Effects of Illicit Discharge


An illicit discharge is any flow or dumping to a municipal separate storm sewer of any substance that is not composed entirely of stormwater; exceptions are non-stormwater discharges allowed by the NPDES Permit and discharges resulting from emergency firefighting activities. One goal of the stormwater permit is to eliminate illicit discharges.

  1. Temperature
  2. Pollutants

Stormwater runoff generally increases in temperature as it flows over impervious surfaces. In addition, water stored in shallow, unshaded ponds and impoundments can increase in temperature. Removal of natural vegetation (such as tree canopy) opens up water bodies to direct solar radiation. Elevated water temperatures can impact a water body's ability to hold dissolved oxygen to support fish and other aquatic organisms.