Rooftop garden possibility for Place Riel

The Sheaf - News; Thursday, 22 September 2005 Written by Crystal Clarke

While rooftop gardening is not a new concept, a project being carried out atop the Dentistry building by a U of S student could be incorporated into the plans for the new Place Riel building. Many buildings on campus, and around the prairies for that matter, could benefit from this new-to-the-prairies concept of rooftop gardens. Cimberly Kneller spent her summer setting up the research project for her honours undergrad thesis - and got a summer job out of it while she was at it. The Facilities Management Department (FMD) took the environmental initiative last year when it hired Sustainability Coordinator Margaret Asmuss, and subsequently hired five summer students this past summer. “This project was headed up by FMD, but the whole project idea of this came from Bill Archibald [head of the Geography department]. We are doing a temperature response difference between the plants and the roof itself and we expect to see a 10-15 degree difference between the sedums and the gravel [plots],” said Kneller. It seems simple enough to understand. However, there have been limited studies as to what plants would work well under the harsh prairie conditions. In fact, this study uses German guidelines because there is so little research from North America. “This is the first one in Saskatchewan and anything that’s been tried in the prairie region hasn’t worked yet. So this will be huge if it does,” said Kneller. This system has huge benefits with limited input costs. Kneller watered the plants only while they were establishing themselves and has let them fend for themselves ever since. Also, the structural requirements for an extensive roof system are 40-50lb/square foot of extra weight. “It is not difficult to put on an existing roof,” says Kneller. In terms of this being an option for Place Riel, USSU VP (Student Issues) Sarah Connor said the project is worth looking at. “I definitely want to throw the idea out there, but I’m not even sure when the plans will be done…especially if this study works.” The benefits of rooftop gardens can be extensive. Kneller quoted from a study done in Scotland that said “20 percent of poor water quality is from runoff from urban areas…. A Portland study said that rooftops make up about 40 percent of their impervious surfaces in the city alone…. If we can green that we can eliminate a lot of water quality problems.” After all, on average 75 percent of rain could be retained in an extensive green roof system. Not only does a rooftop garden affect water quality, but it can also reduce cooling costs and impacts on the environment from this cooling. “Primarily, there are summer benefits,” said Kneller. In fact, there can be a reduction in air conditioning costs, which translates into a one-story building with a green rooftop cutting cooling costs by 20-30 percent. Not to mention smog and greenhouse gas emissions, which could even be used as carbon credits to help reach the Canadian government’s promise to meet the Kyoto Protocol goals. This study uses 23 different plant species over a number of boxes in this specific scientific study. Over the winter, Kneller will be keeping track of what species survive the harsh prairie winter, the temperature difference on the roof compared to the garden plots, and the water runoff.