In ports located around estuaries, countermeasures against sedimentation of navigation channels and harbor basins due to the deposition of discharged sediments through rivers are required. Examining countermeasures against sedimentation and siltation is important research subjects to resolve the following existing challenges: shortage of disposal site of dredged sediments and reducing the cost of maintenance dredging. Maintaining navigation channel and harbor basins are more serious problems in many ports in Southeast Asian and other countries, which are situated next to cities developed in estuaries of large rivers.

In this research, focusing on estuaries not only in Japan but also overseas including in Southeast Asian countries, we aim to understand the transport dynamics of sediment supplied by rivers including the transport of highly concentrated fluid mud and its seasonal variations, taking regional characteristics into consideration. We also make a simulation model of these sediment transport processes in the estuarine and coastal zones.

This fiscal year, in a collaborative study under a joint-study agreement with the Indonesian government agency BPPT, we studied estuary turbidity distribution around Patimban Coast(August). Also, we conducted on-site studies of highly concentrated turbid water where the Shinanogawa River flows out into the estuary and in an area within Niigatanishi Port (November, December). In addition, we conducted transport experiments of local bottom mud transported by waves and flows, and quantitatively evaluated changes in transport amount depending on mud content rates and other factors.