ABSTRACT The research unequivocally showed that pump-induced seismo-deformations exist, especially in boreholes equipped with electric and diesel pumps. Central to seismo-deformations are the mechano- and the geo-acoustic effects on both the borehole water and the aquifer. These aspects of the pump instigate the proposed diaphragmatic deformation hypothesis. In an aquifer the pump vibrations manifest as Rayleigh waves. By virtue of the driving source, the waves are harmonic (White, 1965). To be effective in engineering the proposed diaphragmatic deformation on a hydrostratigraphic unit situated several metres below the ground surface, the waves propagate along the borehole. The component of the Rayleigh wave orthogonal to the unit instigates the deformation and thus oscillations are generated in drawdown curves. Oscillations are a common feature in pumping test data and the masking effect of abstraction makes them inconspicuous. However, the derivative technique when applied to the signal enhances the phenomenon. The technique suppresses the abstraction effect in the data leaving the time-dependent oscillations. The spikes obtained in some of the derivatives of the pumping test data may suggest a one-sided deformation, probably the upper lip to a hydrostratigraphic unit. Coupled with the effects of Rayleigh waves is the pressure variation on the water level caused by the sound. The humming sound of a pump in operation is capable of subjecting borehole water to constant pressure variations thus leading to inherent oscillations in the pumping test data. The conspicuousness of oscillations in the raw pumping test data (Figure 1.2) can be attributed to the high resolution of the equipment used and interferences of different wave forms existing in the system. For a borehole that is continuously in operation, the impact of seismo-deformations on the physical integrity of an aquifer can be detrimental. In hard-rock fractured Karoo aquifers, the induced seismo-deformations can be of astronomical severity. The fact that successful boreholes are drilled in the Karoo within a short distance of a failed or �dried up� borehole is a clear evidence of structural failure. Bedding fractures in particular are very susceptible (Rasmussen, 1998). The radial extent of failure depends on the strength of the vibrations which are habitually intense close to the borehole and decay exponentially-like with distance. The ultimate failure of hydrostratigraphic units after prolonged pumping, which is common in the Karoo, may be due to the evolution history of deformation that accumulates as residual strains and stresses (Botha and Cloot, 2002). The research also revealed that ground displacements are smaller when discharging than when not. According to the hypothesis, this is due to the decreasing hydrostatic pressure essential in opposing the normal stress from a pump. It is in this view that groundwater should be considered as a hydroskelatal component of an aquifer and the rationale of lowering the discharge rate should not only be seen as a process to prevent dewatering but as a mechanism for preserving the dynamic equilibrium between the normal stress emanating from a pump and the hydrostatic force offered by water. Offsetting the equilibrium can lead to irreversible plastic deformation and aquifer subsidence (Botha and Cloot, 2002). The failure of numerical models to simulate the oscillations completely indicates that the wave that triggers the proposed diaphragmatic deformation of a fracture is more complicated than the simple harmonic waveform caused by pump vibrations. The wave should be a convolution of the vibrations, sound and the natural ground roll. Besides, the pump vibrations on reaching a geological feature of interest in a multi-stratigraphic geologic terrain would have undergone multiple reflections and transmissions with the ultimate waveform being a distortion of the primary signal. The research conducted showed that pump-induced seismo-deformations should have the same status as the discharge rate in aquifer management. It is clear that the introduction of measures aimed at reducing the transmission of seismic waves to an aquifer should be a priority in order to deter the pump-induced seismo-deformations. This includes preventing the pump and the borehole casing from coming into direct contact; incorporating gadgets to tone down the frequency of the mains; and installing shock absorbers between the pump and the ground. The selection of pumps should be based on the seismological properties of the aquifer that is to be used and its hydrogeological properties.

