Understanding temporal variability in groundwater levels is essential for water resources management. In sub-Saharan Africa, groundwater level dynamics are poorly constrained due to limited long-term observations. Here, we present the first published analysis of temporal variability in groundwater levels at the national scale in sub-Saharan Africa, using 12 multidecadal (ca. 1980s to present) groundwater level hydrographs in Burkina Faso. For each hydrograph, we developed lumped parameter models which achieved acceptable calibrations (NSE = 0.5-0.99). For eight sites not showing significant (p < 0.001) long-term groundwater level declines, we reconstructed groundwater levels to 1902, over 50 years before the earliest observations in the tropics. We standardized and clustered the eight reconstructed hydrographs to compare responses across the sites. Overall, the 12 hydrographs were categorized into three groups, which are dominated by (1) long-term declines (four sites), (2) short-term intra-annual variability (three sites), and (3) long-term multidecadal variability (five sites). We postulate that group 1 is controlled by anthropogenic influences (land use change and abstraction). Correlation of modeled water table depth and groundwater response times with hydrograph autocorrelation suggests that hydrogeological properties and structure control differences between groups 2 and 3. Group 3 shows a small recovery in groundwater levels following the 1970/1980s drought. Differences in intra-annual to multidecadal variability in groundwater levels have implications for water management and highlight the value of long-term monitoring. Reconstructions contextualize current groundwater status, forecasts, and projections. The approach developed is generic and applicable where long-term groundwater level data exist.

Granting safe water access worldwide is a major objective of the Sustainable Development Goals. Water access is a manifold concept that encompasses collection time, distance from the household, water quality, affordability, and reliability of water sources, among other factors. GIS-based methods can be particularly useful in improving water access estimates, particularly in rural areas of developing countries. Based on an extensive water point database (n = 770), this paper explores the main challenges involved in mapping water access in two rural communes of Burkina Faso. Water access is estimated in terms of coverage per surface area. Coverage is filtered into four distinct categories of improved water sources, namely existing infrastructures, operational infrastructures, permanent infrastructures, and permanent infrastructures that provide safe water. The outcomes suggest that the study area is better endowed with water access than rural Burkina Faso and the remainder of the African continent, although there are important questions regarding groundwater quality. The outcomes highlight the conceptual differences between coverage and access, as well as some of the practical difficulties involved in estimating water access beyond standard ratios. The shortcomings include the absence of continuous monitoring of infrastructure functionality and water quality, as well as water affordability, among others. Enhancing national borehole databases with items aligned with the United Nations’ definition of water access is recommended.

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This study aims to characterize water table fluctuations and estimate groundwater recharge in the Tougou catchment located in the Sahel zone of Burkina Faso. Water table fluctuation and groundwater budget approaches are developed on an experimental site equipped with observation wells. The trends of water fluctuations in the different layers of the weathering profile are similar. There is a time-lag response of groundwater recharge to the daily precipitation occurrences. The interaction between the upper (clayey alteration) and lower (transition zone-fractured schist complex) parts of the weathering profile shows that generally the hydraulic head in the upper part is higher than that of the lower part due to difference in drainage porosity. The latter varies at the catchment scale between 0.006 and 0.009 and is inversely proportional to the saturated thickness of the clayey alteration layer. The groundwater recharge is annually estimated between 36 and 49 mm, which correspond to 6% and 9% of mean annual rainfall in the catchment. Annual evapotranspiration was estimated to be about 223 to 443 mm.