Conference Abstracts

All Abstracts were presented at the Groundwater Conferences

Displaying 651 - 700 of 795 results

Title	Presenter Name	Presenter Surname	Conference year	Keywords
Developing A Transboundary Aquifer Analytic Framework To Support Localised Groundwater Decision-Making Using Big Data	Zaheed	Gaffoor	2019	transboundary, big data
Abstract Big data analytics (BDA) is a modern and innovative platform of applications that include advanced analytical techniques such as data mining, statistical analysis, artificial intelligence, machine learning, and natural language processing. Regional data are generated through groundwater monitoring, remote sensing applications or global circulation models (GCM), however this is often too course for a local understanding. Groundwater managers rely on locally relevant information for effective operational decision making, however this is often missing. A Transboundary Aquifer (TBA) Analytic Framework was developed to match, integrate and model local hydrogeological data with regional earth-observation data using BDA. Drawing on the literature on BDA, a reference architecture for the TBA analytical framework was identified for application to various groundwater management scenarios in the Ramotswa Dolomitic Aquifer (Botswana - South Africa) and Shire Valley Alluvial Aquifer (Malawi - Mozambique). The TBA analytical framework allows for local clouds to store the local and regional structured and unstructured datasets and interconnecting these local clouds through a federated cloud infrastructure. In this regard, tools that are incorporated in the TBA analytical framework include data ingestion operators, data transformation operators, and feature extractors. Various machine learning algorithms and statistical techniques are incorporated in the TBA analytical framework to downscale the regional datasets. The downscaling involves selection of potential predictors and predictants variables based on data needs to address local groundwater management scenarios such as regulating groundwater abstraction to prevent groundwater depletion. Using the downscaled data the TBA analytical framework can be utilised to uncover patterns and statistical relationships in the datasets in order to model local groundwater processes such as cone of depression, groundwater levels forecasting, well protection zoning, amongst others.
The connectedness of transboundary groundwater researchers: from network analysis to network-building	A	Fernald	2023	network analysis, network-of-networks, transboundary groundwater
Abstract The Transboundary Groundwater Resilience (TGR) Network-of-Networks project brings together researchers from multiple countries to address the challenges of groundwater scarcity and continuing depletion. Improving groundwater resilience through international research collaborations and engaging professionals from hydrology, social science, data science, and related fields is a crucial strategy enabling better decision-making at the transboundary level. As a component of the underlying data infrastructure, the TGR project applies visual analytics and graph-theoretical approaches to explore the international academic network of transboundary groundwater research. This enables the identification of research clusters around specific topic areas within transboundary groundwater research, understanding how the network evolved over the years, and finding partners with matching or complementary research interests. Novel online software for analysing co-authorship networks, built on the online SuAVE (Survey Analysis via Visual Exploration, suave.sdsc.edu) visual analytics platform, will be demonstrated. The application uses OpenAlex, a new open-access bibliographic data source, to extract publications that mention transboundary aquifers or transboundary groundwater and automatically tag them with groundwater-specific keywords and names of studied aquifers. The analytics platform includes a series of data views and maps to help the user view the entire academic landscape of transboundary groundwater research, compute network fragmentation characteristics, focus on individual clusters or authors, view individual researchers’ profiles and publications, and determine their centrality and network role using betweenness, eigenvector centrality, key player fragmentation, and other network measures. This information helps guide the project’s data-driven international networking, making it more comprehensive and efficient.
Decision making with web-based geo-spatial databases coupled to groundwater models	John	Wise	2015
Abstract Model calibration and scenario evaluations of 2D and 3D groundwater simulations are often computationally expensive due to dense meshes and the high number of iterations required before finding acceptable results. Furthermore, due to the diversity of modelling scenarios, a standardised presentation of modelling results to a general audience is complicated by different levels of technical expertise. Reducing computational time In this presentation we look briefly at the use of Reduced Order Models (ROM's), which is one of the recent developments in groundwater modelling. The method allows significant speed-up times in model calibration and scenario evaluation studies. In saturated flow for example, these approaches show speed-up times of >1000 when compared to full models created with Finite Element of Finite Difference methods. These methods are demonstrated to a case study in the Table Mountain Group, in which we show a simplified parameter calibration and scenario evaluation study. Standardising presentation In order to present the results to as wide an audience as possible, the use of a web-browser as a GUI is proposed, where the web-page is coupled to a geo-spatial database and data is presented in a spatial and numeric format. The use of the spatial database manager PostgreSQL with PostGIS is proposed. Through a browser interface, users can run modelling scenarios using the ROM, which is evaluated in near real-time. Following the evaluation of the model, we show how PostGIS can spatially present data on a base-map such as google maps. In keeping with the current trends in online map customisation, viewers can interactively choose to overlay the base-map with a data-type (such as pressure or hydraulic head contours or flow direction) that is most intuitive for their level of familiarity with the data. Conclusion In using advanced modelling techniques and a simplified browser based presentation of results, high-level decisions in water resource management can be significantly accelerated with the use of interactive scenario evaluations. Furthermore, by reaching a broader audience, public participation will be significantly enhanced.
Monitored Natural Attenuation on-sites with different geological setting	Bongani	Masombuka	2015
Abstract When considering how to reduce contamination of petroleum hydrocarbons in shallow aquifers, it is important to recognize the considerable capacity of natural processes continuously at work within the secondary sources of contamination. This natural processes are technically referred to as Monitored Natural Attenuation (MNA), a process whereby petroleum hydrocarbons are deteriorated naturally by microbes. This approach of petroleum hydrocarbon degradation relies on microbes which utilise oxygen under aerobic processes and progressively utilises other constituents (sulphates, nitrates, iron and manganese) under anaerobic processes. MNA process is mostly evident when light non-aqueous phase liquids (LNAPLs) has been removed while the dissolved phase hydrocarbon compounds are prominent in the saturated zone. The case studies aim at determining feasibility and sustainability of Monitored Natural Attenuation process at different sites with varying geological setting.
Practical Solutions for Academic Based Applications – Understanding the importance of correct aquifer test data interpretations	Jorette	Van Rooyen	2021	Gw-Sw interaction, test-pumping, FC, Monitoring
Abstract It has become increasingly apparent that understanding fractured rock mechanics as well as the interactions and exchanges between groundwater and surface water systems are crucial considering the increase in demand of each in recent years. Especially in a time where long term sustainability is of great importance for many water management agencies, groundwater professionals and the average water users. Previous callow experience has shown that there is a misunderstanding in the correct interpretation and analyses of pumping test data. The fracture characterisation (FC) method software provides a most useful tool in the overall understanding of a fractured rock aquifer, quantification of the aquifer’s hydraulic (flow regime and flow boundary conditions) and physical properties, only if the time-drawdown relationships are correctly interpreted and when the theoretical application principles are applied. Interpretation is not simply a copy and paste of the aquifer test data into the software to get a quick answer (especially when project time constraints are considered), however, recent experiences with numerous field examples, required intricate understanding of the geological environment, intended use and abstraction schedules coupled with the academic applications on which the software was based for correct interpretation. Through the application of correct interpretation principles, a plethora of flow information becomes available, of which examples will be provided in the presentation itself. By achieving this, flow can be conceptualised for inputs into a conservative scale three-dimensional numerical flow model and calibrated based on measurable data in a fraction of the time of a conventional regional model. Although higher confidence levels are achieved with these practical solutions, monitoring programmes are still required to provide better insight of the aquifer responses to long-term abstraction and recovery.
