The Indus Basin aquifer is the second-most overstressed water basin in the world

[Cherokee]

About one third of Earth's largest groundwater basins are being rapidly depleted by human consumption, despite having little accurate data about how much water remains in them, according to two new studies led by the University of California, Irvine (UCI), using data from NASA's Gravity Recovery and Climate Experiment (GRACE) satellites.



This means that significant segments of Earth’s population are consuming groundwater quickly without knowing when it might run out, the researchers conclude. The findings are published today in Water Resources Research.



"Available physical and chemical measurements are simply insufficient," said UCI professor and principal investigator Jay Famiglietti, who is also the senior water scientist at NASA's Jet Propulsion Laboratory in Pasadena, California. "Given how quickly we are consuming the world’s groundwater reserves, we need a coordinated global effort to determine how much is left."

The studies are the first to comprehensively characterize global groundwater losses with data from space, using readings generated by NASA’s twin GRACE satellites. GRACE measures dips and bumps in Earth’s gravity, which are affected by the mass of water. In the first paper, researchers found that 13 of the planet's 37 largest aquifers studied between 2003 and 2013 were being depleted while receiving little to no recharge.

Eight were classified as "overstressed," with nearly no natural replenishment to offset usage. Another five were found to be "extremely" or "highly" stressed, depending upon the level of replenishment in each. Those aquifers were still being depleted but had some water flowing back into them.

The most overburdened aquifers are in the world’s driest areas, where populations draw heavily on underground water. Climate change and population growth are expected to intensify the problem.



"What happens when a highly stressed aquifer is located in a region with socioeconomic or political tensions that can’t supplement declining water supplies fast enough?" asked Alexandra Richey, the lead author on both studies, who conducted the research as a UCI doctoral student. "We’re trying to raise red flags now to pinpoint where active management today could protect future lives and livelihoods."



The research team -- which included co-authors from NASA, the National Center for Atmospheric Research, National Taiwan University and UC Santa Barbara -- found that the Arabian Aquifer System, an important water source for more than 60 million people, is the most overstressed in the world.



The Indus Basin aquifer of northwestern India and Pakistan is the second-most overstressed, and the Murzuk-Djado Basin in northern Africa is third. California’s Central Valley, used heavily for agriculture and suffering rapid depletion, was slightly better off, but was still labeled highly stressed in the first study.



"As we’re seeing in California right now, we rely much more heavily on groundwater during drought," said Famiglietti. "When examining the sustainability of a region’s water resources, we absolutely must account for that dependence."



In a companion paper published today in the same journal, the scientists conclude that the total remaining volume of the world’s usable groundwater is poorly known, with estimates that often vary widely. The total groundwater volume is likely far less than rudimentary estimates made decades ago. By comparing their satellite-derived groundwater loss rates to what little data exist on groundwater availability, the researchers found major discrepancies in projected "time to depletion." In the overstressed Northwest Sahara Aquifer System, for example, time to depletion estimates varied between 10 years and 21,000 years.



"We don’t actually know how much is stored in each of these aquifers. Estimates of remaining storage might vary from decades to millennia," said Richey. "In a water-scarce society, we can no longer tolerate this level of uncertainty, especially since groundwater is disappearing so rapidly."



The study notes that the dearth of groundwater is already leading to significant ecological damage, including depleted rivers, declining water quality and subsiding land.



Groundwater aquifers are typically located in soils or deeper rock layers beneath Earth’s surface. The depth and thickness of many large aquifers make it tough and costly to drill or otherwise reach bedrock and understand where the moisture bottoms out. But it has to be done, the authors say.



To read the technical papers, visit:



Quantifying renewable groundwater stress with GRACE - Richey - 2015 - Water Resources Research - Wiley Online Library



and



Uncertainty in global groundwater storage estimates in a total groundwater stress framework - Richey - 2015 - Water Resources Research - Wiley Online Library



GRACE is a joint mission with the German Aerospace Center and the German Research Center for Geosciences, in partnership with the University of Texas at Austin. JPL developed the GRACE spacecraft and manages the mission for NASA's Science Mission Directorate, Washington.



