Linking Riverbank Erosion Dynamics and Livelihood Vulnerability in a Rapidly Urbanising Mekong Delta River Corridor

Riverbank erosion threatens settlements, infrastructure, and river-dependent livelihoods along the Bassac River in the Vietnamese Mekong Delta. This study examines long-term bankline change from 2001 to 2025 and develops expert-informed priorities for assessing livelihood vulnerability within the Can Tho reach. Six Landsat images were analysed in QGIS using the Linear Regression Rate method, while present-day hydraulic conditions were investigated through Acoustic Doppler Current Profiler measurements at five representative locations. An Analytic Hierarchy Process based on interviews with 10 experts was used to derive relative weights for livelihood sensitivity and adaptive-capacity indicators and variables. Accretion was more spatially extensive than erosion along both banks; however, the left bank experienced a greater total extent and magnitude of erosion. Spatially extensive erosion was identified in Binh Thuy, whereas more intense but localised hotspots occurred near Cai Rang and Cai Von. The exploratory hydraulic observations varied among the five selected locations but showed no consistent correspondence with historical erosion magnitude and are therefore interpreted only as a snapshot of conditions on the survey date. Experts assigned weights of 0.547 to sensitivity and 0.453 to adaptive capacity. Savings capacity, decreased food production, extent of land loss, and the ability to shift livelihoods were among the highest-ranked variables. The physical and expert-derived findings support a differentiated and staged approach to riverbank-risk management, but they should be interpreted as complementary evidence rather than as a household-level vulnerability assessment. Future research should combine repeated seasonal hydraulic and bathymetric surveys, bank-material investigations, exposed-asset mapping, and household-based vulnerability assessments.