When you think of a country’s water resources, you may not realise that there are many kinds. Some is surface water, such as dams and rivers. There’s also groundwater, which includes aquifers and, in some places, artificial recharge schemes that transfer surface water below-ground to store it.

Groundwater reserves in Africa are estimated to be 20 times larger than the water stored in lakes and reservoirs above ground. These are the freshwater stores that flow in rocks and sediment beneath the Earth’s surface.

All-natural water found in the earth’s subsurface is called groundwater. When we look hard enough, we can find groundwater almost everywhere. But that does not mean that we can start pumping groundwater at any location. In many places, the amount of groundwater available (yield) is so little, or the water is so deep, that it is not financially viable to pump it. Another problem might be the quality of the water.

About 30% of the water on the planet is under the ground, out of sight and not easily accessed. Little is known about this “invisible” groundwater.