Storm Water Compliance
The University of Minnesota maintains Municipal Separate Storm Sewer System (MS4) permits for its Twin Cities (UMTC) and Duluth (UMD) campuses. These permits require the University to reduce pollutants to the maximum extent practicable by implementing Best Management Practices (BMPs) as required by the National Pollutant Discharge Elimination System (NPDES) State Disposal System (SDS) General Permit MNR040000.
The University will also include appropriate site-specific erosion and sediment control when planning projects at other campuses and locations as necessary to protect water resources.
This document establishes administrative procedures that (1) prohibit illicit discharges and connections; (2) reduce pollutants to the maximum extent practicable; (3) establish construction site runoff requirements for waste, sediment and erosion; and (4) establish post-construction runoff controls for new development and major renovation projects.
1. Discharge Prohibitions
Illegal discharges. No person will discharge to the storm drain system materials other than stormwater. The following non-storm water discharges are exempt from this prohibition: uncontaminated groundwater infiltration, uncontaminated pumped groundwater, water line flushing, irrigation water, uncontaminated foundation and footing drains, air conditioning condensation, water from crawl space pumps, street wash water, discharges from potable sources, and flows from firefighting. The prohibition will not apply to water discharges permitted by the MPCA under a National Pollutant Discharge Elimination System/State Disposal System (NPDES/SDS) permit, provided that the discharger is in full compliance with the terms of the permit and that written approval has been granted by DEHS for discharge to the storm drain system. DEHS may exempt other non-storm discharges that are not the source of pollutants to the storm system; examples are short term construction site dewatering where there is no visible sediment and the discharge is pretreated to remove solids and monitored regularly; and dye testing of sewer lines.
Illicit Connections. Illicit connections to the storm drain system are prohibited. The illicit connection of greatest concern is sanitary effluent released to the storm drain system. This prohibition includes such connections made in the past, regardless of whether they were permitted at the time of connection. Upon discovery of such connections, notify DEHS staff immediately. A plan to disconnect the connection and redirect to the sanitary sewer system must be submitted to DEHS and Energy Management.
Spills. Spills of hazardous materials must be reported by dialing 9-1-1. Public reporting of illicit discharges can be made by anyone through U Report or by calling 612-626-6002.
2. Reduction of Pollutants to the Maximum Extent Practicable
Activities, Operations, Facilities. The University through DEHS or FM will identify activities, operations, and facilities that may cause pollution or contamination to the storm drain system. FM and CPM staff will implement the Best Management Practices (BMPs) to the extent they are technologically achievable to prevent or reduce pollution. DEHS or FM will periodically monitor compliance with established BMPs.
Facilities Management is responsible as owner and operator of the stormwater conveyance system and stormwater treatment systems.
3. Construction Site Stormwater Pollution Prevention Plans
National Pollutant Discharge Elimination System (NPDES) Construction Permits. The University will ensure that NPDES Construction Permits are in place before commencement of construction for all new development or redevelopments that require such permits. Permits are required for any construction activity disturbing
- one acre or more of land;
- less than one acre of land if that activity is part of a "larger common plan of development or sale" that is greater than one acre; and
- less than one acre of soil, but the Minnesota Pollution Control Agency (MPCA) determines that the activity poses a risk to water resources.
Permits will include the requisite Storm Water Pollution Prevention Plans (SWPPP). The SWPPPs will be prepared by the Architect/Engineer to comply with NPDES permit requirements and adhere to the storm water standards established by this procedure. These requirements will become part of the contractual relationships with the Architect/Engineer and the Contractor through contractual language or through the incorporation of University Construction Standards into the contracts.
FM staff will approve all NPDES Construction permit applications and SWPPs, and arrange for the owner's signature on permit applications. DEHS will be copied on permit applications. DEHS is the University’s point of contact with regulatory agencies.
Construction Site Erosion and Sediment Controls and Waste Controls. All construction projects are required to have appropriate temporary erosion and sediment controls. If deemed necessary, based on known conditions (environmental, utility locations) documented in the project design and engineering review process, FM may require projects that disturb less than one acre of land to have erosion and sediment controls.
For large projects requiring an NPDES permit, Capital Project Management (CPM) project managers will ensure that
- the Architect/Engineer documents design intent and SWPPP controls which meet University and State of Minnesota standards;
- the Contractor implements these controls according to schedules and specifications in the construction documents; and
- the Contractor inspects for effectiveness of these controls and corrects any problems. The Contractor must document all inspections and corrections. The Contractor will provide an Erosion Control Supervisor who has a valid certification in erosion prevention to direct the Contractor's and subcontractors' operations.
