Sustaining Social Integration After Development-Induced Resettlement: A Longitudinal Study of Three Gorges Migrants in Rural China

Social sustainability has become a central concern in development-induced resettlement, yet little is known about how social integration and community relations are sustained over long time horizons. Drawing on a retrospective longitudinal ethnographic reconstruction spanning 21 years (2004–2025) of Three Gorges Dam resettlers relocated to rural Anhui, China, this paper examines the co-evolution of group boundaries, interaction strategies, and social networks between migrants and local residents. Using group boundary theory, we identify three sequential phases of interaction: initial boundary demarcation and social distancing, subsequent bridge-building through economic cooperation and relational ingratiation, and a later stage of pragmatic, transactional engagement. We show that the gradual erosion of migrant–local boundaries is driven by economic interdependence, cultural adaptation, individualization, and rural out-migration. Rather than resulting in deep social fusion, long-term integration stabilizes in a form of “thin integration,” characterized by low-density but sustainable social ties, institutionalized conflict resolution, and routine coexistence. This study conceptualizes social integration as a dynamic process of social sustainability, demonstrating how resettled communities maintain social order and functional cohesion amid structural change. The findings contribute to debates on sustainable rural development, forced migration, and the long-term governance of resettlement communities.