Coastal erosion at the Pak Phanang River Basin Changwat Nakorn Si Thammarat

Abstract

Coastal Erosion at Pak Phanang River Basin: Changwat Nakorn Si Thammarat has generally experienced the problem of shoreline erosion and it has been a continual occurrence for 30 years as the result of many elements. This thesis aims to evaluate of the characteristics of waves, currents, and longshore transport in the nearshore zone of the Gulf of Thailand as well as the historical changes of the shoreline at the Pak Phanang areas. Shoreline comparison in the years 1975, 1995 and 2002, shoreline changes during each period. The study results revealed that there were changes of the Pak Phanang shoreline especially in the period of 1995-2002. In the period of 1975-1995 the highest erosion area was found at Ban Plai Sai which had an approximate erosion rate of 6.84 m/year. In the period of 1995-2003, the high rate of erosion (more than 10 m/year) from this study was found at Ban Plai Sai. It had an approximate erosion rate of 11.3 m/year and Ban Nam Sup had an approximate erosion rate of about 10 m/year. The most severe erosion, about 6-8 m/year during 1995-2002, had occurred at the shoreline between Ban Ko Fai to Ban Nam Sap. This study illustrates collected data relayed to estimate the critical urgent problem areas. The prioritization method of shoreline protection analyses outline the rate of erosion overlaid with layer of landuse, layer of economic-social index, layer of economic loss value and layer of existing shoreline protection measures. The area of ultimate urgency is in the Ban Kong Kong. This area has proved to be high priority due to evident erosion.