Urban streams face a multitude of environmental issues today. Land cover change and anthropogenic pollution threaten urban streams and the ecosystems and the human populations they support. One of the biggest obstacles facing urban streams is the overbearing presence of impermeable surfaces like roads and sidewalks, which lead to more stream runoff, more polluted runoff, and more severe flooding events, detrimental to the health of already-fragile ecosystems. As part of the Urban Vegetation Community-Based Participatory Research Project (UrbVeg CBPR), this research aims to  assess recent changes in urban vegetation and hydrological trends. Cobbs Creek is a roughly 12 mile-long Pennsylvania stream and tributary of the Delaware River that borders Philadelphia and Delaware counties. Cobbs Creek faces freshwater salinization which affects geochemical cycling, vegetation ecology, and microbial community health, all of which may be exacerbated by too many impermeable surfaces in the watershed. Water salinity is currently regulated by the PA Department of Environmental Protection and the EPA, but these guidelines do not reflect the salinization crisis affecting many urban streams today. The time between peak precipitation and peak discharge in a stream is called the lag time. Longer lag times are usually indicative of healthier watersheds, with plenty of permeable land cover to allow precipitation to percolate through the earth. This research attempts to analyze the relationship between permeable surface cover and lag time in the Cobbs Creek watershed. The following research questions are addressed in this project: 1) How has land cover and land use changed along with water quality in Cobbs Creek? 2) How does vegetation cover affect stream ecology in an urban environment? 3) Can streamside vegetation cover be used to effectively predict lag time? These questions will continue to be addressed through analysis of historical datasets, in-situ water quality monitoring, and remote sensing.