Using SWMM as a tool for hydrologic impact assessment in a small urban-rural basin within high resolution GIS

Urban growth is one such phenomenon that drives deep changes in land use patterns. From a hydrological perspective, the urbanization increase s the impervious surfaces, which result in decrease of infiltration and increase of runoff. In this context, we present the SWMM model applicability to assess the hydrologic impact of on going urbanization process on Capivara basin, which is characterized by a land use gradien t from upstream (rural) to downstream (urban), based on two different municipal planning scenarios. During the calibration and verification periods the peak flow, volume and time to peak modeled by SWMM were in general good agreement with observed data. This stu dy has shown that SWMM might be used as a reasonable tool for hydrologic impact assessme nt in basins under ongoing urbanization process because of its vertical water balance is on ly based on impervious area percentage, that means is quite appropriated for predicting scenario s.