A decade of satellite gravimetry data across three arid sub-Saharan basins tells a consistent story: extraction has outpaced natural recharge in every basin we examined, and the gap is widening rather than stabilising.
We combined satellite-derived groundwater storage anomalies with borehole yield records and abstraction licensing data to estimate basin-level water balances over a ten-year window. In each basin, cumulative extraction exceeded modelled recharge, with the steepest deficits appearing where irrigation abstraction and urban supply drilling overlap geographically.
Abstraction licensing in these basins is largely allocated on a per-application basis without reference to a basin-wide balance, which means no single authority is positioned to see the cumulative draw-down until it shows up as falling yields at existing boreholes.
Toward sustainable abstraction limits
We propose basin-specific abstraction ceilings derived directly from the gravimetry-based recharge estimates, allocated across sectors rather than approved license-by-license. This requires linking licensing authorities to a shared monitoring dataset, which in most of the basins studied does not currently exist in an operational form.
Absent that link, the most exposed basins are on a trajectory toward yield failure at existing boreholes within the coming decade — a cost that falls hardest on the smallholder and pastoralist users least able to drill deeper in response.