The evaluation of groundwater resources in the crystalline basement of northern Nigeria

Acworth, R. Ian (1981). The evaluation of groundwater resources in the crystalline basement of northern Nigeria. University of Birmingham. Ph.D.


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A methodology of assessment is presented of the groundwater
resources available in fracture zones, within the weathered mantle of gneiss, migmatite and granite. A model of weathering is developed, and values of porosity, hydraulic conductivity and electrical resistivity assigned to the different grades of weathering. A geophysical technique is developed, based upon a combination of electrical resistivity profiling and sounding, which allows a volume
estimate of the various weathering grades to be made. A finite difference algorithm is used for this estimate which enables the apparent resistivity response of an inhomogeneous resistivity distribution to be calculated. An iterative approach is then adopted, adjusting the resistivity model until the calculated response agrees
with the field data.

An analysis of recharge in a savanna climate is developed based upon the Monteith equation for predicting evapotranspiration, and upon a model of unsaturated zone soil moisture movement. The recharge
function developed is included in a one dimensional catchment water balance model. The results from this model are compared with observed runoff and groundwater hydrographs.

The estimate of recharge is combined with the estimate of aquifer storage to produce an assessment of available groundwater. Optimal methods for the development of the resource are discussed. While developed in Northern Nigeria, the methodology of assessment is applicable to any similar geological and climatological environment.

Type of Work: Thesis (Doctorates > Ph.D.)
Award Type: Doctorates > Ph.D.
College/Faculty: Faculties (to 1997) > Faculty of Science
School or Department: Department of Geological Sciences
Funders: None/not applicable
Subjects: G Geography. Anthropology. Recreation > GE Environmental Sciences
Q Science > QE Geology


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