Groundwater fingerprinting for identifying potential project risks	Meris	Mills	2015
Abstract Implementation of a mining project in South Africa involved dewatering of a fractured rock aquifer at considerable depth below ground level. Groundwater quality within this aquifer is not suitable for domestic use due to high levels of salinity. Numerous geological investigations in the area indicate that the target aquifer is confined, with a different piezometric head to the shallower aquifers. However, regulators and other interested and affected parties expressed concern regarding the potential mixing of more saline groundwater from the deeper aquifer to be dewatered with groundwater from shallower aquifers, which are extensively used for farming and domestic purposes. A large database of groundwater quality monitoring data collected over 16 years was available to investigate the degree of mixing between the deeper more saline and shallower freshwater aquifers. The groundwater chemistry of selected boreholes with known geological profile, depth and construction was used to develop groundwater fingerprinting criteria for each of the aquifers in the area. These fingerprinting criteria were then applied to private and exploration boreholes in the area in order to identify the main aquifer from which groundwater was being sourced. Once the boreholes were classified in terms of groundwater origin, an attempt was made to identify indicators of mixing with deeper, more saline groundwater from the aquifer being dewatered. Groundwater fingerprinting allowed identification of impacts related to the mining operations. The data showed that there was no upward mixing of water related to dewatering operations, but rather that surface spillages and disposal schemes may have resulted in minor changes in shallow groundwater quality. {List only- not presented}
A methodology for uncertainty quantification of dewatering volumes under the context of open-cast mining	C	Rivera Villarreyes	2023	FEFLOW, Groundwater Modelling, mining, PEST, PESTPP
Abstract Groundwater modelling at the mine sites involves assumptions from the geological model, mining stages, parametrization, and fractures, among others. Modelling work mainly focuses on calibrating against historical measurements before operations (pre-mining) or afterwards (transient calibration). Calibration is carried out mainly with gradient-based algorithms. However, the majorlimitation is the number of model runs, since the number of parameters can easily reach hundreds or more. PEST has become the common tool for parameter estimation. The Jacobin calculation required for the Levenberg Marquardt algorithm requires several model runs. This, a limited factor for the calibration and, subsequently, uncertainty quantification. The next generation of PEST, named PESTPP, is gained popularity in the groundwater community. The great advantage of PESTPP,, compared to the classical PEST, is its new module, Iterative Ensemble Smoother (IES). PESTPP-IES covers both parameter estimation and uncertainty quantification in one goal. Its empirical formulation of the Jacobian matrix reduces the number of runs; thus, the numerical bottleneck can be significantly reduced. PESTPP-IES has been extensively tested in an open-pit mine at the geological complex conditions in the Peruvian Andes. The work involves the task of model simplification, e.g., from a regional model to a detailed local pit model, calibration and uncertainty quantification of pit dewatering volumes. Detailed model was kept calibrated based on hydraulic-head measurements, and dewatering volumes were predicted. All these consider transient changes in the mining plan within the same FEFLOW model. Results validate the methodology and practicability in mining applications.
Groundwater Resource Quantification And Impact Assessment: We Need A South African Code Similar To SAMREC	Koos	Vivier	2015
Abstract Quantification of groundwater is important as it should determine the maximum sustainable use of the resource. The SAMREC Code that is required for mineral resource quantification sets out minimum standards, guidelines and recommendations for public reporting of exploration results for mineral resources and reserves. The code serves as the basis for mineral asset valuation and provides quality assurance to the process and an understanding of the results. In groundwater far too often, various methods are used for resource quantification that leads to various results even should the same resource be investigated by two different hydrogeologists. In far too many cases, the resource is not quantified properly which leads to vast over or under estimations. The result is a lack of trust in groundwater resources. As has been done in the international arena, it is similarly proposed that a code be developed for South Africa to ensure that the sustainability of groundwater resources is determined and the impacts of utilization on the water Reserve and the environment be quantified at a minimum level and that basic hydrogeological principles are followed. A South African Groundwater Regulation Code for sustainable resource quantification and impact assessment (SAGREC) is developed that is proposed to guide groundwater investigations and development processes from planning to baseline assessments, drilling and aquifer testing to resource quantification and sustainability modeling. The aim is to ensure trust being built on groundwater as a resource due to projects that follow a formal process that quantifies the assurance of supply and determines the environmental impacts.
Characterisation And Protection Of Deep Aquifers In South Africa: Characterisation	Francois D	Fourie	2017	Deep aquifers, Aquifer characterization, groundwater flow, Groundwater Quality
Abstract This paper describes the characteristics of the deep aquifer systems in South Africa as derived from the available data. The study formed part of the larger WRC project K5/2434 (Characterisation and Protection of Potential Deep Aquifers in South Africa). A review of the available literature relevant to potential deep aquifers in South Africa was done to allow characterisation of these aquifer systems. In addition, data obtained from the geological logs of the SOEKOR and KARIN boreholes were considered. This paper focuses on deep aquifers in 1) the Karoo Supergroup, 2) the basement and crystalline bedrock aquifers, 3) the Table Mountain Group, 4) the Bushveld Igneous Complex and 5) the dolomites of the Transvaal Supergroup. From the available data the deep aquifer systems are described in terms of the following characteristics: lithology, occurrence, physical dimensions, aquifer type, saturation level, heterogeneity and degree of isotropy, formation properties, hydraulic parameters, pressurisation, yield, groundwater quality, and aquifer vulnerability. The results of the study show that the deep aquifer systems of South Africa are generally fractured hard-rock aquifers in which secondary porosity was developed through processes such as fracturing and dissolution. The primary porosity of most of the rocks forming the aquifers is very low. Apart from the dolomite aquifers, most of the water storage occurs in the rock matrices. Groundwater flow predominantly takes place along the fractures and dissolution cavities which act as preferential pathways for groundwater migration. The aquifers are generally highly heterogeneous and anisotropic. The deep aquifers are generally confined and associated with positive hydraulic pressures. The groundwater quality generally decreases with depth as the salinity increases. However, deep dolomite aquifers may contain groundwater of good quality. Due to the large depths of occurrence, the deep aquifer systems are generally not vulnerable to contamination from activities at surface or in the shallow subsurface. The deep dolomite aquifers are a notable exception since they may be hydraulically linked to the shallower systems through complex networks of dissolution cavities. The deep aquifers are, however, very vulnerable to over-exploitation since low recharge rates are expected.
Blast curtain optimized with a numerical model for TSF seepage control	Robel	Gebrekristos	2015
Abstract Preventing the spread of seepage from tailings storage facilities (TSF's) in groundwater is necessary as it often contains toxic contaminants. Experience has shown that seepage from TSFs is inevitable and that zero seepage remains difficult even with complex liner systems. Multiple seepage control methods are often required to minimise seepage to ensure that environmental regulations are met. Control methods can be grouped into either barrier or collection systems. Barrier systems are used to hinder seepage whereas collection systems are used to intercept seepage. A blast curtain, which is the focus of this article, is a type of collection system that is still at a conceptual level but has seen little or no application worldwide. It works in principle, similarly to a curtain drain, but is typically extended to greater depths depending on the aquifer vulnerability. Numerical modeling has shown that this mitigation measure could add another line of defence for seepage control. The depth and effectiveness of the curtain can be optimized with a numerical model to ensure optimal interception of contaminated seepage around the TSF. Depths of up to 30 m in fractured aquifers have been simulated in this study. A blast curtain is constructed by drilling a set of boreholes around a TSF in close proximity to one another and then fracturing the rock using either explosives or fracking methods to create a more permeable zone. This is then combined with a series of scavenger wells or natural seepage to abstract the contaminated water. Numerical simulation has shown that blast curtains are effective especially if groundwater flow is horizontal. The effectiveness decreases if the vertical flow component is significant. A blast curtain can result in the lowering of the water table, however, local depression is a less of a concern than potential groundwater contamination. {List only- not presented}
The Impact Of Angled Survey Lines On ERT Surveys Using The Wenner (?) Array	Unarine	Mukhwathi	2019	ERT
Abstract The electrical resistivity tomography (ERT) method has become one of the most commonly used geophysical techniques to investigate the shallow subsurface, and has found wide application in geohydrological studies. The standard protocols used for 2D ERT surveying assume that the survey lines are straight; however, due to the presence of infrastructure and other surface constraints it is not always possible to conduct surveys along straight lines. Previous studies have shown that curved and angled survey lines could impact on the recorded ERT data in the following ways: 1) the true geometric factors may differ from the assumed geometric factors and thus affect the calculated apparent resistivities, 2) the depths of investigation may be overestimated, and 3) the recorded apparent resistivities may be representative of the subsurface conditions at positions laterally displaced from the survey line. In addition, previous studies have shown that although the errors in the apparent resistivities may be small even for large angles and curvatures, these errors may rapidly increase in magnitude during inversion. In this paper we expand on the previous work by further examining the influence of angled survey lines on ERT data recorded with the Wenner (?) array. We do this by: 1) calculating the changes in the geometric factors and pseudo-depths for angled survey lines, 2) forward and inverse modelling of ERT datasets affected by angled survey lines, and 3) examining the impact of angled survey lines on real ERT datasets recorded across different geological structures.
