Floods are calamities with potential for many fatalities and enormous economic losses. However, the degree of vulnerability to a disaster is a function of human action and behavior. The rapid development of modern metropolitan areas has changed the response of floodplains to rainfall and increased the risk of flooding. The current study is concerned with the flooding along Brays Bayou, a 31-mile waterway located on the southwest part of the city of Houston. The first objective of this study is to simulate the runoff from Tropical Storm Allison and evaluate the use of NEXRAD (next generation radar) for Allison over Brays. T.S. Allison's severity was not identical for all Brays Bayou. Thus, the second objective of this research is to develop scenarios that investigate the significance of the dissimilarity of Allison's rainfall patterns along the watershed to the magnitude of consequences on the middle and lower part of Brays Bayou.