detected in recently recharged (less than 50 years) ground water in the High Plains aquifer. This data set is derived from empirical models developed using multivariate logistic regression to evaluate the vulnerability of the High Plains aquifer to nitrate contamination from nonpoint sources. This data set was generated in a geographic information system from these models and represents the spatial extent of vulnerability of nitrate contamination greater than 4 mg/L across the aquifer.