Water Resources

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Water Resources

• GEOG 201
• 15th 26th April 2002
• Alistair McMaster, Rm 69

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Lecture 1

• Global availability and distribution of water
  resources.
• South African spatial and temporal distribution
  of water resources.
• Utilisation of the water resource in SA
• Future options for water availability
• Water as a social, economic and environmental
  commodity Case study of Mhlatuzi Catchment.

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Accessible Freshwater Global Proportions
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Freshwater in terms of global volumes
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Freshwater Resources Global Distribution of
Mean Annual Runoff (MAR)
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MAR Distribution in Africa
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Mean Annual Precipitation (MAP) - South Africa
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Potential Evaporation South Africa
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MAR South Africa
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Variability of Rainfall in SA
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SA Water Usage
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Utilised 20 350 million m3/yAvailable 13 250
million m3/yLost 16 550 million m3/y
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Major Dams and Interbasin Transfers
Total volume of dams approx 27 000 million m3
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Resource Use vs Resource Potential
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Conclusion

• Freshwater in South Africa is a scarce resource,
  increasingly becoming a highly valued commodity.
• As such, water is being treated more and more in
  economic (tradeable water rights), social and
  political, and environmental terms. (E.g. Sand
  and Sabie river, Mhlatuzi river).
• Often, these different needs are in direct
  competition.
• Thus, the sustainable and equitable management of
  freshwater has become a national issue of
  paramount strategic importance.

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Alternative Sources of Water

• Desalination of Seawater
• Technically feasible, but very expensive.
• Weather Modification
• Feasible can increase yield by 150 million m3/y,
  but big politics.
• Shipping of freshwater
• Feasible, and competitive with desalination
• Icebergs
• Unresolved technical details
• Suppression of evaporation
• Not feasible

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Alternative Sources of Water

• Importation of water
• Zambezi, Lesotho.
• Greater re-use of water
• Especially effluent.
• Water Conservation
• Water demand management (savings of 10)
• Increased efficiency
• Reduced leakages
• Removal of alien vegetation
• Virtual or embedded water
• Reallocation of Water

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Case Study

• Mhlatuzi Catchment Strategic Environmental
  Assessment.
• http//www.dwaf.gov.za/sfra/
• (or Mhlatuzi SEA executive summary in Geog
  Library)