Rooftop gardens protect Grand River

by Molly Waite GVL Staff Writer

1/20/2010

On the third floor of Mackinac Hall, the view from the philosophy department office windows does not include a gray, concrete rooftop but rather a lush expanse of plants. The grasses and other flora did not grow there by mistake but through the careful planning and efforts to reduce Grand Valley State University's impact on the Grand River.

As an important part of the university's commitment to sustainability, green roofs provide a natural and cost-effective way to manage storm water. Storm water is the run-off caused by man-made surfaces such as parking lots, sidewalks and building roofs. The water also carries chemicals and other pollutants with it, causing harm to the Grand River and other local ecosystems.

"We like to show people that we have a green roof and that we're serious about storm water management," said John Koches, associate research scientist of the Annis Water Resources Institute at GVSU. "Having the green roofs is just one way to deal with storm water that would ordinarily flow off the roof. It also prevents storm water flow from the parking lots, cleaning out chemicals that would end up in the river. We've made a conscientious effort to curb all of our storm water flow."

Green roofs are layered with sand, gravel, loam and other coarse textiles to naturally filter out pollutants and absorb excess water flow. Koches said the plants chosen for green roofs are called succulents: low-maintenance, drought tolerant plants with deep root systems.

Norman Christopher, executive director of the Sustainable Initiative, said the plants are put on the roof in trays, so if a group of greenery does not thrive, it can be removed and replaced without serious cost or effort.

"We're still learning about the benefits of green roofs," Christopher said. "The green roofs help us understand the whole concept of waste water management and lessening the impact on our environment."

Green roofs are not the only way GVSU reduces its impact on the Grand River. Indigenous plants strategically placed around campus to form rain gardens function in much the same way to cleanse pollutants picked up by run-off water.

"A lot of people just see them as a beautiful garden, but actually the indigenous plants and flowers, which naturally grow in Michigan, process storm water," Koches said. "A lot of people don't understand that these are not just gardens, but engineered structures with a purpose. There's more to it than just planting pretty flowers."

The installation of green roofs not only limits storm water flow into Grand River but reduces GVSU's carbon footprint.

James Moyer, assistant vice president for Facilities Planning, said green roofs have the ability to sequester carbon, making them a part of the 2010 Climate Action Plan released last Friday. Green roofs also insulate buildings, reducing the costs of heating and cooling.

Some 33,800 square feet of green roof have been planted on four buildings across campus to date and GVSU is also scheduled to install an additional 2,500 square feet of green roof on two more buildings this spring.

"I think that what we've discovered is that these processes are very cost effective, easy to implement and low-maintenance," Koches said. "We're handling water discharges internally and adding the water back to the groundwater systems where they would have ordinarily gone back without man-made structures. It leaves the functions of the landscape intact, serving to keep the campus environmentally friendly at a low cost while maintaining the natural integrity of the sites they manage. The university has really bought into this process, and I think that they're doing a very conscientious job."

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