Modeling Floodplain Inundation for Monument Creek, Colorado

摘要

Annual flood loses has continued to rise in the United States despite the construction of flood control facilities. Floodplain zoning has become an important mode of land use planning with an aim to protect the structures and property within the floodplains. The availability of spatial data, advanced computational facilities and use of geographic information systems (GIS) have made the study of flood zoning very efficient. In this study, an integration of HEC-RAS and Geo-RAS hydraulic models will be used to obtain the water surface profiles throughout the study area in identifying the impact of flood to the study area. The modeling approach is tested for approximately 10.9 km of the Monument Creek at Colorado Springs, Colorado. Previously, Monument Creek has been a subject to severe floods that has led to destruction in the community. In this analysis, flow was routed for different return periods (5, 10,25, 50, 100, 200, and historical flood of 50,000 cfs) for the defined reach to expose the vulnerability of the current infrastructure in the region. Water surface elevation and flood extent was obtained from HEC-RAS, which was geo-referenced and mapped in GIS and critical zones along the creek was distinguished. Further, the flood depth level and flow velocity along the reach as well as on the inundation area was determined using GIS. The use of higher magnitude flood events in assessing the flood risks using GIS and HEC-RAS provides a useful tool in floodplain management system and may assist water managers in land development decision within the channel reach.