Abstract
Interspersed weirs in river basin are not only affected on the flow regime and riverbed deformation but also on the river ecosystem. In this study, the effect of weirs on river environment is discussed using river ecological model. This ecological model consists of one-dimensional unsteady flow, one-dimensional calculation of bed variation, heat balance, water quality and biological model. This model is applied to Saba River, where many weirs are installed. In the calculation with weirs (present condition), the water level and intake discharge at the weirs are taken into account. On the contrary, in the calculation without weirs, the water discharge without the intake are assumed. The comparison between these calculations revealed that the intake at the weirs causes the imperceptible change of water depth and temperature, however amount of aquatic livings in stable state remain unchanged.
