Dissertations / Theses on the topic 'Table Mountain Group'

The Table Mountain Group (TMG) Formation is the lowest member of the Cape Supergroup which consists of sediments deposited from early Ordovician to early Carboniferous times, approximately between 500 and 340 million years ago. The Table Mountain Group (TMG) aquifer system is 
exposed along the west and south coasts of South Africa. It is a regional fractured rock aquifer that has become a major source of bulk water supply to 
meet the agricultural and urban water requirements of the Western and Eastern Cape Provinces of South Africa. The TMG aquifer system comprises of an approximately 4000 m thick sequence of quartz arenite and minor shale layers deposited in a shallow, but extensive, predominantly eastwest striking 
asin, changing to a northwest orientation at the west coast. The medium to coarse grain size and relative purity of some of the quartz arenites, 
together with their well indurated nature and fracturing due to folding and faulting in the fold belt, enhance both the quality of the groundwater and its 
exploitation potential for agricultural and domestic water supply purposes and its hot springs for recreation. The region is also home to some unique 
and indigenous floral species (fynbos) of worldwide importance. These and other groundwater dependent vegetation are found on the series of 
mountains, mountain slopes and valleys in the Cape Peninsula. The hydrogeology of the TMG consists of intermontane and coastal domains which 
have different properties but are interconnected. The former is characterized by direct recharge from rain and snow melt, deep groundwater circulation with hot springs and low conductivity groundwater. The coastal domain is characterized by shallow groundwater occurrence usually with moderate to 
poor quality, indirect recharge from rainfall of shallow circulation and where springs occur they are usually cold. The sustainable utilization of the TMG 
aquifer addressed the issues of the groundwater flow dynamics, recharge and discharge to and from the aquifer
challenges of climate change and climate variability and their potential impact on the aquifer system. The concept of safe yield, recharge and the capture principle and the integration of 
sustainable yield provided the basis for sustainable utilization with the adaptive management approach. Methodology used included the evaluation of 
recharge methods and estimates in the TMG aquifer and a GIS based water balance recharge estimation. The evaluation of natural discharges and 
artificial abstractions from the TMG aquifer system as well as its potential for future development. The Mann-Kendal trend analysis was used to test historical and present records of temperature and rainfall for significant trends as indication for climate variability and change. The determination of 
variability index of rainfall and standard precipitation index were additional analyses to investigate variability. The use of a case study from the Klein 
(Little) Karoo Rural Water Supply Scheme (KKRWSS) within the TMG study area was a test case to assess the sustainable utilization of TMG aquifers. 
Results show that recharge varies in time and space between 1% and 55% of MAP as a result of different hydrostratigraphic units of the TMG based on 
geology, hydrology, climate, soil, vegetation and landuse patterns however, the average recharge is from 1% to 5% of MAP. The TMG receives recharge 
mainly through its 37,000 km2 of outcrop largely exposed on mountainous terrain. Natural discharges from the TMG include 11 thermal and numerous 
cold spring discharges, baseflow to streams and reservoirs, and seepage to the ocean. Results from this study also show increasing temperature 
trend over the years while rainfall trend generally 
remain unchanged in the study area. Rainfall variability persists hence the potential for floodsand droughts in the region remain. Global and Regional Models predict about 10% to 25% reduction in rainfall and increase in variability in future. Impacts of 
his change in climate will affect the different types of aquifers in various ways. Increase in temperature and reduction in rainfall will increase 
evapotranspiration, reduce surface flows and eventually reduce shallow aquifer resources. Coastal aquifers risk upsurge in salinisation from sea level 
rise and increase in abstractions from dwindling surface water resources. While floods increase the risk of contamination to shallow aquifers droughts 
put pressure on all aquifers especially deep aquifers which are considered to be more reliable due to the fact that they are far removed from surface conditions. Future population growth and increase in freshwater demand will put more pressure on groundwater. Recharge to groundwater have been 
over-estimated in certain areas in the past leading to high abstraction rates from boreholes causing extensive groundwater storage depletion evident by high decline in groundwater levels in these areas and hampering sustainable management of the aquifer resources. Over-abstraction have resulted in 
loss of stream flow and baseflow reduction to streams during summer, complete loss of springs and reduction of flow to others. Flow to wetlands, 
riparian vegetation, and sometimes loss and shifts in dependent ecosystems have also resulted from over-abstraction. Sustainability has spatial and 
temporal implications due to changing climate and demand. The study recommends adaptive management practices in which several factors are 
considered in managing groundwater together with surface water resources in order to maintain ecological and environmental integrity. The KKRWSS 
and other groundwater supply schemes in the Western and Eastern Cape Provinces demonstrate the huge potential of the TMG to provide freshwatersupply for domestic and irrigation water needs however, the huge decline in groundwater levels due to over-abstraction in the KKRWSS and 
other groundwater schemes underscores the need for sustainable utilization of the TMG groundwater resources for present and future generations with 
minimal impacts on the quality, dependent hydrological and ecosystems as well as the environment.

