Critical Study Of Ground Water Potential Of Part Of Obubra Local Government Area, Cross River State, Nigeria

ABSTRACT: The vertical electrical sounding (VES) technique employing the Schlumberger electrode array was used to survey some villages in Obubra Local Government Area of Cross River State with a view to determine the groundwater potntial of the area. The study area is located between longitude 80 12� and 80 16� E and latitudes 50 45� and 60 15� N. a total of seventeen (17) electrical soundings were undertaken using the ABEM TERRAMETER model SAS 300, maximum current electrode spread of 500m was attained. The data were interpreted using resist computer software programme to obtain the final model for each VES location. These models were combined to produce a profile showing the geoelectric sections of the subsurface. Correlation of the inferred geoelectrical models showed that the first layer is composed of the sand mixed with clay and its resistivity is between 157 and 497Wm. The second layer inferred as clay has a resistivity range between 17 and 67Wm. the third layer suspected to be sandstone had resistivity range of 541-7603Wm. The fourth layer suspected to be shale had a resistivity range of 97-574Wm, while the last layer is sandstone with resistivity range of 309-4412Wm. The sandstone layers (3rd and 5th) are considered to be the potential aquifer units in the area.

REFERENCES

[1] Abem, (1992). Geophysical instruments catalogue. ABEM Printed Matter No. 90320, Bromma Atlas Copco.

[2] Fetters, C. W. (2001). Applied hydrology. Bell and Howell Company, Columbus.

[3] Fitterman, D. V. & Stewart, M. T. (1986). Transient electrognetic sounding for groundwater Geophysics, 51, 995-1005.

[4] Griffiths, D. H. (1976). Application of electrical resistivity measurements for the determination of porosity and permeability in sandstones geo-exploration, 14, 207-213.

[5] Hemkler, C. J. (1985). A VES modelling programme for Schlumberger automatic analysis resistivity inversion. (SAA-V. 0.92), 560. Pers. Comm.

[6] Kogbe, C. A. (1989). Geology of Nigeria Rockview (Nigeria) Limited, Jos Nigeria 2nd Ed. 457-468.

[7] Murrat, R. C. (1970). Stratigraphy and paleogeography of the Cretaceous and lower tertiary in Southern Nigeria. African Geology (Edited by Dessauvagie, T. F. J. & Whieman, A. J.). Ibadan: University of Ibadan Press. 251-268.

[8] O�Laoghaire, D. T. & Himmeiblan, D. M. (1974). Optical expansion of a water resources of system. Academic Press. New York.
[9] Okon-Umoren, O. E. (1983). Resistivity studies of Okpoma area,Ogoja Division. M.Sc. Thesis, Department of Physics, University of Calabar, Calabar � Nigeria.

[10] Okon-Umoren, O. E. (1992). Integrated Geophysical studies of the Calabar Flank. Ph.D Thesis, Department of Physics, University of Calabar, Calabar � Nigeria.

[11] Okwueze, E. E. & Ezeanyim, V. I. (1985). The vertical electrical sounding (VES) method in laterite regions and in iron-rich glaciated areas. Nigerian Journal of Mining and Geology, 22, 193-198.
[12] Okwueze, E. E. (1983). Geophysical investigation of the bedrock and the groundwater-lake flow system in the trout lake region of Vilas country, Northern Wisconsin. Ph.D Thesis.

[13] Onuaho, K. & Mbazi, F. (1988). Estimation of aquifer transmissivity from electrical sounding data: The case of Ajjali sadstone Aquifers Southwest of Enugu, Nigeria. In: Groundwater and mineral resources of Nigeria, Ogogbu, C. O. (Ed). Vieweg-verag, 17-30.

[14] Overmeeren, R. A. (1989). A continuation of electrical resistivity, seismic refraction and gravity measurement for groundwater exploration in Sudan. Geophysics, 46, 134-138.

[15] Short, K. C. & Stauble, A. J. (1967). Outline of the geology of Niger Delta. America Association of Geology Bulletin, 51, 661-779.

[16] Telford, W. M. Geldart, L. P. & Keys, D. A. (1990). Applied Geophysics. (2nd ed). London: Cambridge University Press.

[17] Umaro, A. F. & Schoenick, K. (1992). Hydrogeological investigations of the aquifers Bauchi area. Journal of Mining and Geology, 28, 45-53.

[18] Verma, O. & Bischoff, J. H. (1989). Laboratory and field studies of the application of electromagnetic prospecting for groundwater on Marojo Island, Brazil. Geophysics, 54, 23-30.

[19] Zohdy, A. A. R. & Bisdorf, R. J. (1989). Schlumberger Sounding Data processing and Interpretation program. U. S. Geological Survey.

[20] Zohdy, A. A. R., Eaton, G. P. & Mabey, D. R. (1984). Techniques of water-resources investigations of the United States Geological Survey. Washington: United States Government Printing Office.