Conference Abstracts

All Abstracts were presented at the Groundwater Conferences

Displaying 51 - 100 of 795 results

Title	Presenter Name	Presenter Surname	Area Sort ascending	Conference year	Keywords
Assessing Spatial, Temporal Depth Variation Of Groundwater Salinity Variation, Cape Flats Aquifer, South Africa	Danica	Carnow	Western Cape	2017	sampling, Salinity, Irrigation, Water quality, unconfined aquifer, urban
Abstract The use of specific-depth sampling technique to demonstrate groundwater quality variation different groundwater units of unconfined aquifers has not been widely published. To demonstrate the feasibility of such technique, the unconfined Cape Flats Aquifer (CFA) in Cape Town of South Africa was studied. The aquifer underlies an urbanised area which is vulnerable to contamination from industrial and agricultural activities, waste disposal sites, landfill sites, and formal and informal settlements. The study assessed Spatio-temporal and depth variation salinity levels in CFA using electrical conductivity (EC) as an indicator of salinity. Groundwater samples were collected using specific-depth sampling, and analysed using multi-parameters probes and standard laboratory methods for EC, temperature, pH and major ionic concentrations. Statistical analysis was used to compare mean concentrations of selected parameters to guidelines set by Department of Water and Sanitation and Food and Agricultural Organization to establish fitness for irrigation use. The results showed high EC levels (212.26 mS/m) at shallow depths (9m) and low EC levels (78.53 mS/m) at greater depths (39m) proposing anthropogenic influence. Potassium, sodium, chloride, and the Sodium Adsorption Ratio (SAR) exceeded permissible ranges set for irrigation water suggesting that groundwater be used with caution. A conceptual diagram was developed to explain sources and processes contributing to groundwater salinization of the aquifer. The diagram illustrated that irrigation return flow, in residential and agricultural areas, contributed significantly to salinity levels. In conclusion, groundwater in the CFA is suitable for irrigation use but should be used with caution as shallow depths contain groundwater with elevated salinity levels. It is recommended that the specific-depth sampling technique be used to understand how the physical, chemical and microbiological constituents vary with depth in these groundwater units.
Isotope Constraints On The Source And Residence Time Of Spring Water From The Table Mountain Group Aquifer, Paarl, South Africa	Jodie	Miller	Western Cape	2017	large-scale abstraction, urban water supply, fractured rock, springs, Tritium, residence time
Abstract Large scale groundwater abstraction is increasingly being used to support large urban centres particularly in areas of low rainfall but presents particular challenges in the management and sustainability of the groundwater system. The Table Mountain Group (TMG) Aquifer is one of the largest and most important aquifer systems in South Africa and is currently being considered as an alternative source of potable water for the City of Cape Town, a metropolis of over four million people. The TMG aquifer is a fractured rock aquifer hosted primarily in super mature sandstones, quartzites and quartz arenites. The groundwater naturally emanates from numerous springs throughout the cape region. One set of springs were examined to assess the source and residence time of the spring water. Oxygen and hydrogen isotopes indicate that the spring water has not been subject to evaporation and implies that recharge to the spring systems is via coastal precipitation. Although rainfall in the Cape is usually modelled on orographic rainfall, δ18O and δ2H values of some rainfall samples are strongly positive indicating a stratiform component as well. Comparing the spring water δ18O and δ2H values with that of local rainfall, indicates that the springs are likely derived from continuous bulk recharge over the immediate hinterland to the springs and not through large and/or heavy downpours. Noble gas concentrations, combined with tritium activities indicate that the residence time of the TMG groundwater in this area is decadal in age with a probable maximum upper limit of ~40 years. This residence time is probably a reflection of the slow flow rate through the fractured rock aquifer and hence indicates that the interconnectedness of the fractures is the most important factor controlling groundwater flow. The short residence time of the groundwater suggest that recharge to the springs and the Table Mountain Group Aquifer as a whole is vulnerable to climate change and reductions in regional precipitation. Any plans for large-scale abstraction to supplement the City of Cape Town water supply would need to factor this in to models of maximum sustainable yield.
Conceptualization Of Groundwater Flow System In Heuningnes Catchment	Vincent	Banda	Western Cape	2017	hydrochemical, groundwater flow
Abstract Records review and field based methods were used to collect and interpret groundwater level and hydro- chemical data to characterise groundwater occurrence and flow system in the Heuningnes catchment, Western Cape Province of South Africa. Our research outcome indicates that the study area has alluvial and fractured rock aquifers. The groundwater system has a rainfall driven recharge mechanisms resulting in freshwater in higher altitudes situated in the northern and western parts of the catchment. Highly saline waters are found in low-lying areas. Few samples showing high salinity water exhibit a signature of seawater although in many instances the groundwater chemistry is by and large governed by the geological formation. Groundwater potentiometric surface map shows that the general groundwater flow direction is southwards. In relation to the surface water bodies, groundwater mainly flows towards the Nuwejaars River especially in the northern and north-west part of the study area resulting in fresh water in this part of the river. As this is an ongoing study, these preliminary findings provide the required insight for further analysis and investigation. Future work will involve carrying out aquifer hydraulic tests and collection of water samples for analysis of major ions and stable isotopes. Further discussion will wait for the validation of these results to inform a meaningful implication of such findings.
Assessing groundwater dependence of wetlands and streams within the Table Mountain Group Aquifer: A Case Study from the Kogelberg	Dale	Barrow	Western Cape	2021	Ecosystems, datasets, conceptualisation, Monitoring
Abstract Ewart Smith, J; Snaddon, K; de Beer, J; Murray, K; Harillal, Z; Frenzel, P; Lasher-Scheepers, C Various analysis techniques are available for assessing the groundwater dependence of ecosystems. Hydrogeological monitoring within the Kogelberg and greater Table Mountain Group (TMG) aquifer has provided various datasets from multiple scientific disciplines (hydrological, hydrogeological, geochemical, climatic, ecological and botanical). Using a variety of analysis techniques, and using the Kogelberg as a case study, this paper assesses the groundwater dependence of several ecological sites (wetlands and streams). The starting point is a sound geological and hydrogeological conceptualisation of the site. The approach involves conceptualisation and analysis within each scientific discipline, but also requires bridging between areas of specialisation and analysis of a variety of datasets. This paper presents the data and analyses undertaken and the relevant results as they pertain to several sites within the Kogelberg.
Mountain Catchment Studies and Catchment Management	Nicolette	Vermaak	Western Cape	2015	catchment management
Abstract The mountain catchments of the Western Cape winter rainfall area were identified as areas needing more study in the early 1960s and so the Mountain Catchment studies were born. A number of study areas were suggested for these studies, but it was finally narrowed down to three sites. The studies in Jonkershoek had already started in 1935, with Zachariashoek and Jakkalsrivier added on in the 1960s. The Zachariashoek site was the only one that included groundwater as part of the experimental setup. A number of publications had been written about the work done in Zachariashoek. Most of the publications focused on changes in runoff after deforestation and fires, as well as the recovery patterns of the vegetation. The studies in Zachariashoek were done from 1964 till its termination in 1991 because of a lack of funding. The groundwater component consisted of 14 boreholes, with recorders on the five boreholes near the five weirs. The Zachariashoek area is made up of three catchments, Zachariashoek, Bakkerskloof and Kasteelkloof. It is adjacent to the Wemmershoek catchment. Bakkerskloof was the control catchment, while different burn cycles were part of the experimental setup of the two other catchments. The vegetation of Kasteelkloof was burned every 6 years with a 12 year cycle for Zachariashoek. Monitoring of the 5 weirs, 14 boreholes and the 9 rain gauges was done every week, with recorders on all five weirs, five of the 14 boreholes and at least 4 of the rain gauges. This data was entered into the data bases of the Department of Water and Sanitation, stretching from 1964 to 1986, with a complete record contained in 10 small field books. In this publication, we will look at the experiments done in Zachariashoek to see how this long term monitoring data can assist in managing the water resources within a catchment, taking into account the effects of deforestation and fires on surface water, groundwater and recharge to groundwater, the interaction between groundwater and surface water, as well as climate change.
Why is groundwater a Cinderella Water Resource?	Roger	Parsons	Western Cape	2019	Awareness, development
Abstract For years hydrogeologists have bemoaned the fact the groundwater is often pushed aside in favour of surface water resources being developed for water supply purposes. This is despite the advantages of groundwater being less vulnerable to the impact of drought, generally significantly cheaper to develop and being ubiquitous in character. The intangible character of groundwater was thought to be a major factor in water resources engineers favouring surface water resource development, as well their limited appreciation of the character, exploration, development and management of the resource. But is this really the case? Recent experiences in developing groundwater as an alternative source of water across the Western Cape Province in the face of failing municipal water supplies has highlighted poor communication being a central issue. It was observed that the hydrogeologists had little appreciation of the controls and constraints that govern getting groundwater to the user. Further, their recommendations around the use of groundwater were at times confusing to the uninitiated. Engineers, on the other hand, were found to not adhere to recommended pumping regimes nor appreciate groundwater management requirements. The treatment of groundwater emerged as a constraint that added greatly to the complexity of developing these supplies and requiring ongoing operation and maintenance efforts.