Groundwater forms an essential part of water supply in the Limpopo Province, South Africa. However, at planning level this message seems to be skewed and misinterpreted. Although a vast number of water supply schemes are developed using groundwater as a resource, these schemes are reported to fail and the resources are not considered sustainable. Therefore mistrust in groundwater has developed, planners effectively eliminate groundwater from integrated water resource planning and groundwater continues to be seen only as an ad hoc or emergency supply. The Groundwater Resource Information Project (GRIP) was introduced to compare available information with verified field information and it presents the information to planners and engineers in a format that is sensible and easy to incorporate, therefore presenting groundwater as an integrated sustainable and strategic resource. The work implemented during this project describes a hydrocensus - an information capturing and presentation protocol that can be introduced anywhere at any scale to give planners the opportunity to consider already developed groundwater infrastructure and incorporate it into the overarching planning. The methodology was developed to describe to the user how he/she should go about when conducting a hydrocensus to serve both the needs of water services and water resource managers The development of groundwater in South Africa is discussed to provide a perspective on how groundwater was dealt with in the past and is looked upon now. Issues concerning groundwater resource mapping as attempted by the Department of Water Affairs and Forestry (DWAF) and the Water Research Commission (WRC) are discussed and commented on. Also discussed is the availability and format of groundwater data when creating maps and how the data are captured in the different databases. All the maps however are derived from ques tionable and unverified field data. The legal perspective on groundwater in terms of the National Water Act (NWA), the Water Services Act (WSA) and the Environmental Conservation Act (ECA) is also briefly discussed. The different uses of water are mentioned where groundwater may have a significant contribution. Shortcomings in the Act are also discussed. The proposed methodology spells out the so-called Groundwater Resource Information Project (GRIP) and with marketing in the 21st century becoming more important in science, the slogan â Get a GRIP on groundwaterâ was adopted. The methodology highlights the importance of an integrated team with various responsibilities and deliverables, the importance of field and office procedures and the involvement of the community. It describes various verification stages where a quality control officer checks field data through ad hoc site visits and where historically disadvantage individuals previously not involved with a project of this nature, can learn from more experience individuals. Information gathered clearly illustrates that vast amounts of money are spent on groundwater development and that the majority of villages in Limpopo already have boreholes in close proximity. The raw data can be used for immediate planning, operation and management purposes. The core of GRIP is, however, dissemination of information and much time was spent to develop an interface where data is captured, validated and placed on a database accessible through the World Wide Web. The data can be downloaded through various methods available on the web page and exported as an Excel spreadsheet. The data can then be imported in a GIS tool and manipulated to develop a series of planning maps, develop site -specific water supply business plans or help planning engineers with dayto- day requests. Prior to GRIP, it was difficult and time consuming for planners in Limpopo to get access to reports compiled by specialists for municipalities or consulting engineers, but through the means de veloped in GRIP, planning engineers are enabled to stand up in meetings and with hard evidence in hand support future groundwater development and planning, making it truly part of integrated water resource management (IWRM). This study lasted from the beginning of 2002 up to the middle of 2004. Further implementation of GRIP continues in Limpopo and the Eastern Cape and there is a strong possibility that is might be implemented in Kwazulu/Natal and the Free State. The GRIP website, other technology and legislation may change with further implementation of GRIP

Waste generation is a widespread phenomenon around the world, of which the majority is disposed by landfilling. In landfills, waste constitutes an integral part of the hydrological system, and thus poses a threat to down-gradient groundwater and surface water receptors. This research was undertaken with the purpose of determining the interactions between landfill and the underlying Karoo aquifer, investigating the impacts of a domestic waste landfill on the aquifer and further predicting the magnitude of future contamination. A domestic waste landfill site at Sasol Synfuels (Secunda), located on the Karoo aquifer, was investigated in order to achieve these objectives. This site (Charlie I Landfill) has been used by the refinery to dispose of all non-hazardous/general waste produced for the past twenty years. It is not lined. There is no information available on the type and volume of waste disposed, and the impact on groundwater was not quantified. The landfill is classified as GMB+ (i.e. producing significant amounts of leachate), with the bord-and-pillar mining method taking place underneath the