Institute for Groundwater Studies (IGS)
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Browsing Institute for Groundwater Studies (IGS) by Subject "Aerial photographs"
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Item Open Access Establishing geobotanical-geophysical correlations in the north-eastern parts of South Africa for improving efficient borehole siting in difficult terrain(University of the Free State, 2007-11) Meulenbeld, Paul Martin Peter Bernard; Van Tonder, G. J.English: The determination whether certain botanic species can be associated and linked to the existence of groundwater resources by considering the relationship of these species with certain lithologies has been studied in the present research with the aid of geophysics, geology, soil quality analysis (geochemistry), aerial photographs and proven borehole records. Ordinary scientific groundwater exploration makes use of methods such as aerial photographic interpretation, geological modelling of the area under investigation by making use of published geological maps and field reconnaissance work, geohydrological concerns and geophysical data interpretation. The scientific approach can further be enhanced by incorporating other scientific fields such as botany and soil science. Any botanical species is a living organism that requires nutrients to function and live. Nutrients are derived from the soil wherein it grows, while soil is a weathering component of the original underlying rock. Differences in soil can be attributed to changes in the composition or type of the natural rock. By including soil and botany in groundwater exploration, the chances of success are increased. Numerous case studies are presented to illustrate that certain botanical species prefer to grow in nutritious places derived from weathered rock, where this rock acts as a groundwater resource. Soil samples taken from these places indicate different soil quality compositions when compared to the surrounding common veld. This phenomenon is representative throughout the entire study, representing various geological formations. The presence of alien rock formations in a fairly homogenous geological environment is indicated by means of geophysical profiles and soundings. Existing boreholes, whether at or removed from geobotanical communities, indicate the importance of such communities since they hint to the keen observer the likely presence of groundwater at such a community. The current study presents aquifer yields obtained at geobotanical communities and the average yield of aquifers in the same geological environment, where most boreholes are drilled without the incorporation of geobotanical indicators. Lastly, the value of soil quality samples is discussed with a preference for CEC-values to indicate geobotanical communities and/or the presence of groundwater. The statistical treatment of the data indicates distinctively that statistically significant regressions exist between geology, geophysics and groundwater as the explanatory variables and CEC and geobotany as the dependent variables.