Abstract
Pollutant in a stagnant water area of a semi-enclosed bay has remained a serious water environmental problem. In order to activate tidal exchange, Komatsu et al.(1993) proposed a method, “Pond Method”, which can surely create a one-way flow by operating two water gates with tide. In the Karatsu Port, located in the northern part of Kyushu Island, a waterfront development on the basis of excavation of a canal has been planned. In this paper, we try to apply the Pond Method and other water restoration methods to the Karatsu Port and investigate the effects of these methods by the numerical simulation. As a result of this research, it was made clear that the ratio of the residence time by Pond Method to one by the excavation of the canal is only 3.2% and that this method is extremely effective for the field of a very weak tidal current.
