countries in this region could supply 130 liters of drinking water per person per day from groundwater aquifers, without exceeding 25% of the long-term average recharge, with most using less than 10% (WaterAid, 2022).

In places experiencing groundwater stress, access to shallow groundwater aquifers could enable farmers to irrigate their fields for up to two drought years. Nonetheless, the extraction rate is only 1%–25% of the existing renewable groundwater resources (WaterAid, 2022). Therefore, unlike in India, where groundwater irrigation led to a significant decline in resources, tapping into groundwater could be a sustainable choice for SSA, provided that measures are taken early in the process to prevent its over-exploitation.

Although water scarcity is a growing issue in SSA, our analysis shows a large, mostly untapped abundance of groundwater resources. The main challenge lies in a lack of knowledge and initiative to utilize these groundwater resources, as well as a policy framework for preventing over-extraction. The cost of accessing groundwater may also present a barrier for Africans, given the region’s average GDP per capita of 1700 USD.

To address this issue, our analysis focuses on local shallow groundwater aquifers, which are abundant and relatively easier to access, due to their proximity to the earth’s surface. SSA has the highest share of local shallow aquifers (out of its total endowment) globally, comprising 60.77%, closely followed by South Asia at 54.54%.

# **2.1 Groundwater Aquifers**

Groundwater is an integral part of meeting the global demand for water. Estimates suggest nearly 50% of drinking, 40% of irrigation, and over 30% of industrial global water demands are currently sourced from groundwater (UNESCO and UN-Water, 2022); (Margat & van der Gun, 2013).

Aquifers, or groundwater aquifers, store precipitation that seeps through the soil. The aquifer itself is the rock or sediment that collects and holds groundwater in empty spaces underground. Some of these aquifers are easy to access, whereas others lie under rocks that are harder to cut through.

Following the definitions of the Water Global Practice at the World Bank, we broadly have four aquifer types that we use in our analysis. These categories are based on various geological and hydrogeological characteristics of aquifers. The four categories of aquifers (or aquifer systems) are complex aquifers, karstic aquifers, major alluvial aquifers, and shallow/local aquifers.

A complex aquifer consists of several interconnected layers of permeable and impermeable materials. These types of aquifers can have a high storage capacity and can provide a reliable source of water for agriculture. However, the complexity of the aquifer can make efficiently managing and extracting water difficult. A karstic aquifer is formed in soluble rock such as limestone or dolomite and can have many cracks, fissures, and caves that allow the rapid movement of water. These types of aquifers can be suitable for agriculture because they can provide a steady supply of water. However, the rapid movement of water through the aquifer can also lead to contamination from pollutants. An alluvial aquifer 4