Rain was collected from 2010 to 2012 at 15 locations around the Cape Fold Belt, at the same time as samples from rivers, springs, seeps and boreholes, totalling 435 samples. Precipitation ranged from -75 ‰ to +40 ‰ for δD and -12 ‰ to +8 ‰ for δ¹⁸O , showing seasonal patterns, with lower δ values in winter and higher in summer. Certain anomalous δ values can be attributed to individual weather events, such as thunderstorms. Using weighted data, the meteoric water line is δD = 6.15 δ¹⁸O + 8.21, which is similar to previous equations. The best fit line for groundwater δ values is δD = 7.09 δ¹⁸O + 10.08, the steeper gradient and higher intercept reflecting the predominance of heavy rainfall events with lower δ values in recharge, known as selection. The range of -47 ‰ to 0 ‰ for δD and -8 ‰ to -1 ‰ for δ¹⁸O values for all groundwater data is about half that of the rain values, due to the averaging effect from mixing during groundwater flow. Rainfall isotope composition is negatively correlated with continentality, as defined by the product of distance to the Atlantic and the closest coast. Isotope composition of rainfall is also strongly negatively correlated with altitude. Sites that are elevated within the landscape have a reduced altitude effect, such as tall peaks, whereas mountain valleys display enhanced altitude effects. Temporal and spatial variations in the strength of the amount effect reveal meteorological variability and emphasise the need for long term monitoring.

Research findings in current study provide a new insight into the fractured rock aquifers in the TMG area. Some of the results will have wide implications on the groundwater management and forms a solid basis the further study of the TMG aquifers.

Table Muntain Group has been identified as one of the major Regional Aquifers in South Africa. the vast distribution of it leads to a great diversity in its hydrogeological properties, which influences the dynamics of recharge, discahrge and storage, resulting in groundwater occurrances unevenly distributed in TMG area. Thereby a proper regional groundwater resource evaluation focusing on the quantification of recharge, discharge and storage, is of most importance for the efficient groundwater utilization and management of TMG aquifers.The response of TMG aquifer to pumping stress is studied in Kammanassie Mountains by groundwater flow modeling. 3D hydrogeological model is constructed, which helps to improve the understanding of the conceptual hydrogeological model. Detailed groundwater-related analyses are performed on the basis of previous data sets. Groundwater numerical model is then established according to the conceptual model to stimulate the aquifers responses to various pumping scenarios. Some general data processing approaches are also develooped in this study that can be expected to apply to analog studies.

