Leakage properties of the multi-aquifer system underlying the Greater Onitsha water scheme borehole field,Anambra State,Nigeria |
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| Authors: | G. I. NWANKWOR B. C. E. EGBOKA |
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| Affiliation: | 1. Department of Geosciences , Federal University of Technology , PMB 1526, Owerri, Nigeria;2. Department of Geological Sciences , Anambra Stale University of Technology , Awka Campus, PMB 5025, Awka, Nigeria |
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| Abstract: | Abstract Leakage properties and the potential for land subsidence due to groundwater withdrawal from a multi-aquifer water supply system were investigated by applying leaky type curve and one dimensional consolidation models to drawdown data that were obtained during a pumping test experiment in an aquifer-aquitard system. The producing aquifer has transmissivity and storativity values of 5.3 × 10?3 m2 s?1 and 9.54 × 10?4 respectively. It is recharged through leakage at a rate of 5.67 × 10?8 m s?1, giving a leakage amount of more than 0.007 m3 s?1. Drainage of the aquifer-aquitard system could result in aquitard compaction of between 50 and 180 mm year?1 for pumping periods of 6 and 22 h day?1, respectively. The observed leakage has important implications for land subsidence problems and waste disposal practices in the area. |
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