These trenches can also be located in traditional drainage systems to reduce the volume of water that reaches a manhole. They convey water through a perforated pipe that infiltrates runoff along the way. Due to the volume of stormwater runoff, the University has a number of concrete channels conveying water that could be retrofitted. While each swale is different, there are a number of design strategies that will allow a natural swale to hold the water of a hard channel. It is also important to meander the swale to lengthen its journey, to include check dams to slow the water and small basins to hold sediment, and to plant the swales with willows and other deep-rooted woody native plants.
Planting provides biofiltration and encourages infiltration through the root channels.
All these design approaches slow water, which promotes infiltration. In several areas of the University, such as the valley below Gilmer Hall, some detention capacity has been provided in remnant stream sections. While these detention structures provide temporary storage for flood flows, previously free flowing water becomes an unsightly, stagnant pool. Reestablishing a flowing stream and recreating the floodplain in a series of terraces will bring life back to the water and expand flood storage. Planting in these basins should include a rich mix of appropriate aquatic species to provide biofiltration and a more attractive water garden.