Climate Change

Wednesday, August 16, 2006

DO WE HAVE ENOUGH FRESHWATER?

The Western Cape or in particular Cape Town heavily depend on the annual winter rainfall to supply the province and city of their freshwater supply. The regular and consistent winter rainfall also regulates - as it has done it for the past 5 millions years, - this Mediterranean’s floral and faunal diversity. However with the steady rise of Carbon dioxide concentrations in the atmosphere, resulting in global warming, the whole rainfall pattern is expected to change. Climate computer modelling from the Hadley Centre predicts up to a 25% decrease in the annual rainfall in this province. With a population that are booming, Cape Town is fast becoming South Africa premier city after Jozi. The demand for water in this water scarce province will soar and to rub salt to our wounds, the climate will be inconsistent and heavy, prolonged droughts can be expected. The effect of a prolonged drought will be felt across this multiracial province from the poorest of the poor, to the boere and to the rich and famous. So what are the options?

Tony Robinson looks at the economics of water from the sea and ask whether desalination would be viable in South Africa, since it is quite successful in other countries. According to him, desalination is no the panacea to South Africa’s water shortages but it will provide a security of supply in times of need. The technology is available and several other countries and islands have employ this processes since most of these countries and islands don’t have the benefits of mountainous catchment areas, rivers and dams in place to get their freshwater. According Robinson (2006) about 80 % of all salt removing processes is happening in the Middle East, where water production is coupled with the power stations. This process in Middle East involves the usages of gas, oil and nuclear power to boil the sea water, where it condensed for drinking water. The Europeans, Americans and Aussies make use of reverse osmosis, which is the application of pressure to separate the salt and the water. This method or a simple version of this method have been in place since 1881 on the island of Malta and have supplied the people and its tourist booming industry (Robinson 2006).

So why don’t we implement such programmes? The reasons according Tim Robinson is that our dam water is cheap and it provide little motivation to save water. He say that only 10 % of this water are recycled while the other 90% that are treated just run into our oceans. Only 2% are used for drinking, cooking and washing of hands purposes while approximately 35% and 20% are used on baths, showers and garden respectively.
If the government can encourage its people and industries to save more than the current percentage, and not just when there is a water crisis, this province will not be surprised when human-induced climatic conditions take its toll.

Reference:Robinson T. 2006. Sweet water from the sea. Progress Magazine. p 34 -37


PLAGIARISM DECLARATION
1.I know that plagiarism is wrong. Plagiarism is to use another’s work and to pretend that it is one’s own.
2. I have used the CSE/CBE convention for citation and referencing. Each significant contribution to, and quotation in this project from the work, or works, of other people has been attributed, and has been cited and referenced.
3. This assignment is my own work.
4. I have not allowed, and will not allow anyone to copy my work with the intention of passing it off as his or her own work.

5 Comments:

  • Ja jong, wanneer gaan ons leer?? I agree that we should all save water 'vannie boere' to the poorest of the poor. Education is the key here, as I have said before. And water should get exponentially more expensive the more you use. Maybe then those people with massive gardens that choose to water their green deserts will stop it and golf courses will start looking at alternative water supplies...

    By Blogger Karen Marais, at August 17, 2006 8:07 PM  

  • Unfortunately, Karen, it is the first choice 'alternative' water supplies that is one of the biggest threats to the environment. The first thing that happens after water restrictions are put in place is a shift (by those who can afford it) to the use of boreholes and well points which directly use the ground water and are not yet adequately regulated. This is to a large degree responsible for our falling water tables.

    There is actually a graded scale of payment for water in place - at least for the local population, I do not know if it applies to industry.

    By Blogger Gwen, at August 21, 2006 9:15 AM  

  • I know there is a graded scale, but it isn't graded enough, as it does not prevent those with money wasting water! And with alternative I was actually thinking in the line of recycling and not bore holes or well point! I agree that those should be regulated as I know from where I grew up in Pretoria, how drastically the water table dropped as everyone that could afford it had a bore hole or well point put in. We had massive old trees in our garden that died because of that... WESSA's last newsletter had an interesting article on water recycling amongst other things to reduce one's ecological footprint.

    By Blogger Karen Marais, at August 21, 2006 5:02 PM  

  • With CEO's getting R13 million bonuses (Eskom), how can the scale be graded enough?

    I realised that you were not thinking of boreholes, the point that I was making was that they are the first things many people think of. Other alternatives need more promotion to make people aware of them.

    Would it be possible for me to copy the article you mentioned?

    By Blogger Gwen, at August 23, 2006 9:05 AM  

  • One of the issues is the economic costs to water production. Natural water production that involves only detention (a catchment and a dam) is the cheapest production and until fairly recently there was no attempt to cut wasteful consumption. Personally I think all new building should be engineered to capture 80% or rainfall on their roofs for use in at least garden/ground watering. This would also reduce and buffer stormwater discharge and reduce the risk of floods for the low-lying areas of Cape Town.

    Engineered solutions to getting freshwater have also included towing Icebergs from the Polar regions and Cloud Seeding, the latter is a very dangerous environmental practise, I have a video somewhere that you can watch on this subject.

    Back to the reverse osmosis - this is expensive because of its energy demands, but way back on Robben Island they installed such a plant since it was cheaper to run than to put the pipelines under the sea to the island.

    Finally there has been too much though that you can use Groundwater - Atlantis was planned with Groundwater being its only water source - the consequence huge lowering of the water table. A lower water table not only can cause deep-rooted plants to lose their water supply but worst still, when close to the sea, for an intrusion of saltwater (saltater wedge) to replace the extracted freshwater - the quickest way to make a desert. Although they say it is not the case - I think this is happening to Swakopmund in Namibia.

    By Blogger Rich Knight, at August 30, 2006 12:00 PM  

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