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Apart from the pollution of water resources, the overuse of water is also a problem. In looking at the water cycle, it is easy sometimes to think that water is a never-ending resource. In a sense this is true because water cannot be destroyed. However, the availability of water may vary from place to place. In South Africa for example, many regions are extremely dry and receive very little rainfall. The same is true for many other parts of the world, where the scarcity of water is a life and death issue. The present threat of global warming is also likely to affect water resources. Some climate models suggest that rising temperatures could increase the variability of climate and decrease rainfall in South Africa. With this in mind and remembering that South Africa is already a dry country, it is vitally important that we manage our water use carefully. In addition to this, the less water there is available, the more likely it is that water quality will also decrease. A decrease in water quality limits how water can be used and developed.

At present, the demands being placed on South Africa's water resources are large. [link] shows the water requirements that were predicted for the year 2000. The figures in the table were taken from South Africa's National Water Resource Strategy , produced by the Department of Water Affairs and Forestry in 2004. In the table, 'rural' means water for domestic use and stock watering in rural areas, while 'urban' means water for domestic, industrial and commercial use in the urban area. 'Afforestation' is included because many plantations reduce stream flow because of the large amounts of water they need to survive.

The predicted water requirements for various water management areas in South Africa for 2000 (million m 3 /annum)
Water management area Irrigation Urban Rural Mining and bulk industrial Power generation Afforestation Total
Limpopo 238 34 28 14 7 1 322
Thukela 204 52 31 46 1 0 334
Upper Vaal 114 635 43 173 80 0 1045
Upper Orange 780 126 60 2 0 0 968
Breede 577 39 11 0 0 6 633
Country total 7920 2897 574 755 297 428 12871

Case study : south africa's water requirements

Refer to [link] and then answer the following questions:

  1. Which water management area in South Africa has the highest need for water...
    1. in the mining and industry sector?
    2. for power generation ?
    3. in the irrigation sector?
    4. Suggest reasons for each of your answers above.
  2. For South Africa as a whole...
    1. Which activity uses the most water?
    2. Which activity uses the least water?
  3. Complete the following table, by calculating the percentage (%) that each activity contributes to the total water requirements in South Africa for the year 2000.
    Water use activity % of SA's total water requirements
    Mining and bulk industry
    Power generation

Now look at [link] , which shows the amount of water available in South Africa during 2000. In the table, 'usable return flow' means the amount of water that can be reused after it has been used for irrigation, urban or mining.

The available water yield in South Africa in 2000 for various water management areas (million m 3 /annum)
Water management area Surface water Ground Irrigation Urban Mining and bulk industrial Total local yield
Limpopo 160 98 8 15 0 281
Thukela 666 15 23 24 9 737
Upper Vaal 598 32 11 343 146 1130
Upper Orange 4311 65 34 37 0 4447
Breede 687 109 54 16 0 866
Country total 10240 1088 675 970 254 13227

Questions & Answers

who was the first nanotechnologist
Lizzy Reply
technologist's thinker father is Richard Feynman but the literature first user scientist Nario Tagunichi.
Norio Taniguchi
I need help
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hydrothermal synthesis
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Maira Reply
nanopartical of organic/inorganic / physical chemistry , pdf / thesis / review
what are the products of Nano chemistry?
Maira Reply
There are lots of products of nano chemistry... Like nano coatings.....carbon fiber.. And lots of others..
Even nanotechnology is pretty much all about chemistry... Its the chemistry on quantum or atomic level
no nanotechnology is also a part of physics and maths it requires angle formulas and some pressure regarding concepts
Preparation and Applications of Nanomaterial for Drug Delivery
Hafiz Reply
Application of nanotechnology in medicine
has a lot of application modern world
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Jyoti Reply
ya I also want to know the raman spectra
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
yes that's correct
I think
Nasa has use it in the 60's, copper as water purification in the moon travel.
nanocopper obvius
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
STM - Scanning Tunneling Microscope.
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, Siyavula textbooks: grade 10 physical science. OpenStax CNX. Aug 29, 2011 Download for free at http://cnx.org/content/col11245/1.3
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