Coastal Evolution at Nha Trang Bay, Vietnam

Abstract: Over the past years the southern beach of Nha Trang, located in the south central of Vietnam, has started to indicate signs of erosion in the northern part. As the beach plays an important role for this touristic hotspot, the fear that the erosion will become severe has been raised. The limited knowledge and previous performed studies of the general coastal processes affecting the shoreline evolution has motivated this master thesis and abovementioned were investigated through field trips, data collection and simulations. Data and samples of sediment, beach profiles, shoreline position, wave and current properties and longshore sediment transport were collected. The model EBED was used to simulate the nearshore wave climate from deep water wave data for the previous 25 years. The resulting wave climate was further used as input data to the shoreline evolution model GENESIS, which calculated the net transport rate and the shoreline evolution. The field measurements and data analysis indicated a relatively stable shoreline, except for in the northern part where the retreat of the shoreline was visible. Beach nourishment would improve the condition of the northern part of the beach but required renourishment every second year. The wave climate in the bay is highly affected by the northeast monsoon, which generates a longshore sediment transport to the south, and the sheltering surroundings with the many islands and mountains.