Illicit Discharge Detection and Elimination

According to the MPCA's Guidance Manual For Small Municipal Seperate Storm Sewer Systems:

"Federal regulations define an illicit discharge as "…any discharge to a MS4 that is not composed entirely of storm water…" with some exceptions. These exceptions include discharges from NPDES-permitted industrial sources and fire-fighting activities. Illicit discharges are considered "illicit" because MS4s are not designed to accept, process, or discharge such non-storm water wastes. It is important to note that illicit does not mean illegal.

Illicit discharges enter the system through either direct connections (i.e. wastewater piping either mistakenly or deliberately connected to the storm drains) or indirect connections (i.e. infiltration into the MS4 from cracked sanitary systems, spills collected by drain outlets, or paint or used oil dumped directly into a drain). The result is untreated discharges that contribute high levels of pollutants including heavy metals, toxics, oil and grease, solvents, nutrients, viruses, and bacteria to receiving waterbodies. Pollutant levels from these illicit discharges have been shown in EPA studies to be high enough to significantly degrade receiving water quality and threaten aquatic, wildlife, and human health."

Best Management Practices: New practices will be added as they are completed.

• UMD 301 - Campus storm water system
• UMD 301 - Glensheen storm water system
• UMD 301 - Limno storm water system
• UMD 302 - Examples of illicit discharges
• UMD 302 - MPCA reportable spill areas
• City of Duluth sampling for illicit discharges on Oregon Creek 2001

Illicit Discharge Best Management Practice Summaries

UMD 301 - Mapping Storm Water System

UMD already has detailed storm sewer maps for the campus, available from Facilities Management. These maps already meet the goal of identifying all storm sewer pipes greater than 24 inches and include pipes much smaller. These maps also identify the receiving waters and interconnected City of Duluth lines. Over the next few years, those outlying properties currently unmapped will be addressed, although none have pipes greater than 24 inches.

UMD 302 - Illicit Connection Detection

Spring 2003 we are videotaping our major storm lines verifying line location and looking for any currently unknown connections. Standard dry weather inspections are not applicable because underground springs and high groundwater tables around most of our buildings are drain tiled and discharge into these storm lines.

UMD 303 - Non-Storm Water Discharge Prohibition

This is a University wide BMP to prohibit non-storm water discharges through ordinance or other regulatory means as required in Part V(G)(3)(b) of the General Permit. The Policy will apply to all University facilities in Urbanized areas of Twin Cities, Duluth or other University facilities that may be included as MS4s.

Discharges to Trout Waters:

UMD properties discharge storm water into, or upstream of, the following trout streams: Tischer Creek (Glensheen), West Branch of Tischer Creek (north side of campus), Miller Creek (NRRI), East Branch of Amity Creek (Research and Field Studies), and the Lester River (Limnology). According to the MPCA MS4 permit, prior to new or expanded discharges into these steams the following determinations must be made and documented that:

1. There is no feasible and prudent alternative to the proposed discharge;
2. All feasible and prudent measures to avoid impacts will be implemented; and
3. All feasible and prudent measures to minimize impacts will be implemented.

If the discharge cannot be avoided, measures must be developed to protect water quality and prevent temperature increases. Acceptable measures include diversion away from the stream and use of filter strips, infiltration, biofiltration, or enhanced swales to treat runoff before discharge to the trout water. Innovative alternatives to ponds are specifically encouraged for trout water discharges if they provide equivalent treatment.