University of Minnesota, Duluth
OP-23: Rainwater Management

Mission: The mission of the University of Minnesota Duluth Storm Water Pollution Prevention Program is to reduce, to the maximum extent practicable, the possible negative impacts of the campus on the surrounding watersheds and ultimately the Lake Superior ecosystem.

To this end, the University of Minnesota Duluth has developed a program in conjunction with the Minnesota Pollution Control Agency to uphold the EPA's Clean Water Act.

Goals

* To meet the requirements of the NPDES Phase II storm water requirements, the Clean Water Act, applicable Minnesota laws and statutes, and university of Minnesota environmental policies and Procedures.
* To minimize and/or regulate storm water surge volumes by promoting storm water sensitive design.
* To educate our community about storm water issues.
* To manage on-campus storm water problems efficiently and effectively.
* To promote overall watershed protection by working with Minnesota Pollution Control Agency (MPCA); Minnesota Department of Natural Resources (MNDNR); and the Municipal Separate Storm Sewer System (MS4) owners and agencies represented by the Regional Stormwater Protection Team (RSPT)

The UMD Stormwater Program is a comprehensive effort to educate the campus about stormwater and try innovative solutions, preserve water quality of our local creeks and Lake Superior, and meet the requirements of our State Stormwater Permit (or MS4 permit: Municipal Separate Storm Sewer System).

The campus Stormwater Permit is at: http://d.umn.edu/facilities-management/programs/swppp

Examples of storm water controls used at UMD are:
Rain Gardens and Bio-retention Areas are gardens that collect, filter and use storm water reducing the amount of water discharged to a storm water system. Flowering plants and grasses (preferably native species) that can withstand a cycle of flooding and drought are usually used.

Infiltration / Filtration Basins are open earthen impoundments designed to retain storm water and to infiltrate it into the soil. The design should include an inlet-settling basin to remove coarse materials prior to flowing into the infiltration basin. The surface may or may not be vegetated. Infiltration basins are used when you have permeable soils to accept the water, filtration basins have drain tile systems that collect the filtered water and discharge it to a storm sewer.

Infiltration / Filtration Trenches are trenches that are 1 to 2 feet wide, and 2 to 10 feet deep. They are typically lined on the sides and bottom with permeable filter fabric and backfilled with coarse aggregate. Trenches may be surface or subsurface levels, and design may include a vegetative filter strip. Trenches are effective in removing suspended sediments, floating debris, and bacteria. In most cases, trenches will have some overflow connection to the storm sewer. Infiltration trenches are used when you have permeable soils to accept the water, filtration trenches have drain tile systems that collect the filtered water and discharge it to a storm sewer.
Pervious (Permeable) Pavement is a structural support surface that allows water to flow through the material into a subsurface of gravel or rock, and ultimately into the soil or other post construction storm water control. Pavements can be made of concrete, asphalt, plastic, or composite materials. They can look like standard concrete or asphalt pavement, paving block or even grass.

Swales are vegetated, shallow channels with gentle side-slopes. Treatment occurs as storm water flows through the dense vegetation. Removal mechanisms for pollutants include filtration, sedimentation, adsorption, and infiltration into the soil profile. Swales are used to remove sediment and pollutants that adhere to the sediment.
Filter Strips are vegetated, gently sloped strip, 10 feet or more in down-slope length (50 to 75 feet is recommended for good performance). Vegetation may be turf, or forested with trees and shrubs. Filter strips must be designed to accept sheet flow, and are typically used in conjunction with other treatment control measures, such as grassy swales or infiltration trenches.

Underground Detention devices are tanks that can take large volumes of storm water quickly and then slowly discharge that water back into the storm water system. Underground systems are usually more expensive than other systems, but are useful on small sites.