University of Minnesota, Twin Cities
OP-27: Rainwater Management

The University follows B3 and doesn’t specifically reference LID for development and redevelopment.

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 implement Best Management Practices (BMPs) as detailed in the campus-specific Storm Water Pollution Prevention Program in addressing storm water runoff from these campuses, with the goal of reducing pollutants to the maximum extent practicable. The University will implement these BMPs at other campuses and locations for all applicable construction projects and as otherwise appropriate. The required BMPs include implementation of a regulatory control program to address (1) prohibitions of illicit discharges and connections; (2) reduction of pollutants to the Maximum Extent Practicable; (3) establishment and enforcement of construction site runoff controls for waste, sediment and erosion; and (4) establishment and enforcement of post-construction runoff controls for new development and major renovation projects. This document establishes administrative procedures implementing the regulatory controls for these permits.

1. Discharge Prohibitions
Illegal discharges. No person will discharge to the storm drain system materials other than storm water. The following non-storm water discharges are exempt from this prohibition: uncontaminated groundwater infiltration, springs, uncontaminated pumped groundwater, water line flushing, irrigation water, uncontaminated foundation and footing drains, air conditioning condensation, water from crawl space pumps, street wash waters, discharges from potable sources, and flows from firefighting. The prohibition will not apply to non-storm 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. The construction, use, maintenance or continued existence of illicit connections to the storm drain system is prohibited. The illicit connection of highest concern is sanitary effluent released to the storm drain system. This prohibition includes such connections made in the past, regardless of whether such connections were permissible at the time of connection. Upon discovery of such connections, written notification must be made immediately to DEHS. A plan to disconnect and redirect, if necessary, to the sanitary sewer system (upon approval of the authorized regulatory agency), must be submitted to DEHS within seven working days.
Spills. Spills and any known or suspected release of prohibited wastes must be reported to DEHS (UMTC: 612-626-6002, UMD: 218-726-7139). Public reporting of illicit discharges can be made on-line through the University web site (www.ureport.umn.edu).

2. Reduction of Pollutants to the Maximum Extent Practicable
Activities, Operations, Facilities. The University through DEHS or its designated campus storm water point-of-contact, in consultation with campus representatives, will identify activities, operations and facilities that may cause pollution or contamination to the storm drain system. DEHS staff will work with appropriate managers, staff, and contractors to implement the Best Management Practices (BMPs) to the extent they are technologically achievable to prevent or reduce such pollutants. DEHS or its designated campus storm water point-of-contact will periodically monitor compliance with established BMPs.

Facilities Management is responsible for planning, funding, operation, and maintenance of the storm water conveyance system and storm water treatment BMPs. These activities are carried out in accordance with the campus Storm Water Pollution Prevention Program.

UMTC and UMD will each maintain a storm water advisory task force, comprised of, at a minimum, representatives from Facilities Management Engineering, Landcare, Parking, and DEHS. The purpose of this task force is to develop operational practices and identify desired outcomes related to the storm water program and water quality. This taskforce will coordinate with academic research and teaching activities that utilize or impact storm water BMPs.

3. Construction Site Storm Water 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. Such 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.
These 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. DEHS and its designated campus storm water point-of-contact will review, approve all NPDES Construction permit applications and SWPPs, and arrange for the owner's signature on permit applications.

Construction Site Erosion and Sediment Controls and Waste Controls. All construction projects that fall under the NPDES Construction Permit criteria (see above) are required to have temporary erosion and sediment controls. If deemed necessary, based on known conditions (environmental, utility locations) documented in the project design and engineering review process, DEHS or its designated campus storm water point-of-contact may require projects that disturb less than one acre of land to have erosion and sediment controls. For each project that requires an NPDES permit, Capital Planning Project Management (CPPM) project managers will ensure that

the Architect/Engineer incorporates into construction documents and SWPPPs these controls which will meet the established standards of this procedure and the State of Minnesota. Standards for temporary erosion and sediment controls and waste controls are detailed in Appendix A. Projects on the Duluth campus must also comply with additional requirements described in Appendix: Duluth Campus Additional Requirements;
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 with a valid certification in erosion prevention to direct the Contractor's and subcontractors' operations. Certification will be the equivalent of that offered by the University of Minnesota Erosion and Sediment Control Certification Program.
DEHS or its designated campus storm water point-of-contact will review these plans during the design phases of a project and 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 Storm Water Management
The University in its construction and planning processes is committed to minimizing the negative impacts on the natural site hydrologic cycle as much as possible by treating storm water close to where it falls, reducing downstream impacts thereby improving the overall water quality and clarity, recharging groundwater through infiltration as local soils and subsurface conditions allow, and re-using storm water wherever possible.

