Typology of world’s river basins regarding socio-ecological resilience to ten major water related risks

Risks to the planet's freshwater systems are currently subjected to soaring concern worldwide. We applied the coupled Social-Ecological Systems approach to study and systematize the risks due to ten major water related stressors (variability, overuse, groundwater, floods, droughts, organic pollution, salinity, eutrophication, drinking water, sanitation). We used gridded socioeconomic indicator data for the analysis of human exposure and its vulnerability (adaptive capacity) to these stressors in 540 river basin units covering the whole world. Among the stressors, lack of appropriate sanitation scored highest, followed by droughts and eutrophication. The large and densely populated Asian basins, Ganges-Brahmaputra-Meghna, Indus, and Yangtze, topped, followed with the largest African basins (the Nile, Niger, and Congo/Zaire). The other top-ten basins were Rajasthan Inner Basins, Huang, Hai, and Myanmar South Coastal Basins. The ranking changed when weighting the stressor data (on physical entities) with socioeconomic vulnerability data (on societal ones). Each included basin unit manifested a specific risk profile. For the basin units, we developed a typology using principal component and cluster analyses. This allowed us identification of the roles of vulnerability and population exposure in worldwide river basin risk framework and revealed distinctive basin clusters associable with the following characterizations: (1) too little water – high salinity – high variability – overexploited, (2) high organic pollution, eutrophic, flood prone – highly populated, (3) water abundant, (4) lacking infrastructure – low socioeconomic development. These clusters largely form a sequence as for instance there are basins that fall at the edge of (1), with many similarities already to (2), etc. The analysis provides a new perspective to comparison of world’s river basins and looking for novel learning opportunities for river basin management and risk reduction policies, especially in a multihazard-multirisk setting allowing the identification of the basin-specific risk profile and the roles of vulnerability and exposure.