MODELING THE EFFECTS OF THE DEVELOPMENT OF FM 156 ON THE BIG FOSSIL CREEK - WEST TRINITY RIVER WATERSHED

Urban development increases the runoff created from a property, requiring analysis to ensure the watershed in question is not negatively affected, and adjacent properties are not adversely impacted. This study focuses on a project currently being done by the Texas Department of Transportation, including the widening and reconstruction of FM 156 in Saginaw, Texas, within the Big Fossil Creek Watershed. This project runs through a FEMA floodway, presenting challenges in the allowed scope of work. The focus of this study is to model the watershed using the hydraulic analysis software, HEC-RAS, and to design the proposed 4-lane roadway profile, including two bridges. This hydrologic and hydraulic analysis, along with economic and environmental consideration, show the proposed roadway cannot be economically designed to pass the desirable design criteria but can be improved from its existing condition. With right-of-way acquisition being a major constraint, the roadway was designed for the 10-year storm as to follow FEMA regulations and TxDOT criteria.