Indiana Department of Environmental Management


Indiana Department of Natural Resources

Impaired Stream

A stream or other surface water body determined by field assessment to no longer meet the state water quality standards for its designated protected use.

Impervious Surface

Ground cover that does not allow, or minimally allows, for infiltration of water (e.g., roofs, paved parking lots, and roads) and which increases the volume and speed of runoff after a rainfall.


Movement of surface water into the soil, where it is absorbed by plant roots, evaporated into the atmosphere, or percolates downward to recharge ground water.

Intermittent Stream

A defined channel in which surface water is absent during a portion of the year, as ground water levels drop below the channel bottom.


Indiana University – Purdue University