New stadium uses drainage system to stay green

TCF Bank Stadium installed an eco-friendly system to control rainwater pollution and stop flooding of city sewers.

Jill Jensen

The new TCF Bank Stadium not only looks nice, but itâÄôs also designed to maximize efficiency and sustainability. One element essential to the stadiumâÄôs green design is its complex and cutting-edge storm water management system. Using a turf system designed by two University of Minnesota alumni, Jason Lamers and Mark Apfelbacher , rainwater is collected in the stadiumâÄôs lawn in front of University Avenue. The soil is 16 inches deep and can hold 60,000 gallons of water. Although it can be hard to tell, the entire lawn is depressed 6 inches , giving the turf area an additional 72,000 gallons of water holding capacity, Lamers said. The turf is also fortified by mesh tilled into the ground that can support up to 80,000 pounds of trucks, equipment, and people. The water is held in that area and slowly drains out over a period of 24 hours, avoiding the sudden flush of water into the city systems that cause flash floods and erode storm sewers. Water draining from streets and lawns into the sewers collects pollutants, and with all the water being directed to the same area, the problem compounds. While the water drains from the soil in front of TCF Bank Stadium into a rate-control pond located across the street on the corner of Oak Street and University Avenue, it is also purified through a biofiltration process, one of the eco-friendly highlights of the system. The filtration process uses soil and plants to filter water, leaving it as clean as or cleaner than it began. âÄúThey say the water that comes into the pond is technically drinkable,âÄù said John Slack , designer of the systemâÄôs rate-control pond. Storm water management is meant, in part, to direct water away from impermeable streets and buildings into storm sewers and flood tunnels where most of it then drains into the Mississippi River. As it rains the pond fills and continues to drain steadily into the city storm sewer system well after the rain stops. At most times the âÄúpondâÄù is not really a pond. It will only fill when it rains; the rest of the time it is just a dry pit, designed to be visually pleasing because it is in a high traffic area, Brian Swanson , project director for the stadium, said. The design ended up following a Mississippi River theme, using native limestone and plants to mimic the natural and physical aspects of the river, Slack said. Slack explained the pond in terms of dual requirements. âÄúIt needed to aesthetically function for the University,âÄù he said. âÄúIt also needed to function from an engineering standpoint for the stadium.âÄù