The Comparative Impacts of Meadow and Sedum Species on Green Roof Hydrology

The goal of this thesis is to compare the stormwater management potential of two common green roof plant communities – native grasses and forbs, known as “meadow” species, and Sedum species – over a range of irrigation volumes. The physical and biological mechanisms involved in water retention provided by the green roof vegetation was measured and compared. Plants retain stormwater through three different mechanisms: water consumed through the roots which remains in the biomass, water transpired through the leaves during photosynthesis, and water intercepted by the leaves which then evaporates. Overall, the meadow species consumed roughly 50% more water through their roots, while Sedum intercepted roughly 70% more water; however, these processes occurred over different timescales and at different magnitudes, and were significantly impacted by variations in climate. This study highlights the complexities of plant water relations, and will contribute to a more holistic understanding of green roof performance and benefits.M.A.S