In 1997 a group of investigators at Virginia Tech initiated a study, funded by the USEPA, to develop procedures for integrated assessment of environmental, economic, and biological impacts of alternate land development scenarios. The Upper Roanoke River Watershed (URRW) in southwest Virginia was chosen as the case study watershed. HSPF was selected as the hydrologic model because of its widespread use in evaluation of the hydrologic impacts of land use change. The model was applied to a 145 km2 (56 mi2) sub-watershed (Back Creek) of the URRW. Four different development tracts (i.e. high density, medium density cluster, medium density conventional, and low density) were defined for creating various hypothetical scenarios of residential development, both with and without a network of primary and secondary roads. Continuous hydrologic simulation was performed using data for water years 1995–1998 to investigate the hydrologic effects of various spatial arrangements of development, measured in terms of effects on various error statistics. The entire effort was aided by the development of a macro-based scenario generator that partially automated the analysis of development scenarios.