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Journal of Environmental Hydrology
ISSN 1058-3912 |
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Electronic Journal of the International Association for
Environmental Hydrology
JEH Volume 19 (2011), Paper 21 Posted September 30, 2011 DELINEATION OF FRESH-BRACKISH WATER AND BRACKISH-SALINE WATER INTERFACES USING VES SOUNDINGS IN SHANI, BORNO STATE, NIGERIA
O.T. Nkereuwem ABSTRACT Eighteen VES stations established and sounded in 1991 along a SE-NW profile in Shani area were re-visited and sounded afresh in 2010. It was observed that VES stations (1 - 9) which revealed four-layered curves in 1991, now revealed six-layered curves in 2010, with significant reductions in layer resistivity values. Analyses of water samples obtained from a hand-dug well and a borehole close to VES stations 3 and 7 respectively, revealed the water from the shallow hand-dug well to be fresh with a TDS value of 0.4 ppt and the water from the deeper borehole to be brackish with a TDS value of over 17 ppt. Two parallel faults reported along the basin of River Hawal by Carter et al.(1963) are suspected to act as migratory routes of salt water to the Bima sandstone aquifer in Shani area. This study has permitted the delineation of the fresh water - brackish water and brackish - saline water interfaces in Shani. The study has revealed that due to considerable mixing of the freshwater with the saltwater, a zone of brackish water has evolved between the freshwater above and the saline water below. The depth to the fresh - brackish water interface in Shani has been established by this study as ranging from 50 to 53 m below ground surface, thus enabling water developers in the area to produce salt-free water for human and industrial uses. Reference: Nkereuwem, O.T., S.N. Yusuf, and M.U. Mijinyawa. 2011. Delineation of fresh-brackish water and brackish-saline water interfaces using VES soundings in Shani, Borno State, Nigeria. Journal of Environmental Hydrology, Vol. 19, Paper 21. CONTACT: S.N. Yusuf Department of Geology University of Maiduguri Borno State, Nigeria E-mail: Email: solomonnyusuf@yahoo.com |
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