DETECTING COASTAL FEATURE CHANGES IN MEKONG DELTA USING MULTI-TEMPORAL LANDSAT AND GOOGLE EARTH IMAGES

International audienceInvestigating coastal feature changes is a crucial task focusing onthe identificationof potential factors that trigger the degradation of the coastal ecosystem. However, in-situ field investigations can be costly, time-consuming and almost impossible for multi-decadal assessment. In this study, the evolution of coastal features (including shoreline patterns and coastal habitats) in KienGiang province, the north-westernmost part of the Mekong Delta, was investigated using multi-temporal Landsat data and high resolution Google Earth Images (GEIs). The aims of this study are threefold: (i) to delineate and detect the inter-decadal shoreline evolution based on Landsat data; (ii) to detect the coastal land cover changes using Landsat data and GEIs; (iii) to evaluate the anthropogenic pressures on the coastal ecosystem, particularly the mangrove ecosystem. The results of this study revealed that from 1989 to 2014, the shoreline pattern of the study area has greatly changed due to the erosion and accretion phenomenathat were driven by intensive human activities along the coastline. The rate of the coastal erosion hascontinuously increased until the present day with adominant erosion zone shifted from north to south. On the other hand, the coastal land cover has significantly and constantly changed. The bare surface has remarkably decreased while the other land covers such as the urban area, vegetation cover and inland water surface have successively increased. This reflects the increasing trend of human activities in this coastal region. Moreover, the contrast variation pattern of the paddy area and inland water surface shows that the socioeconomic situation in the study site haschanged from rice oriented to aquaculture oriented, which took place in early 2000s. The extent of the mangrove forest has continuously declined from 1995 until now. The conversion ofthe adjacent coastal land cover was found to have potential negative impacts on the degradation of the mangrove area. Moreover, concentrated economic activities such as the intensive shrimp breeding and rice cultivation, industrial development and increasing number of human inhabitants also have resulted in severe damage to the mangrove ecosystem