Example of using the watershed]management system iWMSj to evaluate the effect that Sabo dam has on reducing sediment discharge

Yoko TOMITA, Toshio MORI, Yoshiiku MUSASHI, Tomoyuki SUZUKI and Takahisa MIZUYAMA

We have been developing a system called a watershed]management system (WMS). It consists of a rainfall]runoff model, a sediment discharge model and a deformation of riverbed model. WMS was applied to the Sumiyoshi River, and the parameters of the model were determined by considering the observation results. By conducting simulations under various conditions, for instance it was found that several Sabo dams in a downstream area are enough to control the amount of sediment caused by rainfall over a period of 10 years if their sediment trapping capacity is maintained by removal works. This paper explains the model, and describes the validation results.