Evaluation of the natural recovery in an artificially modified geography

The purposes of this study were to obtain geographical and geological information before the dyke of the Isahaya Land Reclamation Project is opened, and to evaluate the natural recovery in the excavated area in Isahaya Bay. The presence of no new sediment within the ditches suggests that the natural return to the original geography is difficult after being artificially modified. However, the presence of many fish in the ditches suggests that the hollows are not necessarily a cause of the occurrence of low oxygen water, and that the hollows do not need any special measures to recovery geographically.