site at the depths of 90- 120m. This implies a lower probability of subsidence at this position. Field investigations indicate that there is a contaminant plume emanating from the landfill, which is mostly concentrated in the upper part of the soil horizon. This horizon is mainly composed of clayey loams and clay, averaging 3m in depth with a laboratory estimated maximum hydraulic conductivity of 0.0128 m/day. It is underlain by the Karoo sediments (sandstones and shales). Regional groundwater levels have been disturbed by the presence of the landfill site, with the higher water table closer to the site and the deeper water table moving away from the site. According to the blow yields obtained, slug tests for boreholes and piezometers, as well as the pumping tests, an average K- value of 10-2 was obtained for the aquifer, except in regions where a dolerite sill or fractures exists. Soil and water quality analyses indicate little contamination to groundwater; while contamination is mainly concentrated in the upper soil zone (i.e. originates from the surface leachate springs at the edge of the landfill). Modelling of the contaminant plume also indicates a slow migration of the plume to the adjacent areas. The physical properties of soils indicate that retardation (by biochemical reactions, sorption, cation-exchange etc.) of contaminants will occur with only very small quantities reaching groundwater. The presence of leachate springs and low levels of contaminant concentrations in groundwater indicates a limited vertical movement of contaminants. Therefore, leachate produced by the landfill site does not infiltrate into the groundwater system.

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INTRODUCTION 1.1 General The 1996 constitution of South Africa considers the availability of drinking water a basic human right. Considerable emphasis is therefore currently placed on the identification of sustainable water supplies. Groundwater is the sole source of potable water for many urban and rural communities in South Africa and efficient methods of exploration, development and management of groundwater resources are required. The vast majority of South African aquifers are of the secondary type, that is, their waterbearing properties were developed through secondary processes such as faulting or fracturing. It is estimated that approximately 90% of South African groundwater occurs in secondary aquifers. More than 50% of South Africa is underlain by rocks of the Karoo Supergroup. These rocks are typically dense and not extensively fractured so that their permeabilities are low when compared with primary porous formations. The existing geophysical techniques, particularly magnetic, electromagnetic and resistivity methods, have been used for many years to locate groundwater in South Africa, but with varying degrees of success. The magnetic method is used almost exclusively to locate and delineate intrusive magmatic bodies and the contact zones between the intrusive bodies and the host rock are then considered to be targets in groundwater exploration. The electromagnetic and resistivity methods are used to map the subsurface conductivity distribution of the area under investigation. From the conductivity information inferences regarding the subsurface geology are made and geological structures are mapped. Although highly weathered zones containing groundwater will in some instances produce large enough conductivity contrasts to allow direct detection by means of the electromagnetic or resistivity method, groundwater exploration by geophysical means is in general an indirect process whereby subsurface geological structures that may act as, or be associated with aquifers are identified. In the past groundwater exploration in Karoo rocks mostly targeted intrusive dolerite bodies. When such bodies do not occur in the area being explored, the magnetic method is of little use for groundwater exploration. The electromagnetic and resistivity methods on the other hand are also frequently unsuccessful in locating Karoo aquifers due to a lack of conductivity contrast between the fractured zones and the surrounding host rock. 5 One method that promises to circumvent many of the difficulties associated with conventional geophysical techniques in siting water in Karoo aquifers, is the electroseismic (ES) technique. This method, which is based on the conversion of seismic energy to electromagnetic energy in deformable fluid-filled porous rocks, does not only depend on the rock properties but also the fluid. Indeed there are indications that the method may hold particular advantages for Karoo formations, where bedding-parallel fractures often form the main conduits of water to boreholes Botha et al. (1998). The rock properties that play a particular important role in ES techniques include the bulk and shear moduli of deformation. The same parameters also determine the extent to which rocks will deform under the influence of stresses, with a corresponding reduction in the apertures of fractures present in the rock (Makurat, 2001) and the ability of the fracture to transmit water (Botha and Cloot, 2002). Indeed, Botha et al. (1998) show that a 20% decrease in the aperture of the fracture will cause a drop of almost 50% in the yield of a fracture and that the over-pumping of a borehole could cause the fracture to collapse. ES techniques may therefore not only be useful in siting boreholes, but also provide information on the elastic properties of the rock matrix that is vital for the management of boreholes in fractured rock formations.