Test Pumping: Comparing the Farmer Test, Constant Head Test and SANS 10299-4:2003 methodologies with regards to estimating groundwater abstraction. Data, analyses and recommendations.	Kes	Murray	Western Cape	2021	test-pumping, Irrigation, training, Water security
Abstract Estimating pumping rates for the purpose of equipping boreholes with suitable pumps that will not over abstract either the boreholes or the aquifer(s) that are intersected is often assessed through test pumping of the boreholes prior to pump selection. While the South African National Standard has guidelines on the methodologies and durations of these tests (SANS 10299-4:2003), many production boreholes in the agricultural and industrial sectors are still equipped based upon so called Farmer Tests or Pump Inlet Tests (PIT), often of a short (6-24 hour) duration. These tests are also frequently and incorrectly confused with a Constant Head Test (CHT), both of which are different in methodology to SANS 10299-4:2003 testing, which relies to a high degree on data collected during a Constant Discharge/Rate Test (CDT or CRT) and recovery thereafter. The study will assess differences in test pumping methodology, data collection, analysis methodology and final recommendations made between Farmer Tests and SANS 10299-4:2003 methodology tests for 20 boreholes in which both tests were performed. The selected sites cover a variety of geological and hydrogeological settings in the Western Cape. Test comparisons include boreholes drilled into the Malmesbury Group, Table Mountain Group and Quaternary alluvial deposits, with tested yields ranging from 0.5 – 25 L/s.
Western Cape Coastal Groundwater Resources: Potential For Artificial Recharge And Conjunctive Use	Sumaya	Israel	Western Cape	2017	groundwater potential, artificial recharge, mixed use
Abstract Western Cape groundwater resources are often considered in isolation, per quaternary or aquifer depending on the level of management. This is an attempt to look at groundwater resources in its entirety for the major aquifer areas of the Western Cape. Atlantis in the Western Cape has been successfully operating for about 4 decades using artificial recharge, recycling of treated waste water and storm water. It is currently under used due to clogging of borehole screens and pumps with iron. However, there is no question of the potential for use and the volumes of water that the aquifer is able to supply. The Cape Flats Aquifer (CFA) has been identified in the past as a potential source to augment Cape Town’s municipal water supplies. Studies to assess the viability of the aquifer as a water supply to the Cape Metropolitan area all concluded that the CFA is a viable resource that can supply a projected sustainable yield of about 18 Mm3/a of bulk water. Artificial recharge was tested in the Cape Flats and showed great promise. The Langebaan area along the West Coast has an existing well field supply, which is able to supply the town. Artificial recharge was tested in Langebaan Road during 2009, and showed promise for the Langebaan area. In essence, the Western Cape has a large volume of untapped resources which could improve the water situation. Climatic data, groundwater levels, and chemistry for these areas are explored to consider the potential for artificial recharge, abstraction and use and the extent to which artificially recharged and existing resources can supply the coastal areas of the Western Cape.
A conceptual model for methane occurrences in the Western Karoo as part of a geochemical baseline for shale gas development	Danita	Hohne	Western Cape	2023	Western Karoo, shale gas development, shallow and deep groundwater, thermogenic and biogenic methane; isotopes
Abstract Although methane occurrences have been documented in Karoo groundwater in the past, the advent of possible unconventional oil and gas extraction now made it important to determine the type and origin of this methane to assess the possibility of shallow-deep groundwater interaction. During groundwater surveys from 2016-2021, methane was detected at three sites in the Western Karoo: the Soekor sites KL1/65, QU1/65 and an unidentified shallow groundwater borehole (BHA). The Soekor wells were drilled in the 1960-1970s to depths of between 2500-3500 meters in South Africa’s search for oil. On the other hand, Borehole BHA was drilled in 1998 and only up to a depth of 298m. This study aimed to determine methane’s origin through gas and isotope analyses. To do this, groundwater, rock and soil samples were analysed to determine whether the methane is thermogenic or biogenic and its origin. We determined that methane was both thermogenic and biogenic and probably originated from different layers of the Karoo formations and that mixing occurs between deep and shallow aquifer systems at these Soekor sites. This information was used to develop a final conceptual model of what the Karoo underground system might look like and to make recommendations for establishing a groundwater baseline.
Feasibility of iron and manganese removal by in-situ ozonation - Atlantis Aquifer Case Study	Kate	Robey	Western Cape	2015
Abstract The development of groundwater supply schemes is on the increase in South Africa. However, the sustainability of many of these wellfields is threatened due to the presence of iron (Fe2+) and manganese (Mn2+) ions in the groundwater. Their occurrence can manifest in problems with water quality and supply to consumers. The World Health Organisation recommends the removal of iron and manganese to below 0.3 mg/? and 0.1 mg/? respectively, to circumvent water quality risks. However, production borehole clogging is of greatest concern in the operation of wellfields due to the severe cost implications associated with reduced production. Clogging is caused by the precipitation of iron- and manganese-oxides at the borehole screen initiated by biogeochemical processes. Since Fe2+ and Mn2+ ions and the bacterial populations are naturally present in anoxic/anaerobic aquifer systems and the ingress of oxygen through pumping cannot be entirely prevented. The only approach to controlling borehole clogging is through management and rehabilitation procedures. Locally, these procedures have been implemented and in severe clogging cases the Blended Chemical Heat Treatment method has been applied. However, the effectiveness of rehabilitation has been limited. This can be ascribed to factors such as the incorrect production borehole design
Possible recharge areas for two of the Lower Berg aquifers units, Western Cape	Nicolette	Vermaak	Western Cape	2015	groundwater recharge
Abstract The question about the natural recharge areas for two of the Lower Berg river aquifers units, Elandsfontein Aquifer unit and Langebaan Road aquifer unit, has been keeping geohydrologists working in the area without a definite answer. Tredoux and Engelbrecht have postulated that it must be from the higher grounds around Hopefield, while Woodford hinted that an offshoot fault from the Coleso fault system could also cause the systems to be recharged from the Darling hills. Isotope studies had been done for the proposed Hopefield recharge area, but none has so far been done for the possible Darling recharge system. This paper will look at the studies done up to date and evaluate the data available for the boreholes drilled in the area in an attempt to get a clearer understanding of the two possibilities. It will also identify possible gaps in our knowledge of the area and the steps that would make it possible to fill in the gaps.
Identifying Potential Managed Aquifer Recharge Zones In West Coast Aquifers, Western Cape	Ashleigh	Tomlinson	Western Cape	2019	Poster, recharge, MAR
Abstract The overexploitation of water resources has resulted in a global decline in groundwater levels. Managed aquifer recharge (MAR) is a globally acceptable practice to manage the depletion of water in overexploited aquifers in regions with limited water availability. The West Coast of South Africa experiences a semi-arid climate with predominantly dry summers. This study aims to identify potential areas suitable for MAR in the Saldanha Bay area to maximize the water available to these areas during the dry season. This will be done through the delineation of the aquifer(s) units to determine the distribution of suitable aquifers, understanding the aquifer(s) hydraulic and hydrogeological characterises and investigate the water quality. This study focuses on 1) Frequency domain electromagnetic and electrical resistivity geophysical methods to characterise the subsurface; 2) Aquifer testing, to estimate the hydraulic properties of the aquifer(s); 3) Water quality sampling and analysis for water quality investigations. Practical considerations like distance from suitable water sources will also be considered. The expectations for this study, based on the results that should be obtained from these methods, should include the identification of several zones that would allow for MAR practices
Are Farmers Drying Out The Cederberg? Deep Groundwater Flow And Isotopes In The Table Mountain Group.	Roger E	Diamond	Western Cape	2017	TMG, Isotopes
Abstract The Table Mountain Group is a major fractured rock aquifer system throughout the Western Cape, with many interconnected but semi-independent parts, each having its own recharge area, flow paths and discharge area. Groundwater is known to travel long distances and reach great depths, including through the Olifants River syncline, such as at The Baths hot spring near Citrusdal. Stable isotope compositions of rain and groundwater in the Cederberg and Olifants River Mountains were measured over a period of 2-3 years. Rainfall in the Cederberg averaged -22‰ and -4.7‰ for D and  18O respectively, whereas rainfall in the Olifants River Mountains averaged -11‰ and -3.0‰ similarly. Groundwater used by farmers in the Olifants River Mountains averaged -13‰ and -2.9‰ similarly. The similarity between groundwater and rainfall isotope compositions in the Olifants River Mountains suggests local groundwater movement. It was concluded that the source of groundwater abstracted by farmers in the Olifants River Mountains is from the peaks west of the Olifants River with little to no contribution from the Cederberg, east of the Olifants River syncline. Geological evidence (thinning of the Olifants River syncline and increased faulting northwards) supports this conclusion.
Groundwater Exploration And Monitoring At Selected Western Cape Schools	Candice	Lasher	Western Cape	2015
Abstract POSTER The Department of Transport and Public Works has been involved with the building and upgrading of schools in the Western Cape, as well as providing green areas for sports fields. Due to the excessive costs of using municipal water the option of using groundwater for irrigation was investigated by SRK Consulting. A number of successful boreholes have been scientifically sited, drilled and tested since 2011. The boreholes have been equipped with pumps and data loggers have been installed in several. These data loggers measure time-series water levels and temperature while the flow meters measure the discharge rate and the quantity of groundwater used. Currently groundwater is being abstracted to irrigate the sports fields. Initially some problems were encountered. Boreholes were not operating optimally due to incorrect pump sizes resulting in water levels to be at pump inlet depths and pumps were not being switched off for recovery. However, due to continuous monitoring, the pumping rates and times were adjusted accordingly. It is imperative that all boreholes are equipped with loggers and continuously monitored to ensure that the boreholes are being optimally and sustainably used. Monitoring groundwater abstraction and aquifer water levels provides critical information for proper groundwater resource management. It is envisaged that schools will become proactive and participate in the groundwater monitoring. The latter will assist with groundwater awareness and assist in the use of alternative water sources and ease the burden on already stretched conventional sources.
