University of Minnesota, Duluth
OP-27: 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 will develop, implement, and enforce a storm water pollution prevention program to protect water quality and satisfy the appropriate requirements of the 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)

Some 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.

A unique and visible feature of Swenson Civil Engineering is its management of storm water runoff including scuppers made from reclaimed wood and a French drain system. The scuppers on the roof of the building were constructed from recycled wood; and runoff is collected in tanks beneath the building. In non-winter months, the water in the tanks is used to fill a 2,000 gallon sediment transport/wave tank.

Civil Engineering has a partial green roof, and the Bagley Outdoor Classroom's lower roof is a green roof. Both of these roofs utilize a tray system.

There are various types of porous paving on our campus: one test area of two types of pavers (one a recycled-content rubber paver, the other a traditional cement brick paver) located on the loading dock of the Lund Building. There is another test area by the entrance to Rec Sports. The loading dock area of Civil Engineering also utilizes pervious pavers.

UMD has several rain gardens, as part of our commitment to protect Lake Superior. The largest is referred to as “The UMD Rain Garden” which can hold 60,000 gallons of water, and is located on College Street near the Lund Building. Interpretive signs and self-guided tour brochures can be found along the sidewalk. Flowers bloom from as early as May to September.

UMD has two wet-ponds to treat post-construction stormwater runoff: Fire Hall Pond (built 1979) and Eric Clarke Pond (built 1965), both of which were dredged back to their original capacities in 2001. Continued maintenance and inspection Best Management Practice for ponds and their outfalls is at: http://www.d.umn.edu/fm/stormwater/swppp/6b-3.pdf

There are many vegetated swales on campus. The parking area at Glensheen was modified in 2004 to include a combination of grassy swales, a bioretention area, and outlet shoreline protection to improve the current quality and lessen the quantity of the discharge water. This project won a 2006 Governor's Minnesota Government Reaching Environmental Achievements Together (MnGREAT) Award for superior environmental achievement by Minnesota's public agencies. Other vegetated swales exist on campus, described here: http://www.d.umn.edu/fm/stormwater/post_construction.html

All post-construction stormwater control technologies are described at: http://www.d.umn.edu/fm/stormwater/post_construction.html The largest, and most exciting, example of treating stormwater is our campus UMD Rain Garden: the UMD Rain Garden is composed of plantings, a drain tile system, and a water level control system. It can hold as much as 60,000 gallons of water. Rain gardens are part of UMD’s commitment to protect Lake Superior. More information, including a tour guide, is available at: http://www.d.umn.edu/sustain/raingarden/index.html Recently, the newest Resident Hall on campus, Ianni Hall, was constructed with a sand volleyball court that doubles as a stormwater filtration area.