'Huge' water resource exists under Africa

 

Related Stories

Scientists say the notoriously dry continent of Africa is sitting on a vast reservoir of groundwater.

They argue that the total volume of water in aquifers underground is 100 times the amount found on the surface.

The team have produced the most detailed map yet of the scale and potential of this hidden resource.

Writing in the journal Environmental Research Letters, they stress that large scale drilling might not be the best way of increasing water supplies.

Across Africa more than 300 million people are said not to have access to safe drinking water.

Demand for water is set to grow markedly in coming decades due to population growth and the need for irrigation to grow crops.

Africa aquifer map

Freshwater rivers and lakes are subject to seasonal floods and droughts that can limit their availability for people and for agriculture. At present only 5% of arable land is irrigated.

What is ground water?

When water falls as rain or snow, much of it either flows into rivers or is used to provide moisture to plants and crops. What is left over trickles down to the layers of rock that sit beneath the soil.

And just like a giant sponge, this ground water is held in the spaces between the rocks and in the tiny inter-connected spaces between individual grains in a rock like sandstone.

These bodies of wet rock are referred to as aquifers. Ground water does not sit still in the aquifer but is pushed and pulled by gravity and the weight of water above it.

The movement of the water through the aquifer removes many impurities and it is often cleaner than water on the surface.

Now scientists have for the first time been able to carry out a continent-wide analysis of the water that is hidden under the surface in aquifers. Researchers from the British Geological Survey and University College London (UCL) have mapped in detail the amount and potential yield of this groundwater resource across the continent.

Helen Bonsor from the BGS is one of the authors of the paper. She says that up until now groundwater was out of sight and out of mind. She hopes the new maps will open people's eyes to the potential.

"Where there's greatest ground water storage is in northern Africa, in the large sedimentary basins, in Libya, Algeria and Chad," she said.

"The amount of storage in those basins is equivalent to 75m thickness of water across that area - it's a huge amount."

Ancient events

Due to changes in climate that have turned the Sahara into a desert over centuries many of the aquifers underneath were last filled with water over 5,000 years ago.

The scientists collated their information from existing hydro-geological maps from national governments as well as 283 aquifer studies.

The researchers say their new maps indicate that many countries currently designated as "water scarce" have substantial groundwater reserves.

However, the scientists are cautious about the best way of accessing these hidden resources. They suggest that widespread drilling of large boreholes might not work.

Dr Alan MacDonald of the BGS, lead author of the study, told the BBC: "High-yielding boreholes should not be developed without a thorough understanding of the local groundwater conditions.

"Appropriately sited and developed boreholes for low yielding rural water supply and hand pumps are likely to be successful."

With many aquifers not being filled due to a lack of rain, the scientists are worried that large-scale borehole developments could rapidly deplete the resource.

Man filling jerry can African water supplies may be more resilient to climate change than was thought

According to Helen Bonsor, sometimes the slower means of extraction can be more efficient.

"Much lower storage aquifers are present across much of sub-Saharan Africa," she explained.

"However, our work shows that with careful exploring and construction, there is sufficient groundwater under Africa to support low yielding water supplies for drinking and community irrigation."

The scientists say that there are sufficient reserves to be able to cope with the vagaries of climate change.

"Even in the lowest storage aquifers in semi arid areas with currently very little rainfall, ground water is indicated to have a residence time in the ground of 20 to 70 years." Dr Bonsor said.

"So at present extraction rates for drinking and small scale irrigation for agriculture groundwater will provide and will continue to provide a buffer to climate variability."

The publication of the new map was welcomed by the UK's secretary of state for international development, Andrew Mitchell.

"This is an important discovery," he said. "This research, which the British Government has funded, could have a profound effect on some of the world's poorest people, helping them become less vulnerable to drought and to adapt to the impact of climate change."

 

More on This Story

Related Stories

The BBC is not responsible for the content of external Internet sites

Comments

This entry is now closed for comments

Jump to comments pagination
 
  • rate this
    +2

    Comment number 306.

    i'm taking the positive view on this good news which is down to research and hard work,well done to all those involved. let us hope technology can turn potential into more food etc..can be harvested on this great continent.this may be a time when world aid can do some everlasting good.

  • rate this
    0

    Comment number 305.

    #282. Rhyfelwyr

    http://www.telegraph.co.uk/news/politics/2967374/England-is-most-crowded-country-in-Europe.html

    I think they exclude micro country's and principality's like Monaco & Liechtenstein

  • rate this
    +7

    Comment number 304.

    "Demand for water is set to grow markedly in coming decades due to population growth and the need for irrigation to grow crops."

    We, as a planet, should work to control population growth. The population hasn't grown to "future proportions" yet. The future is not entirely pre-determined.

  • rate this
    0

    Comment number 303.

    .


    I've got a new & original idea, why don't we blame all of Africa's woes on the West (ie White people) this way no one has to shoulder any responsibility! Brilliant eh?!

    .

  • rate this
    +3

    Comment number 302.

