The existing detention basin at Moses Milch Drive in Howell Township, New Jersey, receives runoff from the residential development along Moses Milch Drive, and discharges the runoff with little to no water quality treatment into Gravelly Run, which in turn flows into the Metedeconk River. Metedeconk River is the primary source of drinking water supply for Brick Township Municipal Utilities Authority (BTMUA).
BTMUA retained FPA to provide engineering design and construction observation services to convert the existing detention basin to an extended bio-retention basin to provide water quality treatment improving the quality of stormwater runoff leaving the basin. The project was completed through a partnership between Brick Utilities and Howell Township with funding from the New Jersey Department of Environmental Protection. The design included removal of the existing low flow channel and underdrains, modifying the existing outlet control structure to increase detention time allowing for settlement and removal of the suspended solids, loosening the compacted soils within the basin and using native water tolerant plants and a special mixture of soils to filter out pollutants and promote infiltration of stormwater runoff. Two bio-retention basins were also designed along the roadway to treat runoff from a portion of the road that discharged directly to Gravelly Run bypassing the basin. The project was completed in November 2015.