Flood flow analysis using one and two dimensional numerical models; the case of Kars Digor district central main streams

The aim of this study is to analyse flood flow using HEC-RAS one-dimensional steady and two-dimensional unsteady models and obtain flood hazard and risk maps with the help of Mappers component. Moreover, this study also aims to investigate the applicability of one-dimensional steady flow model in unsteady, multidimensional flood flow simulation with respect to flood control and management. Geometric, flow and boundary condition data required for numerical modelling were obtained from Electronic Public Procurement Platform and U.S. Geological Survey web site. The results of both one and two dimensional modelling indicated the need for precaution as flooding occurred along the main channel. In this study, one-dimensional steady flow modelling of a new channel constructed by General Directorate of State Hydraulic Works to prevent flooding in the same area after completion of flood analysis was also carried out. It was seen that the new channel prevented the occurrence of flooding. A comparison of one and two dimensional models was made using the flow depths and velocities at the control points and also the flood risk maps. The results showed that one-dimensional steady flow model could be applied to the modelling of unsteady flow cases. Keywords: HEC-RAS, flood modelling, flood hazard and risk maps, flood control and management