    Why do scientists just repeat what is already known every twenty years as if it is an astounding discovery? We are supposed to have access to all information all of the time. Obviously not in universities. Or is the news a PR blurb for some scam or other? I note the UK tax payer funded it.

    I think the Germans mapped the aquifers during the war, but that the water was contaminated with oil.

  • rate this
    0

    Comment number 301.

    I agree with Mischiefmaker. These conic water reserves should be used to make the desert bloom, but sustainably. Areas can become deserts by over farming as the U.S.A. started doing in the early 20th century in its heartland, creating dust bowls where fertile farmland was. Conversely, man can help change deserts to fertile land by using conic water to develop deep rooted flora, i.e., trees.

  • rate this
    +2

    Comment number 300.

    THIS IS BAD NEWS FOR AFRICA. How I wish all our natural resources were hidden from our current crop of corrupt leaders with their greedy western multinations who exploit African resources with impunity and arrogance.
    Until we get African Nationalist who care for their own, I pray not a litre of this reserve is touched. Go to DRC and many other countries and see the rape of Africa.

  • rate this
    +2

    Comment number 299.

    Excellent article, a great news to Africa, and a relief to those light hearted and caring people around the world to know that there is a hope. However, many in Algeria and Libya know about "fossile water", and both countries signed agreements as to the percentage eah country could pump. Mouamar Qaddafi knew this and initiated a 26 year, $20 bn project called The Great Man-Made River.

  • rate this
    +2

    Comment number 298.

    Great news! 20 years from now, China, Europe and America will have plenty of fresh water to drink from Congo.... Just one more resource to plunder from the Africans.

  • rate this
    -3

    Comment number 297.

    It will be funny to watch when all of these countries go to war with one another over it GO zimbabwe!

  • rate this
    0

    Comment number 296.

    #289 Drunken Hobo - its not cultural, not in the main at any rate. In the absence of education, local understandings take precedence. Its mainly socio-economic.

    If you gave SOME Africans money, generally those with their hands on power, in a centralised power structure, left by colonialists, then yes, they would secure their position militarily. As Europeans have for centuries.

  • rate this
    +4

    Comment number 295.

    Given how things work across the African continent having control over resources like water is likely to set off regional conflicts. You only have to examine the current issue of the Sudan oil fields how this plays out. Best intentions are not enough someone always tries to make a profit often corrupt government leaders. Favoritism for some tribal areas but not for all is another issue. We'll see.

  • rate this
    +2

    Comment number 294.

    this is actually no news
    lets establish a democratic Africa then everything will flow smoothly
    organization here in EU seem to be keen on raising money for people without water in Africa, but what they dont know is that those money do not touch the average person they are taken by the corrupt systems

  • rate this
    +1

    Comment number 293.

    Should it really be a surprise? It seems since I can remember we have always been asked to donate money so that some village in a place we have never heard of can drill a hole in the ground and get lovely clean water! Good for them though, I am amazed that it has taken so long to produce a graph like this. Unfortunately, water demand increasing, are we looking at future super powers?

  • rate this
    -1

    Comment number 292.

    Well let's get digging!! This is a great opportunity for British companies to make vast profits getting this water out of the ground!

    Let's hope "do gooders" don't muck this up for Britain.

  • rate this
    0

    Comment number 291.

    Thats Africa sorted now. No more need for hand outs. Get rid of the corrupt officials and replace them with people who will improve the quality of life for the people.

  • rate this
    +3

    Comment number 290.

    #269 Happy Barrel - where do you think our economic "growth" comes from. You don't think we are getting more efficient do you?

    Its from growth of economically active population, immigrant or otherwise. Those bankers' bonuses don't pay themselves.

    If you want to "fix" immigration, let the banks go bust instead of propping them up, let cheap credit dry up and the economy collapse;-)

  • rate this
    -1

    Comment number 289.

    276 carbonbasebloke

    To paraphrase an old saying: Give an African a well, and they'll drink for a lifetime, give an African the money for a well, and they'll spend it on weapons and recruiting child soldiers.

    Africa's problems are far bigger than a lack of food or water; it's a cultural problem - and that's much harder to fix, as you have to change an entire way of life.

  • rate this
    -1

    Comment number 288.

    The birth rate is too high in Africa and with a possible tapping in of a ready clean water supply the spill over of people out of Africa will do the planet no good at all. Population increase needs to be educated and controlled the world over and this needs to happen in Africa before the water supply comes good.

  • rate this
    0

    Comment number 287.

    If those complaining about overpopulation would like to sacrifice one or two of their family or castigate their children when they have one or two of their own then maybe we can talk about various ecosystems carrying capacities.

    Your may say one or two are ok.Really ? Aren't they going to consume the same amount as four or five Africans?

    How do we decide who to cull? Indeed,who decides?

 

Page 5 of 20

 

More Science & Environment stories

RSS

Features

BBC © 2014 The BBC is not responsible for the content of external sites. Read more.

This page is best viewed in an up-to-date web browser with style sheets (CSS) enabled. While you will be able to view the content of this page in your current browser, you will not be able to get the full visual experience. Please consider upgrading your browser software or enabling style sheets (CSS) if you are able to do so.