Petroleum liquids are a basic building block of our modern lives. Uses include fuels, lubricants, and the raw material for manufactured products. The by-product of these uses has been the inadvertent release of petroleum liquids. A result of our utilization of petroleum liquids is a legacy of soil and groundwater impacted by petroleum liquids. The aim of this research is to provide an overview of LNAPLs in South African urban areas, transport mechanism of the LNAPLs in the subsurface, framework for detecting and evaluating LNAPLs under South African conditions. LNAPL is a convenient label for petroleum liquids in soils and groundwater. The acronym stands for Light Non Aqueous Phase Liquid. âLightâ highlights the fact that petroleum liquids (i.e., gasoline) are less dense than water; âNon Aqueousâ highlights the fact that petroleum is not completely miscible in water. An LNAPL contamination assessment was conducted at a service station after a complaint was raised by a resident who found free product (petrol) in her borehole. A multitude of private boreholes were found during the hydrocensus survey. A petroleum contamination assessment was done through soil vapour survey (SVS), hand auger holes and rotary percussion drilling. No significant petroleum vapours were detected due to clay soil which has low transmission of vapours. Hand auger holes were restricted to shallow depth due to the lack of penetration though the clay soils. Percussion drilling was needed to gather groundwater information (i.e., quality and quantity). Free product (petrol) was found within the percussion and some of the private boreholes. Groundwater samples were collected and analyzed for BTEX (Benzene, Toluene, Ethyl benzene and Xylenes) compounds. No detectable levels of BTEX were found in the soil samples. Risk assessment was done suing the RBCA approach and BP RISC software. BTEX concentrations of groundwater samples have triggered the Tier 1 risk based screening level for the risk values of carcinogenic and non-carcinogenic through groundwater ingestion, indoor and outdoor vapour inhalation exposure pathways. BP RISC was used to conduct Tier 2 evaluation and carcinogenic risk does exist in the receptor borehole through groundwater ingestion risk pathway. AQUA-WIN finite element model was used to determine the abstraction rate that could be used to conduct a pump-and-treat system. Free product could be recovered within two years after commencing with pump and treat system. Due to the lack of South African regulations with regard to petroleum contamination, the pump and treat system was stopped as soon as the product was recovered and monitoring of the dissolved phase hydrocarbons was continued. The establishment of South African guidelines and risk assessment protocols for petroleum hydrocarbons is outlined and strongly recommended for implementation.

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.

