Post-Construction Site Runoff Controls

Runoff from developed areas can significantly affect nearby waterbodies. Studies indicate that the most cost-effective approach to stormwater quality management is to incorporate prior planning. Designing sites to control the flow rate, total volume and pollutant load in stormwater discharge can prevent two substantial impacts of post-construction runoff:

Increased volume of water and rate of runoff. Impervious surfaces, like parking lots, driveways, and rooftops, interrupt water’s natural and gradual percolation through vegetation and soil. Instead, water runs off of surfaces like rooftops, asphalt and concrete and is routed to drainage systems. Large volumes of runoff quickly flow to the nearest receiving water and cause downstream flooding, streambank scouring, loss of aquatic life and property damage.

Increased pollutants in stormwater runoff. As runoff flows over areas altered by development, it picks up harmful sediment and chemicals such as oil and grease, pesticides, heavy metals and nutrients (e.g., nitrogen and phosphorus). These pollutants often become suspended in runoff and are carried to streams, ponds and lakes. On those waterbodies, pollutants enter the food chain, eventually ending up in the tissues of fish and humans.

The Town Land Use Ordinance, Section 15-263.1[1] requires the implementation of post-construction run off controls. The Stormwater Division performs inspections to ensure property owners are providing long-term maintenance of these controls.