Urbanization effects on the channel morphological changes in the Kuils River, Western Cape	Naeem	Davids	Western Cape	2015
Abstract POSTER The human interferences in river catchments includes impoundment construction, sediment mining, bank revetment and artificial cutoff, which eventually leads to changes in the hydrology system and channel transportation ability, and may reduce channel stability. In past 10 years the Kuils River had been upgraded between Van Riebeeck Road and the Stellenbosch Arterial route to reduce flood levels. The stretch of the river between the R300 and Van Riebeeck Road was also upgraded: reducing any possibility of flooding, by concrete-lining of some areas of the river that are within the Kuilsrivier Municipal Area. Producing a cross-section of a river channel is of great importance in river studies. To determine the discharge one should survey the profile of a feature such as a meander or riffle, it is necessary to produce a cross-section of the river. In order to focus on restoration requirements of a river, a map of the river is needed. This provides an indication of what exactly the river currently is. Habitat mapping is intended to access the stream. Woody debris, substrate, aquatic vegetation is measured continuously throughout a river, to be able to identify conservation and restoration needs. The cross section 1.3 of site 1 indicates that the channel width from January 2002 is almost similar in width of September 2012. The depth of the channel is about 0.5m deeper when compared to January 2002. The Kuils River banks are covered in grassy vegetation, with some trees with deep and large roots that provide protection against undercutting along rivers. The banks of Site 1 are covered long weeds and annual grasses with shallow root systems, which don't provide stability when the banks were saturated after high rainfall. The Kuils River area is used for various types of land uses and this also impacts the channels eg. Urban, Industrial and Agricultural use. Because of canalization occurring upstream one can see evidently the changes within the channel.
Assessment Of Groundwater Iron Concentration In Aquifers With Focus On Geological, Hydrogeological And Hydrogeochemical Conditions For Its Occurrence, Western Cape, South Africa	Presanta	Bissonram	Western Cape	2019	Poster, hydrochemical, iron
Abstract Due to the recent drought in the Western Cape province of South Africa, surface water can no longer meet our current demand of water and as a result groundwater usage has increased. High iron concentration in groundwater is a problem which results in iron encrustation and iron clogging. This results in decreased borehole yields, decreased water quality and expensive treatments to remove iron encrustation or the drilling of entirely new boreholes. From both international and local literature there are two common factors which stand out which is that high concentration of iron in groundwater is a global issue, the second common factor is that the occurrence and influencing factors of high iron concentrations are site specific. Boreholes drilled for drought relief in health facilities across the Western Cape have reported increased concentrations of iron. Understanding of the geology, hydrogeology and hydrogeochemical conditions that cause the increased iron concentrations in groundwater at these specific locations is required. The objectives of this research project are to: 1) Assess spatial and temporal variations in iron and manganese concentrations; 2) Establish site specific processes that control the concentration of iron in groundwater; and 3) model the geochemical processes that impact iron levels in groundwater. These objectives will be achieved through historical groundwater quality data analysis, geochemical modeling, field work where samples will be collected and laboratory analysis of the samples collected. The information provided from this research project will allow for the effective management decisions to be made in terms of iron removal from groundwater and early preventative measures that can be made to ensure iron clogging and encrustation does not occur. The study is currently ongoing and there are currently no results available at this point however, at the time of the conference there will be information ready to share.
Existing Springs in City of Cape Town and Environs: Spring Use Strategy	Louise	Soltau	Western Cape	2015
Abstract Cape Town... Home to over 3 and a half million people, the second most populated city in South Africa was born in the shadow of the Table Mountain. The mountain offered all the elements vital for human settlement... most importantly WATER. The reports of the abundance of fresh water and fertile land at the foot of the mountain and surrounds inspired the VOC to set up a refreshment station at the Cape. By the late-1800s, spring water was solely used for domestic supply to the settlers of Cape Town. Until the 1930s, the Stadsfontein or Main Spring was still being used as a source of drinking water but because of on-going concerns about the safety of the water for human consumption, and sufficient water being available from the new schemes like Steenbras and Wemmershoek, a decision was taken to discontinue using the Stadsfontein for drinking water purposes. Since then most of the water joined the stormwater to the sea, until 2010 when the City recommenced using the water for irrigation at Green Point Stadium and the Commons. City of Cape Town faces a number of water supply challenges. These include managing the ever increasing demands on the current water supply. The City of Cape Town Springs Study was born from this 2001 Water Demand Management study and it aims primarily to examine the possibility of using spring water as an alternative source of water for non-potable supply. Of these, the springs which hold the most potential for use are found in two areas - the CBD area of Oranjezicht, home to the Field of Springs
Cape Town: Where sweet waters meet the sea	Matthys A	Dippenaar	Western Cape	2017	Tourism, Drought, Hydrological Heritage Overview
Abstract The City of Cape Town is a favourite tourist destination. With Table Mountain being one of the new seven natural wonders of the world, Cape Town is also uniquely positioned where the Benguela and Atlantic ocean currents meet. Proximate environs play home to some of the most unique biodiversity found in the world with the fynbos biome protected in numerous reserves such as the Cape Peninsula, Table Mountain and Kogelberg Nature Reserves. Cape Town is also South Africa’s cultural heartbeat where artists, film makers, designers and wine connoisseurs contribute to the tourism of the country. The recent drought and increasing demands through urbanisation are raising concerns regarding water scarcity and supply. Will the city be able to supply this growing demand, notably with additional stress due to climate change? The Hydrological Heritage Overview aims to address the important power water has over Mankind and how we can harness that to our benefit without compromising the environment. The selection of Cape Town (following completion of Pretoria and Johannesburg) supplies the opportunity to address the mechanical impacts of water: Table Mountain formed through the action of water, and was shaped into its characteristic landform due to subsequent erosion by water action. Additional emphasis on the power of water relates to aspects of hydropower, the impacts of floods and droughts, and additionally of the power of water as it is harnessed as a vital life supporting resource and as a means of recreation. As the final deliverable of this project, a short 12-minute documentary film has been made for the information of the general public and interested parties. The film showcases the water history of the City of Cape Town, emphasising supply from springs, dams and, more recently, artificial groundwater recharge. Although not a technical presentation, showcasing of the film will advance citizen science and public appreciation for the value of water.
Nutrient Retention In Stream Sized Rivers, Related To Riparian Land Development And Climatic Change	Reuben	Lazarus	Western Cape	2017	Seasonal cycles, Pollution, physicochemical environment
Abstract The Western Cape of South Africa is rich in small stream sized rivers forming part of its water resources. The Lourens river and Eerste river, both situated in this region are the base for this study. Rivers are affected by their surrounding environments and the continuous development around these rivers could affect their health adversely. Diverse land-use patterns contribute to a wide range of pollutants with different characteristics. Indeed, some of the pollution levels in the Eerste and Lourens rivers were linked directly to specific land-use practices surrounding the rivers. However, the large change in weather during a seasonal cycle causes a significant difference in pollution levels too, because the transport of pollutants from the source to the rivers is primarily based on surface run-off, which in turn is predominantly dependent on the precipitation of the region. A six months long monitoring in 2016 showed that processes like surface run- off, together with first flush events and dilution control the pollution concentrations in the Lourens river and Eerste river. Physicochemical parameters, major agricultural nutrients and industrially produced heavy metals all reacted differently to these processes, thus, providing an insight into the effects continuous development and climate change have on surface water as a national resource. Interestingly, both rivers included sections with substantial retention and/or reduction of pollutants. The natural riparian vegetation, hyporheic zone and microbial community present in these rivers are proposed to be the main drivers behind both rivers’ ability to reduce or retain pollutants. These drivers are sensitive to their environment and react differently depending on the weather, available nutrients, and physicochemical environment. With the effects of climate change becoming more apparent, it is important to study the impact of warmer temperatures, longer droughts, and heavier rain events, for instance, on the pollutant retaining capabilities of these streams.
In-Situ Iron Removal Treatment In A Primary Aquifer, The Atlantis Example	L.	Nhleko	Western Cape	2017	Iron Removal, Atlantis Aquifer
Abstract In a town where 98% of the population relies on groundwater-dominated resources, Atlantis is also plagued by varied abstraction rates that promoted iron and manganese borehole clogging. Conventional treatment methods, such as pump-and-treat technology, can be costly and inefficient. In-Situ Iron Removal (ISIR) technologies addresses issues such crucial skilled operators, handling and storage of chemicals, expert management, and the disposal of generated sludge. ISIR has been successfully practised worldwide especially in Europe, for well over a 100 years. In South Africa however this methodology has not filtered through, although our groundwater systems have clogging problems related to iron and manganese precipitation. Atlantis in the Western Cape has benefitted from a pilot study that looked into ISIR and the unique idea of utilizing ozonation. The pilot project was successful, although applied on a small scale. This called for a further study that is now looking into extending the range of treatment, applying the principles of the Vyredox method, and lengthening the treatment period to 3 months of continuous injection. The study also aims to develop the engineering design criteria for full scale application. The success of this project and the technology to be developed goes a long way towards achieving Sustainable Development Goal 6 and improving South Africa’s groundwater systems.
