Give an example of a structural BMP.

A retention pond is a structural Best Management Practice (BMP) designed to manage stormwater runoff. It functions by collecting and holding stormwater, allowing it to infiltrate the ground or evaporate, thus reducing the volume of runoff that would otherwise flow directly into streams or other bodies of water. Retention ponds are engineered features typically designed with specific dimensions and volumes to accommodate expected rainfall events, and they often include features such as outlet structures to control the release of water.

Structural BMPs, like retention ponds, are usually constructed in a way that provides physical removal or treatment of pollutants, helps in flood control, and enhances groundwater recharge. These features are integral in urban planning and stormwater management strategies to mitigate the effects of increased impervious surfaces in developed areas.

In comparison, options like rain gardens and vegetated roofs are typically considered non-structural BMPs. While they do help manage stormwater by enhancing infiltration and reducing surface runoff, they are more about using vegetation and natural landscapes rather than constructed facilities designed explicitly for stormwater management. A silt fence, while useful for erosion control during construction activities, is more of a temporary measure rather than a long-term structural BMP. Thus, a retention pond stands out as the correct example of a structural