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2.1.4 Groundwater Abstraction in Urban Residential Areas
This is the abstraction of groundwater through boreholes, by private
householders or water supply agencies.
Extent of Use
The technique is extensively used in a number of countries in Africa. In
rural areas, it may be the only reliable source of water supply. In urban
centres, it augments conventional municipal supplies.
Operation and Maintenance
The operation and maintenance requirements for groundwater abstraction
systems usually relate to type of pumping system used. For poorly
constructed boreholes, collapse may be experienced.
Level of Involvement
Both household and water supply agencies make use of this technology.
Borehole drilling and components costs have been estimated to be about
$3 000 for a typical installation. Energy costs depend on source of energy
used, usually the cost of electricity.
Effectiveness of the Technology
Household use of groundwater reduces demand for treated urban water. It
is also efficient for industrial use since each industry can treat the
water to meet its own requirements.
This technology is suitable in all areas with groundwater reserves, in
particular, during droughts.
There could be environmental damage from over pumping as the water table
recedes. In years of water shortage, this over-pumping may negatively
affect the groundwater discharge into rivers, lakes and reservoirs.
The advantages of this technology include its site-specificity; no
significant delivery (reticulation) systems are necessary. The technology
may be used where urban services are poor or unreliable.
Over pumping may lead to ground subsidence. Subsidence is of great
concern in crowded urban areas. Further, groundwater is susceptible to
contamination from wastes.
Generally, there are no cultural problems with the use of groundwater
Further Development of the Technology
Techniques for the rapid assessment of safe yield to avoid over pumping
Simpson, G.C. 1990. Research into Groundwater Abstraction in
Residential Areas. Vol 1. Water Research Commission Report No.
211/1/90, Division of Building Technology, CSIR, Pretoria.