Bioretention and Permeable Pavement Performance in Clay Soil

Urbanization is altering the composition of landscapes nationwide, with urban areas characterized by a high proportion of impervious surfaces that adversely affects the water cycle of the region. The loss of infiltration of runoff into soil reduces ground water recharge. Increased surface runoff, velocity, and pollution, all byproducts of rainfall on impervious surfaces, impede urban waterways tremendously. Increase in volume of runoff can lead to flooding, with receiving water bodies exhibiting stream bank erosion and channelization. Low-impact development (LID) is a way to mitigate the adverse effects of increasing impervious cover, using decentralized measures to retain stormwater runoff on site, and thereby seeking to mimic the natural predevelopment hydrology of a site. Effectiveness of LID practices in various regions in the United States has been evaluated. However, modeling studies have suggested that the adaptability of LID designs to other regions is problematic, requiring modified solutions to be field tested in every location to confirm how they will perform. Therefore, a great need still exists to evaluate these practices in the field and to collect quantitative data on LID practices' performance, especially in clay soils characterized by low infiltration. This project evaluates urban stormwater best management practices in a typical urban watershed in the Dallas Fort Worth area. The objectives were to design, construct, and demonstrate the effectiveness of permeable pavements and bioretention area at the Texas A&M AgriLife Research and Extension Center in Dallas. Reduction in both volumes and pollutants concentration were recorded for all BMPs.