For more information on GRACE, visit:



Grace Mission | NASA



and



GRACE - Gravity Recovery and Climate Experiment



NASA uses the vantage point of space to increase our understanding of our home planet, improve lives and safeguard our future. NASA develops new ways to observe and study Earth's interconnected natural systems with long-term data records. The agency freely shares this unique knowledge and works with institutions around the world to gain new insights into how our planet is changing.



For more information about NASA's Earth science activities, visit:



Earth | NASA







Alan Buis
Jet Propulsion Laboratory, Pasadena, California

818-354-0474
alan.buis@jpl.nasa.gov



Janet Wilson
UC Irvine

949-824-3969
janethw@uci.edu

2015-206

Last Updated: June 21, 2015
Editor: Tony Greicius

Tags: Climate, Earth, GRACE (Gravity Recovery And Climate Experiment), Water

 

[tranquilium]

Well, humanity does not yet possess the technology for large scale weather manipulation. Consequently it is not possible to wait for natural replenishment of underground water. A potential solution to the problem is artificially divert rivers from water rich regions to alleviate the stress on underground water, possibility even returning some to underground reservoirs.

An example is the China's South to North water transfer project:
北京迎来“南水” 多年超采地下水将获补充-新华网
The project diverts water from the water rich south region to the stress Northern China aquifers, the divert water is not only used directly, part of the water is injected back into underground reservoir to replenish the supply.

The catch is that since rain fall pattern generally stays the same in local areas, to find a water rich region and can divert water to dry regions, the country must has already been very large to have a diverse rain fall pattern. Such engineering projects are also very very expensive, to the point few countries can actually afford it.

 

[Super Falcon]

What measures has been taken it is very very alarming

 

[VCheng]

What measures has been taken it is very very alarming

Just one of the consequences of overpopulation and failure to plan long term. Such shortages are only the beginning of a very trying time ahead, not just for Pakistan, but many other countries around the world.

 

[Kabira]

Solution is more dams and slower growth in population.

 

[Echo_419]

Just one of the consequences of overpopulation and failure to plan long term. Such shortages are only the beginning of a very trying time ahead, not just for Pakistan, but many other countries around the world.

I think all of the world should come together to solve this problem by finding new ways to purify ocean water & safely,Sustainably dispose the waste generate by it

 

[Super Falcon]

We are not doing any one of them insteam wasting money on buses

 

[VCheng]

I think all of the world should come together to solve this problem by finding new ways to purify ocean water & safely,Sustainably dispose the waste generate by it

That desalination technology exists already, but is expensive and requires large amounts of energy to run. Can Pakistan afford that?

 

[Ragnar]

This peak that human population achieved in the 20th century is anyway unsustainable:

In earlier centuries there seemed to be some bottlenecks. Hope some stability is provided before all resources of the planet are consumed.

 

[Echo_419]

That desalination technology exists already, but is expensive and requires large amounts of energy to run. Can Pakistan afford that?

My point was all countries should try to make that technology more economical so third world countries like India & Pakistan can afford them

 

[VCheng]

My point was all countries should try to make that technology more economical so third world countries like India & Pakistan can afford them

The cost will come down with widespread adoption of the technology, but it will never be cheap due to the energy inputs required.

 

[Echo_419]

The cost will come down with widespread adoption of the technology, but it will never be cheap due to the energy inputs required.

Perhaps a joint South Asian project can he established,south Asia has a massive coast line after all
On second note me making out with Taylor swift has more chances than the above proposal

 

[VCheng]

Perhaps a joint South Asian project can he established,south Asia has a massive coast line after all
On second note me making out with Taylor swift has more chances than the above proposal

South Asia will remain mired where it is unless it moves past its grievances and learns to co-operate to meet present and future challenges.

 

[Echo_419]

South Asia will remain mired where it is unless it moves past its grievances and learns to co-operate to meet present and future challenges.

Let's give it a century