A scientific method of assessing the groundwater contribution to lakes and wetlands	Roger	Parsons	2015
Abstract The intangible nature of groundwater provides challenges when trying to understand and quantify the role of groundwater in the hydrology of lakes and wetlands. This task is made even more difficult by the frequent absence of data. However, by adopting a scientific approach, it is possible to assess the hydrogeological contribution
Units for joint management of cross-border groundwater impacts in Transboundary Aquifers: An overview of concepts and methodologies	C	Morales	2023	cross-border groundwater impacts, hotspots identification, joint management units, time and space scales factor, transboundary aquifers, zoning
Abstract This study aims to contribute to the conceptual and methodological development of units of joint management in transboundary aquifers (TBAs) to prevent and mitigate cross-border groundwater impacts (GWIs) in quantity and/or quality. Joint management units are a relatively new but growing topic in the field of TBAs, and their conceptualisation and appropriate identification are still at an early stage. By reviewing the literature on the subject and elaborating on its terminology, main features, and current methodological progress, a comparison of the existing methodologies for identifying such units is analysed. On this basis, trends and recommendations for further research and application of such methodologies to the joint management of TBAs are presented. The literature on this issue is scarce and has been published mainly in the last five years. These publications lack consistency in the use of concepts and terminology. The above has led to miscommunication and semantic issues in the concept behind such units and in comprehending the particular challenges of identifying them. Still, some directions and methodologies for identifying or directly delineating these management units have been proposed in the literature. However, no analysis from these methodological attempts has been conducted; thus, there are no lessons to be learned about this progress. This research looks forward to closing these gaps and making headway toward dealing with cross-border GWIs in TBAs, thus helping countries meet international law responsibilities and maintaining stable relationships among them.
Groundwater Assessment using Borehole Magnetic Resonance	Benjamin	Birt	2019	magnetic resonance
Abstract Hydraulic behaviour of an aquifer is defined in terms of the volumes of water present, both producible and not (specific yield and specific retention), and the productivity of the water (hydraulic conductivity). These parameters are typically evaluated using pumping tests, which provide zonal average properties, or more rarely on core samples, which provide discrete point measurements. Both methods can be costly and time-consuming, potentially limiting the amount of characterisation that can be conducted on a given project, and a significant measurement scale difference exists between the two. Borehole magnetic resonance has been applied in the oil and gas industry for the evaluation of bound and free fluid volumes, analogous to specific retention and specific yield, and permeability, analogous to hydraulic conductivity, for over twenty years. These quantities are evaluated continuously, allowing for cost-effective characterisation, and at a measurement scale that is intermediate between that of core and pumping tests, providing a convenient framework for the integration of all measurements. The role of borehole magnetic resonance measurements in hydrogeological characterisation is illustrated as part of a larger hydrogeological study of aquifer modeling. Borehole magnetic resonance has been used for aquifer and aquitard identification, and to provide continuous estimates of hydraulic properties. These results have been compared and reconciled with pumping test and core data, considering the scale differences between measurements. Finally, an integrated hydrogeological description of the target rock units has been developed.
Taking Capture Principle into Practice	Helen	Seyler	2015
Abstract The 'maintainable aquifer yield' can be defined as a yield that can be maintained indefinitely without mining an aquifer. It is a yield that can be met by a combination of reduced discharge, induced recharge and reduced storage, and results in a new dynamic equilibrium of an aquifer system. It does not directly or solely depend on natural recharge rates. Whether long-term abstraction of the 'maintainable aquifer yield' can be considered sustainable groundwater use should be based on a socio-economic-environmental decision, by relevant stakeholders and authorities, over the conditions at this new dynamic equilibrium. This description of aquifer yields is well established scientifically and referred to as the Capture Principle, and the link to groundwater use sustainability is also well established. However, implementation of the Capture Principle remains incomplete. Water balance type calculations persist, in which sustainability is linked directly to some portion of recharge, and aquifers with high use compared to recharge are considered stressed or over-allocated. Application of the water balance type approach to sustainability may lead to groundwater being underutilised. Implementation of the capture principle is hindered because the approach is intertwined with adaptive management: not all information can be known upfront, the future dynamic equilibrium must be estimated, and management decisions updated as more information is available. This is awkward to regulate. This paper presents a Decision Framework designed to support implementation of the capture principle in groundwater management. The Decision framework combines a collection of various measures. At its centre, it provides an accessible description of the theory underlying the capture principle, and describes the ideal approach for the development operating rules based on a capture principle groundwater assessment. Sustainability indicators are incorporated to guide a groundwater user through the necessary cycles of adaptive management in updating initial estimations of the future dynamic equilibrium. Furthermore, the capture principle approach to sustainable groundwater use requires a socio-economic-environmental decision to be taken by wide relevant stakeholders, and recommendations for a hydrogeologists' contribution to this decision are also provided. Applying the decision framework in several settings highlights that aquifer assessment often lags far behind infrastructure development, and that abstraction often proceeds without an estimation of future impacts, and without qualification of the source of abstracted water, confirming the need for enhanced implementation of the capture principle.
Investigating the influence of fine ash leaching in a tailings dam on the underlying aquifers	Paul JH	Lourens	2015	primary aquifers
Abstract Groundwater in South Africa is the most important source of potable water for rural communities, farms and towns. Supplying sufficient water to communities in South Africa becomes a difficult task. This is especially true in the semi-arid and arid central regions of South Africa where surface water resources are limited or absent and the communities are only depended on groundwater resources. Due to a growing population, surface water resources are almost entirely being exploited to their limits. These factors, therefore, increases the demand for groundwater resources and a more efficient management plan for water usage. For these reasons, the relation between the geology and geohydrology of South Africa becomes an important tool in locating groundwater resources that can provide sustainable quantities of water for South Africans. It was therefore decided to compile a document that provides valuable geohydrological information on the geological formations of the whole of South Africa. The information was gathered by means of interviews with experienced South African geohydrologists and reviewing of reports and articles of geohydrological studies. After gathering the relevant information, each major geological unit of South Africa together with its geohydrological characteristics was discussed separately. These characteristics include rock/aquifer parameters and behaviour, aquifer types (primary of secondary), groundwater quality, borehole yields and expected striking depths, and geological target features and the geophysical method used to locate these targets. Due to the fact that 90 % of South Africa's aquifers are classified as secondary aquifer systems, groundwater occurrence within the rocks of South Africa is mainly controlled by secondary fractures systems; therefore, understanding the geology and geological processes (faulting, folding, intrusive dyke/sills & weathering) responsible for their development and how they relate is important. However, the primary aquifers of South Africa (Coastal Cenozoic Deposits) should not be neglected as these aquifers can produce significant amounts of groundwater, such as the aquifer units of the Sandveld Group, Western Cape Province. Drilling success rates and possibility of striking higher yielding boreholes can be improved dramatically when an evaluation of the structural geology and geohydrological conditions of an area together with a suitable geophysical method is applied. The ability to locate groundwater has been originally considered (even today) a heavenly gift and can be dated back to the Biblical story of Moses striking the rock to get water: "behold, I will stand there before thee there upon the rocks thou shalt smite the rock and there shall come water out of it" (Exodus 17:6).
Vapour Intrusion Risk Assessment: Case Studies using Modelling and Direct Measurement from Contaminated Sites in South Africa	Stephen	McKeown	2015
Abstract Vapour intrusion (VI) is recognized to drive human health risk at numerous sites that have been contaminated by petroleum products and other volatile contaminants. The risks related to VI are typically evaluated using direct measurement (vapour sampling) or modelling methods. ERM has developed a toolbox approach using a combination of exclusion distance criteria, direct measurement and modelling methods to assess risks and achieve closure. For direct measurement, samples of vapour are taken beneath the floor slab of buildings (sub-slab sampling) or from the air inside the buildings (indoor air sampling). Modelling methods are often used to estimate the partitioning of volatile contaminants from soil or groundwater sources into the vapour phase and the subsequent transport of vapours from the subsurface environment into habitable buildings. A limitation of modelling approaches is that they are designed to be conservative to be adequately protective of sensitive receptors. VI models also do not typically take into account the degradation of hydrocarbon vapours in the presence of oxygen, which has been found to be a significant process for petroleum hydrocarbons. The authors have compiled a dataset of petroleum vapour and groundwater results from over 50 petroleum release sites in southern Africa. These data were used to develop exclusion distance criteria for vapours emitted from contaminated groundwater sources (i.e. distance from the source at which sufficient aerobic attenuation has occurred for the VI risk to be negligible). A standard "lines of evidence" approach has been applied to the assessment of VI risk by firstly applying the exclusion distance criteria to sites with groundwater contaminant plumes beneath buildings, and if these are met, the sites are considered to have no unacceptable VI risk. Where exclusion screening criteria are not met, risk is estimated using modelling, and if a potential risk is predicted, then direct sub-slab measurements are taken to more accurately assess the risk. Lastly, where sub-slab assessment predicts a potential VI risk, indoor vapour measurement are taken to evaluate actual risk, taking into account interferences from other sources and background levels of contaminants. Mitigating measures can then be applied as appropriate. Various case studies will be presented including direct measurements at industrial and residential sites overlying contaminant plumes and modelling methods at residential properties adjacent to service station sites. A risk-based approach to the assessment of contaminated land provides a sustainable and cost effective methodology, and also avoids unnecessary remediation. The results show that VI risks can be adequately addressed with a toolbox approach using multiple lines of evidence.
