Watershed Description

Indian Creek is a 256 square mile watershed located in southern Indiana, draining to the Ohio River. The watershed is approximately 48 miles long and 19 miles wide. The headwaters are located in the knobs of Clark and Floyd Counties. The mid- and lower- watershed are located in Harrison County. Major tributaries include Corn Creek, Crandall Branch, Raccoon Branch, Brush Heap Creek and Little Indian Creek. Agricultural land use accounts for 62% (159 sq. mi.) of the land use. Ninety square miles (35%) are forested. Developed land accounts for 6.4 sq. mi. (2.5%).

Indian Creek from the Floyd/Harrison County border to the Ohio River has been included on the Outstanding Rivers List for Indiana as a State Heritage Program Site due to its ecological importance.

Karst Features

The Indian Creek watershed includes numerous karst features such as caves, sinkholes and springs. Karst features are formed over long periods of time as rainwater dissolves limestone. In karst systems, there is often a direct connection between surface streams and groundwater that may be used for drinking water wells. Thus, protecting karst systems from pollution is important to ensuring safe drinking water supplies.

Binkley Cave is an important karst feature. At 22 miles long, it is the longest known cave in Indiana. Studies have indicated that Indian Creek feeds Binkley Cave and the cave is connected to the Blue River. Binkley Cave is also home to 74 animal species, many of which are very rare due to the unique cave environment that they inhabit. The Blue River has been included in numerous categories of the Outstanding Rivers List for Indiana including High Quality Water.

Water Quality

The Indiana Department of Environmental Management (IDEM) has monitored water quality in the Indian Creek and its tributaries. IDEM’s monitoring includes water chemistry, stream habitat and aquatic biology. Data are compared to the State’s Water Quality Standards to identify areas of good water quality, areas affected by pollution and areas that need additional monitoring to understand stream conditions.

The monitoring results indicated that portions of the Indian Creek, Crandall Branch and Devils Backbone have elevated levels of bacteria. Habitat and biological quality were considered to be impaired in Little Indian Creek and Devils Backbone.

A 1998 study of Binkley Cave by the Indiana Karst Conservancy found that springs and pools and underground streams associated with the cave have been degraded by elevated bacteria and nitrate.

Through the monitoring conducted as part of this project, current water quality, habitat and biological health data will be collected. Data will be used to better understand current conditions in the watershed and sources of pollution.