Prediction of Hydrogeologic Risks of Dump Sites using Fuzzy Approach A Case Study of Some Dumpsites at Igbara-Oke, South-Western Nigeria
Bosede O. Ayeni1, Gregory O. Omosuyi2, John C. Nwaiwu3, Adetayo A. Adebayo4
1Bosede O. Ayeni, Applied Geophysics Department, Federal University of Technology Akure, Nigeria.
2Gregory O. Omosuyi, Applied Geophysics Department, Federal University of Technology Akure, Nigeria.
3John C. Nwaiwu, Computer Science Department, Federal University of Technology Akure, Nigeria.
4Adetayo A. Adebayo, Computer Science Department, Federal University of Technology Akure, Nigeria.
Manuscript received on July 02, 2018. | Revised Manuscript received on July 15, 2018. | Manuscript published on July 30, 2018. | PP: 1-8 | Volume-5 Issue-7, July 2018. | Retrieval Number: D1236045418
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© The Authors. Published By: Blue Eyes Intelligence Engineering and Sciences Publication (BEIESP). This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)
Abstract: Geophysical investigation was carried out within the vicinity of some open active waste dumpsites at Igbara-Oke, Southwestern Nigeria along ten traverses with sixty-two (62) Vertical Electrical Sounding (VES) positions being occupied in the East- West and South- North direction to assess the geology and hydrogeologic condition of the subsurface around the dumpsites. The interpreted geoelectric sections showed subsurface layers as top soil with resistivity range of 5- 448 Ωm and thickness 0.30 -7.7m; weathered layer resistivity value varying from 9-250 Ωm had thickness values between 0.4m –7.1m. Thickness of the fractured/fault layer having resistivity values lesser but not greater than 750 Ωm, ranges from 1.2 m to 11m and depth to bedrock thickness extended beyond 17.9m having resistivity value exceeding 1000Ωm. Underlying possible lithological characteristics was inferred using the information from the geoelectric sections. Aquifer systems of weathered/fractured unconfined aquifer, weathered/fractured confined aquifer, weathered layer aquifer, weathered layer/fractured semi-confined aquifer types were delineated. A fuzzy model implemented asserts the relative hazard rating of the dumpsites as 1.72 and 1.67 on a scale of 10, indicating the dumpsites may not be currently posing a risk based on its sizes, waste content and localization of leachates plume.
Keywords: Groundwater, Hydrogeologic, Hydrogeological risks, Fuzzy logic, Relative Hazard Rating.