Complexity versus Simplicity: A comparative analysis of complex geology in hydrogeological modelling	Anton	Lukas	2012	modelling, FEFLOW
Abstract This paper was presented at the GWD Central Branch Symposium, Potchefstroom in 2012 Numerical modelling of hydrogeological systems has progressed significantly with the evolution of technology and the development of a greater understanding of hydrogeology and the underlying mathematical principles. Hydrogeological modelling software can now include complex geological layers and models as well as allow the pinching out of geological features and layers. The effects of a complex geology on the hydraulic parameters determined by numerical modelling is investigated by means of the DHI-WASY FEFLOW and Aranz Geo Leapfrog modelling software packages. The Campus Test Site (CTS) at the University of the Free State in Bloemfontein, South Africa was selected as the locale to be modelled. Being one of the most studied aquifers in the world, the CTS has had multiple research projects performed on it and as a result ample information is available to construct a hydrogeological model with a high complexity. The CTS consists primarily of stacked fluvial channel deposits of the Lower Beaufort Group, with the main waterstrike located on a bedding-plane fracture in the main sandstone aquifer. The investigation was performed by creating three distinct hydrogeological models of the CTS, the first consists entirely of simplified geological strata modelled in FEFLOW by means of average layer thicknessand does not include the pinching out of any geological layers. The second model was created to be acopy of the first, however the bedding-plane fracture can pinch out where it is known to not occur. The third and final model consisted of a complex geological model created in Leapfrog Geo which was subsequently exported to FEFLOW for hydrogeological modelling.
Platinum mines will leave behind a sustainable legacy which will form a vital building block to meet future water demands	Fanie	Botha	2015	aeration and aerobic storage facilities, Nitrate
Abstract Slightly more out of the box idea is the use of anthropogenic aquifers as storage and chemical conditioners. This concept was first introduce by Eland Platinum Mine(EPM) and reported on in previous papers. At EPM water is used through a serious of natural aeration and aerobic storage facilities to reduce nitrate levels. In 2013 another group introduced pilot studies by virtue of abstraction in support of the water conservation and demand management strategy; which has proven that it could enable the operations to overcome water shortage periods and reduce pressure on Rand Water (RW). The pilot sites would deliver water into the dirty water circuit, but within five to ten years it may further be used to overcome months with zero potable water supply. . In platinum mines the more the aquifers are used the cleaner the water becomes, simply because introduced pollutants are not constant sources and country rock is mostly inert. In the future these aquifers have the potential to become larger storage facilities protected from floods and limited evaporation losses. It is foreseen that some of the mines in the western belt may have more water stored in primary aquifers than water stored within major water dams. Yields from these aquifers for individual aquifers may be up to 450 m3/hour and storage of 18 Mm3. . Why then this paper if we are already using it? The issue is that the true value of these aquifers an only be unlocked when they are used as recharging aquifers and thereby actively storing dirty water within a dirty water aquifer. Once we are able to undertake this the positive environmental gains such of environmental overflows, condition dirty water, reduction of pollution and significant reduction of the use of potable water from RW. {List only- not presented}
GIS-PMWIN, A Preprocessor In ArcGIS For Groundwater Modeling With PMWIN	Haili	Jia	2015
Abstract PMWIN5.3 has been one of the most commonly used software for groundwater modeling because of its free source and the adoption of popular core program MODFLOW. However, the fixed formats required for data input and lack of GIS data support have posted big challenges for groundwater modelers who are dealing with large areas with complicated hydrogeological conditions. In South Africa, most geological and hydrogeological data have been captured and stored in GIS format during various national research projects such as WR2005, NGA and etc. Therefore, a proper linkage between PMWIN and ArcGIS is expected to do the preprocessing for modeling in PMWIN. Visual Basic for Application (VBA) embedded in ArcGIS 9.3 was used to develop the linkage. Based on the conceptualization of the study area, the model dimension, discretization and many value setting processes can be easily carried out in ArcGIS other than directly in PMWIN. Then the grid specification file and other input files can be exported as the PMWIN-compatible files. The functions of move, rotation, refinement, sub-model, deleting and inserting row(s) or column(s) of the model have also been developed to avoid the inconvenience aroused from model modification. The linkage can be used with a higher version of PMWIN or ArcGIS. It has been applied to several gold fields in the Witwatersrand gold basin to simulate the groundwater flow and mass transportation for various conditions and scenarios. One of the applications will be presented in this paper. It has been proved that the linkage is efficient and easy to use. {List only- not presented}
OFF-SOURCE: A network to address the potential use of offshore freshened groundwater as an unconventional source of potable water in coastal cities.	H	Wazaz	2023	Offshore groundwater, COST Action, scientific networking, unconventional water resources, Transboundary aquifer
Abstract One-third of the world faces water insecurity, and freshwater resources in coastal regions are under enormous stress due to population growth, pollution, climate change and political conflicts. Meanwhile, several aquifers in coastal regions extending offshore remain unexplored. Interdisciplinary researchers from 33 countries joined their effort to understand better if and how offshore freshened groundwater (OFG) can be used as a source of potable water. This scientific network intends to 1) estimate where OFG is present and in which volumes, 2) delineate the most appropriate approaches to characterise it, and 3) investigate the legal implications of sustainable exploitation of the offshore extension of transboundary aquifers. Besides identifying the environmental impact of OFG pumping, the network will review existing policies for onshore aquifers to outline recommendations for policies, action plans, protocols and legislation for OFG exploitation at the local to international levels. Experienced and early-career scientists and stakeholders from diverse disciplines carry out these activities. The Action leads activities to foster cross-disciplinary and intersectoral collaboration and provides high-quality training and funded scientific exchange missions to develop a pool of experts to address future scientific, societal, and legal challenges related to OFG. This interaction will foster new ideas and concepts that will lead to OFG characterisation and utilisation breakthroughs, translate into future market applications, and deliver recommendations to support effective water resource management. The first exchange mission explored the Gela platform carbonate reservoir (Sicily), built a preliminary 3D geometrical model, and identified the location of freshened groundwater
The Utilisation Of Hydro-Geophysical Methods For Soil Moisture Measurements To Optimise Irrigation Management	Christian	Steyn	2019	soil moisture, Irrigation, flow
Abstract Precision agriculture continuously seeks improved methods to enhance productivity whether it is for greater crop yields or economic viability regarding labour inputs and satisfying the demand in a shorter time span. Soil moisture is one important factor that drives the agricultural industry and is therefore of utmost importance to manage it correctly. A shortage of water may result in reductions in yield, while excess irrigation water is a waste of water resources and can also have a negative impact on plant growth. Knowledge of the spatial distribution of soil moisture is important for determining soil moisture storage and soil hydraulic transport properties. Capturing field heterogeneity without exhaustive sampling and costly sample analysis is difficult. Electromagnetic induction, Frequency Domain Reflectometry, Neutron Scattering and conventional soil sampling have been utilised to determine the spatial variability of soil moisture within a field. Emphasis has been placed on practicality and accuracy of all the methods. Electromagnetics have proven itself to be the primary method to determine soil moisture within the field by comparing the results of the volumetric soil water content present in the field together with a combination of various soil properties such as clay and silt content, sand fraction, concretions, density and soil depth that contribute towards the accumulation of soil water. Electromagnetic induction has the highest resolution of data collected for a specific time period of all considered methods making it economically the best option for soil moisture management within a variable rate irrigation system. Electromagnetic induction has proven to be successful in delineating a field into management zones consisting of different classes based on observed conductivity values. Higher conductive zones are considered with small water demand. Lower conductive zones are considered with a greater water demand through a variable rate irrigation system. These water management zone maps could be informative for modelling, experimental design, sensor placement and targeted zone management strategies in soil science, hydrogeology, hydrology, and agricultural applications.
