When rainwater falls in an urban area it runs across surfaces such as roads, sidewalks and parking lots, picking up any pollutants that cover the surface along the way. This stormwater, and all the new pollutants it picked up, continues flowing off into nearby streams. Not only does this pollute our local waterways, but this pollution can also cause issues as it flows downstream into larger rivers and eventually the Chesapeake Bay. Thankfully, there are numerous best management projects (BMPs) that can be implemented to prevent this polluted runoff or reduce the number of pollutants in the stormwater runoff.
Some of the BMPs utilized are dry detention ponds and retention basins. These practices are designed to capture and hold water for longer periods of time rather than having it all run off at once. This also allows the pollutants to settle to the bottom of the pond. Next up we have practices like bio-swales, raingardens and permeable pavement. Bio-swales are long, often vegetated channels that run down hills or along roadsides.