Site characterisation aims to obtain fundamental data needed to describe the subsurface flow
pathways and distribution of contaminants. The study describes the application of various
geohydrological techniques as complimentary tools to characterise an LNAPL contaminated
fractured - rock aquifer on the Beaufort West study area in South Africa. Field investigations
were designed to define and determine the properties of the fracture preferential flow paths
responsible for LNAPL transportation in a typical Karoo fractured â rock aquifer system. The
research places emphasis on the integration of results to maximise the subsurface geological
understanding in particular location of fracture features chiefly responsible for facilitating
LNAPL migration and distribution.
The core and percussion drilling explorations, cross - correlated with borehole geophysics,
were valuable for geological subsurface investigations in particular locations of bedding
fractures, which are often associated with high hydraulic conductive flow zones. Tracer and
pump tests were conducted to determine hydraulic and mass transport parameters
respectively. Hydraulically conductive bedding plane fracture flow zones were identified by
integrating results from the geological core logs, borehole geophysics and aquifer tests. The
chemical characterisation of the study area was conducted by means of organic hydrocarbon,
inorganic water analyses and volatile organic carbon measurements in the soil during air
percussion drilling.
Based on the findings, the hydrogeological structure of the formation was conceptualised as a
fractured sandstone aquifer, characterised by bedding plane fracture preferential flow paths at
contact areas, with shale and mudstone formations. The study findings demonstrate the merit
and value in the application of various geohydrological tools to complement one another for
optimised site understanding. The findings and recommendations of the case study are not
necessarily confined to LNAPL contaminated fractured - rock aquifers, but may also be
applicable to other types of contaminants in fractured - rock aquifer formations.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:ufs/oai:etd.uovs.ac.za:etd-11222010-140535 |
| Date | 22 November 2010 |
| Creators | Gomo, Modreck |
| Contributors | Prof G Steyl, Prof GJ van Tonder |
| Publisher | University of the Free State |
| Source Sets | South African National ETD Portal |
| Language | en-uk |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.uovs.ac.za//theses/available/etd-11222010-140535/restricted/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to University Free State or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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