A hydrologic unit is an area of land that can contribute surface-water runoff to a designated outlet point. As part of an initiative to create a nationally uniform hydrologic-unit data base, the U.S. Geological Survey and the Natural Resources Conservation Service, in cooperation with the Indiana Department of Environmental Management and the Indiana Department of Natural Resources Division of Water, created a Geographic Information System digital data set of 14-digit hydrologic units in Indiana. The digital data set consists of arcs and polygons defining hydrologic units in Indiana.
Additional publication details
USGS Numbered Series
Digital Data Set of 14-Digit Hydrologic Units in Indiana