Rice University FEMA Project

The main objective of the Rice University FEMA project is to evaluate the existing storm water network on the Rice campus and to compare the improvements of proposed drainage alternatives using a 1D/2D model package (XP-SWMM) that is accepted by FEMA. Rice University is located within the Harris Gully Watershed in Houston, TX, consisting mostly of fully-developed residential and light commercial land uses. Consisting of twin 15X15' box culverts, the Harris Gully captures water from a significant portion of the watershed, including the Rice campus, before draining it into Brays Bayou. To accurately simulate the storm water network hydraulics at Rice, XP-SWMM was selected as the main modeling tool because of its capability of combining a 1D hydraulic model with a 2D rainfall-runoff model to generate floodplain maps. Additionally, a crucial feature of XP-SWMM used in this study is its ability to incorporate the inflow hydrographs generated by other models such as HEC-HMS and HEC-RAS into specific node locations in the model. This allows for the simulation of tailwater effects of Brays Bayou at Harris Gully, a condition which has proven difficult to address using older models. The XP-SWMM model representing existing drainage conditions were successfully calibrated using an actual storm, Tropical Storm Erin, which occurred in August 2007. Comparisons between the proposed drainage alternative and the existing conditions were made, and the proposed alternative was shown to reduce the 100-year inundation levels at specific locations of interest by approximately 0.5 ft.