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 for 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. Problems of maintaining navigation channels and harbor basins are serious also in many ports in Southeast Asian countries, which have often developed in estuaries of large rivers.

In this research, we are focusing on estuaries not only in Japan but also overseas including in Southeast Asian countries. We are conducting several field monitoring to understand the sediment transport process including fluid mud behaviors around river mouth. We are also working on modeling of these sediment-transport processes in the estuarine and coastal zones.

In the field observation at the Patimban coast in Indonesia, we have captured dispersion of turbidity around rivermouth and formation of fluid mud layer near the bed.

In another field survey in the area around the Kumamoto Port in Japan, we observed the particle-diameter variations of suspended sediments, which depends on the types of eposited sediments. By flume experiments, we investigated the sediment load due to current and waves and the transport rates and their dependency on the sediment type were quantitatively evaluated.