The potential for the widespread contamination of groundwater by Dense Non-aqueous Liquids (DNAPLs) in South Africa is substantial, because of the extensive production, transport, utilisation, and disposal of large volumes of DNAPL chemicals. There are a great number of potential sites where DNAPLs may have been released to the subsurface in varying quantities. A basic understanding of the nature and occurrence of groundwater in South Africa aquifer systems is a prerequisite for assessment, monitoring and management of DNAPL contaminated sites. The physical properties of an aquifer that have the greatest impact on the fate and transport of DNAPL contaminants, are the flow rate and flow mechanism present, and the hydraulic conductivity. The major South African aquifer systems have been classified in relation to the dominant flow mechanisms and flow characteristics. The majority of the utilised South African aquifers can be classified as intergranular fractured aquifers. From the results of this study, which included laboratory experiments and the controlled injection of a surrogate DNAPL in the field, it is clear that preferential pathways in fractured rock will determine the flow path of any DNAPL phase contamination. Aqueous plumes of DNAPL contaminants will also be influenced by these pathways (dissolving and or diffusing from the NAPL into the water in fractures and matrix) which can result in spatially variable aqueous plumes in these aquifer systems. The local variations in fracture strike and dip play a far more important role in DNAPL flow than the regional fracture dip or groundwater flow directions. Natural attenuation processes are important consideration under South African conditions. Relatively high organic carbon in the shallow zones assists in retardation of the organic contaminants, while the large unsaturated zone, arid climate and high temperatures leads to significant loss of contaminant mass through volatilization. Although the National Water and Environmental Acts of South Africa are very clear on prevention of pollution to, and management of water resources, no guidelines exist on how to deal with DNAPL contaminated sites. Recommendations have been made relating to the regulations that are required for: · Site assessment · Sampling and monitoring · Implementation of monitored natural attenuation

This dissertation characterised geochemically waste from a copper mine in the Bushveld Igneous Complex, coupled with hydrochemical interpretations. In the first part of the dissertation, the methods involved in the quantification and qualification of mine acidic drainage were discussed. This included paste and rinse pH, Acid and Base potentials, net neutralisation potentials and neutralisation potential ratio. These methods form what is known as Acid-Base Accounting, (ABA). In the second part of this dissertation, the sampling methods and representativeness of the samples were discussed. All these methods are scientifically justifiable as they are in agreement with methods used internationally. In the third and most important part of this dissertation, results where discussed and proven to correlate with visual estimates from the field. In sulphides-containing waste material, Acid Mine Drainage (AMD) is produced due to the ingress of oxygen and water mainly from rainfall, and thus subsequent oxidation of sulphide-bearing minerals with the help of bacteria. However, in the presence of sufficient neutralisation potential, alkaline drainage is favoured as carbonated minerals (mainly dolomite and calcite) buffer the acidity. For this study, copper sulphide is recovered from foskorite ore imbedded with carbonatite which helped at the non acidification of the mine site. In the dissertation, the geochemical software PHREEQC was used and it confirmed that many silicates and alumino-silicates minerals are dissolved in the groundwater. This is an important finding as the presence of silica is an indication that substantial amount of acidity could have been released. This also constitutes reasonable evidence for the fact that chalcocite and covellite which are the main sulphides of copper mined on site can be considered as âweakâ sulphides unlike pyrite which can be more severe to the environment. The software PHREEQC also confirmed that dolomite and calcite control the pH of the water, thus only fairly alkaline values in the range of pH 8 to pH 9.5 are expected on site. With visual investigations, it has been noticed that natural vegetation is taking place around the site even on the most hostile tailings like the magnetite. This is a very important aspect as positive outcome is expected for the fauna after mine closure. The following serve as recommendations: - The neutralisation processes release sulphate into the groundwater, and it is recommended that tracer tests methods be conducted to estimate the travelling time of the salts. - It is also recommended that the mine speed up the re-vegetation process as many animals cross the Kruger National Park to feed themselves within the mine. - It is recommended that more regular monitoring on boreholes be conducted as many dataless. Also it is suggested that anomalous boreholes be investigated, geochemically logged and re-sampled to verify or determine likely origins and interactions. - For further research, standard values of salt loads should be implemented so as to compare acceptable values with abnormal values. - The study of ABA using static tests should always be coupled with the humidity cells methods. While the former provides with the probability of acid formation, the latter provides with the reaction rates. - Additional studies should be conducted exclusively outside the mine to corroborate with the results from inside the mine.

