Delineation of ground-water basins and recharge areas for municipal water-supply springs in a karst aquifer system in the Elizabethtown area, northern Kentucky

Ground-water basins and recharge areas for municipal water-supply springs for the Elizabethtown area, northern Kentucky, were delineated using a hydrogeologic-mapping approach, potentiometric map interpretation, anddye-tracing tests. Five distinct ground-water basins drained by major karst springs are present in the Elizabethtown area. These basins are composed of networks of hydraulically interconnected solution conduits and fractures. The boundaries of the basins for Elizabethtown and Dyers Springs-the primary sources of water for the city of Elizabethtown-weredelineated by the positions of inferred ground-water divides on an existing potentiometric contour map. The results of dye-tracing tests, plotted as straight- line flowpaths, were used to confirm the presence and location of inferred ground-water divides and to adjust the position of the basin boundaries. Recharge areas of 4.8 and 2.7 square miles weredelineated for Elizabethtown and Dyers Springs, respectively. Swallets that drain concentrated stormwater runoff from major highways are presentin the recharge areas for both municipal-supply springs. Each spring is therefore potentially vulnerable to stormwater-runoff contaminants oraccidental spills and releases of toxic or hazardous materials into certain highway drainage culverts.