Port of Seattle Street Sweeping Effectiveness Study

In addition to removing dirt from roadways and parking lots, street sweeping can improve water quality by removing fine particulate matter and other pollutants that runoff would otherwise carry into nearby water bodies. In a study for the Port of Seattle, Herrera evaluated the effects of street sweeping on sediment pollutant concentrations and loading in stormwater, depending on the frequency of street sweeping. Based on the results of fieldwork and data analysis, we recommended that the Port modify its street sweeping program for the Shilshole Bay marina parking lot to reduce discharges of sediment to Shilshole Bay.