ANALYSIS INTO THE COASTAL CHANGE DUE TO THE CRITICAL EROSION AGAINST THE AREAS AROUND THE LOWER GULF OF THAILAND USING SATELLITE DATA AND SPATIAL ANALYSIS MODEL

Thailand has been encountering the erosion along the coastline continuously so far, thus impacting the environment, economy, and society. The objective of this study is to analyze the coastal change due to the critical erosion against the areas around the lower gulf of Thailand by using data obtained from satellite and from spatial analysis model, case study in the coastal area of Songkhla Province. The operational method was implemented by applying data obtained from Landsat 5 TM and Landsat 8 OLI satellites during 30 years as from 1989 – 2019 as the fundamental data for the analysis in this study. Then, the Digital Shoreline Analysis System tool was used in combination with the geoinformatics program. It was found from the analysis into the coastal erosion during 30 years of the study that: (1) from Shoreline Change Envelope analysis result, it was found that the means was 145.880 m; (2) from Net Shoreline Movement analysis result, it was found that the means was - 96.620 m; and (3) from Linear Regression Rate analysis result, it was found that the means was -3.210 m/y. In overall from 30 year period, it was found that the average erosion at the coastal area of Songkhla Province was 28.860 m/y; the area which was affected considerably was the coastal area around the Songkhla Mueang District and the Singhanakhon District. Besides, the study result was consistent with the Department of Marine and Coastal Resources which determines that the area which is eroded more than 5 m/y is categorized as the severely eroded area.