Abstract
In the river assessment, it is necessary to discuss the mass balance in the river ecosystem using river ecological model. A new model of river ecosystem consists of one-dimensional unsteady flow, one-dimensional calculation of bed variation, heat balance, water quality and biological model. This model was applied to Saba River, where water quality and biological environments have been observed at four points in the river basin in two month intervals. The temporal variations of water level, water temperature, dissolved oxygen and amount of attached algae obtained from this model show a good agreement with the observed results, indicating that this model is valid for simulating the mass balance in the river ecosystem.
