Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Seawater intrusion is the first cause of contamination of coastal aquifers

30.07.2007
Seawater intrusion is often the consequence of freshwater aquifers overexploitation. This is a very common and serious phenomenon all over the Mediterranean basin, as well as in other areas with similar weather conditions and population.

In Spain, the most severely affected areas by seawater intrusion are the Mediterranean and South-Atlantic coastlines. Given that Spain is located on a peninsula, seawater intrusion is currently one of the main causes of groundwater pollution. In fact, “about 60% of Spanish coastal aquifers are contaminated by seawater intrusion, a generalised phenomenon in 20% of cases”, points out Prof. José Benavente Herrera, a researcher from the Water Institute of the University of Granada (Universidad de Granada [http://www.ugr.es]), Spain, and senior lecturer at the department of Geodynamics.

According to Prof. Benavente, “freshwater contaminated by a 5% of seawater can no longer be used for common purposes, such as human use, agriculture or farming. That is the reason why salinisation of coastal aquifers – mainly a consequence of an uncontrolled or deficient management – is such a serious phenomenon”. In Southern Spain, “seawater intrusion is contaminating some of the most important aquifer systems in economic terms”, both on the Mediterranean and the Atlantic coastlines. In the world, the most affected areas include Mexico, the North of the Pacific and Atlantic coastlines, Chile, Peru and Australia.

Solutions: prevention and control

A good knowledge of aquifers (subsoil) enables scientists to determine the ‘critical discharge’, i.e. the extent to what aquifers can support water catchments without seawater intrusion taking place. Experts in hydrogeology acknowledge that such is a complex question, but they can currently give advice on prevention and control of situations caused by human activity.

Prof. Benavente states that solutions to prevent salinisation should start by studying every aquifer individually. Therefore, reducing freshwater pumping should be followed by other measures, such as analysing the aquifer’s situation before building reservoirs upstream, as this will account for a serious minimisation of its natural recharge and, possibly, for salinisation if the return flow is not guaranteed. In fact, “ironic as it may be, building up an artificial reservoir could render useless the natural groundwater reservoir downstream”.

Also, says Benavente, in very localised seawater intrusion areas, reducing pumping or extracting water from either smaller or greater depths become indispensable measures. According to Benavente, artificial recharge of aquifers is another efficient measure to prevent salinisation, as it stops seawater intrusion and increases freshwater levels. In this sense, for instance, clean water obtained from urban sewage purification can be used for irrigation of crops and golf fields as well as to create a hydraulic barrier against seawater intrusion.

Some regions in the world – including Spain – are already implementing these measures. Prof. Benavente highlights Los Angeles, USA, and river Llobregat delta, Spain, where sewage water injection as mentioned above has proven to be useful to solve salinisation problems.

Teamwork experience

Among other research works, Prof. Benavente has recently coordinated the European Union Project SWIMED on Sustainable Water Management in Mediterranean coastal aquifers. Scientists from France, Italy, Morocco, the Palestinian Authority, Spain, Switzerland and Tunisia participated in this project, with a budget of 700,000 euros.

Prof. Benavente, together with other scientists from the Water Institute at the University of Granada [http://www.ugr.es], Spain, and from the other countries taking part in SWIMED, has published his research in prestigious international journals specialised in water management, such as Environmental Geology or Water Resources Management.

Antonio Marín Ruiz | alfa
Further information:
http://prensa.ugr.es/prensa/research/index.php

More articles from Ecology, The Environment and Conservation:

nachricht Listening in: Acoustic monitoring devices detect illegal hunting and logging
14.12.2017 | Gesellschaft für Ökologie e.V.

nachricht How fires are changing the tundra’s face
12.12.2017 | Gesellschaft für Ökologie e.V.

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

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

Im Focus: First-of-its-kind chemical oscillator offers new level of molecular control

DNA molecules that follow specific instructions could offer more precise molecular control of synthetic chemical systems, a discovery that opens the door for engineers to create molecular machines with new and complex behaviors.

Researchers have created chemical amplifiers and a chemical oscillator using a systematic method that has the potential to embed sophisticated circuit...

Im Focus: Long-lived storage of a photonic qubit for worldwide teleportation

MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.

Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...

Im Focus: Electromagnetic water cloak eliminates drag and wake

Detailed calculations show water cloaks are feasible with today's technology

Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...

Im Focus: Scientists channel graphene to understand filtration and ion transport into cells

Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.

To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...

Im Focus: Towards data storage at the single molecule level

The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.

Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

AKL’18: The opportunities and challenges of digitalization in the laser industry

07.12.2017 | Event News

 
Latest News

Engineers program tiny robots to move, think like insects

15.12.2017 | Power and Electrical Engineering

One in 5 materials chemistry papers may be wrong, study suggests

15.12.2017 | Materials Sciences

New antbird species discovered in Peru by LSU ornithologists

15.12.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>