Assessment of Mangrove Channel Changes in the Langkawi River Using Geospatial Techniques

Abstract

Channel alterations represent a primary concern within coastal mangrove ecosystems, which possess substantial ecological and socioeconomic value. These mangrove channels in the Langkawi River have encountered a variety of environmental challenges over time, such as urbanisation, pollution, and natural changes. This study aims to evaluate changes in the mangrove channels along the Langkawi River in Pulau Tuba between 2018 and 2023 using remote sensing techniques. The methodology involved a comprehensive assessment of channel changes in these locations through the comparison of satellite imagery data to identify changes occurring within the channels. Based on the initial findings, the primary objective was to classify the mangrove channels using supervised classification of Sentinel imagery. The study successfully identified and classified four distinct land cover types: forest, water bodies, mangroves, and developed open areas, using geospatial techniques in ERDAS IMAGINE 2015 and ArcMap. The second finding relates to the breadth of the mangrove channels, which indicates that the maximum rate of erosion was 65 metres, while the minimum rate was 0.09 metres. Furthermore, there are accretions that occur at a minimum rate of 0.85 and a maximum rate of 26.7 meters. The final findings are presented in the form of a risk analysis map of alterations to the mangrove channel in the Langkawi River. These findings could be valuable to organisations such as LADA, JUPEM, and NAHRIM, particularly for future monitoring and planning purposes.