Abstract
A retarding basin, that temporarily stores stormwater to reduce downstream flow rate, is one of the most effective countermeasures to mitigate existing downstream flooding problems. Effectiveness of the basin is strongly dependent on design of an overflow levee. Experimental works have been commonly employed for the overflow levee design, because the flows around the levee are very difficult to be handled by theoretical and/or numerical methods. The objective of this study is to demonstrate that the numerical model along with appropriate boundary conditions is effective to calculate the stage-discharge relationship, that solves simultaneously flood flows in a channel and inundation flows in a flood plain with the dynamic model, which comprises the finite volume method based on unstructured grid using FDS technique.