The semi-arid regions of southern Africa cover large portions of settled land where domestic and agricultural activities depends on isolated groundwater systems replenished by irregularly occurring rainfall events. Southern African rainfall patterns are regulated by the annual oscillation of winter-summer weather systems and most of all, abrupt changes in regional atmospheric patterns, which may result in either wet/dry cycles. Given the highly differential hydro-climatic conditions and hydrogeological environment in semi-arid regions, effective groundwater recharge events are episodic in nature and largely occur once in every five years. Sustainable, medium-term management of local groundwater resources requires dynamic hydrological information to ensure a healthy supply-demand balance; thus requiring dedicated hydrological monitoring. High-level monitoring programmes on a few experimental sites have produced localised hydrological data, which illustrate how erratic groundwater resources are replenished. For many years, it was postulated that groundwater resources were recharged every time the total annual rainfall peaks a certain threshold. This postulation may hold in humid regions, but surely not elsewhere in the drier parts of South Africa. Semi-arid regions portray a flattish regional landscape with occasionally elevated parent rock windows and mountainous regions. Soil cover is restricted to low-relief areas, and lacks the thick mature soils distinctive of the humid areas. Fractured hard rock windows with very little soil cover represent potential groundwater recharge terrains, allowing recharge-producing surplus rainfall to infiltrate directly into the underlying aquifer. The hydrogeological conditions of hard rock terrains in the same-arid environment do vary in terms of the rock types and their response on weathering processes. Nonetheless, an array of joints and fractures running from ground surface into the SZ represents fast and effective pathways when episodic high rainfall events occur. Mature soil/regolith profiles in plain areas enhances surface run-off and support local floods in rivulets where riparian vegetation and open-water evaporation intercepts most of the available bank storage and depression recharge. Atmospheric moisture is, in principal, generated by warm, evaporating maritime waters, and is therefore marked by its hydrochemical signature. This signature changed abruptly during its continental migration, and finally manifests as cloud water. Winter rainwater specifically demonstrates the impact of oceanic aerosols, hence characterized by a prominent NaCl composition. Summer rainwater is a diluted version due to continental rainfall/evapotranspiration events, and is transformed by anthropogenic airborne substances peaking during the late-winter months. The hydrogeochemical composition of rainwater is therefore quite diverse, and needs logic monitoring to understand its seasonal cyclic oscillation. Short-term hyetograph observations report episodic rainfall events, occurring mostly over the January-March period of wet hydrological cycles. These are spaced over a period of 4 to 8 days, of which at least one rain event exceeds ~45 mm, associated with a rain-rate intensity of >1.5 mm·h-1. Extraordinary depleted rainwater hydrochemistry and isotopic compositions are associated with these rain weeks, which are significantly different from normal seasonal concentrations. Wet Clâ concentrations during these high rainfall periods are almost an order of magnitude lower than the average annual values. Hyetograph-hydrograph sets confirm that extraordinary groundwater recharge occurs as the result of episodic rainfall events. Hydrogeochemical profiling in the upper section of the unsaturated zone verify the presence of different compositions which probably indicate different modes of recharged rainwater percolation in fractured, hard rock terrains. Hard rock profile sections below the rebound water table interface containing almost 50% less Clâ than country-wide background values of ~40 mg·H-1. Isotopic compositions in a typical rain week period report similar depleted concentrations and resemble a prominent amount effect. Such depleted rainwater is merely linked to specific seasons, for example the rainfalls of 2003-2004, 2005-2006 and 2007-2008 hydrological years can be clustered as high rainwater input periods with notable lighter isotopic compositions; around - 7.5â° M18O, -41â° M2H. The fact that most of the two (2) meter vertical profiles reported relatively negative isotopic compositions (-8â° M18O, -44â° M2H), indicates a high probability of preferential recharge with pristine rainwater with even more negative isotopic composition. Direct groundwater recharge estimations from local, short-term rainfall and groundwater rebound stage hydrochemical data proposes a recharge value <2% in most flat lying, semi-arid regions. Although fractured hard rock terrains are isolated, it allows in the order of 4%, where as local mountainous areas are high at 14%; obviously enhanced by orographic rainfall development. Recharge on dolomitic terrains are highly variable due to diverse ground surface conditions, and may vary between 6% in flat lying plains to 13% in mountainous regions (Kuruman Hills at Kuruman). Groundwater recharge varies significantly spatially. The control by prominent soil/regolith cappings is that high that establishing realistic recharge figures for a particular area, will require a dedicated soil mapping programme to identify direct recharge terrains.