Abstract
The Sudd is the largest tropical wetland in the world, and its ecosystem services are fundamental to the livelihoods, well-being, and cultural systems of communities living within the region. Although human adaptation to seasonal flooding has long been a defining feature of socio-ecological interactions in the Sudd, changing flood dynamics increasingly challenge existing adaptation pathways. This study investigates the changing dynamics of human adaptation to flood risk among flood-affected populations through an empirical assessment of community experiences and responses. Using a mixed-method approach combining focus group discussions, semi-structured interviews, participatory mapping, and field observations, we conducted a thematic analysis of locally grounded evidence. The results reveal that unprecedented flooding between 2019 and 2022 produced severe disruptions to livelihoods, settlements, mobility patterns, and social systems across the Sudd. Communities reported strong perceptions of a shift in flood regimes, characterized by increased flood magnitude, expanded inundation extent, and prolonged periods of water persistence. These changes have altered established patterns of mobility, with temporary displacement increasingly evolving into longer-term migration and, in some cases, permanent relocation among pastoralist and sedentary populations. Migration occurs across multiple spatial scales, including within states, between states, and across national boundaries, resulting in the abandonment of some flood-prone settlements. The study also develops a spatio-temporal socio-hydrological framework that conceptualizes flood adaptation as a dynamic process operating across interconnected household, community, regional, and national scales over time. The framework advances understanding of how hydrological change, migration, governance, and social transformation shape adaptation pathways in the Sudd and other climate-sensitive wetland systems. These findings demonstrate that strengthening flood resilience requires adaptation strategies that integrate hydrological change with local knowledge, mobility, and social institutions. By providing rare empirical evidence from one of the world’s least-studied and most inaccessible wetland systems, this study advances understanding of human adaptation to flood risk and offers context-specific insights for resilience planning in the Sudd and other climate-vulnerable wetlands.