Three decades of pastoralist settlement dynamics in the Ethiopian Omo Delta based on remote sensing data

Abstract River deltas provide important livelihoods to local populations, but at the same time are under increasing anthropogenic pressure. The opening of the Gibe III dam on the Omo River in Ethiopia in 2016 attracted international attention due to the importance of the free-flowing River for pastoralist communities in the Omo Delta. Sustainable river basin management requires spatially explicit, long-term information about human settlements to mitigate negative impacts on people's livelihoods. Based on remote sensing time-series, and supplemented with ground-truthing, we mapped settlement-dynamics of the pastoralist Dasanech tribe. The inhabited area more than doubled from 1992 to 2009. From 2009 to 2019, settlements became more permanent and concentrated in the North of the Delta. Our results indicate that the Omo Delta has overall gained in importance as a livelihood area, but that the livelihoods of the traditionally nomadic people are shifting in the context of increasing investment in infrastructure. Management of future river flow at dams should consider the location and the trajectory of change in downstream settlements.