From the site: "This dataset is a coverage of the physiographic provinces, aquifer outcrops and recharge rates for Tennessee. Each polygon is attributed with its associated physiographic region name (Miller, 1974), aquifer type and composition (Connell and Barron, 1993, p. 2), and aquifer recharge rates (Hoos, 1990 p. 19). The dataset was created to make generalizations about an aquifer's capabilities of transport and recharge and to give names to those regions. The linework was constructed by digitizing a map, prepared by Bradley and Hollyday (1985), at a scale of 1:1,000,000. At the request of State officials, aquifer boundaries in the West Tennessee area were modified to reflect work reported by Parks and others (1982). The coverage was created for the publication by Connell and Barron (1993). The coverage was validated and attributed with physiographic names and aquifer recharge rates in 1997-98."