Abstract
It is well known that various pollutants are accumulated in estuaries of the urban areas under the strong influences of urban run-off and wastewater discharge, and also by tidal flows and flood. Fluctuations of flow rate and water quality during high and normal water levels were analyzed by using both of a one-dimentional unsteady flow model and a diffusion model. Numerical simulations were carried out for water quality, flow rate and pollution loads under various flooding conditions. Resuspension was dominant only in the upper stream and sedimentation was a major factor for water quality variation in the lower stream. The summary of the results is shown as follows ; Cumulative loads of SS were in proportion to flood flows ; Sedimentation of SS was obtained about 100 ton between Dengaku bridge in the upper stream and Gotanda bridge 3.0 Km downstream ; The maximum cumulative BOD load obtained at the same interval was about twice as much as the value in the upper stream under the flooding conditions.
