Groundwater: key to Africa's agri potential

Groundwater is an essential tool in agricultural production. However, it remains an untapped resource in Africa, as this recently published report shows.

Groundwater, which accounts for approximately 99% of all liquid fresh water on earth and is distributed over the entire globe, albeit unequally, has the potential to provide societies with tremendous social, economic, and environmental benefits, including climate change adaptation.

It already provides half of the volume of water withdrawn for domestic use by the world’s population, and around 25% of all water withdrawn for irrigation, serving 38% of the world’s irrigated land. Yet despite its enormous importance, this natural resource is often poorly understood, and consequently undervalued, mismanaged, and even abused.

In the context of growing water scarcity in many parts of the world, the vast potential of groundwater and the need to manage it carefully can no longer be overlooked.

Groundwater storage depletion occurs when discharge exceeds recharge. Although climate variability and climate change can play a role in this, most cases of long-term groundwater storage depletion result from intensive abstraction.

The rate of global aggregated groundwater storage depletion is considerable: from the beginning of the present century, estimates are between 100km³/year and 200km³/ year (accounting for roughly 15% to 25% of total groundwater withdrawals). Groundwater pollution reduces the suitability of abstracted groundwater for drinking purposes and affects groundwater-dependent ecosystems. There are many sources of anthropogenic groundwater pollution: most of them are located at or near the land surface, but several other sources inject pollutants into the subsurface at greater depths below the surface.