Mariko NOZAKI
Analysis of sediment transport by flood waves with temporal changes of Altitude
Tokuzo HOSOYAMADA
A fatal flood disaster occurred due to heavy rainfall in Chuetsu area of Niigata Prefecture, on July 13, 2004. The flood water breached levees in many places along the Kariyata River. The levee breach occurred by overtopping flow near Nakanoshima town was 50 m wide. Due to levee breach, many houses were broken and substantial areas were under muddy flood water in Nakanoshima. For better understanding and prevention of flood disasters, a two-dimensional numerical model for unsteady flow and non-uniform sediment transport model is analyzed using finite difference method on staggered grid.
The present study is useful for making the hazard map for evacuation of people in river basin by predicting the position of levee breach, the attainment time of the flood flow, flood water flow depth. Moreover, this model also predicted process of sediment transportation, settling, deposition and re-suspension and bed change along the Kariyata River and floodplain region in Nakanoshima Town. The movement of the sediment which was from the river during flooding was understood. As a result, the levee breach of Kariyata River was expressed and it was confirmed that the ground altitude was change due to sediment re-suspension and deposition. Comparison between simulation and observation still shows some differences. This should be solved in the future study.
Please use "previous botton" to return the previous page