Risk assessment and water resources management are required to get a reliable estimation in not only the subcatchment scale, but also the catchment scale. A simple 1-D model considering slope runoff and channel flow with soil erosion and sediment transport is presented in order to predict the consequences of extreme flood event. In this study, proposed numerical model was applied in appetsu river basin. The results indicated agreement between observed and calculated discharge. Furthermore,

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... ar flood events can be calculated at the identical model parameters. In addition" the proposed model was employed to simulate sediment transport problems. The results indicated that suspended sediment load increased before flood peak. However, more study is needed to precisely decide the calculation parameters as well as sediment transport.