An assessment of the contribution of surface and subsurface flows to river flows of the Sandspruit in the Berg River Catchment,	Matthew	Damons	Western Cape	2015
Abstract Studies showed that the primary origin of salinity in river flows of the Sandspruit in the Berg Catchment located in the Western Cape Province of South Africa was mainly due to the weathering of the shales, while atmospheric deposition contributed a third of the total salinity. The salts are transported to rivers through surface runoff and subsurface flow (i.e. throughflow and groundwater flow). The purpose of this study was to determine the relative contributions of subsurface flow and surface flows to total flows in the Sandspruit River, Berg Catchment. Three rain events were studied. Water samples for two rain events were analyzed for environmental tracers ?18O, Silica (SiO2), Calcium (Ca2+) and Magnesium (Mg2+). Tracers used for two component hydrograph separation were ?18O and SiO2. These tracers were selected as Ca2+ and Mg2+ provided inconsistent contributions of both subsurface flow and surface flow. Two component hydrograph separations indicated that groundwater is the dominant contributor to flow, while surface runoff mainly contributes at the onset of the storm event. Groundwater response to precipitation input indicated that boreholes near the river have a greater response than boreholes further away from the rivers, which have minor response to the input of precipitation. Keywords: Stable Isotopes, Sandspruit River, Tracers, Hydrograph separation, Salinity
Parameter estimation for artesian aquifer in Table Mountain Group Aquifer by analytical and numerical simulation methods	Xiaobin	Sun	Western Cape	2015
Abstract Accurate parameter estimation for fractured-rock aquifer is very challenging, due to the complexity of fracture connectivity, particular when it comes to artesian flow systems where the potentiometric is above the ground level, such as semi-confined, partially confined and weak confined aquifers in Table Mountain Group (TMG) Aquifer. The parameter estimates of these types of aquifers are largely made through constant-head and recovery test method. However, such a test is seldom carried out in Table Mountain Group Aquifer in South Africa due to a lack of proper testing unit made available for data capturing and appropriate method for data interpretation. An artesian borehole of BH 1 drilled in TMG Peninsula Formation on the Gevonden farm in Western Cape Province was chosen as a case study. The potentiometric surface is above the ground level in rainy season, while it drops to/below ground level during the dry season. A special testing unit was designed and implemented in BH 1 to measure and record the flow rate during the free-flowing period, and the pressure changes during the recovery period. All the data were captured at a function of time for data interpretation at later stage. Curve-fitting software developed with VBA was adopted for parameter estimation based on the constant-head and recovery tests theories. The results indicate that a negative skin zone exists in the immediate vicinity of the artesian borehole, and the hydraulic parameters estimates of transmissivity (T) ranging from 6.9 to 14.7 m2/d and storativity (S) ranging from 2.110-5 to 2.110-4 appear to be reasonable with measured data collected from early times. However, due to formation losses, the analytical method failed to interpret the data collected at later times. Consequently the analysed results by analytical solution with later stage data are less reliable for this case. The MODFLOW-2000 (Parameter Estimation) package developed by USGS was also adopted to determine these parameters for the same aquifer. It approves that there exist formation losses, which leads to the aquifer response distinctly different at later stage of overflow and recovery tests. The aquifer parameter estimates with early time data of tests by analytical and numerical methods show that there is generally good agreement. However, significant errors could be generated by analytical method applied where there is occurrence of well or formation losses, while these restrictions could be overcome by applying a numerical method.
The presence and concentration of antiretroviral drugs in different water bodies around the Western Cape	Phumelele	Maphumulo	Western Cape	2021	Antiretroviral, chemical formulas
Abstract This study is based on the presence and concentration of antiretroviral drugs in water bodies around the Western Cape Province in South Africa, these areas include wastewater treatment plants, water treatment plants, stormwater, and landfill boreholes. South Africa has the highest rate of HIV and AIDS in the entire world, statistics from 2018 show that 7.7 million South Africans are infected with HIV/AIDS and 68% of them are on antiretroviral treatment (UNAIDS). South Africa has the largest antiretroviral treatment program (ART) in the world, due to the lack of proper water and sanitation these drugs are deposited in the environment poorly and reach water bodies, therefore, contaminating them. This study involves the collection of samples from areas such as Mitchell’s Plain, Khayelitsha, Athlone, Cape Flats, and Atlantis around the western cape, these samples are analyzed to determine the presence of 5 antiretroviral drugs used in South Africa which are Efavirens, Lopinavir, Nevirapine, Ritonavir, and Tenofovir. Water samples are prepared for analysis by filtering 2.5ml water through a 1µm glass fiber filter, the sample is then placed into sample vials and analyzed on HPLC-QTOF/MS. Mass Hunter software is used to identify the specific ARVs in the water samples analyzed, by searching for the compounds via their chemical formulas. With a match made if their chemical formula, retention time and mass to charge ratio of the compounds correspond. Concentrations range between 0.0855ng/ml Nevapine to 4.3289ng/ml Lopinavir, this analysis has determined that all the mentioned antiretroviral drugs are indeed present in different water bodies around the identified areas within the Western Cape in varying concentrations.
Airborne And Ground Geophysical Surveys To Investigate The Deep Geology And Geohydrology In The Beaufort West Area, Western Karoo, South Africa	Matome	Sekiba	Western Cape	2019	Geology, Geohydrology, Airborne, Magnetotelluric
Abstract A geoscientific research project is underway in the Western Karoo Basin near Beaufort West, South Africa. This area has been earmarked for possible gas exploration. The aim of the project is to improve the understanding of the deeper aquifer systems of the Karoo Basin to better predict potential impacts of geo-resource exploration activities on the deep groundwater systems. This paper reports on the airborne and ground geophysical surveys that were conducted in the study area to gain insight into the deep structural geology and its possible association with aquifer systems. Geophysical methods that were used in the investigations include: 1) the airborne magnetic method was employed to detect and delineate non-outcropping dolerite sills and dykes, as well as to map geological structures of regional extent, and 2) the deep-probing magnetotelluric (MT) technique was used to map conductivity contrasts at large depths that could be associated with prominent geological structures. The results of the geophysical surveys showed that the airborne magnetic method was very effective in mapping intrusive magmatic bodies and other major geological structures. The magnetotelluric results indicated the presence of very resistive layers that appear to be associated with dolerite intrusives. Furthermore, the vertical displacement of a conductive zone indicated the possible presence of large-scale faulting. Based on the results of the airborne geophysical investigations, two investigative boreholes were drilled at selected positions to depths of 516 m and 1 402 m to obtain information on the subsurface geological and geohydrological conditions, and to constrain the interpretation of the airborne geophysical data. Downhole geophysical surveys were conducted on these boreholes to obtain in situ geotechnical and structural information. The results of this project show that the combined use of airborne and deeper probing geophysical methods can greatly contribute to the understanding of the deep geological and geohydrological conditions in the Karoo Basin. The approach can be further utilised for similar investigations of other Karoo satellite basins in South Africa and neighbouring countries
The use of Hydrogeochemical Analysis Model to assess groundwater quality for drinking and agricultural use in Heuningnes Catchment	Portia Leah	Mokoena	Western Cape	2015
Abstract POSTER The study aims at using hydrogeochemical model to establish groundwater quality in shallow and deep aquifers in Heuningnes Catchment which is located within Bredasdorp in the Western Cape Province. The catchment is positioned at latitude of 34o42'50"S and longitude 20o07'13"E. The area is about 1400km2 has vleis, lakes and pans and its predominant formation is sedimentary rocks of Table Mountain and Bokkeveld Groups sitting on a crystalline basement of the Malmesbury granites. Comprehensive characterisation of the hydrogeochemical evolution is lacking and the current study argues that the use of hydrogeochemical Analysis Model (HAM) has potential to establish water-type, water source, water mixing/rock-water interactions, salinity, saturated adsorption ratio and hardness-softness of that predominant hydrochemical facies in the study area in addition to assessing the compliance of such water to WHO and South Africa water quality guidelines for drinking and agricultural use. Groundwater samples will be collected in 45 different locations (wellpoints/shallow wells, boreholes and wetland as end member) using in-situ sampling techniques to measure pH, electrical conductivity, total dissolved solids and temperature. Turbidity, total hardness, calcium, chloride and bicarbonate will be analysed using analytical chemistry methods including titrimetric method. Magnesium, potassium, sodium, nitrate and phosphate analysed by Atomic Absorption Spectrophotometer whilst sulfate will be analysed using spectrophotometer. Graphical methods such as piper diagram will be used to present the results to determine water-type, water freshness/hardness, water source, water mixing/rock-water interactions, salinity, saturated adsorption ratio and hydrogeochemical processes. The results from the present study are envisaged to inform formulation of science-based interventions strategies that will lead to sustainable utilization and management of the water resources in the area to improve the livelihoods of people and environmental integrity. Key words: Groundwater quality, Heuningnes Catchment, hydrogeochemical Analysis Model, Piper diagrams, Hydrogeochemistry
Knowledge comes with trial, error and time: The Langebaan Road story	Nicolette	Vermaak	Western Cape	2015
Abstract When planning an experimental setup in the laboratory, it is very important and possible to control all the variables so that one can manipulate particular variables at a given time. Experimental setups under natural conditions could be a challenging task. The success of an experiment depends to a large extent on the correct understanding of the functioning of a natural system. If the conceptual understanding of the natural system is erroneous, it is likely that unexpected results could be achieved. This was the case with the artificial recharge pilot project that was done in 2008 and 2009 at the Langebaan Road wellfield just outside Hopefield in the Western Cape. Years of research gave scientists a fairly good idea of the way in which the aquifer system functioned, especially since the establishment of the well field. This provided information of the response of the aquifer unit to large scale abstraction. The Langebaan Road aquifer unit is a multilayered system with a lower aquifer composed of Elandsfontyn gravel overlaying a bedrock layer of either granite of the Vredenburg or Darling plutons of the Cape Granite Suite or Malmesbury shale. The bedrock was considered impermeable. The upper aquifer layer was composed of mostly the Varswater Formation with peat and clay of the Elandsfontyn Formation forming the confining layer between the two aquifer layers. The extent of the different layers of the aquifer unit was plotted with a fair amount of accuracy and the clay layer was considered to be continuous between the two aquifer layers. Monitoring data for the area was done since 1974 with a gap in data-set between 1991 and 2001. Despite all the data from geophysical work, boreholes drilled, and the monitoring record, the research done prior and during the artificial recharge pilot project in 2008 and 2009 the aquifer units did not respond quite as anticipated. The Artificial Recharge (AR) pilot project team concluded that the aquifer units responded in a particular manner as opposed to the expected response according to the data and conceptual model at hand. It was thus clear that there are gaps in the conceptual model of the aquifer systems in the bigger Lower Berg River Valley that include the Langebaan Road, Elandsfontein and other aquifers that needed to bridge before another pilot test is attempted. Although the artificial recharge pilot project did not yield the expected results, valuable lessons were learned. This article will look at the conclusions and recommendations of the research done on the pilot project and attempt to evaluate the monitoring data (water levels, chemistry and rainfall) from the period just before the beginning of the AR pilot project. The monitoring data would be manipulated using the following techniques
Assessment of Plume Stability in Monitored Natural Attenuation Assessments Using the Centre of Mass and Total Plume Mass Approach	Samuel D	Mohr	Western Cape	2017	Monitored natural attenuation, petroleum, Hydrocarbon, plumes, monitoring network
Abstract Monitored natural attenuation (MNA) is becoming a commonly employed sustainable site remediation strategy for sites with petroleum hydrocarbon groundwater impacts. Natural attenuation is essentially the reduction in contaminant concentration, mass or mobility due to naturally occurring processes within the environment. Aromatic compounds such as benzene, toluene, ethylbenzene, and xylenes (BTEX) are common compounds of concern in the context of petroleum hydrocarbon related investigations because of their relative mobility and toxicity characteristics. Despite this, these compounds have historically displayed a strong affinity towards attenuating temporally and spatially away from the source areas. Evaluating plume stability is an important element of evaluating the overall attenuation of groundwater plumes and numerous methods have been developed in order to assess plume stability including graphical and statistical methods. It is often the case however that these analyses focus on single wells in isolation and do not take an integrated approach to evaluate the attenuation of contaminant mass over the entire plume. The authors present a case study where historical trends in plume characteristics have been used to assess overall plume stability. Trends in parameters such as average plume concentration, total plume contaminant mass, plume area and plume centre of mass were statistically assessed to determine whether the groundwater plume was expanding, stable, or shrinking. The methods employed in the plume stability analysis were found to be effective tools in demonstrating the occurrence of natural attenuation of contaminant plumes. It is important to note that a good quality dataset is required, in terms of a spatially representative monitoring well network and adequate time series data, in order to conduct analyses that will yield meaningful conclusions.
