File:Treatment train schematic.png

File:Treatment train schematic.png

The basic premise for selection of a Best Management Practice (BMP) or group of BMPs is to follow the treatment train approach. Under the treatment train approach, stormwater management begins with simple methods that minimize the amount of runoff that occurs from a site and methods that prevent pollution from accumulating on the land surface and becoming available for wash-off. These methods include

• Better site design;
• Low Impact Development (LID);
• pollution prevention;
• volume minimization;
• stormwater re-use and rainwater harvesting; and
• temporary construction erosion and sediment control techniques.

After all of the efforts possible are made to minimize runoff, the next major BMP then becomes collection and treatment of runoff locally and regionally, either as stand-alone practices or in treatment train combinations. Some of the available BMPs are best used to reduce runoff volume, while others focus on water quality improvement. Some BMPs will be easy to implement, while others involve serious engineering and sophisticated design. Other BMPs used in a treatment train include *bioretention devices, including tree trenches and tree boxes;

• filtration practices such as swales and sand filters, including iron enhanced sand filters;
• infiltration practices such as infiltration trenches and infiltration basins and permeable pavement;
• green roofs; and
• stormwater ponds and stormwater wetlands.