2.2 Knowledge integration
To overcome these problems, instead of aiming for the exact location of such a complex technology, we first performed a classic top-down siting with few essential biophysical criteria to narrow down the suitable river sections with the basic biophysical requirements for sand dams construction and then we used this preliminary points to guide the local participatory research, which completes the overall social-ecological suitability. In this, we diverge from conventional top-down large-scale siting which seldom, if ever, include a local participatory process to “validate” the top-down methodology and do not fully integrate local perception or indigenous knowledge (Ziadat et al., 2012). With our methodology (see Figure 1), we build on qualitative GIS to map communities’ needs, constraints and use their knowledge of local hydrology to integrate out top-down biophysical analysis with missing local social and hydrological information which constitute the “useful knowledge” (Robinson et al., 2016), which is essential to select the sites with the best overall suitability for sand dams construction (Forrester et al., 2015). Particularly relevant for the knowledge integration phase was the field inspection. After the focus group discussions, we showed the map with the biophysically suitable points to a group of key informants (usually the soba, the local administrator, and/or other distinguished community members), asking whether the points were located in mulola (i.e. local term for ephemeral rivers) with high rocky river banks and if they had good sand. Also, we asked which are the main mulola with cacimbas (i.e. scoop holes), which is a good indicator of potential for sand dams (Beswetherick et al., 2018). Apart from refining the selection of biophysical points in this way, we also asked directly to the community whether they had ideas or suggestions for selecting a site. Although this approach is subjected to individuals’ own interest and convenience (for example recommending a river section near their settlements or kimbos), it was a useful exercise to allow the community for a more active engagement, build trust and reciprocity and let the community show their priorities and preferences without constraints.