Vast freshwater reserves discovered under ocean floor

Vast offshore freshwater reserves found by scientists Massive reserves of fresh water have been discovered off the coasts of Australia, China and North America, and could be used to reduce the threat of global water shortages. The findings are part of a new study published in the journal Nature by Australian researchers from Flinders University. They estimate these reserves contain nearly half a million cubic kilometers of fresh water beneath the seabed on continental shelves.
“The volume of this water resource is a hundred times greater than the amount we’ve extracted from the Earth’s sub-surface in the past century since 1900,” says lead author Dr. Vincent Post at Flinders University.
Groundwater scientists have known about such reserves but assumed they occurred only under rare and special circumstances. Post said this water could be used by coastal countries to sustain themselves for decades and reduce the impact of drought and water shortage, an imminent threat.
Post explains that these aquifers were filled with fresh water thousands of years ago, when the coastline was much lower than it is today. When it rained, the water seeped through the ground. As the ice caps melted, the sea level rose and these regions are now underwater.
These reserves are most likely protected by layers of clay and sediment, which prevented the fresh water from mixing with salt water.
“There are two ways to access this water -- build a platform out at sea and drill into the seabed, or drill from the mainland or islands close to the aquifers,” said Post.
Because offshore drilling is expensive, Post suggests the cost and sustainability of tapping these underwater reserves should be compared to the costs involved in building dams and desalination plants. And while it may seem enticing for nations to try and use this water, they have to be cautious of not contaminating the fresh water.
“We should use them carefully -- once gone, they won’t be replenished until the sea level drops again, which is not likely to happen for a very long time,” warned Post.
Source: UPI