Modern analysis of Table Mountain Group sediments began with I. C. Rust's D.Sc. thesis "On the sedimentation of the Table Mountain Group in the western Cape Province" in 1967. Rust defined the stratigraphy of the Table Mountain Group, produced computer generated isopach and palaeocurrent maps for each formation and attempted palaeoenvironmental analyses based on what data he had available. For work dated prior to 1967 the reader is directed to Rust's excellent review in Chapter 2 of his thesis. The thesis served as a basis for Rust's later published work on the Cape Supergroup. Current published palaeoenvironmental models of the lower Table Mountain Group (the Piekenierskloof, Graafwater and Peninsula Formations) are based on a transgressive fluvial - littoral - shallow shelf model (Tankard et al., 1982) following earlier facies and palaeoenvironmental analyses (Tankard and Hobday, 1977: Rust, 1977; Hobday and Tankard, 1978: Vos and Tankard, 1981). The validity of this model has recently been questioned (Turner, 1986; 1987) although no comprehensive alternative has been proposed to date. The sedimentology of the upper Table Mountain Group i.e. the Pakhuis, Cedarberg, Rietvlei, Skurweberg and Goudini Formations (the latter three the newly named Nardouw Subgroup) has not been studied systematically. Good progress has recently been made on the fossil content of the Cedarberg Formation (Gray et al., 1986; Cocks and Fortey, 1986) and palaeoenvironmental analyses initiated in the Nardouw Formation. This thesis documents contributions to the geology of the Table Mountain Group. It is not the intention of the author to present an extensive overview and treatise on the lower Table Mountain Group, but rather to concentrate on three topics that can provide some insight into Table Mountain Group geology. The following three topics were selected 1) Petrology and Diagenesis of lower Palaeozoic sandstones in the s.w. Cape Sandveldt (Clanwilliam and Piketberg Discricts). 2) Palaeoenvironmental indicators in the Faroo Member, (Graafwater Formation) at Carstensberg Pass, R364. 3) Facies analysis of conglomerates and sandstones in the Piekenierskloof Formation: Processes and implications for pre-Devonian braid-plain sedimentology. These topics form the basis of the thesis.

Philosophiae Doctor - PhD
The Table Mountain Group (TMG) Aquifer is a huge aquifer system which may provide large bulk water supplies for local municipalities and irrigation water for agriculture in the Western Cape and Eastern Cape Provinces in South Africa. In many locations, water pressure in an aquifer may force groundwater out of ground surface so that the borehole drilled into the aquifer would produce overflow without a pump. Appropriate testing and evaluation of such artesian aquifers is very critical for sound evaluation and sustainable utilization of groundwater resources in the TMG area. However, study on this aspect of hydrogeology in TMG is limited. Although the flow and storage of TMG aquifer was conceptualised in previous studies, no specific study on artesian aquifer in TMG was made available. There are dozens of flowing artesian boreholes in TMG in which the pressure heads in the boreholes are above ground surface locally. A common approach to estimate hydraulic properties of the aquifers underneath is to make use of free-flowing and recovery tests conducted on a flowing artesian borehole. However, such testing approach was seldom carried out in TMG due to lack of an appropriate device readily available for data collection. A special hydraulic test device was developed for data collection in this context. The test device was successfully tested at a flowing artesian borehole in TMG. The device can not only be used to measure simultaneous flow rate and pressure head at the test borehole, but also be portable and flexible for capturing the data during aquifer tests in similar conditions like artesian holes in Karoo, dolomite or other sites in which pressure head is above ground surface. The straight-line method proposed by Jacob-Lohman is often adopted for data interpretation. However, the approach may not be able to analyse the test data from flowing artesian holes in TMG. The reason is that the TMG aquifers are often bounded by impermeable faults or folds at local or intermediate scale, which implies that some assumptions of infinite aquifer required for the straight-line method cannot be fulfilled. Boundary conditions based on the Jacob-Lohman method need to be considered during the simulation. In addition, the diagnostic plot analysis method using reciprocal rate derivative is adapted to cross-check the results from the straight-line method. The approach could help identify the flow regimes and discern the boundary conditions, of which results further provide useful information to conceptualize the aquifer and facilitate an appropriate analytical method to evaluate the aquifer properties. Two case studies in TMG were selected to evaluate the hydraulic properties of artesian aquifers using the above methods. The transmissivities of the artesian aquifer in TMG range from 0.6 to 46.7 m2/d based on calculations with recovery test data. Storativities range from 10-4 to 10-3 derived from free-flowing test data analysis. For the aquifer at each specific site, the transmissivity value of the artesian aquifer in Rawsonville is estimated to be 7.5–23 m2/d, with storativity value ranging from 2.0×10-4 to 5.5×10-4. The transmissivity value of the artesian aquifer in Oudtshoorn is approximately 37 m2/d, with S value of 1.16×10-3. The simulation results by straight-line and diagnostic plot analysis methods, not only imply the existence of negative skin zone in the vicinity of the test boreholes, but also highlight the fact that the TMG aquifers are often bounded by impermeable faults or folds at local or intermediate scale. With the storativity values of artesian aquifers derived from data interpretation, total groundwater storage capacity of aquifers at two case studies was calculated. The figures will provide valuable information for decision-makers to plan and develop sustainable groundwater utilization of artesian aquifers in local or intermediate scales. With the hydraulic test device readily available for data collection, more aquifer tests can be carried out in other overflow artesian boreholes in TMG. It becomes feasible to determine the hydraulic properties of artesian aquifers for the entire TMG. Thereof quantification of groundwater resources of artesian aquifers in TMG at a mega-scale becomes achievable. This would also contribute towards global research initiative for quantification of groundwater resources at a mega-scale.

