Operation of Multiple Diversion Weirs to Suppress Fluctuation of River Water Levels during Flood Events

Abstract

The aims of this study are evaluating the effect of gate opening of a series of diversion weirs on the temporal and spatial fluctuations of river water level and optimizing the gate opening operation for disaster prevention under the flood condition. A simulation model describing one dimensional unsteady flow was introduced to evaluate the effect of the gate opening of multiple diversion weirs on the downstream current in the Onga River. Using this model, the spatial and temporal variations of the river water level were clarified under the different patterns of gate opening operation. To quantify the impact of the gate opening on the temporal and spatial changes of the river water level, an objective function which represents the temporal changes of the river water level at all computational grids was introduced and the weirs which have the most significant impact on the water level fluctuation was clarified. The method introduced here is effective for quantifying the impact of the gate control on the fluctuation of the river water level and optimizing of gate opening operation to reduce the temporal and spatial changes of the river water level under the flood condition.