Abstract

Urban Hydrology Modeling Using GIS
Track: Water Resources
Authors: Victor de Loza, Nahm Lee

Subcatchment delineation is an essential step for watershed modeling studies. Flow directions can be changed by roads, artificial surfaces, and storm drains. Urban subcatchment delineation is challenging since the flow direction in the drainage network not always align with the topography of the surface. Geographic Information Systems tools can help delineate urban subcatchments. This paper develops a method to delineate urban subcatchments considering drainage network characteristics at the Ross Creek in San Jose, California, utilizing ArcMap10.0. Utility Network identified and corrected network-creek connectivity issues. ArcHydro tools delineated urban subcatchments. Topology tools identified the intersection of subcatchment boundaries and buildings. Spatial Analyst tools estimated runoff parameters and ArcMap's Python Interface converted the shapefile to EPA's Storm Water Management Model, SWMM5.0, format. Research results developed a storm drain model in SWMM5.0 for the Santa Clara Valley Water District. Simulation results indicate that ArcMap10.0 tools can substitute site surveys to delineate urban subcatchments.