Estimation of channel and flood plain roughness using HEC-RAS model: A case study of the Veseočica River, Bosnia and Herzegovina

Abstract

Modeling flow in open channels is essential for determining channel capacity and predicting flood events. The key segment for creating flood hazard and risk maps is a high-quality hydraulic model of the flow in the main bed with its tributaries. Several software packages have been developed for hydrodynamic simulations of flood events. In addition to the geometric characteristics of the watercourse, the equations of a one-dimensional flow model include a parameter that connects all influences that provide resistance to the flow of water. Determining the roughness of a natural channel is one of the most demanding procedures for the development of hydraulic models. Therefore, it is necessary to calibrate and validate the Manning coefficients of the channel roughness using simulation models. In the present study, the estimation of channel and floodplain roughness for the Veseočica River in Bosnia and Herzegovina was performed using the HEC-RAS hydrodynamic model. After calibration and verification of the model, flood hazard maps were created for flood waves with return periods of 20, 100, and 500 years. ArcGIS and HEC-GeoRAS software tools were used to create the flood risk maps.