Coupling HEC-RAS and HEC-HMS in Precipitation Runoff Modelling and Evaluating Flood Plain Inundation Map

The climate change and land use change have raised the challenges associated with increased runoff and flood management. The risks associated with flooding have been increasing with development in flood plain and changing climate resulting in increase in inundation of flood plain. The current study will help to evaluate the extent of flood plain in the study area–copper slough watershed (CSW) in Champaign, Illinois; utilizing the known precipitation and land use. The study of CSW is taken into account, as this is the largest watershed of Champaign City and had undergone major land use change increasing the flooding issues in the region. The conducted research utilizes the hydrologic engineering center-hydrologic modelling system (HEC-HMS) and Hydrologic Engineering Center–River Analysis System (HEC-RAS) as the modelling tool to develop runoff and floodplain inundation evaluation model for known precipitation. The model also incorporates aeronautical reconnaissance coverage geographic information system (ARCGIS) extensions-HEC-GeoRAS and HEC-GeoHMS for the spatial analysis of the watershed. The hydrologic analysis is performed using HEC-HMS while the hydraulic modeling is done using HEC-RAS. Forcing the model with forecasted precipitation can also help with flood warning system by generating pre-flood inundation maps.