. 24/7 Space News .
Tapping fresh water under the ocean has consequences
by Staff Writers
Newark DE (SPX) May 07, 2019

illustration only

The last place most people would expect to find fresh groundwater is tens to hundreds of kilometers offshore in the ocean. Yet not only is that exactly where freshwater can be found, in the ground of the continental shelf beneath the ocean, but simulations have shown that it could be a common occurrence across a range of geologic systems.

These offshore groundwater resources could be exploited for uses such as drinking, agriculture and oil recovery, but new research from the University of Delaware's Holly Michael and Xuan Yu, who worked as a postdoctoral researcher at UD, suggests that tapping into those resources could lead to adverse onshore impacts.

The research was published in Geophysical Research Letters and is part of Michael's National Science Foundation CAREER Award.

Through simulations and computer modeling, the research explores how using offshore freshwater resources could threaten onshore aquifer systems, lead to diminished onshore groundwater availability and cause widespread land subsidence.

Coastal communities may consider using these offshore groundwater resources as populations increase and the limited freshwater resources are degraded by overuse and pollution, but a more immediate use of the offshore fresh and brackish groundwater is to enhance oil recovery.

Water is used in oil drilling by what is known as waterflooding, in which water is injected to support oil-reservoir pressure and to move oil into producing wells.

Salinity is a major factor controlling the amount of oil that can be recovered from a zone that has been waterflooded and a technique known as low-salinity waterflooding - using freshwater to waterflood these offshore oil wells instead of the readily available saltwater - has been shown to increase oil recovery by 14 percent on average.

One of the problems with using these offshore freshwater resources for low-salinity waterflooding in offshore oil production is that the offshore freshwater sources are connected to the freshwater sources on land. That onshore groundwater is filling in the pores of sediment and helping to hold up the surface on which coastal towns are built.

"If you build a city on land surface, you add weight, and you add pressure to the aquifer - the sediments and water underground. When a building is built, geotechnical tests are done to make sure this added pressure will not cause the land surface to sink," said Michael, the Unidel Fraser Russell Career Development Chair for the Environment and an associate professor in the Department of Geological Sciences. "The pressure of the water in those pores creates an upward force and contributes to rigidity in the system."

If that water is pumped out for low-salinity waterflooding, the pressure is changed underground and it can reduce the ability of the aquifer to support the weight of the city.

Subsidence has been seen in megacities with the constant extraction of water below ground, with examples being Venice, Italy and Tokyo, Japan. Pumping offshore freshwater resources for low-salinity waterflooding could have this same affect.

"This affect can hardly be simulated when a simple geologic structure is assumed," said Yu, who is now an associate professor in the school of civil engineering at Sun Yat-sen University in China. "Our model results suggested that the magnitude of subsidence in homogenous and layered geology is much smaller than the heterogeneous cases."

In addition to land subsidence, another possible consequence of oil companies tapping into these offshore freshwater resources is that the freshwater aquifers on-land could experience increased salinization, again through the connection between the offshore freshwater and the freshwater on-land.

The reduction in onshore fresh groundwater from low-salinity waterflooding can also have an impact on coastal population centers, especially in locations where oil reservoirs lie offshore of highly populated cities, such as those in Southeast Asia and the Mediterranean Basin.

Michael said that because scientists are just now realizing that this freshwater exists offshore, the purpose of the paper was to demonstrate the potential for offshore pumping to have devastating effects on coastal communities, before the practice becomes widespread.

"What we are saying in this paper is, 'Wait a minute, the cities on shore might have no idea that offshore activities could potentially affect their resources,'" said Michael.

"Offshore pumping of fresh groundwater could cause subsidence on land, which can cause a range of problems, especially in populated areas. And then there are the fresh, groundwater resources that are being used up that could potentially be a resource for humans in the future."

Related Links
University of Delaware
Water News - Science, Technology and Politics

Thanks for being there;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.
SpaceDaily Monthly Supporter
$5+ Billed Monthly

paypal only
SpaceDaily Contributor
$5 Billed Once

credit card or paypal

Egypt's rebounding tourism threatens Red Sea corals
Hurghada, Egypt (AFP) April 30, 2019
In serene turquoise waters off Egypt's Red Sea coast, scuba divers ease among delicate pink jellyfish and admire coral - yet a rebounding tourism sector threatens the fragile marine ecosystem. The Red Sea is a top scuba diving destination, but Egypt's tourism sector was buffeted by a wave of security shocks through much of this decade, before a partial recovery since 2017. A diving instructor in the town of Hurghada, a top resort, warned that the rebound brought dangers for the corals. Be ... read more

Comment using your Disqus, Facebook, Google or Twitter login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle

Photobioreactor: oxygen and a source of nutrition for astronauts

International Space Station suffers partial power loss, no danger to crew

New concept for novel fire extinguisher in space

Music for space

SpaceX Dragon cargo launch no earlier than May 3

SpaceX, NASA tight-lipped on cause of crew capsule incident

Controlling instabilities gives closer look at chemistry from hypersonic vehicles

NASA accelerates pace of Core Stage production with new tool

ESA to Lose Member State Support if ExoMars Launch Postponed - Director-General

InSight lander captures audio of first likely 'quake' on Mars

All-woman engineering team heads to NASA Mars competition

A small step for China: Mars base for teens opens in desert

China's tracking ship Yuanwang-2 starts new mission after retirement

China to build moon station in 'about 10 years'

China to enhance international space cooperation

China opens Chang'e-6 for international payloads, asteroids next

Iridium Awarded Gateway Support and Maintenance Contract by the U.S. Department of Defense

The Third Installment of the SpaceFund Reality (SFR) rating

ESA opening up to new ideas

Canadian Space Agency Sees Science Cooperation With Russia as Area of Growth

Squid skin inspires creation of next-generation space blanket

Ice-proof coating for big structures relies on a 'beautiful demonstration of mechanics'

Coffee machine helped physicists to make ion traps more efficient

New polymer films conduct heat instead of trapping it

Rapid destruction of Earth-like atmospheres by young stars

Slime mold memorizes foreign substances by absorbing them

Necrophagy: A means of survival in the Dead Sea

Oil-eating bacteria found at the bottom of the ocean

Next-Generation NASA Instrument Advanced to Study the Atmospheres of Uranus and Neptune

Public Invited to Help Name Solar System's Largest Unnamed World

Europa Clipper High-Gain Antenna Undergoes Testing

Scientists to Conduct Largest-Ever Hubble Survey of the Kuiper Belt

The content herein, unless otherwise known to be public domain, are Copyright 1995-2024 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. General Data Protection Regulation (GDPR) Statement Our advertisers use various cookies and the like to deliver the best ad banner available at one time. All network advertising suppliers have GDPR policies (Legitimate Interest) that conform with EU regulations for data collection. By using our websites you consent to cookie based advertising. If you do not agree with this then you must stop using the websites from May 25, 2018. Privacy Statement. Additional information can be found here at About Us.