Résumé
Weathered crystalline rock aquifer systems which underlie much of the tropics including 40% of Sub-SaharanAfrica, represent a distributed and potentially climate-resilient source of freshwater. The impacts of climatevariability, land-use change, and abstraction on these low-storage aquifer systems are not well understood,particularly in semi-arid environments. We review evidence from a multi-decadal chronicle of groundwater levelsin Ouagadougou, Burkina Faso. The chronicle reveals both seasonal responses of low amplitude (~1 m) tomonsoonal rainfall and a longer-term oscillation of greater amplitude (several metres) that can be linked to decadalvariations in precipitation characterized by the Sahelian Drought. The multi-decadal chronicle at Ouagadougoudemonstrates a strong relationship between groundwater storage and climate variability. Current research seeksto: (1) estimate the volume of groundwater storage changes by applying storage co-efficients derived fromgeophysics (MRS) and lysimetry to borehole hydrographs; (2) evaluate the impact of land-use change andabstraction on estimated groundwater storage; and (3) assess the impacts of rainfall intensity on groundwaterrecharge and abstraction on groundwater discharge that has been enabled by the recent introduction of highfrequency(hourly), automated monitoring of groundwater levels.