When the River Moves, Lives Shift: Linking Hydro-Geomorphology to Climate-Induced Migration

Riverbank erosion in South Asia’s deltaic regions presents a growing socio-environmental threat, intensifying displacement and livelihood disruption. This study investigates the erosion–migration nexus along a 44 km reach of the Ganges River in northwestern Bangladesh, integrating three decades of Landsat-based geomorphological analysis with household-level survey data. Between 1989 and 2020, the river’s sinuosity declined approximately by 19%, accompanied by intensified braiding and dynamic erosion–accretion cycles. These geomorphic transformations led to the permanent loss of over 2600 hectares of land and the formation of 1500 hectares of new floodplain terrain, heightening exposure for riverbank settlements. Survey data from 130 households reveal that erosion-induced housing damage and environmental proximity remain key predictors of migration decisions, but socio-economic characteristics shape divergent adaptive responses. Education is positively associated with anticipatory migration (Odds Ratio, OR = 1.86, p < 0.001), while income has a weak and statistically insignificant negative effect, suggesting that better-off households often invest in local adaptation instead of relocating. Institutional support shows weak correlations with migration outcomes, highlighting significant gaps in relief delivery and governance responsiveness. A logistic regression classifier based on five predictors achieved 72.2% sensitivity, demonstrating strong potential for proactive targeting of at-risk populations, though specificity was moderate. These findings underscore the need for integrated, data-driven adaptation policies that bridge geomorphological diagnostics with household vulnerability metrics. By linking physical river transformations with migration behavior, this study offers critical insights for climate mobility governance in erosion-prone deltas globally.