With any new development the amount of impervious area is typically increased due to the construction of a building, parking lot or other facility. These impervious areas affect the flow of stormwater by increasing the volume and rate of runoff. If not properly managed, increased peak flows and volumes can result in flooding and stream erosion. In addition, stormwater runoff can also contain pollutants such as sediment, oils and greases, nutrients and metals, bacteria, fertilizers, and trash. These pollutants are carried by stormwater into the storm sewer system which discharges into our local streams, rivers, and lakes.
In an effort to reduce the amount of stormwater runoff coming from these developements, the State of Tennessee Department of Environment and Conservation (TDEC) required the Town of Collierville revise Ordinance 2012-18: Stormwater Management Regualtions requiring all new development or redevelopment sites approved after March 31, 2015 to include measures to infiltrate, evapotranspire, harvest, and/or use the first inch of every rainfall. These permanent stormwater management practices and site design features are designed to store, treat, infiltrate or reduce the volume of runoff from these sites. UPDATE... TDEC granted a one year extension to allow for more preparation on the new runoff reduction requirements.
Examples of Post Construction Contols
Stream Management Buffers
Water Quality Swales
Water Quality Units
Photos are from various sites in Nashville, TN