Abstract:
Shoreline change at Haad Nathon is caused by wave, longshore current and human activities. This study deals with the shoreline change at Haad Nathon in the last 10 years through the use of field sampling data and available information about the study site. Time-series of significant waves for Hadd Nathon were computed from wind data at Ko Samui meteorological stations. The results showed that the magnitude of the significant wave was rather small, being less than 0.3 m. However, high wind wave condition can occur when the area is under a severe storm coming from the west.The longshore transport computed from current and wave simulations showed that high suspended sediment transport occurred during the southwest monsoon season. The sediment moved both to the north and to the south, but the net transport was northwards. However, the amount of longshore transport was rather small.Human activities caused shoreline change along Haad Nathon too. Along 2-km stretch of the beach there were land reclaim and sea wall constructions. Thus high-tide beach front was lost due to the sea wall. The beach of Wat Jang is the only natural beach that exposed to the sea at all time. Erosion occurs to the beach under severe storm coming from the west. Thus, appropriated measures must be implemented in order to stop the beach erosion at Wat Jang area.