Club works to make U roofs greener

Jason Juno

A University student group is working to make some campus roofs “green.”

The Environmental Studies Club received a grant from the Beautiful U Day Committee for soil to be used on a “green roof” project. The club will first plant the soil for the roof on West Bank ground and show the project’s progress April 21 during Beautiful U Day, said Katie Roth, co-president of the club.

She said the group hopes to start the project sometime in March. The club wants to then persuade the University to actually use the soil it planted for a green roof, Roth said. The group wants to convince the University that green roofs are cost-effective, she said.

The University would have to pay to install the green roof, Roth said, because the grant did not cover that expense.

The University would save money because of lower energy costs if it used the roof, she said, and the green roof would last longer than a normal roof, which would also save the University money.

“It would definitely lead to a more sustainable city,” she said.

James Fisk, the club’s other co-president, said green roofs help make things more natural and benefit the environment.

Having a garden on a building’s roof serves many benefits, from storm water runoff reduction to cooling the building and the city, said Peter Donagh, a professor in the University’s department of landscape architecture.

But green roofs are not new to Minneapolis.

The University used to have a green roof on one of its law buildings, but it leaked, Roth said. The roof was then removed.

Jenn Rowe, University Facilities Management communications specialist, said the University has two green roofs. One is the lawn in front of Coffman Union, which is the roof of the bookstore, and the other is in the Humphrey Institute of Public Affairs, she said.

Storm water runoff not good for bodies of water

The decision to start the project began after Greg Archer, a public health specialist at Boynton Health Service, told the club there was a need for storm water control in the area, Roth said.

Donagh said storm water is a big issue for Minneapolis because the city has so many lakes and the Mississippi River runs through it.

Storm water hurts the river when it runs off roofs and goes into it, he said.

As nongreen roofs heat up, algae begins to grow, which is bad for fisheries, Donagh said. Also, any waste from birds or metal from exhaust fumes on roofs mixes with storm water and goes into the river, he said.

The new public Central Library in Minneapolis will use a green roof when it opens. Donagh said the four inches of soil and the plants the library will use on its roof will soak up 24 of the 30 inches of rain Minneapolis usually receives yearly. All of that rain would otherwise run off into the river.

A cooler city

Another purpose of green roofs is to cool cities. But the Twin Cities’ heat island – hot air that is trapped in the city because it does not move around – is not as severe as Atlanta’s or Chicago’s, Donagh said.

Buildings with green roofs do not have to use as much energy for cooling, because the air coming in from outside is cooler, he said.

On a 90-degree day, the temperature of a green roof would be 88 to 95 degrees after a rain, Donagh said. But under the same circumstances, a black asphalt roof would be 160 to 170 degrees, and a gravel roof would be 110 to 130 degrees, he said.