Philosophiae Doctor - PhD (Earth Science)

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https://hdl.handle.net/10566/17483

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Browsing by Subject "Aquifer vulnerability"

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    GIS and remote sensing-based integrated modelling of climate and land use change impacts on groundwater quality: Cape Flats Aquifer, South Africa
    (University of Western Cape, 2021) Gintamo, Tesfaye Tessema; Kanyerere, Thokozani
    The need to ensure groundwater security is vital, particularly in urban areas. Assessing the impact of land use and climate variables on groundwater quality can help improve sustainable management. The vulnerability mapping of groundwater contamination identifies high-risk areas. Using models and technologies that forecast the distribution of contamination risk over time and place can help prioritize groundwater monitoring. Based on such needs, the Cape Flats aquifer in Cape Town, South Africa, was chosen as the case study for assessing the potential for groundwater contamination risk in urban and coastal hydrogeological settings. The Cape Flats aquifer has been highlighted as an alternate water supply source to augment current supply sources in Cape Town. However, the shallow aquifer is under pressure from agricultural and industrial activities and long-term climate variables, among other factors.
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    Groundwater resource evaluation and protection in the Cape Flats, South Africa
    (University of the Western Cape, 2010) Adelana, Segun Michael Adegboyega; Xu, Yongxin; Mazvimavi, Dominic; Dept. of Earth Science; Faculty of Arts
    The analysis of geologic, hydrologic and hydrogeologic data interpreted to give the characteristics of the Cape Flats aquifer showed the quality of groundwater from the aquifer is suitable for development as a water resource. The conceptual model of the Cape Flats sand shows an unconfined sandy aquifer, grading into semi-confined conditions in some places where thick lenses of clay and peat exists. Recharge rates through the saturated zone of the Cape Flats aquifer have been determined by water table fluctuation (WTF), rainfall-recharge relationship, soil water balance and chloride mass balance methods (CMB). Recharge rates using the WTF vary considerably between wet and dry years and between locations, with a range of 17.3% to 47.5%. Values obtained from empirical rainfall-recharge equation (method 2) agree with those of the WTF. Recharge estimates from the water balance model are comparatively lower but are within the range calculated using empirical method 2 (i.e. 87 - 194 mm or 4 – 21% of MAP). These recharge rates also agree with estimates from the series of other methods applied to sites located in the north-western coast of Western Cape and are comparable to recharge rates obtained elsewhere in the world.