Newsletter and Technical Publications
of Alternative Technologies for Freshwater Augumentation in Africa>
3.1.1 Groundwater Harvesting
Borehole depths vary, depending on geological formations. In sedimentary
rock formations, depths of between 25 and 200 m are common. Technically,
borehole or well development starts with a geophysical investigation to
identify a suitable site. Subsequently, the borehole is drilled through
the overburden, weathered surface rock, and fractured bedrock. Usually
during the drilling process, slotted screens and solid casings are
installed to improve the integrity of well. When groundwater is harvested
for industrial use, high yield boreholes and wells are drilled on
industrial premises and fitted with pumps, powered by either electricity,
oil, or solar energy, to deliver water for use within the production lines
of the industry.
Extent of Use
Groundwater harvesting is widely used by breweries and and in the
canning industry, among others, in water short areas of Africa.
Operation and Maintenance
The principle operation and maintenance requirements of a groundwater
harvesting system relate to the pumping system and associated distribution
network. Solar panels, although requiring less regular maintenance, have
high capital costs. All pumping systems can be maintained at the
maintenance section of the industry with back up support from the
Level of Involvement
This technology is typically implemented at the local level by
Costs vary considerably according to size of the industry, its demand,
pumping rate, type of pumping system, pump efficiency, energy costs, and
other related factors that are industry and site specific.
Effectiveness of the Technology
Groundwater generally supplies a significant percentage of the water
needs in industries using this technology.
This technology is suitable for use in areas of water shortage, or where
municipal supplies are expensive. The abstraction of groundwater, however,
may be regulated by the government in times of drought or emergency.
Few negative environmental impacts have been recorded, but regulation of
pumping rates may be necessary to avoid overpumping. In karstic areas,
such regulation may be needed to minimise the potential for the creation
of sink holes.
Water is made available on site in an appropriate quantity, and
groundwater is generally of high quality. Use of groundwater resources
over municipal supplies can result in significant saving in costs of
Uncontrolled pumping may have a negative impact on the environment.
Use of groundwater is culturally acceptable.