“SHERLOCKS OF STORMWATER” EFFECTIVE INVESTIGATION TECHNIQUES FOR ILLICIT CONNECTION AND DISCHARGE DETECTION

“Come, Watson, Come! The Game is afoot!'…” (Doyle, 1930) Wayne County has operated an Illicit Connection and Discharge Elimination Program for over 16 years. Its staff has gained valuable investigative expertise by experimenting with many different methods, committing lots of trial and error, and having a little bit of luck. Investigating for illicit discharges in the field is very similar to Holmes and Watson solving a case - it requires a mix of science, detection, deduction, and persistence.This paper presents investigation techniques used effectively to identify illicit connections and discharges. These techniques are: Identifying priority areas (i.e. “hot spots”), outfall survey, facility dye testing, televising sewer systems, intensive water sampling, smoke testing, and other creative means. Each technique, its advantages and disadvantages, and the best application for each method are described in detail.In 1999, the Illicit Connection Discharge Elimination Training Program was created and implemented by the Wayne County Department of Environment, Watershed Management Division (WCDOE-WMD).The program was developed to provide training for local and regional governments responsible for locating and eliminating illicit discharges to surface waters. Wayne County determined that such a program is an effective means of transferring technology to others. The key goals of the training program are: Sharing our expertise with other local units of government involved in stormwater management and collaborating efforts to reduce improper discharges to surface water.The Wayne County Training Program is consistent with the Illicit Discharge Elimination Plan (IDEP) requirements of the Michigan Voluntary Storm Water Permit (MIG6100000) and the EPA Phase II Stormwater Permit Regulations. The training program consists of five modules and two specialty training sessions. The modules are: Overview, Basic Investigations, Advanced Investigations, Construction Related Illicit Discharges, Combined Basic/Advanced Investigations and two specialty training sessions. The specialty training sessions are titled “Recognizing and Reporting Illicit Discharges” and “Illicit Discharge Investigation Exercise.” Over 1000 persons, representing various local units of government, have attended the training sessions through March 31, 2004. During the first year of the training effort, eighty-two illicit discharges were reported. Elimination of these illicit discharges prevents an estimated 3.5 million gallons/year of polluted water from entering Michigan surface waters. Wayne County explains its experiences and those of other agencies with selected investigative methods. A case study is based on an actual investigation exemplifying how some of the techniques are used in the field is presented.The “Sherlocks of Stormwater” will provide guidance to others needing to prepare and implement an Illicit Discharge Elimination Plan.