Estimation of groundwater recharge in sedimentary rock aquifer systems in the Oti basin of Gushiegu District, Northern Ghana
Estimation of groundwater recharge in sedimentary rock aquifer systems in the Oti basin of Gushiegu District, Northern Ghana
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DOI：
10.1016/j.jafrearsci.2017.02.035
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发表时间：
2017-07-01
影响因子：
2.3
通讯作者：
Chegbeleh, Larry Pax
中科院分区：
文献类型：
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作者：
Afrifa, George Yamoah;Sakyi, Patrick Asamoah;Chegbeleh, Larry Pax
可持续发展和管理地下水资源以实现最佳社会经济发展，是减轻农村地区气候变化影响的最有效战略之一，因为农村地区的贫穷是造成环境破坏的一个重要原因。这项研究评估了加纳北部地区Gushiegu区的地下水补给及其时空变化，那里的地下水是大多数用途的主要供水来源。利用降水和地下水的同位素资料，推断了研究区部分变质沉积含水层系统中地下水的来源和地下水与地表水的可能关系。尽管这些数据没有明显地建立地下水和地表水之间的强烈关系，但研究表明，该地区的地下水来自大气降水。然而，数据也表明，与该地区的雨水相比，地下水中的重同位素(O-18和H-2)显著富集。利用氯离子质量平衡(CMB)和地下水位波动(WTF)技术对该地区地下水补给进行了定量估算。结果表明，该区地下水补给量为13.9 mm/a~218 mm/a，平均为89 mm/a，约占该区年降水量的1.4%~21.8%(平均8.9%)。该区地下水补给量的时间变化没有明确的趋势，但讨论了与下伏岩性有关的空间变化。结果表明，作为地下水补给的到达饱和带的降水比例在很大程度上受非饱和带材料的垂直导水系数的控制。该地区垂直导水率与湿度变化相结合，对降水的垂直入渗起调节作用。(C)2017爱思唯尔有限公司。保留所有权利。
Sustainable development and the management of groundwater resources for optimal socio-economic development constitutes one of the most effective strategies for mitigating the effects of climate change in rural areas where poverty is a critical cause of environmental damage. This research assessed groundwater recharge and its spatial and temporal variations in Gushiegu District in the Northern Region of Ghana, where groundwater is the main source of water supply for most uses. Isotopic data of precipitation and groundwater were used to infer the origin of groundwater and the possible relationship between groundwater and surface water in the partially metamorphosed sedimentary aquifer system in the study area. Though the data do not significantly establish strong relation between groundwater and surface water, the study suggests that groundwater in the area is of meteoric origin. However, the data also indicate significant enrichment of the heavy isotopes (O-18 and H-2) in groundwater relative to rainwater in the area. The Chloride Mass Balance (CMB) and Water Table Fluctuations (WTF) techniques were used to quantitatively estimate the groundwater recharge in the area. The results suggest groundwater recharge in a range of 13.9 mm/y - 218 mm/y, with an average of 89 mm/yr, representing about 1.4%-21.8% (average 8.9%) of the annual precipitation in the area. There is no clearly defined trend in the temporal variations of groundwater recharge in the area, but the spatial variations are discussed in relation to the underlying lithologies. The results suggest that the fraction of precipitation that reaches the saturated zone as groundwater recharge is largely controlled by the vertical hydraulic conductivities of the material of the unsaturated zone. The vertical hydraulic conductivity coupled with humidity variations in the area modulates the vertical infiltration and percolation of precipitation. (C) 2017 Elsevier Ltd. All rights reserved.