The adoption on this approach in six of Pennsylvania’s 356 specified watersheds implies that the integration of PSRM and GI Science provides cost-effective and technically sound solution sto Pennsylvania’s watershed-wide storm water management problems. Djokic and Maid ment (1991) used Arc Info to simulate the drainage system and assess whether the existing drainage system in a portion of the City of Asheville, North Carolina can accommodate 10- and 25-year return period design flows. Their approach used the rational method to examine contributions from surface terrain (i.e., overland flow), man-made structures (i.e., pipes and channels), and storm water intakes.