An Automated Method to Assess the Suitability of Existing Boreholes for Solar-Based Pumping Systems: An Application to Southern Madagascar

Groundwater provides a strategic resource in the face of uncertain climate conditions in arid and semi-arid regions. Solar-based groundwater pumping is quickly gaining ground across rural sub-Saharan Africa, promoted by national and international organizations as the new technology of choice for water supply and irrigation. A crucial question in large-scale developments is whether pre-existing boreholes can be fitted with solar pumps. Based on data from southern Madagascar, this paper provides an automated method to deal with this. Our approach relies on a combination of hydrogeological criteria, including well screen depth, drawdown in relation to the static water column, and pumping efficiency. The results show that 60% of the existing boreholes in the study region are potentially suitable for the installation of solar pumps. Out of these, 54% would be able to supply water to large rural communities (>1000 people), whereas the remaining 46% present the potential to provide water to medium communities (500 to 1000 people). There are, however, concerns as to whether the information contained in the dataset is fully representative of current borehole conditions. Furthermore, the potential for installation of solar-based supplies must be placed in the context of the available resources and local capacities in order to ensure future sustainability.