Results from this study enables a better understanding of groundwater surface water interactions in the TMG, particularly regarding aquatic ecosystems. It has also highlighted the necessity to do proper impact assessments before proceeding with bulk abstraction from this important aquifer. The results also demonstrated the importance of differentiating between real groundwater and non-groundwater discharge contributions to surface hydrology and where these interface areas are located.

Includes bibliographical references (leaves 139-146).
Fynbos, the native vegetation of the Western Cape of Southern Africa experiences a mild, Mediterranean type climate with hot dry summers and cool wet winters. In terms of climate, fynbos is comparable with other Mediterranean systems found around the Mediterranean in Europe, in parts of Chile, south-western Australia and in the Chaparral in California (Aschmann, 1973). The Cape Floristic Region, of which fynbos is part, is one of the world's most botanically diverse regions, home to an estimated 9030 vascular species (Goldblatt, 1978; Goldblatt and Manning, 2002). The region has exceptionally high levels of endemism. Almost 69% of its 8920 species of flowering plants are endemic (Goldblatt and Manning, 2002), and, despite its small area, it is regarded as one of the six global plant kingdoms (Takhtajan, 1986). Ericaceae, Iridaceae, Proteaceae and the Restionaceae are well represented and there are a number of families that are endemic or nearly so (Goldblatt and Manning, 2002). The largest is the Penaeaceae, followed by Grubbiaceae, Roridulaceae and Geissolomataceae, which together contain 15 endemic genera (Goldblatt and Manning, 2002). These families are almost without exception evergreen sclerophyllous shrubs and are thought to be palaeoendemic remnants from an ancient temperate flora, when conditions were cooler and wetter (February et al., 2004). As a result, many of these species are restricted to wetter areas such as wetlands and mountain seeps (February et al., 2004). Many of these seeps, as well as other groundwater-fed ecosystems, are likely to be connected to the Table Mountain Group (TMG) aquifer from which the city of Cape Town may begin to abstract water.

Understanding of Groundwater Dependent Ecosystems (GDEs) and their extent within the Table Mountain Group (TMG) aquifer is poor. To understand the dependence to basic ecological and hydrogeological concepts need explanation. The use of current literature aided in identification and classification. From the literature it has come clear that groundwater dependence centers around two issues, water source and water use determination. The use of Geographical Information System (GIS) showed its potential in proof of water sources. Rainfall data and a Digital Elevation Model (DEM) for the Uniondale area have been used to do watershed delineation, which is in line with locating GDEs on a landscape. Thus the conceptual approach should be a broad one that sets a basis for both investigation (scientific research) and institutional arrangements (management).

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.

The focus of this study was on recharge mechanisms and recharge estimation within the Table Mountain Group area. The study evaluated recharge processes and recharge estimation methods in the Table Mountain Group aquifer systems.

