Mapping groundwater recharge in Africa from ground observations and implications for water security

Abstract Groundwater forms the basis of water supplies across much Africa and its development is rising as demand for secure increases. Recharge rates are a key component assessing groundwater potential, but have not been mapped Africa, other than from global models. Here we quantify long-term average (LTA) distributed recharge period 1970–2019 134 ground-based estimates upscaled statistically. Natural diffuse local focussed recharge, where this mechanism widespread, included discrete leakage large rivers, lakes or irrigation excluded. We find that measurable LTA found in most environments with decadal depths arid semi-arid areas 60 mm (30–140 mm) 200 (90–430 respectively. A linear mixed model shows at scale African continent only rainfall related to recharge—the inclusion climate terrestrial factors do improve model. Kriging methods indicate spatial dependency 900 km suggesting important scales. estimate 15 000 3 (4900–45 ), approximately 2% estimated storage continent, characterised by stark variability between high-storage/low-recharge sedimentary aquifers North low-storage/high-recharge weathered crystalline-rock tropical Africa. security greatly enhanced distribution, many countries low possess substantial storage, whereas experience high, regular recharge. The dataset provides first, approximation renewability can be used refine validate continental hydrological models while also providing baseline against future change.