3.2 Socio-economic conditions for best siting of sand dams in
Namibe
The main themes related to water security emerged from the qualitative analysis of focus group discussions are the following:
1. Water scarcity: The overall water quantity available for the community is not enough for the different uses.
2. Few water points: The community has access to a limited number of water points, including larger mulola for cacimbas, wells and other non-conventional sources.
3. Difficult access: The water sources are hard to access. For example the community have to dig several or very deep cacimbas to collect water.
4. Unequal access: Families within the community are located far from the water points and have to walk for considerably longer time compared to the families living in the proximity of water points.
5. Human-animal conflict: The water points are for both human and animal water consumption, thus creating conflict between the quantity of water available to both and create potential health risk from water contamination.
6. Violent conflict: Particular conditions about the water points create conflict between members of the community, groups of the same community or between the local community and other communities (for example pastoralists from elsewhere transiting in the community).
Although the environmental conditions vary, especially from the drier southern communities in Virei compared to the wetter ones in Bibala, the prevalence and severity of these water-related problems strongly depend on the specific socio-economic conditions of each community. In fact, the natural water availability is mostly related to the presence of larger mulola able to retain water in the sandy riverbed for relatively long periods, albeit particular conditions apply to places like Nascente, which stands next to a water spring (the term “nascente” is, in fact, the Portuguese for “water spring”). The main differences in water availability between the communities are determined by the socio-economic access, which makes the better served communities (e.g. with more wells) more resilient to hydroclimatic water stress. This condition is reflected in the themes “Few water points”, “Difficult access” and “Unequal access”. In fact, apart from Munhino and Tchitemo, which are the most economically developed and best served communities with several wells along the main mulola, all the other communities score between high and very high in these three water-related problems (Table 1). Human-animal conflicts are quite common in all of the communities, while violent conflicts are particularly sever in Nascente, with the conflictual relationships with transhumant pastoralists transiting in the community and often occupying the only water point at the expanses of the local community (see table S1 in supplementary material for a more extensive description of the severity of water-related problems).
Based on the community-specific water-related problems, we identified the main conditions to account for during the siting on a sand dam. Although the characteristic change depending on the local conditions and local population needs, they can be overall summarized in:
1. Proximity to kimbos: important to plan for a location that can serve a large part of the community.
2. Proximity to non-served locations: selecting sites in places without other water sources to increase the coverage, thus promoting equal access to water.
3. Proximity to roads: To allow easy access for transporting materials mechanized vehicles and reduce the costs of construction. It is secondary in case the local community is willing to open the way by clearing the vegetation and/or self-construct the dams..
4. Proximity to strategic places: for example located in pasture areas if the purpose is to serve animals or close to arable land or community farms in case of agricultural use.
5. Proximity to transhumance routes: Where mobile pastoralism is the main characterizing conditions of local communities, planning the sand dams in areas frequently used by herders during seasonal mobilizations can help them save time when fetching water points and increase the chance of survivor for their cattle.
Ideally, these socio-economic conditions would be integrated into the quantitative multicriteria analysis to refine the selection of suitable points. However, the generic problem of data scarcity in SSA, worsened by the long and recent civil war history, together with the intrinsic nature of mobile pastoralists make these data impossible to quantify statistically and even more so at the spatial level. For example, parameters like “Proximity to kimbos” is hardly quantifiable because kimbos are temporary construction made with locally available material (mostly wood, bushes and mud) and they change place depending on pasture availability and informal clan rules managing the distribution of the land within the community. For these reasons, the abductive approach proposed in this study provides a viable way to integrate local perspective and necessities with top-down biophysical conditions for sand dams suitability.