Projects that disturb 1 acre of land or more, except for linear projects such as utilities, sidewalks and paths, mill and overlay, and other resurfacing activities will implement a storm water management plan that minimizes impervious cover, promotes infiltration, and captures and treats the storm water runoff using acceptable Best Management Practices (BMPs) or any combination of BMPs, with highest preference given to green infrastructure techniques and practices (e.g., infiltration, evapotranspiration, reuse/harvesting, conservation design, green roofs, etc.). At a minimum, these standards will include the following required performance criteria:

Runoff: Rate and QuantityControl 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 all new and redeveloped impervious (non-vegetated) areas.
Runoff Quality
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 for all installed stormwater BMPs. The O&M manual must outline maintenance requirements and schedules for completion.
Stormwater management limitations
The use of infiltration techniques will be prohibited when the infiltration structural stormwater BMP will receive discharges from, or 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, without higher engineering review, sufficient to provide a functioning treatment system and prevent adverse impacts to groundwater, when the infiltration device will be constructed in areas

with predominately 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.
Mitigation provisions
In locations where it is determined not feasible to meet the requirements for post-construction runoff quality (i.e., TSS and/or TP standards), either 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 with the following requirements:

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 MBPs, 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 possible 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
Designing and implementing structural stormwater BMPs on sites of 1 acre or greater is the University of Minnesota’s first priority.
Criteria to evaluate stormwater treatment options should include technical performance (rate and water quality, longevity, maintenance and operating cost), first (capital) cost and available land. Alternative compliance methods may be considered only after any other mitigation strategies are evaluated.

As part of the design process, CPPM project managers will ensure that

CPPM will coordinate civil engineering scope of services with University subject matter experts (Energy Management Utilities);
Architect/Engineer incorporates post construction BMPs into construction documents to meet these standards to the maximum extent practicable and, as part of the plan review process, that the A/E will submit to DEHS the Construction Project Worksheet documenting project compliance with this requirement; and
the Contractor implements these BMPs according to the construction documents.
DEHS will review plans and submittals for compliance and review contractor compliance during and after construction. Failure to comply with this procedure may result in formal project review and appropriate corrective actions as described in the Enforcement Response Procedures (Appendix C).

The 17th Ave Residence Hall toilet flushing system uses grey water from the rooftop.
Cistern at the Landcare building used as a source of water for Landcare’s water truck.

The University has numerous bio-filtration systems. We also have two media filtration systems.

The Minnesota Landscape Arboretum’s Green Roof is part of the “Harvest the Rain” exhibit located in the Margot picnic shelter area, just north of the main parking lot. This previously ordinary picnic shelter now sprouts a colorful array of plants in an effort to highlight a growing trend in water runoff management. The green roof was installed at the Arboretum in the spring of 2009. This innovative roofing material demonstrates an increasingly popular method of water management and how it can be good for the environment, the home, and the landscape.

http://www.arboretum.umn.edu/green_roof.aspx

Below is description of the Porous Pavement around TCF Bank Stadium:
Porous pavement is a pervious surface that allows storm water to percolate or infiltrate through and into the soil or drainage system below. The soil naturally filters the water and during the process, pollutants are removed. Impervious surfaces, in contrast, force storm water to runoff into the groundwater and storm drainage systems untreated. The purpose of porous pavement is to reduce storm water runoff, reduce the pollutants in runoff, and replenish groundwater supplies. In areas where minor flooding is a problem, pervious surfaces are often used to reduce the pooling of water by allowing it to seep through the surface.

None

Rain gardens are gardens that are planted where rainwater is purposly channeled into the site. Depending on the slope and amount of rain that can move into the
garden, there may be standing water at all times or only after a significant rainfall. This list includes plants for the lowest part of the rain garden in shallow water or
wet soils, to the upland or dry portion of the rain garden.

http://www.extension.umn.edu/garden/yard-garden/landscaping/best-plants-for-tough-sites/docs/08464-rain-garden.pdf

One retention pond and one detention pond. If I had to describe them I would say they are roundish and slope to a low point.

http://stormwater.safl.umn.edu/updates-may-2012

Swales have been experimented with next highways around the institution.

Several underground retention systems.
The Landcare Building (new) has a 10,000 gallon stormwater cistern which collects rainwater for irrigation use.