Students at the School of Architecture and Planning, along with UNM professor Bill Fleming, are leading by example with their “green roof,” a unique rooftop garden that recycles rainwater and helps reduce energy costs.
The green roof has been atop George Pearl Hall for the last five years, Fleming said. It consists of several layers that collect and store rainwater, which is then used to water the “green layer,” made up of soil and native plants.
“When the new building was pre-planned I suggested that we have a green roof to demonstrate sustainable design and to demonstrate that we can capture water from the rooftop stormwater in cisterns and use that to water the green roof,” he said.
Aside from the benefits the green roof shows in the irrigation of water, the roof is also about 10 degrees cooler in the summer than another roof on the other side of the building that doesn't have soil and plants. In the winter it demonstrates a greater thermal capacity and insulation, and so it saves heating costs in the winter and cooling costs in the summer, Fleming said.
The aesthetic benefits of the greenery on the roof also have the bonus benefits of cleaning the air, he said.
Plants such as the grasses, shrubs, cactus and the wildflowers on the roof take carbon dioxide and other pollutants created by cars and filter them out, Fleming said.
“We have a problem with climate change and global warming, and so the roof is helping that because it's sequestering carbon — not allowing that carbon to go into the air, which causes the planet to heat up,” he said.