Author(s): Hiroki Takaoka; Haruyuki Hashimoto; Kichan Park; Shinya Ikematsu
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Keywords: Slope erosion; Bed erosion; Bank erosion; Lateral erosion; Bank failure; Erosion rate
Abstract: The outflow of a large amount of sediment from the bare mountain slopes causes serious problems of flood overflow, irrigation and water pollution in the downstream areas. When we consider their measures, it becomes important to predict the sediment outflow from the mountain areas. The prediction of sediment outflow requires the knowledge of erosion rate of mountain slope and the formation processes of gullies and river valleys in mountain areas. The purpose of this study is to investigate bed and bank erosions and develop the prediction method of steep channel variation. We make experiments on bed and bank erosions and propose a bank failure model in a steep open channel. By the measurements of channel bed level and channel width, we estimate the flow velocity and sediment concentration at any positions and the one-dimensional calculation of unsteady flow. As a result we obtain the relationship of the bed and bank erosions and hydraulic quantities, such as flow velocity and sediment concentration. Using the erosion rate equations and the bank failure model, we can simulate channel variation in a steep channel.
Year: 2004