The Effects of Freeze-Thaw Cycles on the Infiltration Rates of Three Bioretention Cell Soil Mixtures

摘要

The expansion of urban and suburban areas is a world-wide phenomena. One product of this development is a dramatic increase in impermeable surfaces and a consequent increase in stormwater runoff. Bioretention cells are one best management practice frequently used to mitigate the environmental impacts of urban stormwater runoff. To ensure that a bioretention cell will continue to perform adequately in the long term, it is imperative that the environmental conditions it will experience and their effect on its performance through time are considered during its design. Although bioretention cells are frequently used for stormwater management, very few quantitative data exist on how they perform through time and in varied physical environments. In regions with seasonal freeze-thaw cycles, it is important to understand the effects of freeze-thaw cycles on the infiltration rate of bioretention cell soil mixtures so that the integrity of the design will not be compromised by seasonal change.This project uses laboratory tests to investigate the effects of freeze-thaw cycles and sediment input on the infiltration capacity of three different bioretention cell soil mixtures. These results will provide an analog for long-term changes in bioretention cell infiltration rates due to freeze-thaw cycles, providing critical data on which soil mixture would be best implemented in geographic regions susceptible to freeze-thaw activity. Furthermore these results will inform design standards for bioretention cells to ensure their long-term performance.