Thesis (MSc)--Stellenbosch University, 2003.
ENGLISH ABSTRACT: The Cape Town metropolitan area has limited water supply due to rapid population and urban growth. In many instances, surface water is the only source in water supply schemes. There is a need for additional water supplies to supplement the existing water sources. Groundwater systems can be used as primary or supplemental water supply sources especially in areas where there is high demand for water resources. The aim of this study is to evaluate the groundwater potential within the Table Mountain Group (TMG) with the assistance of remote sensing and Geographical Information System (GIS). Previous hydrogeological studies have found the TMG to be the second largest hydrogeological unit in South Africa with extensively fractured and multi-porous rock. The study area is 5660 km2 with TMG covering 1336 km". In this study a Landsat Enhanced Thematic Mapper Plus (ETM+) image was used to identify lineaments. The identified lineaments were overlaid with vegetation, drainage patterns, faults and fractures digitized from 1:250 000 geological maps and borehole yields to show areas with promising groundwater resources. The results did not show correlation between vegetation and lineaments. Most of the lineaments intersected drainage lines at some points, and a few were parallel to the drainage lines. Forty five percent of the digitized faults and fractures overlap with the Landsat lineament. The most dominating lineaments are oriented in a NW-SE direction. High yielding boreholes with average yield of about 12 lIs were found within the distance of 150m from the lineaments. The lineaments were further analysed to locate areas that could be suitable for groundwater exploration. These areas were identified using Landsat lineaments, boreholes and a Digital Elevation Model (DEM). The results showed that the most favourable lineaments and geological features were oriented in a 135-180° and 0-45° direction and areas with slopes of less than 40% were found to be suitable for drilling boreholes. The amount of available groundwater within the TMG was also investigated by looking at both volume of recharge and amount that could be held in storage. Rainfall data was used to estimate recharge. Groundwater recharge was calculated to be 5% of the total precipitation that falls on this area. Based on the average rainfall of 600mm per annum, the results show that TMG has an average recharge value of 30mm per annum. The total recharge for the area covered by TMG, which has an area of 1336km2 , is 160 million nr'. Geological profiles and cross sections were drawn to determine the storage capacity of the TMG, which was estimated to be 525 million m.3 According to a study done by the Department of Water Affairs and Forestry (DW AF) in 1996, the anticipated water demand in the Cape Town metropolitan area will increase from 243 million m3 in 1990 to 560 million m3 in 2020. The estimated volume of water that can be stored within the TMG can meet the current demand for the next 10 years and supplement the existing surface water sources. Groundwater vulnerability of the TMG to contamination was assessed and mapped by using the DRASTIC index. The results demonstrate that the TMG area is at low risk to contamination.
AFRIKAANSE OPSOMMING: 'n Vinnig groeiende bevolking en stedelike uitbreiding plaas toenemende druk op Kaapstad se water voorraad. Addisionele waterbronne sal benodig word om bestaande bronne aan te vul. Oppervlakwater is in die meeste gevalle die enigste waterbron, maar grondwater het die potensiaal om te dien as 'n primêre of aanvullende voorsieningsbron, veral in areas waar groot water tekorte bestaan. Die doel van hierdie studie is om die grondwaterpotensiaal van gesteentes van die Tafelberg Groep (TBG) te evalueer deur van afstandswaarneming en geografiese inligtingstelsels gebruik te maak. Geohidrologiese studies het getoon dat die TBG gesteentes met sy veelvuldige nate en breuksones, die tweede grootste geohidrologiese eenheid in Suid Afrika is. Die studiegebied beslaan 5660 km", waarvan 1336 km2 deur Tafelberg Sandsteen beslaan word. Vir hierdie studie is 'n "Landsat Enhanced Thematic Mapper Plus (ETM+)" beeld gebruik in die identifisering van breuksones (lineamente). Verdere analises is uitgevoer om areas geskik vir grondwater ontginning te identifiseer. Geïdentifiseerde verskuiwings op Landsat beelde is met plantegroei, dreinerings patrone en bekende verskuiwings en fraktuur sones vanaf gelogiese kaarte vergelyk in 'n poging om areas met belowende grondwaterbronne uit te wys. Bekende boorgat posisies en lewerings volumes was 'n primêre databron vir die berekening van groundwater reserves. Die studie het egter geen korrelasie tussen plantegroei en die voorkoms van lineamente gevind nie. Die riviere in die studiegebied word op verskeie plekke deur verskuiwings gekruis. Slegs 'n paar van die verskuiwings lê parallel met die dreinering. Daar is gevind dat vyf-en-veertig persent van bekende verskuiwings en fraktuursones met die geïdentifiseerd op Landsat beelde oorvleuel. Die mees prominente lineamente het 'n NW-SO oriëntasie. Boorgate met lewerings van gemiddeld 12 lis is binne 'n 150m afstand van die verskuiwings gevind. Die verskuiwings is ook geanaliseer om die mees produktiewe areas vir grondwater ontginning te identifiseer. Landsat beelde, boorgate en 'n Digitale Elevasie Model (DEM) is gebruik om moontlike boorposisies te identifiseer. Die mees produktiewe verskuiwings en geologiese verskynsels het 'n N 135-180W en NO-450 oriëntasie, terwyl areas met 'n helling < 40% vir die boor van boorgate geskik is. Berekeninge oor die hoeveelheid water wat binne die TBG gesteentes beskikbaar is, is gemaak deur die hoeveelheid aanvulling en stoorkapasiteit van die TBG gesteentes te beraam. Grondwater aanvulling, soos bereken vanaf reënval data, is 5% van die totale presipitasie van 'n gegewe area. Met 'n gemiddelde jaarlikse reënval van 600mm in die studie gebied is die TBG se jaarlikse aanvulling ongeveer 30mm. Daar word beraam dat die totale aanvulling in die 1336km2 TBG area 160-miljoen m3 per jaar is. Geologiese profiele en dwarsnitte is gemaak om die stoorvermoë van die TBG te bepaal, en is beraam op 525-miljoen rrr'. 'n 1996 navorsing studie deur die Departement van Waterwese en Bosbou toon dat waterverbruik in die Kaapse Metropolitaanse gebied sal toeneem vanaf die 1990 vlak van 243-miljoen m3 tot 560 miljoen m3 teen 2020. Die berekende volume water wat binne die TBG gestoor word, kan die water aanvraag oor die volgende 10 jaar bevredig en as aanvulling dien vir oppervlak waterbronne. Die kwesbaarheid van die TBG akwifer vir besoedeling is met behulp van die DRASTIC indeks geëvalueer en gekarteer. Die resultate toon dat die TBG 'n lae risiko vir besoedeling het.

