Swales
Slowing, conveying, and treating runoff
Both dry swales and wet swales are gently sloped, vegetated channels that slow, convey, and treat runoff by promoting infiltration and settling of pollutants.
Swales work well for low density residential areas and roadways. However, pollutant removal is limited by rapid flow velocity during storms – installing check dams, swale media, or underdrains can help slow the flow and enhance infiltration.
5 Things to Know About Swales:
- Works well for roadway drainage and low density residential areas
- Pollutant removal can be variable depending on velocity of flow during storms
- Performance of swales can be enhanced by check-dams, swale media, or underdrains
- For wet swales, the design is appropriate for the water table and slope conditions
- Most swales include grass as vegetation, and so require regular mowing maintenance
Related Resources
View All ResourcesDesign Spec
Design Spec: Grass Channels, 2011Developed by the Virginia Department of Environmental Quality, this design specification (Version 2, 2013) provides guidance on using grass channels...