In recent years, there has been an effort to change the way we think about storm water and the methods that we use to capture and relocate this water. Innovative methods are being developed to retain and/or detain storm water for a period of time after a rain event in order to slow down the surge of water that often occurs after such an event. Historically, the thinking was to remove surface water as quickly as possible from an area such as streets and parking lots. However, despite solving the problem in the “upstream” locations, these methods tend to cause significant problems to occur in the “downstream” locations due to the cumulative volumes of water generated in a relatively short amount of time.
At the corner of Scott & Taylor Avenue, on the site of the 4515 McKinley Research Building’s green space, Washington University’s School of Medicine has installed a detention basin in an effort to contribute towards the university’s overall sustainability efforts and comply with the storm water management requirements mandated by the Metropolitan St. Louis Sewer District. A detention basin is a low lying area that is designed to temporarily hold a set amount of water while slowly draining to a creek, channel, or storm sewer system. Detention basins are also used for flood control when large amounts of rain could cause flash flooding. In addition to the design of the basin, the selection of the plant material that has been installed also contributes to the basin’s effectiveness. Native grasses such as Schizchyrium scoparium (Little Bluestem) and Carex annectans (Yellow-fruited Sedge) have been planted, as well as perennials such as Asclepias tuberosa (Butterfly Milkweed) and Liatris spicata (Dense Blazing Star). Because these native plants have evolved here, they are well suited for our local environment. The native plants have deep root systems that help to promote pore space in the soil and thus aid in the infiltration process during a rain event. The deep root systems also help to sustain the plant during periods of drought and assist in anchoring the soil to reduce erosion. Native plants provide habitat and a food source for birds and butterflies, as well.