- Posted December 11, 2013 by
This iReport is part of an assignment:
Fresh Water below Sea water
A recent report in Nature estimates the amount of fresh groundwater around the world at about 120,000 cubic miles — that's 100 times more than all the groundwater that has been pumped up from wells since the 1900s. The reserves are scattered across coastal regions around the world.
Researchers drilled down at various spots and used modeling techniques to calculate how much water there is altogether. The water isn't immediately drinkable, but it's much less salty than seawater and therefore cheaper to desalinate.
The study's lead author, Vincent Post of the National Centre for Groundwater Research and Training in Australia, says scientists knew such freshwater reserves existed but thought they formed only under rare conditions, according to ScienceDaily.
"Our research shows that fresh and brackish aquifers below the seabed are actually quite a common phenomenon," Post tells the science news site. He adds, "Knowing about these reserves is great news because this volume of water could sustain some regions for decades."
Two-thirds of the world's population will be living under water stress conditions by 2025, according to estimates by the U.N. Food and Agriculture Organization. In particular, coastal regions of the U.S., South America, the southern parts of Africa, Europe and Australia could see their water supply drop by 20 percent or more by 2050, according to the United Nations Environmental Program.
This isn't the first time scientists have found fresh groundwater buried in the seafloor, but the study is the first global survey of all the known undersea reserves, says Mark Person, professor of hydrology at the New Mexico Institute of Mining and Technology. He says scientists have made such discoveries around the world — including in coastal regions off Massachusetts, New Jersey, Florida, Indonesia and Tanzania.
"There's just been an explosion of interest in documenting all these instances of freshwater," says Person, one of the study's authors.
So how did all this water get there. The depth of these reserves ranges from 650 to 3 miles. Person points out oil companies have to drill much deeper than that to find oil, so their instruments are not turned on at the level of these freshwater reserves.
Post tells ScienceDaily that there are two ways to get to the water: "Build a platform out at sea and drill into the seabed, or drill from the mainland or islands close to the aquifers."
That's not likely to come cheap.