Development of Effective Procedures for Illicit-Discharge Risk Mapping

Abstract

ACADEMIC ABSTRACTAuthorities of municipal separate storm sewer systems (MS4s) are required to address illicit discharges as part of the National Pollutant Discharge Elimination System's (NPDES) stormwater program. Field reconnaissance is an effective measure to detect and identify illicit discharges, but requires substantial staff and financial resources to conduct. While risk analysis techniques and guidelines have been developed to facilitate MS4 prioritization of field operations, neither a standard set of indicators nor a standard operating procedure has been adopted. This study investigates the relationships among indicators waterbodies. This pollution originates from many different sources, and typically enters local waters through pipes that drain rainfall away from houses, developments, shopping centers, and other developed areas. As the process of inspecting, testing, and eliminating these pollution sources requires significant public funds, it is important that local authorities perform these tasks in an efficient manner. This research utilizes a method known as risk mapping to investigate the relationships between different characteristics, such as land use and age of development, and the locations of pollution sources. The study indicates that certain characteristics may help to determine the location of pollution sources, and that lower quality information describing these characteristics reduces the ability of the risk map to predict where pollution may occur. The study emphasizes the importance of accurate information in managing pollution, and suggests that a risk mapping tool may help authorities to locate areas with a high risk for pollution. These areas can be given top priority for inspection, which provides authorities with a better chance to eliminate more sources of pollution in a quick and efficient manner. In the long term, the benefits to local authorities that make use of the recommendations developed in this study should include improved water quality, improved pollution management, and cost-savings for taxpayers.