Riverine communities in the Central Amazon are largely subject to erosion and sedimentation risk

Sedimentary processes cause large changes in riverscapes and alter river banks and margins, leading to major hazards for riverine communities. However, regional mapping of the resulting risk remains scarce, especially in remote Amazon regions. Here, we combine environmental observations with regional socioeconomic information to map erosion and sedimentation risk for Central Amazon river-floodplain communities. We combine long-term trends of open water changes (sedimentation/erosion hazard) with exposure (population size) and social vulnerability (socio-economic indices) to estimate risk at each community. Half of the region’s population, located either in uplands or floodplains, is subject to an unstable riverscape, with 18.5% of the communities affected by sedimentation processes and 26% by erosion. We identified four communities (out of 51 assessed) at very high risk, and seven at high-to-moderate risk. We highlight the need to include sedimentary processes in disaster management strategies in the changing river landscapes of the Amazon. Half of the population of Central Amazon river-floodplain communities are subject to an unstable riverscape, according to an assessment of compound risk which integrates environmental hazard observations with regional socio-economic information.