Observation and Simulation of Floodwater Intrusion and Sedimentation in the Shichikashuku Reservoir

Abstract

Wash load sedimentation during flood events is studied through comprehensive field measurements at the Shichikashuku Reservoir, Japan and numerical simulation. Field data during a flooding event caused by a typhoon in 1996 are used to set the boundary conditions for the model and to verify the simulation. In the field experiments, continuous monitoring of inflow turbidity is shown to be an effective and reliable means of estimating sediment influx. In the simulations, the proposed model is shown to provide an accurate reproduction of floodwater currents and sedimentation in the reservoir. The model achieves good accuracy and resolution by adopting an orthogonal curvilinear grid to discretize the reservoir and by solving the flow field using a three-dimensional standard k–ε turbulence model. The simulation reproduces the observed velocity, turbidity, and distribution of sedimentation well, demonstrating the potential utility of such models in the management of reservoir water quality and sedimentation.