Going “Green”: How are vegetative roofs impacting urban surface water quality and building roof temperatures.
Aaron McCoy*1, Ishi Buffam2, and Richard D. Durtsche1, 1 - Department of Biological Sciences,
Northern Kentucky University, Highland Heights, KY 41099, 2 – Department of Biological Sciences.
University of Cincinnati, Cincinnati, OH.
Human populations around the world are growing, and with this growth, there is a need for the expansion of the
urbanized environment. Researchers over the past half century have been investigating ways to reduce the impacts
of urban centers on the surrounding natural environment, as well as to better improve the quality of urban life. The
scope of our research narrows in on vegetative roofs, and how they affect chemical and physical properties that act
on the modern urban residence. Several studies have, to this date, been published on the effectiveness of a green
roof to reduce bulk runoff flow from a rooftop during a rain event. Few studies have explored the impact of impervious
surfaces such as roofs, on nutrient exchange that would naturally occur in the soil before precipitation reaches an
above ground water source, such as a stream, lake, pond, etc. By running a series of chemical tests on rain samples
from both vegetative, and non-vegetative roofs, we characterized the differences in nitrate, ammonium, and cation
levels between the roof types. We were also interested in the effect a vegetative roof has on roof surface
temperature, so we analyzed data from temperature probes placed on both a traditional roof, and buried in a
vegetative roof, over the course of a summer. We found that green roofs substantially alter runoff water quality and
roof surface temperature.