Abstract
Topographic changes in the Co May River mouth located 9 km east of Vung Tau in Vietnam were investigated. Around this river mouth, the development of an asymmetric shoal in the east-west direction was observed, suggesting the predominance of southwestward longshore sand transport. Furthermore, sand was transported and deposited inside the mangrove forest by storm waves in the hinteland of the right bank of the river mouth, and then sand bar was eroded by longshore sand transport in the upstream direction along the river bank, resulting in the develoment of a sand spit at uptream end. Also, the exposure of the bed composed of the cohesive material and the roots of the dead trees showed that the right river bank is subjected to the sand deposition under the storm wave condition and wave abraision owing to longshore sand transport.
