ESTIMATIONS OF FLOW AND BED VARIATION WITH THE BEDFORM TRANSITIONS USING TEMPORAL CHANGES IN WATER SURFACE PROFILE AND COMPARISON WITH ESTIMATION RESULTS ASSUMING FIXED BED

Abstract

 In this study, we estimated the flow discharge, roughness coefficient, riverbed level, and sediment discharge with bedform transitions based on the temporal variations of the water surface profile. The estimation method uses the 1D shallow water and continuity equation for the sediment discharge as governing equations. The method was verified against experimental data on bedform transition such as transition – flatbed - dune II. The verification showed that the present estimation method could reproduce the flow discharge, roughness coefficient, average bed level, and sediment discharge. We also examined the difference between the estimation results assuming the river bed as a fixed bed. It showed that an estimation result based on the river bed after the flood events had the highest reproducibility of the flow discharge.