Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

The rate at which groundwater reservoirs are being depleted is increasing

17.07.2014

In what parts of the world and to what degree have groundwater reservoirs been depleted over the past 50 years?

The Frankfurt hydrologist Prof. Petra Döll has been researching this using the global water model WaterGAP. Her conclusion: The rate at which groundwater reservoirs are being depleted is increasing, but that the rate is not as high as previously estimated.

In what parts of the world and to what degree have groundwater reservoirs been depleted over the past 50 years? The Frankfurt hydrologist Prof. Petra Döll has been researching this using the global water model WaterGAP. She has arrived at the most reliable estimate to date by taking into consideration processes which are important in dry regions of the world.

The values calculated were compared with monitoring data from many different wells and data from the GRACE satellites. These satellites measure changes in the Earth's gravity field. Döll has come to the conclusion that the rate at which groundwater reservoirs are being depleted is increasing, but that the rate is not as high as previously estimated.

90 percent of water consumption is due to irrigation for farming purposes. Only the comparatively small remainder is used for potable water and industrial production. As an example, 40 percent of the cereals produced around the world is irrigated. However, in many cases this results in increased scarcity of water resources and puts a burden on ecosystems. In dry regions, the amount taken from groundwater reservoirs can easily exceed the amount being replenished, so that the groundwater reservoir is overused and depleted.

"By comparing the modelled and measured values of groundwater depletion, we were able for the first time to show on a global scale that farmers irrigate more sparingly in regions where groundwater reservoirs are being depleted. They only use about 70 percent of the optimal irrigation amounts", explains Petra Döll from the Institute of Physical Geography at the Goethe University.

The rate at which the Earth's groundwater reservoirs are being depleted is constantly increasing. Annual groundwater depletion during the first decade of this century was twice as high as it was between 1960 and 2000. India, the USA, Iran, Saudi Arabia and China are the countries with the highest rates of groundwater depletion.

About 15 percent of global groundwater consumption is not sustainable, meaning that it comes from non-renewable groundwater resources. On the Arabian Peninsula, in Libya, Egypt, Mali, Mozambique and Mongolia, over 30 percent of groundwater consumption is from non-renewable groundwater.

The new estimate of global groundwater depletion is 113,000 million cubic meters per year for the period from 2000 to 2009, which is lower than previous, widely varying estimates. This can be considered to be the most reliable value to date, since it is based on improved groundwater consumption data which takes the likely deficit irrigation into account, and since the model results correlate well with independent comparative data.

The increased use of groundwater for irrigation also results in a rise in sea levels: According to Döll's calculations, sea level rise due to groundwater depletion was 0.31 millimetres per year during the period from 2000 to 2009. This corresponds to roughly one tenth of the total sea level rise.

The work was funded by the Deutsche Forschungsgemeinschaft through the priority program "Mass transport and Mass distribution in the System Earth".

Publication Döll, P., Müller Schmied, H., Schuh, C., Portmann, F.T., Eicker, A., (2014): Global-scale assessment of groundwater depletion and related groundwater abstractions: Combining hydrological modelling with information from well observations and GRACE satellites. Water Resour. Res. 50, doi: 10.1002/2014WR015595.
Online publication: http://dx.doi.org/10.1002/2014WR015595

Information Prof. Petra Döll, Institute of Physical Geography, Riedberg Campus, Phone: (069)798-40219: p.doell@em.uni-frankfurt.de.

The Goethe University is an institution with particularly strong research capabilities based in the European financial metropolis of Frankfurt. It celebrates its 100th year of existence in 2014. The university was founded in 1914 through private means from liberally-orientated citizens of Frankfurt and has devoted itself to fulfilling its motto "Science for the Society" in its research and teaching activity right up to the present day. Many of the founding donors were of Jewish origin. During the last 100 years, the pioneering services offered by the Goethe University have impacted the fields of social, societal and economic sciences, chemistry, quantum physics, neurological research and labour law. On January 1st, 2008, it achieved an exceptional degree of independence as it returned to its historical roots as a privately funded university. Today it is one of the ten universities that are most successful in obtaining external research funding and one of the three largest universities in Germany with centres of excellence in medicine, life sciences and humanities.

Publisher: The president of the Goethe University Frankfurt am Main. Editorial department: Dr. Anne Hardy, Public Relations Officer for Scientific Communication. Abteilung Marketing und Kommunikation, Grüneburgplatz 1, 60629 Frankfurt am Main, Phone: (069) 798-12498.

Weitere Informationen:

http://dx.doi.org/10.1002/2014WR015595

Dr. Anke Sauter | idw - Informationsdienst Wissenschaft

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

A Map of the Cell’s Power Station

18.08.2017 | Life Sciences

Engineering team images tiny quasicrystals as they form

18.08.2017 | Physics and Astronomy

Researchers printed graphene-like materials with inkjet

18.08.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>