Table of Contents

 

Other chapters of relevance include “Water storage”, “Irrigation”, “Boreholes and windmills”, “Rainwater harvesting”, “Wetlands”, “Waste management”, "Weather and climate" and “Invasive alien species”. Also take a look at the “Precision farming” chapter (precision farming saves water!)

 

1. Overview

“Apart from being essential to all life forms, water is one of several primary inputs in all sectors of an economy and is, therefore, a crucial resource with huge political significance and long political-economic history”. Willem de Lange (CSIR)

South Africa is a dry country by world standards. Its climate varies from desert and semi-desert in the west to sub-humid along the eastern coastal area. Its average rainfall of about 450 mm per year is well below the world average of about 860 mm. Evaporation is high, which places extra pressure on this resource.

No truly large perennial river – such as the Congo, Ganges, Mekong, Nile or Rhine which can serve as a reliable source of water – occurs in South Africa . The highly variable rainfall together with the general steep topography and shallow soils, contribute to the flashy character of our rivers. Groundwater is also limited due to the geology of the country, much of which is hard rock with little water bearing capacity. To further aggravate the situation, the spatial distribution of the water resources is highly skewed with 60% of the total annual runoff arising in only 20% of the surface area of the country (eastern parts). The western parts are much more arid than the eastern part of the country.

Source: www.sancold.org.za/index.php/about/about-dams/dams-in-south-africa

Find updates on the country's dams at www.dwa.gov.za/Hydrology/Weekly/Province.aspx

 

Agriculture is an important sector contributing to the country’s food security, rural welfare and contributing to job creation. Its irrigation component consumes over 60% of the country’s water resources to do this, placing a considerable responsibility on the shoulders of all in the sector. Agriculture faces increased competition for water resources from domestic and industrial users. The following table presents the water resource allocations per water user group:

Water user/sector Proportion of allocation
Agriculture: irrigation 60%
Agriculture and nature conservation 2.5%
Municipal: urban 24%
Municipal: rural 3%
Industrial 3%
Afforestation 3%
Mining 2.5%
Power generation 2%
Source: "The State of SA’s water resources" presentation by Trevor Balzer (Department Water & Sanitation 2014) 
Upstream and downstream: Green Trust/WWF SA media field trip surveying the work done in removing invasive alien plants. .

In global terms, South Africa is classified as water scarce country. It is the 30th driest country in the world. Possible interventions include:

  • Better use of irrigation technology
  • Recycling water to a potable standard.
  • Desalination of seawater or brackish water.
  • Alien vegetation control: a significant volume of water is used by alien vegetation and control measures aimed at reclaiming the water is an option.
  • Inter-basin and trans-country transfers: The importation of water from central Africa remains an option.
  • Minimise leakages. Leakages is not only wasted water, it is foregone income as well.
  • Virtual water (see next heading)
Source: Dr Willem de Lange, CSIR