FM will review plans during the design phases of a project and may review Contractor compliance during and after construction. Failure to comply with the SWPPP and this procedure will be addressed as stated in Appendix: Stormwater Enforcement Response.
4. Post Construction Stormwater Management
The University committed to minimizing the negative impacts of its activities on the natural hydrologic cycle as much as possible by treating stormwater close to where it falls and reducing downstream impacts. The goal is to improve overall water quality and clarity. The University prefers recharging groundwater through infiltration as local soils and re-using storm water wherever possible.
Projects that disturb 1 acre of land or more will minimize impervious cover, promote infiltration, and capture and treat stormwater runoff using acceptable BMPs . Linear projects such as utility construction, sidewalks, or road resurfacing activity may be exceptions when BMPs are infeasible.
Projects should incorporate the following performance criteria:
- Control the rate of runoff from the post-development site to match the runoff rates for the native soil and vegetation conditions for the 2-year and 10-year, 24-hour design storms.
- Prohibit discharge from the site for 1.1 inches of runoff from impervious (non-vegetated) areas.
- Provide treatment systems designed to remove 80% of the post-development Total Suspended Solids (TSS).
- Provide treatment systems designed to remove 60% of the post-development Total Phosphorus (TP).
- Prepare and submit an Operations and Maintenance (O&M) manual which outline maintenance requirements and schedules for stormwater BMPs.
The use of infiltration techniques will be prohibited when the infiltration structural stormwater BMP will be constructed in areas
- where industrial facilities are not authorized to infiltrate industrial stormwater under an NPDES/SDS Industrial Stormwater Permit issued by MPCA;
- where vehicle fueling and maintenance occur;
- with less than three (3) feet of separation distance from the bottom of the infiltration system to the elevation of the seasonally saturated soils or the top of bedrock; and
- where high levels of contaminants in soil or groundwater will be mobilized by the infiltrating stormwater.
The use of infiltration techniques will be restricted when adverse impacts to groundwater are expected. Infiltration may be restricted in areas
- with Hydrologic Soil Group D (clay) soils;
- within 1,000 feet up-gradient, or 100 feet down-gradient of active karst features;
- within a Drinking Water Supply Management Area (DWSMA) as defined in Minn.R.4720.5100, subp. 13; and
- where soil infiltration rates are more than 8.3 inches per hour.
In locations where it is determined not feasible to meet the requirements for post-construction runoff quality due to site conditions or lack of space or the project is unable to recycle storm water locally, mitigation project can be completed at a different location.
Mitigation project areas are selected in the following order of preference:
- Locations that yield benefits to the same receiving water that receives runoff from the original construction activity
- Locations with the same Department of Natural Resources (DNR) catchment area as the original construction activity
- Locations in the next adjacent DNR catchment area up-stream
- Locations anywhere with the University's jurisdiction
Mitigation projects must involve the creation of a new structural stormwater BMPs or the retrofit of existing structural stormwater BMPs, or the use of a properly designed regional structural stormwater BMP.
- Mitigation projects must be completed within 24 months after the start of the original construction activity.
- Cost for mitigation projects must be provided by the original construction project, and must meet all requirements of this Procedure.
In situations where it is not feasible to implement a structural stormwater BMP solution, the University may employ decision-making processes recognized by the State of Minnesota, such as Minimal Impact Design Standards (MIDS), to determine other forms of alternative compliance.
Alternative compliance actions will be evaluated based on benefits to water quality and rate of water runoff, improved operating cost (savings), and reduced first (capital) costs.
Site Design and Construction Process
Stormwater treatment options should be based on performance, capital, and maintenance cost and available land. Alternative compliance methods may be considered after other standard mitigation strategies are evaluated.
As part of the design process, CPM project managers will ensure that
- Civil engineering services are coordinated with University subject matter experts;
- Project design incorporates post construction BMPs into construction documents;
- the Contractor implements these BMPs; and
- documentation is provided to DEHS to record compliance.
On the Duluth campus, the following design requirements also apply:
- Portable toilets should be placed and secured so as to minimize the chance of an illicit discharge into one of the special waters in and around campus.
- Catch basins installed in concrete must be imprinted with "NO DUMPING LEADS TO LAKE.”