Changes in streambed sediment characteristics and solute transport in the headwaters of Valley Creek, an urbanizing watershed

Changes in streambed sediments were monitored in conjunction with Q series of conservative solute tracer injections over a 2-year period to assess the effects of urbanization on two streams in the Valley Creek watershed, located in Chester County, Pennsylvania approximately 30 km west of Philadelphia. The modeling package OTIS was used to analyze the solute transport behavior. Comparison of the results from the two streams demonstrates that the fine sediment fraction of the streambed controls hydraulic conductivity and transient storage exchange in this gravel- and cobble-bed Piedmont system. One site had a narrow (10–40 m) riparian corridor of mowed lawn and woody brush. At this site, the silt-clay fraction ( d