Shoreline variation in Can Gio District, Ho Chi Minh City, Vietnam from geospatial technology

Can Gio is a coastal district in the Southern coastal area of Ho Chi Minh City (HCMC), Vietnam. This area has been and is being affected by the problem of shoreline variations, affecting human life and ecosystems. The article presents the results of applying geospatial technologies to evaluate the shoreline variations in space, thereby determining the rate of shoreline accretion and erosion for the study area in 1998, 2009 and 2019. The technique of separating water and land based on the Modified Normalized Difference Water Index (MDNWI) is used to extract the shoreline from Landsat satellite image data. We used the Digital Shoreline Analysis System (DSAS) module to calculate the variation rate. The results show that, within 21 years, from 1998 to 2019, Can Gio District has lost about 500 ha of land. Thanh An Commune has the largest erosion area, accounting for 29% of the erosion area of the whole district. The highest erosion rate of up to 18,2 m/year was recorded in the Nga Bay River area, and the highest accretion rate of 29,2 m/year was recorded on the left bank of Dong Tranh River. This research result supports ecological and environmental management in coastal areas facing the risk of climate change and rising sea levels.