Interannual variability in rainfall isotope composition as a tracer of spring water flow.	Roger E	Diamond	Western Cape	2015	Table Mountain Group, springs, rainfall isotopes
Abstract Table Mountain reaches 1086m elevation, the upper half of which comprises Table Mountain Group (TMG) quartzite with extensive fracture porosity. The lower half of the mountain comprises a mixture of Cape Granite intruded into Malmesbury Group metapelites, both of which are poor aquifers, but are in places overlain by scree slopes predominantly composed of TMG quartzite boulders. The region experiences a Mediterranean climate with warm, dry summers and cold, wet winters, with rainfall ranging from 600-1600mm/a depending largely on proximity to the mountain. Several springs issue from the slopes of the mountain, ranging in elevation from 15-410masl and in flow from non-perennial to 30L/s. Water chemistry reveals very little about spring water flow, as the waters have very low dissolved solids. Samples of 10 of these springs were taken twice per year for 3 years while rainwater was sampled at 120masl at the University of Cape Town (UCT) and at 1074masl at the Upper Cableway Station. These samples were analysed for oxygen and hydrogen stable isotope composition, mostly by mass spectrometer, but also by laser spectroscopy. The isotope results reveal an altitude gradient between the two rainfall stations of -0.075?/100m for ?D and -0.48?/100m for ?18O. Employing this isotope gradient, the average recharge altitude for the springs is 304masl, compared to an average discharge altitude of 156masl. Using this difference in altitude and the average slope of the terrain, a typical flow path of 1km from recharge to discharge point can be derived. Additionally, there are shifts in the weighted annual mean isotope composition of rainfall at UCT. For the years 2010-2012, the shifts are paralleled by similar shifts in the mean isotope composition at the springs for each of those years. This suggests rainfall discharges in the same winter season it has been recharged. In combination with the evidence for long term reliability of some of the springs over the dry season and during droughts, this suggests a layered flow of groundwater in the scree aquifer, allowing both long term steady discharge of deeper groundwater, as well as short term discharge of recently recharged rain. In combination with the flow path derived above, hydraulic conductivities in the realm of 10-20m/d can be calculated for the scree aquifers.
Assessment Of The Spatial Coverage Of Groundwater Dependent Ecosystems In A Semi-Arid To Arid River Gouritz River Basin	T	Mbandezi	Western Cape	2017	Shallow groundwater, groundwater dependant ecosystems, remote sensing
Abstract The presence of shallow groundwater at locations with limited spatial coverage in drylands have since time immemorial supported plant and animal communities. These locations often have in comparison to the surrounding dry landscapes high biomass production and biodiversity. The presence of groundwater makes these locations attractive for development of groundwater dependent human activities such as irrigated crop production, and livestock production. Groundwater abstractions from locations that are not necessarily close to these plant and animal communities, but tapping into the same aquifer systems have also a potential to affect the availability of water to these ecosystems which is critical for their existence. The importance of these groundwater dependent ecosystems is not well understood due to limited knowledge about their spatial coverage. Some of the groundwater dependent ecosystems occur in areas that are not accessible such as mountain slopes, or in remote areas. The long-term impact of groundwater usage on some of these ecosystems has not been evaluated, with most of the knowledge about these impacts being based on anecdotal information obtained from the respective land owners. Remote sensing offers an opportunity to map the spatial coverage of groundwater dependent ecosystems in drylands. A distinguishing characteristic of these systems is the active plant growth especially during periods when throughout the landscape, there is limited or no water to support plant growth. Monitoring plant growth during the dry season using indices such as the NDVI enables detection of groundwater dependent ecosystems. Knowledge about the rates of actual evapotranspiration at locations with these ecosystems enables an estimation of the amount of water required to support them during the dry season. The MODIS 16 actual evapotranspiration rates (ETA) which are globally available can be used for evaluating water use by groundwater dependent ecosystems. This paper explores the mapping of the spatial coverage of groundwater dependent ecosystems using remote sensing based vegetation indices in parts of the Gourizt River basin in South Africa. The rates of waters use by the identified groundwater dependent ecosystems are estimated using actual evapotranspiration rates based on MODIS 16. The paper also examines possible long-term changes to the spatial coverage of groundwater dependent ecosystems.
Arsenic In The West-African Water Reserves: Investigation Into Sources Of The Contaminant Through Case Studies In The Region	Andre	van Coller	Western Africa	2013	Contaminant, investigations, Groundwater reserve
Abstract The mineral-rich basin of the West African region has vast reserves of gold, diamond as well as iron ore deposits. Throughout the regional geological setting characterised by structural variations and intrusive belts with metamorphic mineral-rich sequences covered by saprolite soils, one common chemical constituent remains a constant in the water reserves. Arsenic is in high concentrations throughout the region with chemical ranges commonly above the various country guidelines as well as international IFC and WHO standards. The aqueous chemical species is associated with arsenopyrite-rich mineralogy of the regional greenstone belts and highly weathered soils. This conference presentation investigates the natural source of the arsenic through baseline data, as well as the effect of mining on the already high concentrations of arsenic in both the groundwater and surface water. Natural levels of various chemical species in the regional area are already high at baseline level. One of the main research questions is thus whether mining and other anthropogenic activities will have an impact on the environment or will the changes to concentrations be so insignificant to allow the ecosystems and water users to continue in their current ways without any effect. Various case studies in Burkina Faso, Liberia, Sierra Leone and other countries have been combined to investigate the arsenic-rich resources of the West African region through groundwater specialist investigative methods with emphasis on geochemical modelling of the fluid–rock and fluid–fluid interactions leading to the aqueous chemical conditions in the region.
The Geohydrological Setting Of The Elandsfontein Phosphate Mine, West Coast	Julian E	Conrad	West Coast, Western Cape	2017	Phosphate mine, numerical modelling, dewatering, injection system
Abstract The Elandsfontein Phosphate Mine is situated midway between the Langebaan Lagoon and the town of Hopefield. It is located on the Cape West Coast, within the Saldanha Bay Municipality. The mine is positioned within the Elandsfontein Aquifer Unit – which comprises an upper and lower aquifer separated by an aquitard. The economic phosphate layer is situated within the saturated zone of the Upper Aquifer Unit. There are fresh water inflows into the Langebaan Lagoon and all measures must be taken to ensure the natural geohydrological flows are not impacted. Numerous groundwater studies and numerical modelling was carried out to optimize the best way of minimizing the impact on the geohydrology of the area. The dewatering system that has been designed includes re-injection of the groundwater approximately 2 km down-gradient of the open pit. This paper reviews the geological and geohydrological setting of the area and the outcomes of the dewatering and injection systems in place.