Comparitive analyses between LAK3 package and the high K techniques used for numerical simulation of lake-aquifer interactions	Jannie	Weitz	2015
Abstract Modelling of groundwater systems and groundwater-surface water interaction using advanced simulation software has become common practice. There are a number of approaches to simulate Lake-aquifer interactions, such as the LAK Package integrated into MODFLOW, the high conductivity and fixed stage approaches. LAK and the high conductivity approaches were applied and compared in simulating Lake- aquifer interaction in the Lake Sibayi Catchment, north-eastern, South Africa using the finite difference three-dimensional groundwater flow model, Visual MODFLOW Flex under steady state conditions. The steady state model consisted of two layers: an upper layer consisting of the Sibayi, KwaMbonambi, Kosi Bay and Port Durnford Formations which have similar characteristics, and a lower model layer representing the karst, weathered and calcareous Uloa Formation. The bottom model boundary is constrained by the impermeable Cretaceous bedrock. The model area covers the surface and groundwater catchments of Lake Sibayi which is constrained in the east by the Indian Ocean. A no-flow boundary condition is assigned to the northern, western and southern sides and a constant head boundary is assigned to the eastern side. The Mseleni River and neighbouring plantations were modelled using the River and Evapotranspiration boundary conditions respectively. Input parameters for the various boundary conditions were obtained from the previously developed high resolution conceptual model, including recharge
Governing Groundwater Wisely To Provide For Current And Future Generations.	Zine	Matshakeni	2015
Abstract POSTER About 97% of the earth's freshwater fraction is groundwater, excluding the amount locked in ice caps (Turton et al 2007) and is often the only source of water in arid and semi-arid regions and plays a critical role in agriculture, this dependency results in over-exploitation, depletion and pollution (Turton et al 2007). Groundwater governance helps prevent these issues. CSIR defines governance as the process of informed decision making that enables trade between competing users of a given resource, as to balance protection and use in such a way as to mitigate conflicts, enhance security, ensure sustainability and hold government officials accountable for their actions (Turton et al 2007). Realising the issues of groundwater governance is a requirement for developing policy recommendations for both national and trans-boundary groundwater governance. Groundwater level decline has led to depletion in storage in both confined and unconfined aquifer systems (Theesfeld 2010). There are about six institutional aspects, namely voluntary compliance, traditional and mental models, administrative responsibility and bureaucratic inertia, conflict resolution mechanisms, political economy and information deficits (Theesfeld 2010). Each of these aspects represents institutional challenges for national and international policy implementation. Traditional local practices should not be disregarded when new management schemes or technological innovations are implemented. The types of policies that impact governance include regulatory instruments, economic instruments and voluntary/advisory instruments. Regulatory or command and control policy instruments such as ownership and property right assignments and regulations for water use are compulsory. Economic policy instruments make use of financial reasons such as groundwater pricing, trading water right or pollution permits, subsidies and taxes. Voluntary /advisory policy instruments are those that influence voluntary actions or behavioural change without agreement or direct financial incentives. These are ideal types though no policy option ever relies purely on one type of instrument. The aim of these policies is to have an impact on governance structures (Theesfeld 2010). The national water act (1998) of the Republic of South Africa is not widely recognized as the most comprehensive water law in the world even though it is the highlight of socio-political events; socially it is still recent in most sites although the law was implemented 15 years ago (Schreiner and Koppen 2002). Regulations for use include quantity limitations, drilling permits and licensing, use licenses, special zone of conservation and reporting and registering requirement. In general when drilling and well construction are done commercially they increasingly fall under the scope of regulatory legislation. This paper will focus mostly on traditional and mental models; procedures that a certain community is dependent on should be taken into account before replacing with technological advanced tools. Consultation of the public can cause conflicts which lead to poor groundwater management. Keywords: Groundwater governance, policy, policy instruments.
Modelling recharge in an opencast coal mining environment, applying model parameters on a catchment scale.	Freek	van Devnter	2015
Abstract The provision, usage and discharge of water resources are major concerns for coal mines, both underground and opencast. Water resources in a coal mining environment will often account for a significant portion of the daily operational cost. In order to cut costs, the mine will often collect as much runoff as possible to recycle for future use. This on-going recycling of site water and management of the resource demands a complete site water balance model in order to understand the dynamics of the resource within the boundaries of the mine. To improve the understanding of the dynamics of the resource on a much larger scale, and the effect it will have on recharge in an open cast coal mine environment, one must consider alternative modelling approaches which can compensate for such conditions. This amounts to describing recharge as a modelling component in a physically based distributed model. The main goal of this project is to calculate recharge into the main pit at this specific colliery by applying parameters on a quaternary catchment scale. The colliery is located just west of the town of Ogies, Mpumalanga on the peripheral region of the quaternary catchment B20G. The physiography of the quaternary catchment B20F is described as a central Highveld region gently sloping to the north. The geohydrological modeling application MIKE SHE (developed by DHI) was used to develop a fully integrated catchment model. The model was created mainly to simulate the impact of human activities on the hydrological cycle and hence on water resource development and management. Different modules of MIKE SHE that was used during the modelling stage include saturated- and unsaturated flow and a small degree of overland flow. Key words: Mpumalanga, MIKE SHE, recharge
Potential for co-disposal of fly-ash and coal discard: Results from geochemical modelling and laboratory studies	Meris	Mills	2015
Abstract Geochemical investigations for a planned coal mine indicated that the coal discard material that would be generated through coal processing would have a significant potential to generate acid rock drainage. A power station is planned to be developed in close proximity to the coal mine, and the potential for co-disposal of coal discard with fly-ash material required examination. Fly-ash is typically highly alkaline and has the potential to neutralise the acidic coal discard material. In order to investigate whether this was a viable option, the geochemical interaction between the coal discard and fly-ash was investigated. Geochemical data, including acid-base accounting, total chemical compositions, leach test data and kinetic test data, were available for the coal discard material and the fly-ash. Using these data as inputs, a geochemical model was developed using Phreeqci to predict the pH of leachate generated by mixing different ratios of coal discard and fly-ash. The ratio of coal discard to fly-ash was established that would result in a leachate of neutral pH. Using this prediction, a kinetic humidity cell test was run by a commercial laboratory for a total of 52 weeks using the optimal modelled ratio of discard and fly-ash. Although leachate pH from the kinetic test initially reflected a greater contribution from fly-ash, the pH gradually decreased to the near-neutral range within the first 20 weeks, and then remained near-neutral for the remainder of the 52-week test. During this period, sulphate and metal concentrations also decreased to concentrations below those generated by either the fly-ash or coal discard individually. The addition of fly-ash to the coal discard material provided sufficient neutralising capacity to maintain the near-neutral pH of the co-disposal mixture until the readily available sulphide minerals were oxidized, and the oxidation rates decreased. At the end of the test, sufficient neutralising potential remained in the humidity cell to neutralise any remaining sulphide material. The results of this investigation suggested that, under optimal conditions, co-disposal of fly-ash with coal discard is a viable option that can result in reduced environmental impacts compared to what would be experienced if the two waste materials were disposed of separately.
Integrated System Approach To Evaluate Natural Processes And Hydrodynamics Linked To Groundwater-Surface Water Interaction	Teboho	Shakhane	2015
Abstract This study was aimed at developing an integrated groundwater-surface water interaction (GSI) model for a selected stretch of the Modder River by considering the following five different aspects of the GSI: 1) the distribution of different aquifer systems (structural connectivity) along the river 2) the hydraulic connectivity between the aquifer systems, 3) the volumes of water abstracted from the aquifers by streamside vegetation, 4) the volumes of water replenished to the groundwater system through rainfall recharge, and 5) the exchange fluxes between the various components of the groundwater-surface water system. The distribution of the aquifer systems was investigated by means of a) geo-electrical surveys, and b) in situ slug tests while their hydraulic connectivity was investigated by hydrogeochemical routing. The volumes of water abstracted by streamside vegetation were estimated by the quantification of the transpiration from individual plants and the groundwater recharge was estimated by a root zone water balance. The water exchange fluxes between the groundwater and surface water were determined from a simple riparian zone groundwater budget. The results of the geo-electrical surveys and slug tests allowed the delineation of the riparian area aquifers (RAA) and the terrestrial area aquifers (TAA) on both the south-eastern and north-western sides of the river. Based on the results of hydrochemical analyses, saturation indices and inverse mass balance modelling, the GSI involves flow of water from the TAA to the RAA, and finally to the river on the south-eastern side while it involves flow from the river into the RAA with a limited exchange with the TAA on the south-eastern side. The dominant vegetation on the study area was found to be the Acacia karroo and Diospyros lycioides. The close similarities in isotope compositions of the xylem sap and the borehole water samples suggested that the Acacia karroo sourced its water from the groundwater storage while differences in isotope compositions suggested that the Diospyros lycioides did not source water from the groundwater storage at the time of measurement. The results of groundwater recharge estimation in the study area highlighted the fact that both the antecedent moisture and the rainfall amounts determine whether recharge to the groundwater system will take place. Finally, the results of baseflow estimation indicated that the river is a gaining stream along the south-eastern reach while acting as a losing stream along the north-western reach.
