Illicit discharges—pollutants entering the storm sewer system from non-stormwater sources—can pose serious risks to public health, water quality, and the environment. As part of its Municipal Separate Storm Sewer System (MS4) permit through the Minnesota Pollution Control Agency (MPCA), the City of Eden Prairie partnered with SRF to create a proactive Illicit Discharge Detection and Elimination (IDDE) Response Plan.
This plan outlines a clear, coordinated process for how the city will respond when illicit discharges are identified within its storm sewer system.
A Cross-Departmental Plan for Compliance and Community Impact
SRF worked closely with Eden Prairie’s Environmental Coordinator, Engineering, Public Works, Utilities, Police and Fire, and Planning departments to develop a comprehensive response strategy. In addition to mapping workflows and responsibilities, the project also included a robust education and outreach component.
SRF developed several public-facing and staff resources, including:
- Educational brochures covering sustainable stormwater management, pet waste disposal, and IDDE awareness
- An interactive field-use document for City staff responding to illicit discharges
- Custom training presentations and a video combining live action and animation
- In-person training sessions held in collaboration with police, fire, and utility departments
Prioritization and Mapping Through GIS Tools
To further support enforcement and field response, SRF designed an IDDE inspection plan using GIS analysis to prioritize storm sewer outfalls based on risk. Factors such as pipe age, diameter, land use, proximity to sensitive areas, known violations, and septic systems were used to create a weighted risk model.
- Detailed maps and location-based inspection lists were produced.
- An interactive inspection form was created to log violations and guide real-time decision-making.
- SRF also reviewed the City’s existing stormwater ordinances and recommended enhancements to strengthen regulatory alignment with IDDE goals.
These tools not only help Eden Prairie meet its MS4 requirements but reflect the City’s broader commitment to environmental stewardship and sustainable stormwater management planning.
Resource Links:
Municipal Stormwater (MS4) – Minnesota Pollution Control Agency
MCM 3 Illicit Discharge Detection and Elimination
City of Eden Prairie
Internal Category:
Municipal Engineering & Utilities
More from:
Minneapolis, MN
