Monitoring of Seepage in Agba Dam, Kwara State, Nigeria, Using Vertical Electrical Sounding Technique
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Date
2015
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School of Engineering and Engineering Technology, Federal University of Technology Minna
Abstract
The geophysical investigation has been undertaken at Agba Dam, Ilorin; located around the southern flanks of the Nigeria basement complex. It is bounded by longitudinal E 0040 35’ 0.72” – E 0040 35’ 40.6” and latitude N 080 28’ 23.3” – N 080 28’ 40.1”. This was aimed at investigating possible seepage along the dam’s flank. The vertical Electrical Sounding (VES) technique was used for the field study. Twenty VES stations of four profiles were established along the bank of the dam and data were acquired using the Schlumberger electrode configuration. The resistivity values in the surveyed area vary from 9.28 Ωm to 9409.37 Ωm. Three major geo-electric layers were delineated which are: topsoil, weathered layers, and fresh basement. The 2D pseudo-section along the profiles revealed the lowest resistivity of 30 Ωm at the depth of 3m. This observation could be a signature of seepages around those areas. Also, a minor conductive zone that appears close to the dam embankment could signify inceptions of buried erosion. This could be inimical to the future sustenance of the dam. The highest resistivity of 1000 Ωm was discovered at the depth of 10 m around VES 13 which is the area of the Dam embankment. This implies that the structure of the Dam embankment is not compromised and is still effective.
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Research Subject Categories::NATURAL SCIENCES