Figure 4: Apparent Resistivity Distribution for HP of ɑ=40m. The fifth layer is the fractured/highly weathered hydrogeological significance and will readily serve rock material. The resistivity values range from the needs of shallow hand-dug wells. 100 600 ohm-m and the thickness varies from 6.5 The fractured/highly weathered rock material has – 56m. The layer is the most reliable aquiferous thickness varying from 6.5 to over 56 metres, with – horizon within the subsurface in the area. layer resistivity from 100 to This unit is 600Ω-m. The last layer is the fresh granite bedrock. The encountered everywhere along all the traverses but resistivity values are generally above 1500 ohm-m. at varying depths which is not less than 15m below Depth to bedrock ranges from 16.5 to over 72 ground surface. It is a unit that is of highest metres. hydrogeological significance in the area and it is Both the weathered rock material and the expected to be a large reservoir of groundwater at rocks occur at shallow depths and their deeper depth. Areas with large thickness are resistivity values will allow area only limited expected to support boreholes with high yields hydraulic conductivity characteristics. The small (Olorunfemi, 1990). In most places, the hard rock amount of storage in them will be prone to easy unit of low permeability overlies this aquiferous pollution from the ground surface. However, where zone making it more difficult for pollution by found, they may constitute low to medium infiltrating water.
Figure 4: Apparent Resistivity Distribution for HP of ɑ=40m. The fifth layer is the fractured/highly weathered rock material. The resistivity values range from 100 – 600 ohm-m and the thickness varies from 6.5 – 56m. The layer is the most reliable aquiferous horizon within the subsurface in the area. The last layer is the fresh granite bedrock. The resistivity values are generally above 1500 ohm-m. Depth to bedrock ranges from 16.5 to over 72 metres. Both the weathered rock material and the rocks occur at shallow depths and their resistivity values will allow area only limited hydraulic conductivity characteristics. The small amount of storage in them will be prone to easy pollution from the ground surface. However, where found, they may constitute low to medium hydrogeological significance and will readily serve the needs of shallow hand-dug wells. The fractured/highly weathered rock material has thickness varying from 6.5 to over 56 metres, with layer resistivity from 100 to 600Ω-m. This unit is encountered everywhere along all the traverses but at varying depths which is not less than 15m below ground surface. It is a unit that is of highest hydrogeological significance in the area and it is expected to be a large reservoir of groundwater at deeper depth. Areas with large thickness are expected to support boreholes with high yields (Olorunfemi, 1990). In most places, the hard rock unit of low permeability overlies this aquiferous zone making it more difficult for pollution by infiltrating water.
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