Modelling the Subsurface Geology and Groundwater Occurrence of the Matsheumhlope Low Yielding Aquifer in Bulawayo Urban, Zimbabwe
Modelling the Subsurface Geology and Groundwater Occurrence of the Matsheumhlope Low Yielding Aquifer in Bulawayo Urban, Zimbabwe
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模拟津巴布韦布拉瓦约市 Matsheumhlope 低产含水层的地下地质和地下水赋存
DOI：
10.5539/jgg.v5n3p158
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发表时间：
2013
期刊：
影响因子：
--
通讯作者：
Vunganai Midzi
中科院分区：
文献类型：
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作者：
Constant Chuma;D. J. Hlatywayo;Joseph D. S. Zulu;Innocent Muchingami;R. Mashingaidze;Vunganai Midzi
本研究的重点是确定 Matsheumhlope 低产含水层地下和地下水的性质、范围和空间变化，以提高对布拉瓦约大都市区地下水分布的了解。从结晶基底复合体中抽取和利用地下水常常受到高钻孔失败率的阻碍。例如，津巴布韦布拉瓦约市大部分地区的 Matsheumhlope 井田的井眼失败通常归因于许多尚未在当地和区域范围内进行调查的因素。采用电阻率法确定低产含水层地质单元的深度、厚度和层序。卫星数据用于描绘该地区的轮廓并评估该地区的地形特征。从钻孔获得的地质样本与地球物理伪剖面相关联，以便更好地了解该地区的地下和地下水的存在。地理信息系统（GIS）用于模拟地下的地球物理特征，给出该地区潜在的地下水存在情况。研究证实，Matsheumhlope 含水层是研究区高地基岩深度较浅的非均质无承压含水层。结果还显示，短距离内地下地层和地下水势的高度空间变化，从而表明绘制基底含水层的复杂性。该地区的钻孔失败归因于含水层某些部分下方的基岩深度较浅。因此，研究结果建议应使用结构测绘和地球物理方法对整个 Matsheumhlope 含水层的裂缝进行结构和地球动力学分析。
This study is focused on determining the nature, extend and spatial variation of the subsurface and groundwater in the Matsheumhlope low yielding aquifer so as to improve the understanding of groundwater occurrence within Bulawayo Metropolitan area. The abstraction and utilisation of groundwater from crystalline basement complexes have often been hampered by the high rate of borehole failure. For instance, borehole failure in the Matsheumhlope wellfield that characterises the greater part of Bulawayo City, Zimbabwe, is often ascribed to many factors which are yet to be investigated locally and regionally. The electrical resistivity method was used to establish the depth, thickness and sequence of geological units in the low yielding aquifer. Satellite data were used to delineate the lineaments and assess the topographic features of the area. Geological samples obtained from boreholes were correlated with the geophysical pseudo sections to give a better view of the subsurface and groundwater occurrence in the area. Geographic Information Systems (GIS) was used to model the geophysical characteristics of the subsurface giving the potential groundwater occurrence in the area. The study confirmed that the Matsheumhlope aquifer is a heterogeneous unconfined aquifer with a shallow depth to the basement rock in highlands of the study area. The results also showed high spatial variation of subsurface formations and groundwater potential over short distances, thereby indicating the complex nature of mapping basement aquifers. Borehole failure in the area was attributed to the occurrence of shallow depth of the bedrock underlying some parts of the aquifer. Therefore the results of the study recommended that the structural and geodynamic analysis of the fractures of the whole Matsheumhlope aquifer should be done using both structural mapping and geophysical methods.