Newsletter and Technical Publications
of Alternative Technologies for Freshwater Augumentation in Africa>
3.1.2 Surface Water Harvesting
Water demands in industrialized areas tend to out grow the
available water supply. Thus, in order to meet demand, it is necessary to
transfer of water to the site from another basin. Such inter-basin
transfers (IBTs), although expensive, are becoming the only solution to
meeting industrial and mining water demands. The technique involves
building large reservoirs to capture runoff in watersheds that may be
several hundreds of kilometres away from the centre of activity, and
transferring this water by pipeline or canal to the area of use.
Extent of Use
Due to large financial investment required, this technique is limited to
economically-viable projects such as the Lesotho Highlands project in
South Africa and the water projects of Libya.
Operation and Maintenance
These systems have high operation and maintenance costs. There is
usually a need for large and powerful pumping systems as well as extensive
networks of pipelines and canals.
Level of Involvement
Highly qualified engineers and technicians are required to plan, design,
implement and operate inter-basin transfer schemes. Costs This technology
has high capital and operational costs.
Effectiveness of the Technology
This technology is generally effective in ensuring a reliable supply of
water to areas that would otherwise be classified as water short areas. It
is dependent, however, on the rainfall and availability of water in the
remote catchment area, which may be subject to the same vagaries as the
surface water resources in the centre of activity.
This technology is suitable for use in areas where the rate of financial
return is high, such as in the mining complexes of South Africa or the oil
fields of Libya.
There are numerous drawbacks with the use of this technology. Many
affect the biodiversity of the waterbodies connected by the transfer
scheme, and often include public health impacts, especially where there
are open water transfer canals that can serve as water-borne disease
This technology provides water where it is most needed for economic
production, and can assist in bringing development to remote places.
Water provided using this technology is expensive and, hence, the water
may not be affordable by the poor. There are also potential biodiversity
and public health impacts that must be monitored and contained.
This technology is culturally acceptable and is widely used in
water-poor regions of Africa.
Further Development of the Technology
Options need to be thoroughly analysed before embarking on project.
Development of an economic and environmental assessment protocol would be
Department of Water Affairs and Forestry, Private Bag X313,
Pretoria 0001, South Africa.