Concentrations of selected herbicides, herbicide metabolites, and nutrients in outflow from selected midwestern reservoirs, April 1992 through September 1993

This data set consists of digital aquifer boundaries for the High Plains aquifer in the central United States. The High Plains aquifer extends from south of 32 degrees to almost 45 degrees north latitude and from 96 degrees 30 minutes to almost 104 degrees west longitude. The area covers 174,000 square miles and is present in Texas, Oklahoma, New Mexico, Kansas, Colorado, Nebraska, Wyoming, and South Dakota.
This digital data set was created by digitizing the aquifer boundaries from a 1:1,000,000 base map created by the High Plains RASA project (Gutentag and others, 1984).