<p>The Table Mountain Group (TMG) Aquifer is the second largest aquifer system in South Africa, after dolomites. This aquifer has the potential to be a signinficant source of water for the people of the Western Cape. The occurrence of hot water springs in the TMG in relation with the main geological fault systems in SOuth Africa shows that deep flow systmes do exist. Little is known about these deep aquifer systems in South Africa (i.e. flow mechanisms). To close the above-mentioned knowledge gap, this study was initiated. The current study gave a review of some of the aspects that needs to be considered when distinguishing deep groundwater from shallow groundwater.</p>

The study focuses on an alluvial plain situated within a large meander of the Logan River at Josephville near Beaudesert which supports a factory that processes gelatine. The plant draws water from on site bores, as well as the Logan River, for its production processes and produces approximately 1.5 ML per day (Douglas Partners, 2004) of waste water containing high levels of dissolved ions. At present a series of treatment ponds are used to aerate the waste water reducing the level of organic matter; the water is then used to irrigate grazing land around the site. Within the study the hydrogeology is investigated, a conceptual groundwater model is produced and a numerical groundwater flow model is developed from this. On the site are several bores that access groundwater, plus a network of monitoring bores. Assessment of drilling logs shows the area is formed from a mixture of poorly sorted Quaternary alluvial sediments with a laterally continuous aquifer comprised of coarse sands and fine gravels that is in contact with the river. This aquifer occurs at a depth of between 11 and 15 metres and is overlain by a heterogeneous mixture of silts, sands and clays. The study investigates the degree of interaction between the river and the groundwater within the fluvially derived sediments for reasons of both environmental monitoring and sustainability of the potential local groundwater resource. A conceptual hydrogeological model of the site proposes two hydrostratigraphic units, a basal aquifer of coarse-grained materials overlain by a thick semi-confining unit of finer materials. From this, a two-layer groundwater flow model and hydraulic conductivity distribution was developed based on bore monitoring and rainfall data using MODFLOW (McDonald and Harbaugh, 1988) and PEST (Doherty, 2004) based on GMS 6.5 software (EMSI, 2008). A second model was also considered with the alluvium represented as a single hydrogeological unit. Both models were calibrated to steady state conditions and sensitivity analyses of the parameters has demonstrated that both models are very stable for changes in the range of ± 10% for all parameters and still reasonably stable for changes up to ± 20% with RMS errors in the model always less that 10%. The preferred two-layer model was found to give the more realistic representation of the site, where water level variations and the numerical modeling showed that the basal layer of coarse sands and fine gravels is hydraulically connected to the river and the upper layer comprising a poorly sorted mixture of silt-rich clays and sands of very low permeability limits infiltration from the surface to the lower layer. The paucity of historical data has limited the numerical modelling to a steady state one based on groundwater levels during a drought period and forecasts for varying hydrological conditions (e.g. short term as well as prolonged dry and wet conditions) cannot reasonably be made from such a model. If future modelling is to be undertaken it is necessary to establish a regular program of groundwater monitoring and maintain a long term database of water levels to enable a transient model to be developed at a later stage. This will require a valid monitoring network to be designed with additional bores required for adequate coverage of the hydrogeological conditions at the Josephville site. Further investigations would also be enhanced by undertaking pump testing to investigate hydrogeological properties in the aquifer.

Thesis (Ph. D.)--University of Texas at Austin, 2007. / Vita. Includes bibliographical references.

Thesis (Ph.D.) -- Flinders University, School of Chemistry, Physics and Earth Sciences. / Typescript (bound). Includes bibliographical references (leaves 265-281). Also available online.

Thesis (M.S.)--University of Montana, 2008. / Title from title screen. Description based on contents viewed Aug. 27, 2008. Includes bibliographical references (p. 90-94).

Thesis (M.S.)--Stanford University, 2000. / Submitted to the Department of Geological and Environmental Sciences. Copyright by the author.

Thesis (M.Sc.(Environmental and Engineering Geology))--University of Pretoria, 2008. / Abstract in English. Includes bibliographical references (leaves 94-106).

Thesis (M. App. Sc.)--Carleton University, 2003. / Includes bibliographical references (p. 182-187). Also available in electronic format on the Internet.

Thesis (Ph. D.)--University of Hong Kong, 2009. / Includes bibliographical references (leaves 177-192) Also available in print.

Thesis (M.Sc.)--Victoria University of Wellington, 2008. / Includes bibliographical references.