Regulating the regulations for managing groundwater use to improve water security in Southern Africa: Reflection on water use licence application process in South Africa	Mfundi	Biyela	2019	water entitlement, Regulations, WARMS, Southern Africa, South Africa
Abstract In the management of water resources especially groundwater resources, implementing existing regulations is one of the much needed aspects ensuring water security through the regulated use. However, such regulations are not regulated to ensure that they served the intended purpose in their original formulation. In South Africa, a study was carried out to assess the relevance and efficient of adhering to procedural requirements during water use licence application (WULA) process. Lived-experiences and observation methods were used to collect data. The department of water and sanitation was used as a case study. Interpretative analysis approach was used to provide the meaning on the analysed information. The WARMS database was accessed where the number of days that WULA process was extracted. The regulation No. 40713 about WULA process was analysed. The five-year-data prior and post the promulgation of regulation No. 40713 were extracted from WARMS database and evaluated in terms of the duration each application took to be processed for WULA. Data on water use for abstractions from all the regions were obtained from WARMS database and assessed. Dates when applications were submitted and when such applications were finalised were analysis per month and per years for temporal analysis. The number of entitlements received during the particular period and the number of applications recommended to be declined and issued were assessed using exploratory data analysis methods. Graphical method was adapted to increase results visualisation on water use entitlements. Key results showed that the process of WULA was generally slow and reasons were provided for such outcome. However, the temporal analysis revealed an increasing trend in the post promulgation of regulation No. 40713 suggesting that regulations when re-regulated serve its intended purpose. Although such findings are not conclusive but they inform a basis for re-regulating enforcement regulations in Southern African countries with issues similar to South Africa on water entitlement.
Change, Challenge And Opportunity – Some Reflections On Hydrogeology Education, The Sustainable Development Goals And Global Change	B	Misstear	2017	education, training, IAH, Strategic Overview papers, SDGs
Abstract This keynote paper addresses several issues central to the conference theme of “Change, Challenge and Opportunity”. For hydrogeologists to exert greater influence on groundwater management globally, proper education and training is essential. Universities play a key role in educating hydrogeologists in the fundamental principles of groundwater science through taught Masters and other degree programmes. Scientific associations such as the International Association of Hydrogeologists (IAH) also have an important part to play in education and training through short courses, conferences and mentoring schemes, and in enhancing groundwater science through journal and book publications and scientific commissions. IAH’s mission is to promote the wise use and protection of groundwater and, in this respect, a series of Strategic Overview papers have been prepared to inform professionals in other sectors of the interactions between groundwater and these sectors. Two of the Strategic Overview papers focus on the SDGs and global change, and some of the groundwater challenges in these areas are described. Whilst these challenges will provide hydrogeologists with opportunities to influence global water issues in the 21st century, hydrogeologists will need to be able to communicate effectively with all of the stakeholders, using traditional and more modern forms of communication, including social media.
Packer Testing and Analytical Modelling For Groundwater Inflow Estimation for Proposed Shafts	Robel	Gebrekristos	2015
Abstract Two ventilation shafts were proposed to be excavated to depths of 100 and 350 m to intersect an underground mine, in the Bushveld Complex. The area is made up of fractured aquifers and the assignment was to identify the exact positions of the permeable zones within the shafts profiles as well as estimate the groundwater inflow rates at every 5 m interval along the shafts profiles. The project was budget and time constrained and therefore the preferred hydrogeological characterisation techniques, particularly the percussion drilling, aquifer testing and numerical modelling could not be conducted. The study was completed by conducting packer tests in HQ sized holes drilled at the exact positions of the proposed shafts. The packer test data was then interpreted using Thiem equation, a modification of Darcy Equation for radial flow, to estimate the steady state inflow rates into the shafts. Transient state flow is more challenging to calculate analytically, as it is time and aquifer storage dependent. However, transient state flow in shafts exists for the first 10 - 15 days only and is short lived. Thereafter, a steady state flow occurs where the rate is nearly fixed for the rest of the life of mine, unless new external stresses, such as mine dewatering, takes place within the radius of influence. Six months later the shafts were excavated and the permeable zones were encountered at the exact positions as predicted using the packer testing. In addition, the inflow rates calculated using analytical modelling was successful in estimating the inflow rates recorded after the shafts were excavated. The packer testing and analytical modelling was therefore effective in assisting the mine to plan the necessary pumps and management plans within the allocated budget and timeframe.
Characterisation And Protection Of Deep Aquifers In South Africa: Consolidation Of Data Sources	Francois D	Fourie	2017	Deep aquifers, data sources
Abstract This paper describes the results of study aimed at consolidating the available data sources on deep aquifers and deep groundwater conditions in South Africa. The study formed part of the larger WRC Project K5/2434 (Characterisation and Protection of Potential Deep Aquifers in South Africa). Since very little is known about the aquifer conditions below depths of 300 m, all groundwater information from depths greater than 300 m was considered to represent the deep aquifer systems. Various confirmed and potential sources of data on deep aquifers and groundwater conditions were identified and interrogated during this study, namely: 1. Boreholes of the International Heat Flow Commission (IHFC). The IHFC database indicates the location of 39 deep boreholes ranging in depth from 300 to 800 m, with an average depth of 535 m. 2. The Pangea database of the International Council for Science (ICSU). The Pangea database has information on 119 boreholes in South Africa, of which 116 are deeper than 300 m. 3. A database on deep boreholes at the Council for Geoscience (CGS). This database contains information on 5 221 boreholes with depths exceeding 300 m. 4. Information on the deep SOEKOR boreholes drilled during the 1960s and 1970s (at least 38 boreholes). 5. Information on deep boreholes from the database of the Petroleum Agency SA. 6. The National Groundwater Archive (NGA) of the Department of Water and Sanitation (DWS). 7. Information derived from the thermal springs in South Africa. 8. Boreholes drilled as part of the Karoo Research Initiative (KARIN). 9. Information on the locations and depths of underground mines in South Africa. Information on the occurrence of deep groundwater could potentially be obtained from these mines. The study shows that, although information on a vast number of deep groundwater sites is listed in the various databases, the data relevant to the geohydrological conditions are scant at most sites. This paucity of geohydrological data implies that the deep aquifers of South Africa are currently poorly understood.
Combined use of Environmental and Artificial Tracers to Characterise the Vadose Zone.	Yazeed	Van Wyk	2021	Poster, vadose zone, isotopic tracers, recharge mechanisms, Protection, aquifer protection
Abstract Approximately 982 km3 /annum of the world’s groundwater reserve is abstracted, providing almost half of all drinking water worldwide. Globally, 70% is used for agricultural purposes while 38% for irrigation. Most water resources of South Africa are threatened by contamination caused by industrial, agricultural, and commercial activities, and many parts of the country face ongoing drought with an urgent need to find alternative freshwater sources, such as groundwater. Groundwater constitutes approximately 15% of the total volume consumed, hence it is an important resource that supplements insufficient surface water supplies across South Africa. Very little attention has been afforded to understanding the anthropogenically altered vadose zone as a potential source or buffer to groundwater contamination. This is evident from few research studies that has applied multiple isotopic tracers to characterise this zone. Most subsurface systems in South Africa are characterised by fractures, whereby flow and transport are concentrated along preferential flow paths. This study aims to evaluate the performance of different tracer classes (environmental and artificial) with one another, and create a better understanding of the hydraulic properties, mean residence time and transport mechanisms of these tracers. The influence of unsaturated zone thickness on recharge mechanisms will also be evaluated. Site visits will be conducted for the proposed study areas, and the neighbouring sources of contamination will be assessed. The matric potential and unsaturated hydraulic conductivities will be measured using various techniques. Water samples will be collected and analysed for the various tracers from the vadose zone using gravity lysimeters including suction cups. Several tracers will also be injected into boreholes where samples will be collected to calculate tracer residence times (BTC’s) and further constrain the hydraulic properties of the vadose zone. All samples will be analysed, interpreted, and simulated using the numerical finite-element modelling code SPRING, developed by delta h. The software derives quantitative results for groundwater flow and transport problems in the saturated and unsaturated zones of an aquifer. The research is expected to provide more insight into the selection and use of environmental and artificial tracers as markers for detecting, understanding the transport processes and pathways of contaminants in typical altered South African subsurface environments. The impact derived improved characterisation of the pathways, transport, and migration processes of contaminants, leading to groundwater protection strategies and appropriate conceptual and numerical models. The output from this study will determine the vertical and horizontal flux for both saturated and unsaturated conditions.
