SIMULATION OF RIVER CHANNEL CHANGE IN A SUSPENDED DOMINATED RIVER

Abstract

 This study presents a method for analyzing channel fluctuations, including bank erosion, in a river dominated by suspended sediment using 2-D flow model and applies it to the lower reaches of the Sangu River in Bangladesh to understand the charteristics of river channel change. The analysis is conducted for an area of the lower Sangu River basin, using the 2018 riverbed as the initial condition, and the computation results are compared with the actual channel change data. The results of the computation generally evaluate the trends of actual riverbed fluctuations and riverbank erosion. At the meandering area where the flow concentrates, suspended sediment is deposited on the inner bank due to the separation eddy from the main channel, while this such eddy is less formed on the outer bank, causing riverbank erosion when the flood flow returns to the main river channel. Thus, we clarified the process of river channel change caused by the deposition of suspended sediment and riverbank erosion.