In a paper published today in the Proceedings of the National Academy of Sciences, scientists have found that groundwater in some parts of the world is more likely to be underground than underground.
The research was carried out by Dr Mark L. Dittrich of the University of Washington and colleagues from the University and the California Institute of Technology, who found that the average volume of groundwater found in some countries is about 2.5 kilometres (1.4 miles) deep, while in others, it is less than half that amount.
“Our findings show that there are regions in the world where groundwater is more underground than in other regions, and that these differences are largely due to differences in the geology of the region,” the researchers write.
“For example, in countries such as the US, Germany, Canada and the UK, the groundwater depth is generally smaller than the surface.
In countries such of India, Pakistan and Indonesia, groundwater depth varies considerably.
In the case of Indonesia, the average groundwater depth of about 7 kilometres (4 miles).
The researchers also compared the average volumes of groundwater in different regions of the globe.
They found that most of the groundwater found on Earth was underground in North America, Europe and Asia, while the remaining regions contained groundwater in the mid- and high-mixed basins, or underground water tanks.
However, in many countries, groundwater is not evenly distributed across the land.
In many countries that have relatively flat land, the vast majority of groundwater is located in the top two meters (5 feet) of the ground.
For example in the United States, in the south, groundwater wells are typically found below surface water tables, while groundwater wells below surface are typically located above ground water tables.
Other countries are also finding that groundwater is increasingly underground in many regions.
For example, China, India, Brazil, Russia and South Korea have all been finding that their groundwater is underground in some areas.
Dr Dittrewich and his colleagues suggest that groundwater can act as a sponge.
He said: “Gravity can make the soil on the surface, and groundwater can move and distribute the soil into deeper and deeper areas.”
And the researchers found that if a country were to remove all the land that it was building on, the amount of groundwater that could be contained underground would decrease by a factor of 10. “
Gravel can move across a much larger surface than water can move,” he said.
And the researchers found that if a country were to remove all the land that it was building on, the amount of groundwater that could be contained underground would decrease by a factor of 10.
This means that even if the population of a country increased to a million people, the water they would need to store underground would be much smaller than what it is today.
It would be possible to build the world’s largest underground water storage complex, Dr Dittrawich said.
“But this is a big, big question.”
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