Focusing Your IDDE Efforts
As an MS4, you are required to develop and implement an illicit discharge detection and elimination program to find and eliminate non-stormwater discharges and illegal dumping. But how do you best use your limited resources to meet this simple MS4 permit element?
Focusing your program allows resources to be expended efficiently. Consider the following components of a focused program:
What is your actual MS4? MS4 stands for municipal separate storm sewer system and is defined as a SYSTEM of conveyances that is
1. Owned by a state, city, town, village, or other public entity that discharges to waters of the U.S.;
2. Designed or used to collect or convey stormwater (including storm drains, pipes, ditches, etc.);
3. Not a combined sewer; and
4. Not part of a Publicly Owned Treatment Works (sewage treatment plant).
Stormwater system components carrying public water or that are maintained by the town/county/city are also part of the MS4. Identifying ownership and maintenance of the stormwater system components can help you prioritize screening efforts.
• What are your pollutants of concern? Review the impaired and TMDL streams lists to understand the pollutants of concern for your community. Then determine if your MS4 is contributing to the pollutant loading and focus on those areas that may potentially have higher pollutant loadings to focus your screening.
• What do you know about your community? Review stormwater and water quality complaints to look for similarities and complaint groupings, as areas with complaints may need a higher priority for your community. Use your existing data to identify age and type of development, land use and other indicators of potential illicit discharges.
• What other stormwater program elements can be combined or overlapped with IDDE screening? When new capital improvement projects are being developed, screen outfalls in the vicinity of the project to determine if IDs exist and can be removed during the design and construction of the CIP project.
• How effective was your screening program in previous years? Consider previous efforts at IDDE screening in terms of the number and types of illicit discharges actually found. Use patterns or groupings of illicit discharges to refocus program efforts to be more effective.
Examples of varying levels of IDDE programs in the Southeast will be discussed to illustrate the evolution of illicit discharge detection and elimination programs. Lessons learned will also be provided from Phase 1 communities that have gone through several permit iterations.