Application of GIS and remote sensing to assess changes to the West coastline of Ca Mau province in 2015-2020

Abstract

Ca Mau is the country's southernmost province and the only one that borders the sea on three sides, East-West-South, with a 254-kilometer coastline that accounts for 34.5 percent of the Mekong Delta region's coastline and 7.8 percent of the country's total coastline. The coastline has become more complicated in recent years, particularly on the west coast, due to changes in the tidal regime and other factors, such as erosion and accretion. Erosion occurs mainly in Tran Van Thoi, U Minh, and Phu Tan districts, whereas accretion occurs primarily in the Nam Can and Ngoc Hien districts. Through the study of coastline changes using Landsat 8 satellite image period from 2015 to 2020, using Gathot Windsor's image ratio method with thresholding to extract shorelines at time on satellite images. Thence use the DSAS tool of ArcGIS software to calculate the rate of erosion - edimentation in the west coast of Ca Mau province. The results show that edimentation occurs near estuary areas and erosion occurs along the shoreline from Phu Tan district to U Minh district. The edimentation rate of Ngoc Hien district is 82.48m/year, Nam Can district is 108.09m/year, the area near the two large estuaries of Bay Hap river and Cua Lon river. Erosion rates in the areas are Phu Tan district 4.75m/year, Tran Van Thoi district 14.01m/year and U Minh district 3.34m/year. The study shows the effectiveness, reliability and applicability of remote sensing technology in studying coastline changes.