Identifying suitable sites for Managed Aquifer Recharge within the Saldanha Bay Local Municipality, situated in the West Coast of South Africa	Ashleigh	Tomlinson	West Coast, Western Cape	2021	MAR
Abstract The West Coast in the Western Cape of South Africa is a water-scarce area. With pressure from population and industrial growth, recurring droughts and climate change, there is increasing urgency in the West Coast to protect groundwater resources. Saldanha Bay is dependent on groundwater as part of its bulk water supply system. Where the natural groundwater recharge is no longer sufficient to meet the growing groundwater needs, practices such as Managed Aquifer Recharge (MAR) can be used to ensure the sustainability of these groundwater resources. This study aims to identify areas within the Saldanha Bay Local Municipality suitable for Managed Aquifer Recharge to maximize the water available during periods of limited surface water supply. As such, the MAR study site identification requires a comprehensive geohydrological assessment of the Saldanha Bay aquifer. This includes an understanding of the quality and quantity of the source water available for recharge, the aquifer structure and hydraulic properties, the space available to store water, and the compatibility of the recharged water with the groundwater. MAR research methods included Time Domain Electromagnetic (TDEM) airborne geophysical surveys, infiltration tests, pumping tests and hydrochemical analysis. TDEM surveys provided clarity on the various aquifer geological properties. Infiltration and pumping tests shed light on the horizontal and vertical hydraulic properties of the aquifer. PhreeqC modelling outputs helped predict the outcome of the mixing between groundwater and potential MAR water resources. Geological features were delineated through TDEM surveys and inferred five suitable MAR sites where clay layers were missing. Infiltration and pumping tests showed that Langebaan Road is better suited to borehole injection, whereas Hopefield has the benefit of infiltration MAR techniques as an additional option. PhreeqC outputs exhibit that both pipeline and Berg River water show promising results as potential source water resources for MAR as compared to other resources.
Identifying And Modelling Sustainable Groundwater Inflows Into The Verlorenvlei Coastal Estuarine System In South Africa	Jodie	Miller	West Coast, Western Cape	2017	estuarine system, agriculture, hydrochemical, baseflow
Abstract The Verlorenvlei estuarine lake is one of only two freshwater estuarine systems in South Africa. Whilst being important ecologically it is also a critical agricultural region, supporting a significant proportion of South African potato crops as well as a number of other diverse crops. The vlei itself is fed by the Verloren River which is thought to be fed by surface water inflows and baseflow throughout the year along several tributaries, namely the Krom Antonies, Hol, Berg Vallei and Kruismans. Each of these tributaries has a distinct hydrochemical character defined by cation and anion concentrations, as well as O, H and Sr isotopes. Simulated discharge from each tributary suggests that all tributaries contribute to the chemistry of the Verloren River. The Krom Antonies which has the freshest water has the highest discharge at around 50% of surface water inflows, whilst the Hol with the highest EC values contributes around 35% of surface water inflows. In spite of this, the surface water hydrochemistry in the Verloren River, is remarkedly fresh and very similar in character to the surface water of the Krom Antonies. Sr isotopes in each of the tributaries are distinct and support mixing of different components of each tributary above the confluence. However, below the confluence, they drop significantly which indicates mixing with another unidentified Sr-source. This source was thought to be baseflow from the deeper groundwater system, but the Sr isotope composition of deeper groundwater indicates that it is not the contributing component. Recent years have seen dramatic reductions in precipitation, while increases in pumping for agricultural purposes potentially exceeds the long-term sustainable yield of the aquifer system. Identification of this unknown component has therefore become a priority for groundwater management in the area as it is unclear how vulnerable this component will be to climate change and hence what impact climate change will have on the vlei.
Understanding Natural Groundwater Recharge Systems In The Lower Berg River Catchment, West Coast, Western Cape	Clinton W	Andries	West Coast, Western Cape	2017	MAR, geochemical, Lower Berg River Catchment, conceptual model
Abstract The CSIR has embarked on a study to investigate the potential for additional water in the West Coast, Western Cape through the application of Managed Aquifer Recharge (MAR). The benefits of MAR is that it may generate additional water supplies from sources that may otherwise be wasted with the recharged water stored in the aquifer to meet water supply in times of high demand. Determining recharge is the most important aspect of hydrological system. However, the accurate estimation of recharge remains one of the biggest challenges for groundwater investigators. Numerous studies have been conducted using geochemical methods to estimate and distinguish sources of recharge in different groundwater units of unconfined and confined aquifers internationally. The application of geochemical methods to produce accurate conceptual model describing natural recharge in aquifer units of Lower Berg River Region has not been widely published. The Lower Berg River catchment, consisting of 4 primary aquifer units (Adamboerskraal, Langebaan Road, Elandsfontein and Grootwater) will be used to demonstrate the applicability of such methods. The aim of the study is to estimate recharge in the lower berg river catchment, and develop a conceptual natural recharge model that will improve understanding of the aquifer system and be an indicator for water availability in the Lower Berg River Catchment. The objectives in developing the conceptual model includes establish groundwater recharge sources, groundwater flow paths, recharge mechanism and potential mixing of groundwater by using environmental isotopes; and obtain a reliable estimation of its recharge amount using the Chloride Mass Balance. As this study is still in progress, this publication will focus on reviewing literature and the outcomes envisioned from the project as to provide a complete understanding of the complex geology. This will lead to a better understanding of the functioning of natural recharge of the aquifer units in the Lower Berg River Catchment.
Optimized Groundwater Monitoring Design for Managed Aquifer Recharge Using Hybrid Numerical, Geophysical and Chemical modelling approach	Clinton W	Andries	West Coast, Western Cape	2021	MAR, AHP, Monitoring network design
Abstract Israel, S; Kanyerere, T Globally, surface waters are severely unsustainably exploited and under pressure in semi-arid coastal regions, which results in increasing demand for groundwater resources. Currently, Cape Town and its neighbouring towns along the West Coast of South Africa are facing water shortage related problems. Managed Aquifer Recharge (MAR) is a nature based solution to improve groundwater security in drought prone regions such as the West Coast. The objective of this study was to design a groundwater monitoring network using a hybrid hydrochemical, geophysical and numerical modelling approach to assess and mitigate the potential impacts of MAR for the West Coast Aquifer System (WCAS). An Analytical Hierarchy Process method was used to perform a Multi-criteria analysis employed in GIS (ArcMap 10.3). The factors of importance for optimized groundwater monitoring network design were based on available data and consultations with hydrogeologists and environmental scientist at stakeholder workshops. The factors which were considered included: elevation (m), geology, density of existing boreholes (wells/km2), electrical conductivity (mS/m), water rise (m), water level decline (m), transmissivity (m/day), saturation indices and lithological thickness (m). Factors were weighted based on their level of importance for the design of the groundwater monitoring network using Analytical Hierarchy Process (AHP). Priorities were calculated from pairwise comparisons using the AHP with Eigen vector method. The Consistency Ratio (CR) calculated was 5.2% which deems the weighting coefficients statistically acceptable. The results show that high priority monitoring areas occurs in the areas where there are fresh groundwater, high borehole density, elevated topography, higher recharge rates and decline in water levels are found. The monitoring network will include boreholes from the low priority areas to ensure that hydrogeological conditions are monitored and impacts are not worsened. Geophysical, numerical and chemical modelling aspects of the methodological approach will be incorporated into the initial groundwater monitoring network design.
The most valuable resource	Nicolette	Vermaak	West Coast, Western Cape	2015	resource economics
Abstract Mining is becoming a problem in the Western Cape - different kinds of mining and other resources, different problems than in other parts of the country. The West Coast had been declared a development corridor and a mining priority area. It is an arid to semi-arid area, where surface water is scarce, and rainfall relatively low and decreasing as one moves north. Some areas have significant volumes of good quality groundwater available, with potential impacts by the mining activities. This would play the importance of different resources off against the other. Most see resources as minerals, such as gold, silver, phosphate, and others where the value of these resources is measurable. Resources are also human capital, time, water, air, a healthy environment. It is more difficult to measure the value of the second group, as some of them have more than just a Rand and cent value. The value of resources is mostly done by measuring its monetary value, i.e. how much you will get when you sell the resource to a customer, providing the way the value of most resources is measured, i.e. resource economics. Economics is an area that most scientists are not familiar with as it contains a way thinking, of rules and laws unrelated to the way they have been taught. Supply and demand determines the value of a commodity, with scarce resources normally fetching higher prices. The value of the second group of resources is more difficult to determine. When does a resource become a strategic resource? This would be a resource that has a limited supply, does not get regenerated through natural processes and that is needed for defence, energy supply and others important for the stability of a country. There are also a category of resources we cannot live without such as water, and air - pure, fresh air and water. Without it life on this planet will cease to exist. This could be termed critical resources. What do you do if the occurrence of two very important critical resources overlaps, where the extraction of the one will lead to irreparable damage to the other? This article will look at one site where a strategic resource occurs at the same site as an important water resource. It will compare the potential value of the mineral resource with the value of the water resource in the aquifer measured at the current value of water as available to the public. It will also take into account the value of the water resource from the perspective of a healthy functioning ecosystem and a RAMSAR site. This analysis becomes more valuable when considering the potential effects of climate change in the area and the cost of desalination.
