Stormwater runoff is one of the many water quality and quantity challenges in urban settings. Urbanization increases the proportion of impervious surfaces (surfaces that prevent rainfall from soaking into the ground, such as roofs and driveways) in a landscape. Greater amounts of impervious surfaces increase the volume of stormwater runoff to storm sewers and local waterways. As stormwater flows across impervious surfaces, it can transport pollutants to nearby streams and rivers.