Thesis (MA (Geography and Environmental Studies))--University of Stellenbosch, 2007.
The Western Cape province of South Africa is a water scarce area with a Mediterranean climate. The majority of rainfall occurs in the cold winter months and the area experiences hot and dry summers. Studies done to investigate various water supply and water demand management options for the City of Cape Town, concluded that the Table Mountain Group (TMG) aquifer has the potential of yielding high volumes (estimated at 70Mm3/a) of good quality water, but that further research about this source as a potential augmentation supply to the City of Cape Town was necessary before extraction could commence. The aim of the study is to develop a spatial decision support system (SDSS) to be used by a hydrogeology project team, which includes hydrogeologists, environmentalists, ecologists, engineers and other stakeholders. The Table Mountain Group Aquifer (TMGA) SDSS is meant to be a decision support tool, but should also raise awareness about the use of spatial data and information and its capabilities for earth science and other multidisciplinary applications. By means of team discussions and interviews data, spatial analysis and data manipulation requirements were determined. Based on these requirements, four spatial analysis tools were developed. The spatial tool named “Borehole Analysis” analyses stratigraphic information obtained from existing boreholes and hydrogeological point data. The tool determines what groundwater use and monitoring has been undertaken in the area of interest. The “Topographic Analysis” tool identifies any topographical (e.g. rivers) and cadastral (e.g. farm boundaries) data within a certain distance from a possible borehole site. The “Sensitive Area Analysis” tool addresses queries with respect to sensitive areas, such as wetlands, statutory protected areas and private nature reserves. The “Image Classification” tool gives the team members an opportunity to use band ratios during image interpretation. The TMGA SDSS was developed using TNTmips v70, Extensible Markup Language (XML) and Spatial Manipulation Language (SML) and can be run on TNTAtlas v70, which is a free software. The TMGA SDSS enables the team members to have equal and ready access to data acquired by other members. This was found to support intra- and interdisciplinary conversation and facilitate understanding of how the data is being (or could be) used. It also contributes to levels of confidence in decision-making and supports a holistic approach to project design and implementation. Keywords: decision-making, geographic information system (GIS), spatial decision support systems (SDSS), spatial manipulation language (SML)