Remediation of Groundwater at AngloGold Ashanti South Africa	Gawie	van Dyk	2015
Abstract Gold Mining activities the past 60 years at AngloGold Ashanti polluted the groundwater underlain by 4000 ha of land at the Vaal River and West Wits operations in South Africa. Sulphide material in Tailings Storage Facilities, Waste Rock Dumps and extraction plants produce Saline Mine Drainage with Sulphate, minor salts and metals that seep to the groundwater and ultimately into surface water resources. Water regulation requires mines to prevent, minimise/ reduce or eliminate pollution of water resources. The waste philosophy has matured from tolerate and transfer to treat and termination of pollution sources. The impact of the pollution was determined and possible technologies to treat the impact were evaluated. Source controls of proper water management by storm water management, clean dirty water separation, lined water conveyance structures and reduced deposition of water on waste facilities is crucial. The aquifer character determines the possible remediation technology. From the possible technologies phytoremediation, physical interception and re-use of this water was selected. In future possible treatment of the water would be considered. This paper explain the strategy and report on the phased implementation of these plans and the expected results. The establishment of 750 ha of woodlands as phytoremediation, interception trenches of 1250 m, 38 interception boreholes and infrastructure to re-use this water in 10 water management areas is planned. The total volume of 15 Ml/day would be abstracted for re-use from the boreholes and trenches. The woodlands can potentially attenuate and treat 5 ml/day. The established woodlands of 150 ha proof successful to intercept diffused seep over the area of establishment and reduce the water level and base flow. The 2 implemented trenches of 1000 m indicate a local decline in the water level with interception of shallow groundwater within 1-2 m from surface. The 2 production interception well fields abstracting 50 and 30 l/s respectively indicate a water level decline of between 2 to 14 m with regional cones of depression of a few hundred meters to intercept groundwater flow up to 20 meter. Predictions from groundwater modelling indicate that these schemes can minimise pollution during the operational phase and protect downstream water resources. Predictions from modelling indicate that the pollution sources need to be removed to ensure long term clean-up to return the land to save use. The gold and uranium prize is securing the removal of the sources through re-processing of the tailings and waste rock dumps. After removal of the sources of pollution the remediation schemes would have to be operated for 20 years to return the groundwater to an acceptable standard of stock watering and industrial water use. The water quality is observed by a monitoring network of approximately 100 observation boreholes.
Groundwater Sampling: Measurement Uncertainties And Their Implications For Decision Making	Modreck	Gomo	2019	sampling
Abstract The uncertainties associated with both the sampling process and laboratory analysis can contribute to the variability of the results. In most cases, it does appear that if the water samples have been analysed by an accredited laboratory, the results are acceptable. While the accreditation of analytical laboratory and therefore its credibility is very important to uphold quality and integrity, the same should be said about the sampling process. The quality and credibility of a sampling process is typically left to the responsibility of the appointed groundwater practitioner without any criteria to evaluate the quality and integrity of the sampling process. Perhaps the quality and integrity of the sampling process is evaluated based on trust or experience of the practitioner. However without any form of scientific criteria to evaluate the quality and integrity of the sampling process, it is difficult for the sampling process to be scrutinized. The quality and integrity of both the sampling process and laboratory analysis must be scientifically evaluated based on the uncertainty of measurements in line with the monitoring goals/requirements. This presentation discusses the aspects of evaluation of measurement uncertainties associated with groundwater sampling as an important component of quality assessment of groundwater sampling processes. The potential implications of the uncertainties on the final results and their use in decision making is also discussed. The credibility of the decisions made also depends on the knowledge about the uncertainties of the final results
Effects of Urbanization and Agricultural activities on Aquifer storage and Groundwater quality	Athenkosi	Matshini	2015
Abstract POSTER Aquifer stress arising from urbanization and agricultural activities, these two factors affect aquifer properties when prolonged. Increase in urbanization especially those situated on top unconfined or semi-confined aquifer results in pressure on natural resources, this includes water resources, and changes of land use for agricultural purposes with high economic benefits has an effect on groundwater quality to due to application of Nitrogen- fertilizers during crop rotation and this is largely experienced in developing countries. The effects ranges from groundwater quality to aquifer storage as prolonged aquifer withdrawals due to irrigation, construction, manufacturing affects groundwater storage. Assessment of urbanization and agricultural effects on groundwater requires a complex analysis as integration approaches needs to be discovered for a better analysis of the two more specially when assessing groundwater pollution. The study was conducted to assess the impacts of urbanization and agricultural activities on aquifer storage and groundwater quality: by (a) determining the relationship between the occurrence of contamination due to urbanization by assessing contaminants present in the study area (b) develop groundwater protection, and if any offer recommendation for groundwater management. Multiple-well tests were conducted observing the behavior of drawdown and recovery for assessing groundwater storage. Two aquifer properties were observed to yield information about any changes in aquifer storage (transmissivity and storage coefficient) and groundwater quality lab test focusing on TDS, nitrate and pH were conducted. Historical results reflect that before industrial and urban revolution the groundwater contained small amounts of TDS compared with the present results. Increase in nitrate and pH concentrations observed in location closer to agricultural areas. Prolonged aquifer withdrawals increases expansion of cone of depression and therefore increases aquifer vulnerability and the risk of aquifer being polluted, and this increases storage coefficient. This study can be used to formulate protection zones for water resources and practice towards groundwater management.
Effects of artefacts other than horizontal groundwater flux on a single-borehole tracer dilution test: Field evidence	Modreck	Gomo	2015
Abstract This article present field evidence on the effect of artefacts other than the horizontal groundwater flux on the single-borehole tracer dilution test. The artefacts on the tracer dilution were observed during two single-borehole tracer dilution tests conducted in an alluvial channel aquifer in the main Karoo Basin of Southern Africa. Field evidence shows that early time of the tracer dilution plot can be affected by artefacts other than the horizontal groundwater flux. These artefacts have great potential to increase the early time gradient of tracer dilution curve leading to overestimation of the horizontal groundwater flux. A qualitative approach that can be used to isolate and remove portion of the dilution plot that has resulted from artefacts other than the groundwater flow prior to calculating the horizontal groundwater flux is proposed.
Optimizing borehole performance through dynamic flow and chemistry profiling	Steve	Kalule	2021	Drinking water standards, Groundwater Quality, supply boreholes, remediation system, optimised well design, well profiling
Abstract Stringent drinking water standards for constituents like chromium, arsenic, and nitrates, combined with continually higher demand for groundwater resources have led to the need for more efficient and accurate well characterization. Many boreholes are screened across multiple aquifers to maximize groundwater production, and since these aquifers can have different water qualities, the water produced at the wellhead is a blend of the various water qualities. Furthermore, the water entering a well may not be distributed equally across the screened intervals, but instead be highly variable based on the transmissivity of the aquifers, the depth of the pump intake, the pumping rate, and whether any perforations are sealed off due to physical, chemical, or biological plugging. By identifying zones of high and low flows and differing water qualities, well profiling is a proven technology that helps optimize operational groundwater production from water supply boreholes or remediation systems. This frequently results in increased efficiencies and reduced treatment costs. By accurately defining groundwater quantity and quality, dynamic profiling provides the data needed to optimize well designs. Conventional exploration methods frequently rely on selecting well screen intervals based on performing and analyzing drill stem tests for one zone at a time. Using dynamic flow and water quality profiling, the transmissivity and water quality can be determined for multiple production zones in a matter of one to two days. It also allows the location and size of the test intervals to be adjusted in the field, based on real-time measurements. In this paper we discuss dynamic well profiling techniques with project case examples of characterization different types groundwater boreholes for a variety of applications and industries resulting in significant cost saving and sustainable water abstraction.
