Treatment Devices Are Put Through Their Paces Monitoring Program Studies Effectiveness of Underground Stormwater Systems [Ramsey-Washington Metro Watershed District]

Wet detention basins are one of the traditional best management practices (BMPs) for improving the water quality of runoff from urbanizing watersheds. The downside to these basins is their tendency to cause increases in water temperature and require significant space that is not often available in fully developed areas. Other BMPs such as infiltration and filtration gardens are not appropriate in areas where soils are less permeable or contaminated. Another option for developers and water quality agencies are treatment manholes such as proprietary filtration units and hydrodynamic separators. But the efficacy of these treatment devices has not been well documented.