An Investigation Of The Natural Groundwater Recharge And Discharge Of The West Coast Aquifer Systems	Aqeela	Parker	West Coast Aquifer Systems	2019	Poster, recharge, Discharge
Abstract Groundwater in the West Coast has been utilised for many years as there are not many surface water resources in the area, and is therefore extremely important. Despite studies being conducted on the aquifer systems since 1976, they are still poorly understood especially with regards to their recharge and discharge processes. This means that the amount of water entering and leaving these systems are unknown, which may lead to over abstraction. It is therefore important to investigate these systems to prevent overexploitation of the groundwater as it will have adverse effects for both humans and ecosystems dependent on it. As part of a managed aquifer recharge (MAR) project for the Saldanha Bay Municipality, this study aims at providing better insight and understanding on the natural resource volumes. The study focusses on groundwater recharge, flow paths and discharge processes and aims at quantifying the volume of water related to each. The study will be conducted by identifying aquifer characteristics through Frequency Domain Electromagnetic and Electrical resistivity geophysical methods. Groundwater flow paths through the unsaturated zone, into the groundwater and towards the discharge area will be determined using Chloride Mass Balance calculations and water isotope analyses. The mass balance equations along with isotope analyses will then aid in the identification of natural recharge and discharge areas of the West Coast aquifer systems, as well as quantifying the volume of water moving through each aquifer. Temperature profiles will also be generated to identify specific layers of the aquifer systems and to determine their groundwater-surface water interactions. The aquifer characteristics will be used in numerical models to test the conceptual understanding of recharge and flow through the systems as well as assessing the volumes of water available to the users of the system.
Geochemical investigations to improve the prediction of mine water impacts: A case study in the Elandsfontein Aquifer System, West Coast.	Angelo	Johnson	West Coast	2021	Phosphate mine, waste sreams, mine water impacts, PHREEQC, geochemical
Abstract The impact of the future closure of the KROPZ phosphate mine in the West Coast on the various potential receptors including the underlying Elandsfontein Aquifer System (EAS), Langebaan Lagoon (RAMSAR-site) and wetlands were assessed. This abstract/paper describes the geochemical characterization and management options related to the waste streams from the mining activity, to assess the post closure contribution to groundwater flow from the mine towards potential receptors. The PHREEQC geochemical modelling code was used to predict potential mine water impacts. The input water quality parameters used in the model included: background groundwater quality, pit water and processed water generated from phosphate separation process at the mine. Various scenarios were simulated combining the different process water streams with the tailings and soft stockpile material at the mine. The geochemical predictions showed some management options that should be prevented, while also providing guidance to promising options where most of the chemical parameters does not exceed the WUL stage 1 thresholds. There is however, an increase in sulphate concentrations that need attending to before the mine goes into production phase. Currently there seems to be no immediate concern on the Lagoon relating to the prediction of mine water impacts post mine closure. Some of the management scenarios do however show low levels of potential impacts on SANParks property 100 years post closure. These predictions do however correlate to areas where limited calibration data is available. At the time of this abstract the sites for new boreholes have been selected and the initial boreholes are being drilled to confirm aquifer properties in areas with limited data.
Arsenic In The West-African Water Reserves: Investigation Into Sources Of The Contaminant Through Case Studies In The Region	André	van Coller	West African region	2013	Contaminant, case study
Abstract The mineral-rich basin of the West African region has vast reserves of gold, diamond as well as iron ore deposits. Throughout the regional geological setting characterised by structural variations and intrusive belts with metamorphic mineral-rich sequences covered by saprolite soils, one common chemical constituent remains a constant in the water reserves. Arsenic is in high concentrations throughout the region with chemical ranges commonly above the various country guidelines as well as international IFC and WHO standards. The aqueous chemical species is associated with arsenopyrite-rich mineralogy of the regional greenstone belts and highly weathered soils. This conference presentation investigates the natural source of the arsenic through baseline data, as well as the effect of mining on the already high concentrations of arsenic in both the groundwater and surface water. Natural levels of various chemical species in the regional area are already high at baseline level. One of the main research questions is thus whether mining and other anthropogenic activities will have an impact on the environment or will the changes to concentrations be so insignificant to allow the ecosystems and water users to continue in their current ways without any effect. Various case studies in Burkina Faso, Liberia, Sierra Leone and other countries have been combined to investigate the arsenic-rich resources of the West African region through groundwater specialist investigative methods with emphasis on geochemical modelling of the fluid–rock and fluid–fluid interactions leading to the aqueous chemical conditions in the region.
Groundwater and mining on the West African shield: application of mineralogical and weathering profiling	David	Love	West Africa	2015
Abstract The Birimian and Tarkwaian rocks of the Paleoproterozoic West African Shield host some of the most important gold reserves in the world, with Ghana the world's 10th largest gold producer and the region collectively producing more gold than all but five countries in the world. The gold was deposited during successive hydrothermal sulphide alteration events, which were channelled by shear zones and thrusts formed during the regional progressive Eburnean tectono-thermal deformation event. The hydrothermal fluids were auriferous and sulphide-rich, resulting in two distinct types of gold and sulphide mineralisation: (1) gold-bearing quartz- and quartz-ankerite veins, occurring in NNE-SSW trending shear zones or thrust folds, usually in Birimian metasediments, with associated sulphides deposited on the fragmented wall rock and (2) disseminated gold-bearing pyrite and arsenopyrite, occurring in halos within the same shear zones or thrust folds as the quartz veins. The sulphidic nature of the gold deposit leads to a high risk of acid rock drainage (ARD). During operations, inflowing groundwater may carry the ARD into underground workings and opencast pits. Post-closure, as the groundwater rebounds, there is a risk of acidic pit lakes forming or acidic decant of underground mines. However, the occurrence of ARD in such systems can be predicted by a combination of weathering profiling, mineralogical profiling and conventional acid base accounting (ABA). The weathering profile can be divided into three zones, readily distinguishable in borehole core: (i) Oxide Zone, from which both the acid-generating sulphide minerals and the acid-neutralising carbonate minerals have been largely leached, (ii) Transitional Zone, from which the carbonate minerals have been largely leached but the sulphide minerals remain, (iii) a Fresh/Primary Zone, where both sulphide and carbonate minerals occur. The Oxide Zone is generally non acid-generating, the Transitional Zone is acid-generating and the Fresh Zone is potentially acid-generating, depending upon the balance of sulphide vs carbonate minerals. Mineralogical profiles can be prepared from the relative abundance of macroscopic sulphide and carbonate minerals in the borehole core, again providing an assessment of ARD risk. Combined logs can then be prepared from these profiles with acid-generation and neutralisation data from ABAs, illustrating in space where the highest ARD risk zones are located. Using this information, groundwater and mine water management options can be developed for operations and closure, such as prioritisation of open pit backfilling or which levels of an underground mine water should be preferentially excluded from.
Arsenic in the west-African water reserves: Investigation into sources of the contaminant through case studies in the region	Andre	van Coller	West Africa	2015	Arsenic
Abstract The mineral rich basin of the West African region has vast reserves of gold, diamond as well as iron ore deposits. Throughout the regional geological setting characterised by structural variations and intrusive belts with metamorphic mineral rich sequences covered by saprolite soils, one common chemical constituent remains a constant in the water reserves. Arsenic is in high concentrations throughout the region with chemical ranges commonly above the various country guidelines as well as international IFC and WHO standards. The aqueous chemical species is associated with arsenopyrite rich mineralogy of the regional greenstone belts and highly weathered soils. This conference article and presentation investigates the natural source of the arsenic through baseline data as well as the effect of mining on the already high concentrations of arsenic in both the groundwater and surface water. Natural levels of various chemical species in the regional area are already high at baseline level. One of the main research questions is thus whether mining and other anthropogenic activities will have an impact on the environment or will the changes to concentrations be so insignificant to allow the ecosystems and water users to continue in their current ways without any effect. Various case studies in Burkina Faso, Liberia, Sierra Leone and other countries have been combined to investigate the arsenic-rich resources of the West African region through groundwater specialist investigative methods with emphasis on geochemical modelling of the fluid-rock and fluid-fluid interactions leading to the water quality in the region.
Making the Invisible Visible: Do Aquifers Have Agency?	Adrian	Healy	Wales	2023	agency, Groundwater, more-than-human, social, socio-hydrogeology
Abstract In the social sciences, there has been a ‘posthuman’ turn, which seeks to emphasise the role of non-human agents as co-determining social behaviours. In adopting a ‘more-than-human’ approach, the academy seeks to avoid claims of human exceptionalism and extend the social to other entities. In this paper, we explore the extent to which the more-than-human approach might be applied to groundwater and aquifers and the implications that this may have for groundwater science. The role of groundwater in complex adaptive socio-ecological systems at different scales is increasingly well-documented. Access to groundwater resources positively influences societal welfare and economic development opportunities, particularly in areas where surface waters are scarce. The potential adverse effects of human activities on the quantity or quality of groundwaters are also widely reported. Adopting a ‘properties’ approach, traditional social science perspectives typically describe aquifers as structuring the agency of human actors. To what extent might aquifers also have agency, exhibited in their capacity to act and exert power? Drawing on insights from 5 cities across sub-Saharan Africa, we argue for the agency of aquifers in light of their capacity to evoke change and response in human societies. In doing so, we draw on the concept of the more-than-human to argue for a more conscious consideration of the interaction between the human and non-human water worlds whilst acknowledging the critical role played by researchers in shaping these interactions.
The role of groundwater in urban resilience	Adrian	Healy	Wales	2023	Groundwater, Governance, household, Resilience, urban
Abstract The potential role of groundwater in supporting the resilience of human societies is garnering increased attention in the context of climate change. Much of this attention focuses on the resilience of the groundwater resource itself. Less attention has been given to the way that groundwater is used by society and how this may influence human-centred resilience outcomes, particularly in urban settings. In this paper, I explore how questions of scale are fundamental to the role of groundwater in the resilience of urban areas, from the scale of individual households to more regional and catchment-based notions of scale. It is these variations in the geographies of urban groundwater exploitation that provide for the challenges of groundwater governance. Drawing on the practices revealed across 5 diverse cities in sub-Saharan Africa; the paper highlights the variety of ways that groundwater promotes the resilience of urban areas to water stress. The paper finds that groundwater can accommodate a prevalence of ‘self-supply’ and market-based models as urban populations seek to counter failings in public supply provision. Whilst these actions promote the resilience of the urban setting in the short to medium term, they raise important questions for the longer-term sustainability of the resource. The paper considers the implications of these questions for the future governance of resilient groundwater resources and the role of groundwater as part of a wider strategy for urban resilience.
