Wednesday, July 3, 2019

Scientists map huge undersea fresh-water aquifer off U.S. Northeast

As they say, "It's always  in the last place you look".
First up, Science Daily:
Date:
June 21, 2019
Source:
Earth Institute at Columbia University
Summary:
In a new survey of the sub-seafloor off the U.S. Northeast coast, scientists have made a surprising discovery: a gigantic aquifer of relatively fresh water trapped in porous sediments lying below the salty ocean. It appears to be the largest such formation yet found in the world.
In a new survey of the sub-seafloor off the U.S. Northeast coast, scientists have made a surprising discovery: a gigantic aquifer of relatively fresh water trapped in porous sediments lying below the salty ocean. It appears to be the largest such formation yet found in the world. The aquifer stretches from the shore at least from Massachusetts to New Jersey, extending more or less continuously out about 50 miles to the edge of the continental shelf. If found on the surface, it would create a lake covering some 15,000 square miles. The study suggests that such aquifers probably lie off many other coasts worldwide, and could provide desperately needed water for arid areas that are now in danger of running out....MORE

And speaking of arid areas, from the American Geophysical Union's EOS:

Ancient Water Underlies Arid Egypt 
A hidden trove of groundwater is left over from the last ice age.
Aside from the Nile River’s green corridor, much of northeastern Africa is desert. But the arid landscape hides a secret: Vast quantities of groundwater fill an underground aquifer that spans four countries.

A new study using chloride isotopes to date the groundwater under Egypt’s Eastern Desert has found that the water in smaller, shallower aquifers is refilled by the larger, deeper aquifer, where vast quantities of groundwater date to the last ice age.

Most Egyptians live along the Nile and get their drinking and irrigation water from the river. Currently, just 7% of the country’s water usage is supplied by groundwater, but that number is expected to rise, said Mahmoud Sherif, a hydrogeochemist at the University of Delaware and lead author of the new study, published in Earth and Planetary Science Letters. “In the future, as Egypt’s population and agriculture expand, groundwater will become a more important resource.”
The research team set out to date the age of the groundwater under the Eastern Desert to determine the aquifers’ responses to climate conditions and the recharge rates of shallower formations called alluvial aquifers. “These aquifers are closer to the surface and easier to access than the deeper Nubian aquifer,” Sherif told Eos.

“We expected the water in the shallow aquifers to be less than 100 years old,” Sherif said, with the clock starting when the rainwater falls from the atmosphere onto Earth. Instead, some of the water samples were more than a thousand times that age....MORE