Vegetative controls are one of the best highway runoff solutions due to their low costs and widespread applicability.1 Vegetative cover can include grass, trees, shrubs, and other vegetation barriers.
Grassed waterways, or grassed swales, are one of the most common vegetative controls that can improve water quality and prevent erosion by slowing runoff and trapping sediment.2 This structure is usually a U-shaped depression that can be natural or constructed and used in either rural or urban areas. In addition, grassed waterways can provide shelter and food for wildlife and greatly improve landscape aesthetics.
Trees, shrubs, and other ground cover can manage stormwater runoff due to their capacity to intercept and store rainwater.3,4 Trees can improve soil infiltration, thereby decreasing the amount of pollutants in runoff that eventually reach local waters.
Rain gardens are another example of ‘green infrastructure’ designs that can collect stormwater runoff from driveways, streets, or sidewalks.5,6 These are shallow, depressed areas of landscaping with grasses and flowers that are designed to soak up rainwater and provide food and shelter for wildlife.
How it Helps
Although vegetative controls are one of the most common runoff management solutions due to their applicability in many locations, they may not be best suited for areas with high vehicular traffic.1
Design, Type of Vegetation, & Maintenance:
Regarding the design of vegetative controls, planners and engineers will need to look at various factors, including the local topography, soil type, climatic conditions, and quantity of runoff to determine the placement and type of vegetation to use.1,7
To encourage the use of vegetative controls to manage runoff, local governments may have to develop incentives, such as a stormwater credit system, to encourage developers to conserve vegetation or minimize the amount of paved surfaces.3
1) Vegetation Controls at Construction Sites
Construction activities can contribute to a large portion of sediment pollution in urban runoff, so vegetation controls at construction sites may be an effective solution to managing soil erosion and reducing runoff.
2) Rain Garden App
The University of Connecticut offers a free Rain Garden app that allows users to learn the basics of designing a rain garden, how to choose plants, and tips to install and maintain the garden.