Browsing by Author "Oladunjoye, Michael A."
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Item Evaluating the groundwater potential of coastal aquifer using geoelectrical resistivity survey and porosity estimation: A case in Ota, SW Nigeria(ScienceDirect, 2020) Oyesomi, Kehinde; Aizebeokhai, Ahzegbobor P.; Metwaly, Mohamed; Oladunjoye, Michael A.; Bayo-Solarin, BabaMayowa A.; Sanuade, Oluseun A.; Thompson, Cherish E.; Ajayi, Francis S.; Ekhaguere, Osagie A.Geoelectrical resistivity sounding surveys was carried out at two locations (A and B) in the new CanaanCity residential estate of Canaan land Ota, Ogun state in order to locate possible targets for groundwater explorations. A total of twelve (12) vertical electrical soundings were conducted using the Schlumberger array configuration. The interpretations of the VES curves revealed five to six geoelectrical layers at location A which comprises VES1-7. The geoelectric units consist of the topsoil, sandy clay, lateritic clay, confining bed (clayey sand), and main aquifer (sand). The top of the aquifer in this part of the study area is between 40 m and 83.5 m. Likewise, a total of five to seven layers of geoelectrical units were delineated at the location B portion of the study site (VES 8–12) similar to location A with an addition of the shale unit that was interpreted to be that of the Akimbo Formation of the Dahomey Basin. The depth to the top of the productive aquifer within location B is in the range of 40–112.4 m. The delineated basal shale layer is impermeable, serving as the base seal rock for the confined aquifer system. The estimated porosity values range from 28% to 74%, indicating that the highly porous aquifer system in the area is the coastal plain sands mixed with the alluvium sand of the Benin Formation of Dahomey Basin. The study revealed the complexity of the productive aquifer system in the area and its undulating topographyItem Hydrogeophysical Investigations for Groundwater Resources Sustainability in Parts of the Eastern Dahomey Basin, Nigeria(ImprintCRC Press, 2024) Oyeyemi, Kehinde D.; Aizebeokhai, Ahzegbobor P.; Okon, Emmanuel E.; Oladunjoye, Michael A.Geophysical surveys including geoelectrical resistivity and time-domain induced polarization (IP) techniques have been conducted in Ota in Eastern Dahomey Basin. Thirty vertical electrical sounding (VES) profilings were conducted using a Schlumberger array with an AB/2 range of 180–240 m. Two profiles of 2D electrical resistivity imaging and IP surveys were conducted with Wenner array configuration. The delineated geoelectric layers are topsoil (lateritic clay), clayey sand, sandy clay, sand, and shale or clay units. Two aquifers were delineated in the area with the upper aquifer being a fine-to-medium sand and the lower aquifer of a poorly medium-to-coarse sand unit. The aquifer resistivity ranges are 347.4–411.4 https://www.w3.org/1998/Math/MathML" display="inline"> Ω m https://www.w3.org/1999/xlink" xlink:href="https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west 1.amazonaws.com/9781003454908/c35032d3-f666-459f-b1ca a1b405d5a7b1/content/C025_equ_0001.tif"/> and 104.5–143.3 https://www.w3.org/1998/Math/MathML" display="inline"> Ω m https://www.w3.org/1999/xlink" xlink:href="https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west 1.amazonaws.com/9781003454908/c35032d3-f666-459f-b1ca a1b405d5a7b1/content/C025_equ_0001.tif"/> for the upper and lower aquifer, respectively. The hydraulic parameters of both aquifers were estimated using established mathematical relations. The upper aquifer has porosity, hydraulic conductivity, and transmissivity ranges of 19.1% 21.8%, 10.8 × 10−2 (m/s)–17.0 × 10−2 (m/s), and 1.49–2.4 (m2/s), while the lower aquifer unit has porosity, hydraulic conductivity, and transmissivity values of 43%–55%, 248 × 10−2–782 × 10−2 (m/s), and 34.72–101.66 (m2/s). High hydraulic parameters in the two aquifers are important for sustainable groundwater development, ensuring efficient use and protection of this vital resource. Their significance extends to promoting regional economic growth by supporting agriculture, industries, and tourism. Mapping faults in the area highlights the need for hydrogeological modeling to discern their impact on aquifer parameters, vital for precise resource management, and predicting potential effects on availability and quality.