The impact of river rehabilitation on flood mitigation: A case study of Ismetiye creek Bursa

In this study, the impact of channel rehabilitation on the extent of floodplain map for Q500 and Q1000 discharges is investigated in the Ismetiye creek, located in Bursa, Turkey. The necessary data used is discharge and the elevation data for the main channel and the catchment area of Ismetiye creek. Both point elevation data and topographic contour lines are used to create the digital elevation model of the area in Arc Map. Subsequently, it is used to develop the floodplain model of catchment area for extreme discharges using HEC-RAS software for the two cases including before and after the rehabilitation of Ismetiye creek. Water depths and floodplain maps are compared for these two cases. In addition, flood hazard maps, flood velocity maps, and water surface elevation maps are developed and compared. Flow hydrographs in the main channel and overbanks are computed at specified stations along the river. It is observed that rehabilitation works contributed the flood mitigation by reducing overbank flows and flood extent considerably. Finally, some recommendations are proposed for future works.