Picture Station-SI 2015; 14(3): 569

Map of World's Groundwater
A new map of Earth's groundwater supply shows where on the planet water is locked up and "hidden" underground. The map - the first of its kind - provides a visual representation of Earth's groundwater resources and estimates that the planet's total groundwater supply stands at approximately 5.5 million cubic miles (about 23 million cubic kilometers). The scientists obtained measurements of tritium, a radioactive version of the hydrogen molecule, and water flow models that used properties of water and its interaction with different types of rock to estimate how much groundwater the world possesses, where it is distributed and the age of the water in these underground reservoirs. The maps that were developed from the study show that most modern groundwater is found in tropical and mountainous regions. Some of the largest reservoirs can be found in the Amazon basin, the Congo, Indonesia, the Rocky Mountain regions of North and Central America, and the Western Cordillera of South America. By Elizabeth Newbern. Originally from Live Science.