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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 14 (2006), Paper 5 Posted May 27, 2006 A QUANTITATIVE ESTIMATION OF GROUNDWATER RECHARGE IN PART OF THE SOKOTO BASIN, NIGERIA
Segun M.A. Adelana 1 2Darmstadt, Germany ABSTRACT Three basic methods have been quantitatively and comparatively applied to estimate recharge into the groundwater system in the Sokoto Basin. These include empirical (using three simplified equations), hydrochemical (chloride mass balance) and climatic-hydrological methods. The empirical method shows exaggerated values of recharge compared to the chloride and water balance methods. The chloride method shows mean recharge is on the order of 19.6 mm/yr based on an annual rainfall mean of 670 mm from 1916-1993 in the Sokoto area, but suggests that recharge can be highly variable in space and time. For most of the study area the spatial variability of recharge was found to be higher in wetter years than in dry years. Results show recharge around the Wurno and Goronyo areas is <1 % of annual rainfall while for areas outside this region recharge is 3.2 % of annual rainfall. This sharp variation was attributed to local conditions of climate and lithology. The chloride mass balance method appears to be most suitable for estimation of recharge in most of the basin, but is still limited by inadequacy of chloride measurements in rainwater in some areas. Reference: Adelana, S.M.A., P.I. Olasehinde, and P. Vrbka. 2006. A Quantitative Estimation of Groundwater Recharge in Part of the Sokoto Basin, Nigeria , Journal of Environmental Hydrology, Vol. 14, Paper 5. CONTACT: S. Adelana University of the Western Cape Earth Sciences Department (Groundwater Group) P. Bag X 17 Bellville 7535, Cape Town South Africa E-mail: Email:sadelana@uwc.ac.za |
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