Stormwater from impervious surfaces generally has to be treated by one or more best management practices (BMP) before being discharged into streams or rivers. Compost use for treating stormwater has increased in recent years as trials show that compost amended soils and compost blankets prevent erosion and improve water quality. Most of the trials to date have focused on applications where the stormwater sheet flows across a compost amended area or into a retention basin amended with compost. These types of installations are applicable to many locations, but there is a need for an end-of-pipe treatment that can handle concentrated flows. This is particularly true in roadway projects that are linear in nature and cut across land features and go from cut to fill sections frequently. Bioswales are an approved BMP to remove nutrients from stormwater and are widely used in highway construction to move and treat stormwater. However, bioswales are not currently approved for dissolved metal removal from stormwater. Compost amended soils have shown an increased capacity to remove dissolved metals from stormwater. This research will evaluate the effectiveness of a compost amended bioswale to remove dissolved metals from highway runoff. This thesis details the steps necessary for the site selection, design, and implementation of a stormwater BMP field test.
Washington (State). Dept. of Transportation. Headquarters Design Office. Highway Runoff Section
Runoff, Drainage, Best practices, Compost, Swales, Bioremediation, Metals, Detention basins, Drainage structures, Water quality management, Protection against environmental damage.