Geoelectric Sounding for the Determination of Aquifer Transmissivity in Parts of Bayelsa State, South South Nigeria
- 1 Department of Geology & Physics, Niger Delta University, Wilberforce Island, Nigeria
- 2 Department of Geography and Environmental Management, Niger Delta University, Wilberforce Island, Nigeria
Abstract
The application of geophysical methods in combination with pumping tests provides a cost-effective and efficient alternative to estimate aquifer parameters. In this study, nineteen Schlumberger vertical electrical soundings (VES) were occupied in parts of Bayelsa State using a maximum current electrode separation ranging beweeen 300 - 400 m with the aim of estimating the transmissivity of the alluvial aquifer in areas where no pumping test has been carried out. Four of the soundings were carried out near existing boreholes in which pumping test had been carried out. The VES data obtained was interpreted, and layer parameters such as true resistivities and thickness were determined. The geoelectric parameters were used to generate the Dar Zarrouk parameters. Correlating the Dar Zarrouk parameter (e.g longitudinal unit conductance) with transmissivity derived from pumping test data, a constant was found which translate longitudinal unit conductance to transmissivity in a hydrogeological setting where effective porosity is the primary control on resistivity and hydraulic conductivity. Transmissivity determined from the pumping test data range between 1634.0 - 5292.0 m 2 /day while transmissivity values estimated from the longitudinal unit conductance (L c ) range between 721 - 8991 m 2 /day. The transmissivity estimated from the pumping test (T p ) data and transmissivity estimated from the longitudinal conductance (L c ) on comparison show excellent correlation (R 2 = 0.92). The high transmissivity values agree with the geology of the Benin Formation (Coastal Plain sands) consisting of fine-medium-coarse sands. The results give a useful first approximation of the transmissivity and could be used to site exploratory boreholes.
- A. T. Batayneh, “A Hydrogeophysical Model of the Relationship between Geoe Lectric and Hydraulic Parameters, Central Jordan,” Journal of Water Resource and Protection, Vol. 1, No. 6, 2009, pp. 400-407.
- V. Shevnin, O. Delgado-Rodriguez, A. Mousatov and A. Ryjov, “Estimation of Hydraulic Conductivity on Clay Content in Soil Determined from Resistivity Data,” Geofisica Internacional, Vol. 43, No. 3, 2006, pp. 195-207.
- G. V. Keller and F. C. Frischnechk, “Electrical Methods in Geophysical Prospecting,” Pergamon Press, Oxford, 1966, pp. 91-135.
- A. A. A. Zohdy, G. P. Eaton and D. R. Mabey, “Application of Surface Geophysics to Groundwater Investigations,” In: G. V. Keller and F. C. Frischnechk, Eds., Techniques of Water Resources Investigations of the United States Geological Survey, United States Government Printing Office, Washington DC, 1974, pp. 12-26.
- P. Sikander, A. Bakhsh, M. Arshad and T. Rana, “The Use of Vertical Electric Sounding Resistivity Method for the Location of Low Salinity Groundwater for Irrigation in Chaj and Rana Doabs,” Environmental Earth Sciences, Vol. 60, No. 5, 2010, pp. 1113-1129.
- W. Kelly, “Geoelectric Sounding for Estimating Aquifer Hydraulic Conductivity,” Ground Water, Vol. 15, No. 6, 1977, pp. 420-424. doi:10.1111/j.1745-6584.1977.tb03189.x
- O. Mazac, W. E. Kelly and I. Landa, “A Hydrogeological Model for Relations between Electrical and Hydraulic Properties of Aquifers,” Journal of Hydrology, Vol. 79, No. 1-2, 1985, pp. 1-19. doi:10.1016/0022-1694(85)90178-7
- L. C. Amajor and C. O. Ofoegbu, “Determination of Polluted Aquifers by Stratigraphically Controlled Biochemical Mapping: Example from the Eastern Niger Delta, Nigeria,” In: C. O. Ofoegbu, Ed., Groundwater and Mineral Resources of Nigeria, F. Vieweg, Braunschweig/Wiesbaden, 1988, pp. 62-73.
- J. R. L. Allen, “Late Quaternary Niger Delta and Adjacent Areas: Sedimentary Environments and Lithofacies,” American Association of Petroleum Geologists Bulletin, Vol. 49, No. 5, 1965, pp. 549-600.
- K. Short and A. J. Stauble, “Outline of Geology of Niger Delta,” American Association of Petroleum Geologists, Vol. 51, No. 5, 1965, pp. 761-779.
- M. E. Ofodile, “An Approach to Groundwater Study and Development in Nigeria,” Mecon Services Ltd., Ranchi, 1991, pp. 138-148.
- S. Niwas and D. C. Singhal, “Estimation of Aquifer Transmissivity from Dar Zar Rouk Parameters in Porous Media,” Journal of Hydrology, Vol. 50, 1981, pp. 393-399. doi:10.1016/0022-1694(81)90082-2