The Table Mountain group aquifer system has the potential to be an important supply of water. Although the aquifer system is used to some extent, a number of aspects relating to the aquifer system are poorly understood and unquantified. This study aimed to take into consideration the importance of differenct ecosytems, which is essential in predicting the effects of groundwater abstruction. However, the ecological requirements of systems that depend on groundwater are poorly understood. This project identified "
type areas"
for further detailed research into the impacts of large-scale groundwater abstraction from the Table Mountain group aquifer system based on the nature and functioning of ecosystems across groundwater dependent ecosystem boundaries of a regional scale.

>Magister Scientiae - MSc
The current study aimed at providing groundwater recharge estimates in a fractured rock aquifer environment that is occupied by pine plantation and indigenous forests in order to improve the understanding of the effect of pine plantation forests on recharge. This was based on the argument that for the trees to affect recharge, they do not necessarily need to tap directly from the saturated zone, as vegetation may indirectly affect groundwater recharge by interception and abstracting the infiltrating water in the vadose zone before reaching the water table. The study was conducted along the Southern Cape coastline of Western Cape Province in South Africa. This area is 7 km east of George in an area characterized by the occurrence of the Table Mountain Group aquifer. The research presented in this thesis formed part of a Water Research Commission (WRC) project titled “The Impacts of Commercial Plantation Forests on Groundwater Recharge and Streamflow”. To achieve the aim of the current study, three objectives were formulated: i) to characterize the dominantly occurring recharge mechanism ii) to determine long-term groundwater recharge estimates, and iii) to assess the effect of plantation forests on groundwater recharge. As part of characterizing the dominant recharge mechanism in the area, a conceptual groundwater recharge model of the area was developed to explain the recharge mechanism and facilitate an improved understanding of recharge estimates. The model was based on a theoretical understanding and previous investigations conducted in the study area. Methods such as environmental stable isotopes and hydrochemistry were used to refine the conceptual model by identifying the source of recharge and the dominant recharge mechanism. The occurrence and density of lineaments were used as a proxy to delineate potential recharge zones in the area. Recharge was estimated using the Rainfall Infiltration Breakthrough (RIB) and the Chloride Mass Balance (CMB) methods. Additionally, the effect of plantation forests on recharge was assessed using the HYDRUS-2D numerical model. The recharge estimates derived from the RIB and CMB techniques were verified using the published maps by Vegter (1995).

Bibliography: leaves 104-118.
This study gives a first-order estimation of the chemical composition of the recharge, discharge, and ground waters, along with the bedrock, soil, and vegetation of the Olifants River Valley around Citrusdal. The valley occurs in a synclinal fold with the main aquifers, the Table Mountain Group (MG) sandstones of the Peninsula Formation and the Nardouw Subgroup, folded beneath the central valley.

Philosophiae Doctor - PhD
Research findings in current study provide a new insight into the fractured rock aquifers in the TMG area. Some of the results will have wide implications on the groundwater management and forms a solid basis the further study of the TMG aquifers.