FUW TRENDS IN SCIENCE & TECHNOLOGY JOURNAL
(A Peer Review Journal)
e–ISSN: 2408–5162; p–ISSN: 2048–5170
keywords: Very low frequency-electromagnetic, electrical resistivity, pumping test, geoelectric properties
An assessment of three failed boreholes that were earlier drilled at Ibusogboro Area of Ibadan was carried out using integrated Very Low Frequency-Electromagnetic (VLF-EM) and Electrical Resistivity (ER) methods. The aim was to investigate the causes of the borehole failure and to identify suitable site for groundwater development based on geoelectrical properties of the subsurface layers. Sixteen (16) VLF-EM profiles were used to delineate linear geologic structures within the study location. Seven (7) Vertical Electrical Soundings (VES) stations were occupied at the identified lineament zones. Four geoelectric units were delineated. These include the topsoil, weathered/partially weathered layer, fractured basement and the fresh bedrock with resistivity values which ranged between 91 and 698 Ωm, 20 and 213 Ωm, 55 and 225 Ωm, and 149 and 1399 Ωm, respectively. The result of VLF-EM revealed that the failed boreholes were located on unfissured fresh basement rock. The VES carried out at the VLF-EM delineated lineament zones revealed fractured basement at four locations. Test boreholes (BH) 4 and 5 were drilled at VES 2 and 6 to penetrate the fractured basement and yields of 2300 and 4400l litres/h were acquired through pumping test, respectively.
Adiat KAN, Olayanju GM, Omosuyi GO &Ako BD 2009. Electromagnetic profiling and electrical resistivity soundings in groundwater investigation of a typical basement complex – A case study of Oda Town Southwestern Nigeria. Ozean J. Social Sci., 2(4): 33-359. Akinrinade OJ &Olabode OP 2015. Integrated Geophysical Approach to Aquifer Delineation in Crystalline Basement Environment. Int. J. Scient. & Engr. Res., 6(10): 107-127. Ako BD, Olorunfemi MO. 1989. Geoelectric survey of groundwater in the newer basalts of Vom, Plateau State. J. Mining & Geol., 25(1 & 2): 247-250. Ariyo SO, Adeyemi GO & Oyebamiji AO 2009. Electromagnetic VLF survey for groundwater development in a contact terrain; A case study of Ishara-remo, Southwestern Nigeria. J. Appl. Sci. Res., 5(9) : 239-1246. Bayowa OG, Olorunfemi MO, Akinluyi FO & Ademilua OL 2014. Integration of hydrogeophysical and remote sensing data in the assessment of groundwater potential of the basement complex terrain of Ekiti State, Southwestern Nigeria. Ife J. Sci., 16(3): 353-363. Beeson S & Jones CRC 1988. The combined EMT/VES geophysical methods for sitting boreholes. Groundwater, 26: 54-63. Google Map 2016. http://www.satellitecitymaps.com/africa-map/nigeria-map/oyo-state-map/ibusogboro-map/30/09/2016. Hazell JRT, Cratchley CR & Preston AM 1988. The location of aquifers in crystalline rocks and alluvium in Northern Nigeria using combined electromagnetic and resistivity techniques. Quarterly J. Engr. Geol., 21: 59-175. Mbonu PDC, Ebeniro JO, Ofoegbu CO & Ekine AS 1991. Geoelectric sounding for the determination of aquifer characteristics in parts of the Umuahia area of Nigeria. Geophysics, 56(2): 284-291. Olayinka AI 1990. Electromagnetic profiling and resistivity soundings in groundwater investigation near Egbeda Kabba and Kwara State. Journal of Mining & Geology, 26: 243-250. Olayinka AI, Amidu SA & Oladunjoye MA 2004. Use of electromagnetic profiling and sounding for groundwater exploration in the crystalline basement area of Igbeti, Southwestern Nigeria. Global J. Geological Sci., 2(2):243-253. Olorunfemi MO & Fasuyi SA 1993. Aquifer types and the geoelectic/ hydrogeological characteristics of part of the central basement terrain of Nigeria (Niger State). J. Afr. Earth Sci., 16: 309 – 317. Olorunfemi MO, Dan – Hassan MA & Ojo JS 1995. On the scope and limitations of the electromagnetic methods in groundwater prospecting in a Precambrian basement terrain a Nigerian case study. J. Afr. Earth Sci., 20(2): 151 – 160. Olorunfemi MO, Fatoba JO & Ademilua LO 2005. Integrated VLF- electromagnetic and electrical resistivity survey for groundwater in a crystalline basement complex terrain of Southwest Nigeria. Global J. Geol. Sci., 3(1): 71-80.
