Deep Groundwater Might Be a Sustainable Solution to the Water Crisis.
Groundwater supplies 50% of the world’s drinking water and 25% of the water used globally in agriculture. Locally, especially in arid regions of Africa, the Middle East, and elsewhere, these figures can be far higher, making groundwater a critical resource supporting the lives and livelihoods of hundreds of millions of people.
Groundwater is typically sourced from relatively shallow depths belowground, primarily because these sources have historically been easier to locate and access. (The meaning of “shallow” groundwater can vary regionally; here we consider it to mean water within about 400 meters of the ground surface.) But two key factors are contributing to these conventional groundwater resources becoming increasingly unreliable.
Below the ground, other sources of water—what we call deep aquifers, at depths between 400 and a few thousand meters—remain largely unexplored and untapped. Despite being less widely known, such deep aquifers can hold significant reserves of water, as they do beneath parts of Africa, Arabia, Australia, and the Americas.