Using geophysics to detect water-hosting fractures in the Vredefort Dome: A training opportunity	Stephanie	Enslin	Vredefort Dome, Gauteng	2021	Field School, fractures, geophysical methods
Abstract Tamilo, T; Webb, S.J. The Vredefort Dome 120 km southwest of Johannesburg is a meteorite impact crater that formed at approximately 2 Ga. The region hosts farmland, and the town of Parys is situated in the northwestern part of the dome. The dome is the location of the annual Wits University/AfricaArray Geophysical Field School. The aim of the field school is to teach geoscience students several geophysical techniques while conducting scientific research in the area. A geophysical survey during the 2019 field school over an open field just outside of Parys revealed a buried fracture that hosts ground water. A 150 m long magnetic profile over the fractures shows a magnetic low (approximately 500 nT) that correlates with a low resistivity region on the inverted electrical resistivity data (dipole-dipole method). Euler deconvolution depth estimates and magnetic modelling estimate an overburden thickness of around 10 m and a similar fracture thickness. The magnetic low of the fracture is due to weathering and removal of any magnetic material in the granites in the region. Two existing boreholes that lie 618m due south and at a 10 m lower elevation have water levels of around 6.4 m. Both boreholes lie near a riverbed and vegetation, and appear to lie along an extension to the fracture. This fractures detected using geophysical methods seems to form part of a larger fracture system within the Vredefort Dome, that is linked to the formation of the dome. These fractures provide a vital source of water for the local farming community.
The impact of groundwater temperature on water quality in the urban aquifer of the city of Vienna	E	Kaminsky	Vienna	2023	groundwater temperature, groundwater-surface water interaction, trends, Water chemistry
Abstract Rising shallow groundwater temperatures are observed in many cities worldwide and are expected to increase further over the next century due to anthropogenic activities and climate change. The impact of groundwater temperature increase on groundwater quality is poorly understood. This study conducted two high-spatial-resolution campaigns in Vienna (Austria, autumn 2021/ spring 2022). At 150 wells, a comprehensive parameter set (e.g. major ions, nutrients, and water stable isotopes) was analyzed in groundwater collected, and at 812 wells, the water temperature was measured. Results are compared to available long-term data on groundwater chemistry (1991-2020). In theory, temperature triggers a cascade of effects, where, finally, the depletion of dissolved oxygen (DO) causes a switch to anaerobic microbial processes and a deterioration of water quality. No direct relation between DO and water temperature was observed between 10 and 20 °C. However, many wells delivered anoxic groundwater, including the one with the highest measured temperature (27 °C). The highest temperatures were consistently observed near potential heat sources (local scale), with a rapid decrease in temperature with increasing distance from these sources. Long-term data from particular high-temperature wells revealed decreased dissolved oxygen after sudden temperature changes of > 5 K. On a regional scale, it is observed that groundwater-surface water interactions and aquifer properties play a pivotal role in oxygen availability and redox conditions. In conclusion, high-spatial-resolution sampling combined with long-term data analysis is needed to determine the impact of temperature on water quality.
Water Quality Assessment And Water Use Practices Of Groundwater In Vhembe District, South Africa.	Joshua	Edokpayi	Vhembe District	2019	quality
Abstract Groundwater is often used as an alternative source of drinking water in many places of the world mostly in rural areas. There is a perceived claim that groundwater is clean and safe. This study was carried out to assess the quality of various groundwater sources in the Vhembe District of South Africa. Questionnaires were distributed to residents of the area to evaluate the water use practices. Water quality indices were employed to estimate the usefulness of the groundwater water resources. Heavy metals and major ions were analysed using ICP-MS. E. coli and total coliforms were determined using membrane filtration method. Health risk of the heavy metals in the water was estimated using standard protocol. The results of the study showed that most of the metals complied with the South Africa National Standards. Some of the anions exceeded the recommended limit. Majority of the groundwater sources were fit for other uses except drinking due to the levels of E. coli determined. Sources of contamination determined were both natural and anthropogenic. Adequate monitoring of groundwater resources is recommended to avoid possible risk to public health.
3-D electrical conductivity image as a decision-aiding tool in the post-closure management of a South African colliery	Lize	Wessels	Vereniging	2015
Abstract The colliery is situated in the Vereeniging-Sasolburg Coalfield, immediately southwest of Sasolburg in the Republic of South Africa. The stratigraphy of this coal field is typical of the coal-bearing strata of the Karoo Sequence. The succession consists of pre-Karoo rocks (dolomites of the Chuniespoort Group of the Transvaal Sequence) overlain by the Dwyka Formation, followed by the Ecca Group sediments, of which the Vryheid Formation is the coal-bearing horizon. Mainly the lava of the Ventersdorp and Hekpoort Groups underlie the coal. The Karoo Formation is present over the whole area and consists mainly of sandstone, shale and coal of varying thickness. The underground mine was flooded after mining was ceased at the colliery in 2004. The colliery is in the fortunate position that it has a very complete and concise monitoring programme in place and over 200 boreholes were drilled in and around the mine throughout the life of the mine. To stabilise mine workings located beneath main roads in the area, an ashfilling project was undertaken by the colliery since 1999. A key issue is if the mine will eventually decant, and what the quality of the water will be. This is important for the future planning of the company, as this will determine if a water treatment plant is necessary, and what the specifications for such a plant will be, if needed. Therefore it was decided to do a down-the-hole chemical profile of each available and accessible borehole with a multi-parameter probe with the aim of observing any visible stratification. Over 90 boreholes were accessible and chemical profiles were created of them. From the data collected a three - dimensional image was created from the electrical conductivity values at different depths to see if any stratification was visible in the shallow aquifer. The ash-filling operations disturbed the normal aquifer conditions, and this created different pressures than normally expected at a deeper underground colliery. From the three-dimensional image created it was observed that no stratification was visible in the shallow aquifer, which lead to the conclusion that in the event that if decant should occur, the water quality of the decanting water will still be of very good quality unless external factors such as ash-filling activities is introduced. It is not often that it is possible to create chemical profiles of such a large number of boreholes for a single colliery and as a result a very complete and informative three-dimensional electrical conductivity image was created. This image is very helpful in aiding the decision making process in the future management of the colliery and eventually obtaining a closure certificate, and also to determine whether ash-filling is a viable option in discarding the ash.
Application Of A Numerical Groundwater Flow Model Towards The Development Of An Excavation Pit Dewatering Strategy In Vereeniging, South Africa	Jacqueline	Stapelberg	Vereeniging	2019	flow model, dewatering

Vanwyksvlei: Water provisioning and the Blue Drop system - how effective is this?	Danita	Hohne	Vanwyksvlei	2015	Blue drop standards, water supply challenges
Abstract POSTER Vanwyksvlei had always experienced problems with water supply and quality of drinking water. The town relies on 6 boreholes to supply the town with drinking water. Since 2011 the town was told not to use the water that was supplied from the borehole called Soutgat. This meant that the town could now rely only on the water being supplied from the other 5 boreholes.From 2011 till present the town has experienced a lot of problems regarding water supply, due to the fact that the Soutgat could not be used anymore. Extra stress was put on the other boreholes and these were pumped almost dry. The two aquifers are currently failing and monitoring data since 2009 shows that the water levels of the town are decreasing. Due to low rainfall, recharge to the boreholes are much lower, which exacerbates the problem. This poster will examine the effectiveness of using the Blue Drop system in small towns with limited water supply, at the hand of a case study of Vanwyksvlei. This review will take into account factors such as the point at which water quality is tested in the water supply system, the type of water treatment available for the town and a review the usefulness of certain standards in the Blue Drop system which may indicate failure of supply sources.
Establishment Of A Database And A Representative Groundwater Monitoring Network For The Vanrhynsdorp Water User Association	Brian	Dyason	Vanrhynsdorp, Western Cape	2013	groundwater monitoring, Geohydrological
Abstract The aim of this project was to establish a detailed geohydrological database and monitoring network for the karst aquifer within the boundaries of the Vanrhynsdorp Water User Association. An adequate monitoring network is necessary for the Vanrhynsdorp Water User Association to implement sustainable water use management as well as for the Department Water Affairs to ensure its mandate as trustee of all water resources. Hydrocensus projects were conducted in phases as the project escalated from historic town supply during 1978 towards a catchment driven water user association after implementation of the new National Water Act in October 1998 (Act 36 of 1998). With the successive hydrocensuses conducted, the monitoring network also evolved in regard to area monitored, point locations, monitoring schedules and parameters measured. Hydrocensus data were captured on the National Groundwater Archive, time series data on the Hydstra database and chemical analysis on the Water Management System. Time series graphs were compiled to analyse the monitoring data and to create a conceptual model of the karst aquifer. The study showed a general decline in groundwater levels and quality in the study area. The conclusion is that the aquifer is over exploited. It is recommended that an extensive management plan is developed and implemented to ensure sustainable use of this sensitive water resource. The installation and monitoring of flow meters on all production boreholes should be seen as urgent and stipulated as such in licensing conditions. This will ensure the effective management and regulation of this valuable groundwater resource.