By Katie Dunn |
Freezing cold or boiling hot. Those are the temperatures residents tend to feel in Mehling and Christie Halls.
Now a handful of students doing environmental science research may be close to finding a solution to the extreme temperatures in those residence halls. Led by Ted Eckmann, an environmental studies professor, students are investigating how green roofs on these buildings might impact students, the University and the environment.
A green roof can vary from a thin layer of soil and small plants to gardens to deep soil with trees. The roofs being tested at UP would have a thin layer of soil with shallow-rooted native plants.
Junior environmental science major Brooke Holmes, who is spearheading the project, did research last summer with buckets of soil and plants on Christie and Mehling. Holmes was introduced to this project after taking two of Eckmann’s environmental science classes.
“I really love atmospheric science,” Holmes said. “I want to study environmental science of some sort [in grad school]. I’m really interested in water dynamics and soil dynamics.”
The students have been testing which types of soils and species of succulents would create an effective, inexpensive green roof. The research team is testing their green roofs with 15 buckets on both Christie and Mehling, together holding 60 plants, including six types of native succulents.
The trick for making a green roof in Portland is finding plants resistant to dry, wet and windy conditions.
“They just have to be tough,” Holmes said. “Which is a lot harder of a feat than one realizes, if you want to create a green roof that doesn’t have any irrigation system whatsoever.”
According to Eckmann, the key to having plants that can withstand Portland’s four months of dry and eight months of rain is picking native species that have adapted to live in the climate.
“We’re trying to figure out which native species are the best so they won’t be out-competed, which produce the biggest potential money savings on heating and cooling cost,” Eckmann said.
Shiley Hall already has a green roof, but it doesn’t meet the standards Holmes and Eckmann are looking for.
“The significant areas have been taken over by invasive species, and that is ecologically not ideal,” Eckmann said. “It’s also not ideal for the main goal of a green roof, which is to reduce your heating and cooling cost.”
Green roofs could help make the University more energy efficient and save money with heating and cooling, especially in buildings without A/C. Eckmann said the benefits of green roofs could expand past the buildings that lack A/C, and potentially help every campus building.
The warmth and coolness felt in Mehling and Christie can be attributed to the lack of air conditioning and the unshaded roofs, which causes heat to seep from the roofs into the buildings. Green roofs can help negate these effects because plants and soil absorb heat during the summer and keep it in during the winter.
“Have you ever felt a plant that was so hot that it felt like it was burning your skin? No, but you’ve probably tip-toed over bare asphalt because it was too hot,” Eckmann said. “Plants never get that hot, so you put a green roof on and it’s not a small temperature difference, we’re talking many, many degrees Celsius.”
Other benefits of green roofs include controlling water runoff so sewage drains don’t overflow, and stripping nutrients out of the water. Too many nutrients can ruin an ecosystem by causing the wrong kind of plants to grow.
“We have a major issue with over nutrient-izing water, especially in the Willamette,” Holmes said. “If there are certain particles in the rain, then the plants (on a green roof) will hold in the water longer and help clean the water that way.”
The team’s research is only at the midway point since they need at least a year’s worth of data to make any scientific inferences. They hope to work with engineering students in the future to build green roofs to many campus building and help make living conditions a bit more comfortable. Katie Dunn is the sports editor for The Beacon. She can be reached at dunn16@up.edu.
