Abstract
Transport phenomena of contaminants is an interesting problem in the light of the water quality control of rivers. In a tidal river it is affected by the tidal oscillation. Observation data, however, often show the behavior which can not be explained only by the tidal oscillation. In such cases the effect of the secondary undulation which is often observed in the harbour and the canal opening to the sea may also have to be examined. It has been investigated for the sake of the prevention of disasters, but scarcely studied in the field o f water pollution research.
In this paper the effect of such tide induced motions on the water quality are discussed. The river flowing through Tokushima city was chosen as the site of the study, and the field survey was carried out. On the basis of the observation data the characteristics of the oscillatory motion of water is discussed in detail. Concerning the water quality variation, the importance of not only the tidal oscillation but also the secondary undulation is pointed out. Furthermore their effects on the water quantity and quality exchange are described.
