Mapping the Risk Posed to Groundwater-Dependent Ecosystems by Uncontrolled Access to Photovoltaic Water Pumping in Sub-Saharan Africa

Photovoltaic-powered groundwater pumping offers a transformative solution for water services in underserved areas. However, without proper regulation, this technology could overexploit groundwater resources, threatening the groundwater-dependent ecosystems that rely on them. Often overlooked in development planning and water allocation, groundwater-dependent ecosystems hold significant socioeconomic and environmental importance. This study maps the risk to groundwater-dependent ecosystems in Sub-Saharan Africa from uncontrolled access to photovoltaic groundwater pumping using the analytic hierarchy process. It evaluates risks using data on irradiance, groundwater, and population, and novel data on groundwater-dependent ecosystems. Two scenarios are analyzed to improve the robustness of the findings. The results show that 92 percent of Sub-Saharan Africa’s groundwater-dependent ecosystems risk overexploitation if photovoltaic water pumping is implemented without proper controls. Groundwater-dependent ecosystems in Southern and Eastern Africa, particularly in South Africa and Namibia, are found to face higher risks, while those in Gabon, the Republic of Congo, and southern Nigeria tend to be less at risk. Comparing these results with populations relying on unimproved water sources highlights regions like southern Nigeria and South Sudan, which could be prioritized for potential photovoltaic water pumping system investments due to their higher groundwater development needs and lower risks to groundwater-dependent ecosystems. Conversely, areas like Namibia and South Africa, with lower groundwater development needs but higher risks to groundwater-dependent ecosystems, should require targeted investments and very close groundwater monitoring. These findings can help policy makers in targeting investments in photovoltaic water pumping systems and identifying regions needing careful monitoring to ensure sustainable groundwater use and minimal impact on groundwater-dependent ecosystems.