Water quality during winter storm events in Spring Creek, Pennsylvania USA

This study examined the relationship between land cover and three solute (chloride, total organic carbon (TOC), and lead) concentrations during winter rainstorms in 10 subbasins of Spring Creek, Pennsylvania, USA at two spatial scales. Despite similar percent land cover at both scales, correlations between water quality and land cover were stronger at the subbasin scale than at the riparian scale. As basin percent urban land cover increased, mean chloride and lead concentrations increased. Chloride and lead were likely to be a result of roadside sediments and residential housing, as demonstrated by a strong positive relationship between road density and chloride concentration at both spatial scales (r = 0.83, 0.71). Basin percent forested cover at the subbasin scale was weakly positively related to TOC concentrations, suggesting leaf litter as a source. Changes in flow rate related to changes in concentrations of solutes for representative urban and rural subbasins. TOC and lead showed weak positive relationships (flushing effect), while chloride exhibited a strong negative relationship (dilution effect). These different responses to changes in flow rate implied different sources of solutes - soils for TOC and lead and groundwater for chloride. This study underscores some negative effects of increased basin urbanization on stream water quality and potential aquatic ecosystems in small streams during storm events.