Where is the world’s hidden groundwater?

We now know where to find all of the world’s groundwater. A new study has measured the groundwater in the upper 2 kilometres of the Earth’s landmass, and found that less than 6% of its volume is renewable within a human lifetime.

This presents serious issues for water scarcity around the world. With demand for water increasing and climate change reducing supply, it has become increasingly important to understand groundwater levels. The study’s lead author, Tom Gleeson, said: “We’re using our groundwater resources too fast – faster than they’re being renewed.

Multiple datasets were used to create the map below, showing the distribution of the world’s nearly 23 million cubic kilometres of groundwater.

Source: University of Victoria

The study differentiates between old and modern groundwater – modern groundwater is closer to the Earth’s surface and faster-moving. But this makes it vulnerable to climate change and contamination. Old groundwater lies deeper, and is commonly used for agriculture and industry purposes.

Most modern groundwater can be found in tropical and mountainous regions, according to the map. Some of the largest deposits are in the Democratic Republic of Congo, Indonesia and along the Rockies in the US.

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Author: Joe Myers is a Digital Content Producer at Formative Content.

Image: Castaic Lake reservoir is viewed from its previous water level before the water receded, in Castaic, California April 15, 2015. REUTERS/Lucy Nicholson