Conclusions
In this work, we introduced a mixed-method approach combining top-down biophysical suitability with bottom-up participatory research to approach large-scale siting of sand dams. While the introduced analytical framework can be used as a general approach to any integrated, large-scale water harvesting siting, the application to sand dams in drylands Angola helped revealing the presence of existing sand dams, which were not reported in previous scientific literature. The existing sand dams well match the potential site identified with the biophysical assessment, confirming the validity of the proposed approach. Overall, the approach has proved to successfully guide the quick identification of 16 potential sites matching the socio-economic requirements investigated during the participatory phase and validated with the local population. However, challenges do exist. The participatory approach should be central, requiring a careful knowledge integration and constant engagement of local people, which is key for ensuring sustainability beyond the siting phase and the project timeframe. Being this research embedded in a cooperation and development project, a follow-up of the case study could monitor and report on the actual functioning and beneficial use of the sand dams to be built in the selected sites, complementing the scarce literature on the complete life-cycle of sand dams implementations, especially relevant for data-scarce regions like dryland Angola.