The hydrogeology of crystalline aquifers in northern Nigeria and geophysical techniques used in their exploration

Abstract

The large number of rural water supply boreholes sited and drilled in northern Nigeria during the ground water decade of the eighties has provided much data on the hydrogeology of the Basement regolith and has led to the development of new techniques in locating aquifers. Regolith aquifer characteristics and their dependence on geology and environment are reviewed with particular emphasis on lithology, weathering pattern and fracturing in Bauchi, Kano and Sokoto States. Specific capacity is shown to be related to both lithology and grade of weathering; dry season water levels and frequency of occurrence of successful holes are related to lithology. Water quality data for Kano State show some high nitrate concentrations. The process of borehole siting begins with desk study (records and photointerpretation), then field reconnaissance of lithology, structure, water points, topography and soils. EM traverses and resistivity soundings follow in targeted areas. Maximum regolith thicknesses are estimated from the vertical to horizontal coil (EM) response using computed model graphs for 40 m and 20 m coil spacings. VES measurements at these sites give regolith resistivities, hence some estimate of its suitability as an aquifer. In addition EM traverses have located steeply-dipping fracture zones, dykes and pegmatites and interpretation of these in terms of strike and dip has been aided by results from a computer-controlled modelling system.

Assessment of borehole water quality in Yola-Jimeta Metropolis, Nigeria

“…However, the lack of sufficient distribution network and weak treatment facilities coupled with high evapo-transpiration which exceeds precipitation are major challenges to achieving the development target of providing potable water supply in Nigeria (Dankano, 2006;Onugba and Aboh, 2009). Consequently, majority of the people rely on boreholes as their main source of water supply (Hazell et al, 1992;Okafor and Ogbonna, 2003). In Yola-*Corresponding author.…”

GIS-based model of groundwater occurrence using geological and hydrogeological data in Precambrian Oban Massif southeastern Nigeria

“…Granitic rocks offer lowest yield boreholes owing to the impervious nature of the rock, while pegmatites are commonly a locus of tectonic movement and can be prolific aquifers for groundwater (Hazella et al 1992). The sedimentary region is mainly sandstones, silts, gravelly sands, clays, and shale which are porous enough to be producible aquifers.…”

“…5) and the yields were correspondingly higher in the sedimentary region than the basement terrain. There is no significant difference between drilled depths and specific capacity or yield, drilling generally stops once the required depth for the well construction, and the required yield is attained (Hazella et al 1992). Boreholes drilled through thick overburden greater than 25 m yields some appreciable quantity of groundwater and regolith aquifer overlying the Precambrian basement rocks are the main source of groundwater in the basement (Anyeakun and Dapaah-Siakwan 2006).…”

Two-Dimensional Interpolation Polynomial Method for Modelling Ground Water Hydraulic Head at Nariya Area of Kaduna, Nigeria

“…but these methods are often of great financial costs. Examples of these works include Carruthers and Smith (1992), Hazel et al (1992), Adeoti et al (2010), Alile et al (2011), Olaniyan and Olabode (2012) and several others.…”