A scattergun approach to borehole drilling in Africa is likely to be unsuccessful.
the message from a group of UK researchers who have, for the first time,
quantified the amount, and potential yield, of ground water across the whole of
estimate the total volume of ground water to be more than 100 times the
available surface freshwater on the continent, and hope that the assessment can
inform plans to improve access to water in Africa, where 300 million people do
not have access to safe drinking water.
results were published April 20 in Environmental Research Letters.
researchers, from the British Geological Survey and University College London,
warn that high-yielding boreholes will not be found using a scattergun approach,
and a more careful and exploratory approach that takes into account local
ground water conditions will be needed, which they hope their new study will
results show that in many populated areas in Africa, there is sufficient ground
water to supply hand pumps that communities can use for drinking water. These
hand pumps can deliver around 0.026 gallons to 0.079 gallons per second.
for boreholes yielding 1.3 gallons per second or more – the usual amount needed
for commercial irrigation – are not widespread and limited to specific areas,
such as countries in the north of Africa.
to the researchers' methods was the collation of existing national hydrogeological
maps as well as 283 aquifer studies from 152 publications. The vast amount of
data was compiled into a single database in which the researchers were able to
make their calculations.
amount of ground water present in a certain region is reliant on the interplay
between the geology of the area, the amount of weathering and the amount of
rainfall experienced both in the past and present. All of these factors were
considered to estimate the volume and potential yield of ground water in each
result of population growth in Africa and a planned increase in irrigation to
meet food demands, water use is set to increase markedly over the next few
decades. Climate change will pose a huge threat to this increase; however,
ground water responds much more slowly to increasing climatic variability as
opposed to surface water, so will act as a buffer to climate change.
lead author of the study, Dr. Alan MacDonald, says: "Ground water is such
an important water resource in Africa and underpins much of the drinking water
supply. Appropriately sited and developed boreholes for low yielding rural
water supply and hand pumps are likely to be successful and resilient to
boreholes should not be developed without a thorough understanding of the local
ground water conditions."
Most Detailed Maps Yet of Africa's Ground Water
April 30, 2012