PhD Thesis Emmanuel Obeng Bekoe - Cranfield University

Emmanuel Obeng Bekoe Phd Thesis Chapter 2 Hydrol, Humid Tropics & Study Area
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2.3.4 Infiltration
GWP-WATAC (2000) noted that infiltration within West Africa is always poor
because the precipitation intensity exceeds the infiltration rate (Van Giesen et
al, 2000), which is exacerbated by the state of the soil surface, in particular by
soil crusts which develop even on very sandy soils in the region.
2.3.5 Groundwater
Hayward and Oguntoyinbo (1987) reported that two main lithologies control the
distribution of underground water in West Africa: rocks of the Basement
Complex and the sedimentary rocks of the continental shields. Very extensive
regions of West Africa are underlain by the crystalline basement rocks of the
continental shield which are not very productive aquifers, so that the water from
these sources is of only local significance.
Borehole and well yields from the region’s aquifers are generally low and range
from 0.3 to 3 m 3 /h but can reach 10m 3 /h. In some areas, yields as high as
45m 3 /h have been observed (GWP-WATAC, 2000).
2.4 Study Area
2.4.1 Ghana an Overview
The Republic of Ghana is located on the West Coast of Africa (Figure 2.1),
between latitudes 4 o 44’ N and 11 o 11’ N and 3 o 11’ W and 1 o 11’E. It has a total
land area of 23.85 million ha and is bordered by Togo on the east, La Côte
D’Ivoire on the west, Burkina Faso on the north and the Gulf of Guinea of the
Atlantic Ocean to the south which forms a coastline 550 km long. Ghana has a
population of 18.4 million with a growth rate of 2.5 percent per annum and a
mean population density of 77 persons / km 2 (Ghana Census 2000). The
population distribution varies across the 10 administrative regions of the country
with 68 percent and 32 percent of the population living in the rural and urban
areas respectively. About 52 percent of the labour force is engaged in
agriculture, 29 percent in services and 19 percent in industry. Approximately, 39