Student Intern Column: Sustainable Design and Green Roofs
Jackie Olson is a junior majoring in Landscape & Urban Studies/Environmental Studies and a future designer of sustainable architecture. She began her internship for the Office of Sustainability in summer 2018 on the Waste & Recycling Team and since then has found herself collaborating on multiple teams such as Green Greeks, Green Office, and the up-and-coming team Green Allies.
Throughout my studies in Landscape Architecture and my work at the Office of Sustainability, I have come to understand how we can create beautiful facilities through the principles of sustainable design. Sustainable design is centered around the concept of creating spaces that meet the needs of human use, support existing ecosystems, and ensure that all life forms maintain the ability to thrive.
Typical urban development puts a strain on a variety of natural resources. Heavily industrialized societies create factories, buildings, and other structures that end up releasing dangerous chemicals into our atmosphere, including greenhouse gases and pollutants. These structures also require significant energy extraction. By coupling development with sustainable design, however, we can alleviate many of the negative impacts of urban development.
Let’s take the example of a Green Roof. A Green Roof is composed of a vegetative layer of shrubs, grasses, trees, and other plants that reduces the temperature of the roof surface and the surrounding air, as well as improves stormwater management. Green Roofs are used specifically to combat “urban heat islands,” which arise when roads, buildings, and other infrastructure create large expanses of land where “surfaces that were once permeable and moist [have] become impermeable and dry”. This change causes an accumulation of heat compared to less developed areas.
An illustration of an urban heat island. Image credit: NASA/JPL-Caltech.
How Green Roofs Work
Green Roofs utilize multiple different materials, living and nonliving, to mitigate higher temperatures, provide cleaner air, hold and reduce stormwater runoff, and provide visual relief. Green Roofs replace the design practice of creating conventional roofs, which are commonly made of materials such as slate, rubber, and fiber cement. Conventional roof materials are often black, dark gray, and dark brown in color, causing the surface to absorb much of the heat radiation from sunlight. Green Roofs, in contrast, regulate a building’s internal temperature and furthermore lower air pollution. The plants engage in their day-to-day biological cycles including evapotranspiration. The physical structure of plants allow them to absorb heat energy from the sunlight that would otherwise be absorbed by the roofing material and surrounding air. Since these plants reduce the temperature of the roof, the building is able to consume less energy in order to cool it internally. The plants used on Green Roofs can also capture airborne pollutants and filter harmful gases. By improving air quality in two ways—reducing the amount of energy needed to cool the building, and growing plants that can filter toxic substances in our air—Green Roofs allow for the ecosystem to thrive and for future generations to come into a life-supporting environment. Green Roofs also provide structure for stormwater management. Conventional roofs typically use the same material throughout and do not have any stormwater holding features—meaning the water immediately runs off the roof and down the gutters, which may flood the surrounding areas. Rain falls on whatever exists below it and eventually finds its way into a watershed. During the water’s journey, it collects and picks up chemicals, particles and other materials. Often these materials are harmful to our ecosystems.
A map of the Yahara River and its watershed in southern Wisconsin. (Wikimedia Commons)
Green Roofs on the UW–Madison Campus
Education Building A great example of a Green Roof implementation exists right here at UW–Madison. This vegetative rooftop was constructed on the surface of a parking lot behind the Education Building. The goal of this project was to redevelop an area of campus to address green infrastructure goals and meet regulatory requirements. Furthermore, UW–Madison wanted to reduce the environmental impact of stormwater runoff by modifying their land use wherever possible. As stated earlier, stormwater runoff contamination is a huge problem in Madison, WI.
Education Building Green Rooftop
UW–Madison (Photo from 2015 Campus Master Plan.)
School of Human Ecology Green Rooftop
UW–Madison (Photo courtesy Campus Planning & Landscape Architecture.)