Kenya (Dyer & Shapiro, 2023). Generalizing this finding to the context of groundwater irrigation pumps, the study suggests that although high costs may dissuade farmers from using groundwater irrigation, interventions providing information about the costs and benefits of these technologies could enhance productivity through increased adoption. It must be noted, however, that the costs substantially increase beyond 8 m groundwater depth (Sekhri, 2014). Research on groundwater costs across 10 SSA countries indicates the total cost for a pump with a depth of 40-100 meters ranges between USD 6,000 and USD 23,200, on average (Xenarios & Pavelic, 2013). With the expansion of input markets in SSA, these costs could have been substantially reduced over the past decade, and that is why we present some estimates on gains from groundwater access up to 50 m deep in our Appendix.

Another constraint to groundwater access stems from the lack of access to the electricity grid. A proposed solution that reduces the variable cost of electricity is the provision of photovoltaic- (or solar-) powered drip irrigation pumps. Although these pumps may help reduce the variable cost, regulation of their use is crucial to prevent over-exploitation of groundwater resources. Finally, subsidizing the fixed costs of groundwater irrigation technologies (while regulating sustainable use) is another avenue of inquiry for policymakers and future research.

# **9 Conclusions**

Rural poverty in Sub-Saharan Africa is closely linked to the lack of substantial growth in agricultural productivity. Enhancing agriculture productivity could stimulate wider economic growth, promote inclusive development, structural transformation, and poverty reduction. Agricultural productivity growth worldwide has been driven by investments in high return rural public goods, improved policies, and institutions. However, Sub-Saharan Africa significantly under-invests in these areas. This paper explores one untapped growth source—the sustainable use of groundwater for irrigation. We measure potential agricultural production gains in Sub-Saharan Africa through groundwater irrigation.

To do so, we construct a novel dataset by merging gridded agricultural data with local shallow aquifer data and their corresponding details. We then use our dataset to simulate the gains in production that can be achieved if we use groundwater irrigation to fill in the existing crop water deficits that persist in the region’s rain-fed croplands. While running our simulations, we impose conditions during our simulations to only compute gains in regions with sufficient renewable groundwater. We also limit our analysis to aquifers suitable for small-scale irrigation and accessible at low depths to ensure cost effectiveness.

Our findings show the median production gains range from 27.97% to 129.42%, depending on the crop type and the method used to predict crop yield gains. The most pronounced gains are for maize and rice crops. Our results remain consistent, even with changes in the method and dataset used to measure groundwater availability. Most importantly, our analysis enables policymakers to delineate regions likely to experience agricul18