Coastal Change Study : A Case Study of Thai Mueang Beach Thai Mueang District, Phang Nga Province

Abstract

This research aims to study hydrographic data for support of naval operations and the changes of the coast at Thai Mueang Beach, Phang Nga Province. The length of study area is about 5 kilometers along the coast and about 2 kilometers from the shore. The surveys were conducted by beach profiling along the beach and also bathymetric surveying for the scale 1: 5,000 with the area of about 10 square kilometers. The littoral current was measured at the upper and lower of the surveying area whereas the sediment samples were collected along the coast. The field measurements were evaluations for beach slope, coastal bathymetry, longshore currents and coastal changes during northeast and southwest monsoon. The results reveal that the characteristic of changes in the coastal area of Thai Mueang Beach is the dynamic equilibrium. During the southwest monsoon, large waves in vertical line (scarp) cause beach to be eroded and transferred offshore to form underwater sand dune. The beach slope increases. During a period of lower mean sea level or during the northeast monsoon, the beach becomes emergent because of swash and wind-carried sand. The beach slope decreases. To reach this conclusion, the study must be repeated in the same area throughout the year for covering all seasons.