Groundwater Determination for Flood Control in Quarries Around Idanre Area Ondo State Nigeria

Abstract

FAMADEJI M.O., AFENI T.B. and AFU D.J.

The research aimed at locating the rock aquiferous layers using Vertical Electrical Sounding. Geophysical survey investigation was utilized which involves reconnaissance survey and vertical electrical soundings. Water detectors like dowsing rods and a Pool finder were used in narrowing down the search for the aquiferous layers within the rock. Vertical Electrical Sounding (VES) was then used to acquire the resistivity of each layer at the point suggested by the detectors. The acquired data were iterated using DC-Inverse software to analyze and delineate the layers in thickness, depth and actual resistivity. The investigations revealed the points and areas on the ground surface within the quarries where there are likelihood of fractures in the intrusive rocks. At the Site 1 – Hengsheng Quarry Nigeria Limited, Imolumo-Idanre, eight VES points were occupied. VES 1, VES 2, VES 5, VES 6 and VES 7 are aquiferrous and proned to flooding. Hence drilling and blasting operations must be terminated before the specified depths (averagely 10m from the ground surface) while drilling and blasting can be done without fear of flooding at VES 3, VES 4 and VES 8. Moreover, at the Site 2 – Akinchang Quarry Nigeria Limited, Owena-Idanre), six VES points were occupied; Of which VES 1, VES 2, VES 3, VES 4 and VES 6 are aquiferous and proned to flooding at the specified depths (averagely 17m from the ground surface), hence, drilling and blasting must stop before the depths while only VES 5 is very safe and flooding may not be encountered.

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