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

More articles from Earth Sciences:

nachricht NASA finds newly formed tropical storm lan over open waters
17.10.2017 | NASA/Goddard Space Flight Center

nachricht The melting ice makes the sea around Greenland less saline
16.10.2017 | Aarhus University

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Neutron star merger directly observed for the first time

University of Maryland researchers contribute to historic detection of gravitational waves and light created by event

On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...

Im Focus: Breaking: the first light from two neutron stars merging

Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.

Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....

Im Focus: Smart sensors for efficient processes

Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).

When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...

Im Focus: Cold molecules on collision course

Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.

How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...

Im Focus: Shrinking the proton again!

Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.

It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ASEAN Member States discuss the future role of renewable energy

17.10.2017 | Event News

World Health Summit 2017: International experts set the course for the future of Global Health

10.10.2017 | Event News

Climate Engineering Conference 2017 Opens in Berlin

10.10.2017 | Event News

 
Latest News

Researchers release the brakes on the immune system

18.10.2017 | Health and Medicine

Separating methane and CO2 will become more efficient

18.10.2017 | Life Sciences

Ocean atmosphere rife with microbes

17.10.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>