NUMERICAL SIMULATION OF RIVER ECOSYSTEM IN A RIVER BASIN INCLUDEING THE EFFECTS OF WEIRS

Abstract

 A numerical simulation model was developed to describe material cycling and river ecosystem in river channel network, which includes the backwater effects of weirs on flow, thermal environments and material cycle. The model was applied to the Ibogawa-river basin in Hyogo, Japan. The results of the numerical simulation show that the effect of a weir is accumulated and expands in longitudinal direction while passing through a number of weirs. The increased residence time in the reservoir of weir enhances the deposition and decomposition of particulate organic matter.