Pollutant loading to stormwater runoff from highways : impact of a highway sweeping program.

694510742Draft final report; Oct. 1, 2003-Jan. 30, 2009.PDFTech Report0092-04-04RunoffDrainageStreet cleaningWater pollutionWisconsinWisconsin. Dept. of TransportationHorwatich, Judy A.Bannerman, Roger T.Geological Survey (U.S.)Wisconsin. Dept. of Natural ResourcesWisconsin. Dept. of Transportation. Research and Communications SectionNTL-ENERGY AND ENVIRONMENT-Environment ImpactsNTL-HIGHWAY/ROAD TRANSPORTATION-HIGHWAY/ROAD TRANSPORTATIONUS Transportation CollectionThis report describes the methods used to collect stormwater runoff and evaluate a street sweeping program on U.S.Highway 151 in Madison, Wisconsin. The study was a cooperative effort among the Wisconsin Department ofTransportation (WisDOT), U.S. Geological Survey, and Wisconsin Department of Natural Resources. In a swept highwaysection, samples were collected to determine street dirt yields before and after a cleaning from either a vacuum-assisted or amechanical-broom sweeper machine. Sweeping frequencies of twice per day, once per week, and once every two weekswere used during the study. On an unswept highway section of the study, street dirt yields are presented as weeklycollections, and before and after runoff events. Water quality concentrations and flows are also presented for the unswepthighway section. Average concentrations of selected contaminants are compared to concentrations measured in otherstudies of highway runoff.Changes in street dirt yields before and after sweeping and runoff events will be used to calibrate and verify theWinSLAMM model. By modifying the accumulation, event wash off, and street cleaning productivity equations in themodel with the data from this study, WisDOT will be able to evaluate street sweeping programs on urban highways withcurbs. A sweeping program is proposed as a best management practice to attain some of the 40% reduction in TSSprescribed in Wisconsin stormwater regulations. This report includes estimated daily-accumulation rates of street-dirt yieldsand percent of street-dirt washed off during a runoff event. Seasonal estimates of street-dirt yield reductions due to streetsweeping are also presented.Concentrations and flows measured in the unswept highway section were used to calculate contaminant loads for eachevent. Loads were calculated for particulate and dissolved solids, inorganic compounds and trace metals. Sediment loadsmeasured with a water quality sampler are augmented with the weights of sediment captured in a bedload sampler. Loadswill be used to calibrate and verify the contaminant loads predicted at a highway outfall by the model by alteringconcentration files from this study