Groundwater In Sustainable Development Goal 6: The South African Case Study	Sivashni	Naicker	2019	Domesticate, South Africa, United Nations
Abstract South Africa has committed to achieving the United Nations Sustainable Development Goals (SDG's) by 2030. But what does this mean and how does groundwater fit in to this? SDG 6 in particular focuses on ensuring universal access to safe and affordable drinking water for all by 2030. SDG 6 requires that the country protects and restores water-related ecosystems such as forests, mountains, wetlands, aquifers and rivers which are essential if we are to mitigate water scarcity. To accomplish this, South Africa has proceeded to align various plans, strategies, and policies to encompass the targets of the SDG's. This paper will focus on SDG sub-goal 6.3 which incorporates improvement of water quality and sub-goal 6.6 which involves protection and restoration of ecosystems. The methodology given by the UN for the groundwater in indicator 6.3.2 stipulates that countries are required to report on "proportion of water with good ambient water quality", in South Africa however we had to domesticate the indicator i.e. render it suitable for South African conditions so we changed the methodology to "proportion of water the conforms to the Water Quality Objectives (WQO's)" but there are virtually no WQO's developed for groundwater. Four core groundwater quality parameters (Electrical Conductivity, pH, Nitrate and Sulphate) are available through ZQM stations categorized through 65 hydrogeological (Vegter) regions. Groundwater water quality baseline is calculated as a reference period/range per hydrogeological region. For SDG 6.6, the indicator required for groundwater is "Quantity of groundwater within aquifers" The methodology received by the UN for "Quantity of groundwater within aquifers" required a baseline (average reference period of five years) in meters per hydrogeological region. This indicator is again domesticated for South Africa and based on the 40-60 percentiles of groundwater levels per hydrogeological region. There are a number of future indicators that can be included for aquifers under SDG 6.6, but the groundwater sector needs to come together and decide what is important to report on. These SDG targets reporting has given the Water and Sanitation sector a new look at data. It has forced us to critically think of concepts such as baseline and performance monitoring. We now know where our data gaps and targets are, and we have to provide an action plan to address these.
Water Monitoring in the Mining Industry: An Overview	Callie	Pickering	2015
Abstract Water monitoring is a key aspect in the mining industry, in terms of gathering baseline data during the pre-construction stage, identifying potential areas of concern and mitigating source pollutants during the operational stage. A proper water monitoring program assists in the monitoring of plume development and water level rebound during the closure phase. The data made available through consistent long term monitoring should not be underestimated. Monitoring the effect that coal mine operations have on the water quality and quantity of surface and groundwater resources is a complex and multidisciplinary task. Numerous methodologies exist for monitoring of this kind. This paper will supply an overview of the water- rock chemistry associated with coal mine environments and the key indicator elements that should be focused on for water monitoring as well a review of the Best Practice Guidelines requirements in terms of water monitoring. Two case studies of coal mines in KwaZulu Natal will be reviewed, the key challenges outlined and mitigation measures implemented. The impact of requirements such as those set out by the Department of Water and Sanitation in terms of strict water quality limits for water containment and waste facilities as specified by Water Use Licences has also created unrealistic non-compliance conditions. The initial approach to creating a water monitoring programme should involve first identifying gaps in previous datasets and delineating potential sources of contamination. The sampling frequency will depend primarily on the water resource being monitored and the water quality analysis will depend on the type of facility. The facilities required for a specific situation will depend on the type and amount of waste generated, potential for leachate formation, vulnerability of groundwater resources and potential for water usage or resource sensitivity.
Successful field pilot scale nitrate removal using low technology methods	Sumaya	Israel	2015
Abstract Decades of monitoring, characterising, and assessing nitrate concentration distribution and behaviour in the soil profile and it's pathway into groundwater have resulted in a good understanding of its distribution in the country. While the national distribution is of great importance, site specific conditions determine fate, transport, and ultimately concentration in a specific area. Field experimental work included installation of a barrier containing a cheaply available carbon source to treat groundwater. The "reactor"/ tank with dimensions- 1,37m height, 2.15m diameter used for the experiment was slotted for its entire circumference by marking and grinding through the 5mm thick plastic material. The top section was left open to allow for filling and occasional checking of filled material during the experiment. The tank was packed with Eucalyptus globulus woodchips which was freely available at the site. Concentrations of groundwater nitrate at the site were well over what could be expected in any naturally occurring groundwater systems, and would result only by major anthropogenic activities in unconfined aquifer areas of South Africa. The changes in parameter concentrations with time were measured in order to determine the efficiency and life span of the carbon source used for the experiment. This paper considers 35 months of monitoring at a site where a low technology method was implemented. Field implementation was tested at a site which previously experienced some NH4NO3 spills. Main results from the field work showed that nitrate was totally removed at the treatment zone and surrounding boreholes, and even sulphate and NH4+ were removed during the experiment. This shows that the woodchips were successful in affecting denitrification for 35 months. Data also shows that boreholes further downstream from the tank had reduced NO3-, SO42- and NH4+ levels. Using the available biodegradable carbon for the woodchips based on its composition, a barrier lifespan could be determined. The results of calculations showed that the barrier would be effective for at least another 6.9 years from the period of the last sampling date. A total lifespan of about 10 years can thus be estimated.
Building Of A Gravity Lysimeter To Represent An Ash Backfilled Opencast Coal Mine.	Kamohelo	Mokoena	2019	Poster, Lysimeter, coal mine
Abstract Millions of tons of coal ash are produced across the globe, during coal combustion for power generation. South Africa relies largely on coal for electricity generation. The current disposal methods of coal ash are not sustainable, due to landfill space limitations and operational costs. One way/means of disposing of coal ash that could provide environmental and financial benefits; is to backfill opencast mines with the ash. However, a limited number of studies have been conducted to assess the feasibility of this method in South Africa. Thus the aim of the experiment is to monitor bulk ash disposal under field conditions to improve the understanding of the geochemical and hydrogeological processes occurring during the actual deposition of coal ash in opencast coal mines. To achieve the aim (1) a gravity lysimeter will be built containing both mine spoils and coal ash representing field conditions; (2) the factors (CO2, water level and moisture content) affecting acid mine drainage will be monitored in the lysimeter and (3) the change in the quantity and quality of the discharge released from the lysimeter.
Use Of Environmental Isotopes To Determine Hydraulic Connectivity Across The Surrounding Aquifers At Majuba UCG	Gundo	Mathoho	2015
Abstract Environmental isotope techniques have been successfully applied in the field of hydrogeology over the last couple of decades and have proved useful for understanding groundwater systems. This paper describes a study of the environmental isotopes for Oxygen (18O) and Hydrogen (1H, 2H-Deutrium, 3H-Tritium) obtained from various points in and around the underground coal gasification (UCG) site in Majuba, South Africa. UCG is an alternative mining method, targeting deep coal seams that are regarded as uneconomical to mine. The process extracts the energy by gasifying the coal in-situ to produce a synthetic gas that can be used for various applications. The site consists of shallow, intermediate and deep aquifer systems at a depth of 70m, 180 and 300m respectively. The intermediate aquifer is further divided into the upper and lower aquifer systems. Samples were taken from each aquifer system together with supplementary samples from the Witbankspruit and an on-site water storage dam. A total of 15 samples were submitted for isotope analyses. By investigating the various isotopic signatures from all the samples taken, it will be possible to determine if there are similar or contrasting isotopic compositions by deducing possible water source for each sample due to isotopic fractionation caused by physical, chemical and biological processes. This will also be supported by deducing the mean residence time (MRT) for each water source sampled based on the Tritium data as well as the chemistry data already available for different sources. The chemistry data established linkages between the upper and lower intermediate aquifers.{List only- not presented} Key words: Environmental isotopes, UCG, Water source, Isotope fractionation
The Roussillon coastal aquifer: using multiple-point statistics and multi-model ensemble to characterize geological uncertainty impact on water resources estimation	Valentin	Dall’ Alba	2023	Coastal aquifer, Groundwater Modelling, Multi-model ensemble, Uncertainty analysis
Abstract Coastal groundwater is a vulnerable resource, estimated to sustain the water needs of about 40% of the world’s population. The Roussillon aquifer is a regional aquifer near Perpignan (southern France). It covers over 800 km2 of land and is used for irrigation, drinking water, and industrial purposes. The aquifer has experienced significant piezometric lowering in the last decades, weakening the regional resource. An important aspect of modelling the hydrodynamic of this aquifer is the need to integrate data from agriculture and drinking water abstraction, natural and anthropogenic recharge, and account for the aquifer’s complex sedimentary arrangement. An ensemble of groundwater models has been constructed to understand the spatial evolution of the saline/freshwater interface and evaluate the impact of groundwater abstraction. Three sets of physical parameter modelling approaches were used. The first is based on the direct interpolation of pumping tests. The second uses sequential indicator simulations to represent the geological uncertainty. The third is based on a detailed conceptual geological model and multiple-point statistics to represent the detailed geological structure. These models provide parameter fields that can be input for the transient state hydrodynamic simulations. Overall, the ensemble approach allowed us to understand the Roussillon plain’s hydrological system better and quantify the uncertainty on the possible evolution of the main groundwater fluxes and water resources over the last 20 years. These models can help to inform management decisions and support sustainable water resource development in the region.
Management of water-related risks in drinking water supplies	Barbara	Cencur Curk	2023	risk analysis, water-related hazards, water safety plan, water supply system
Abstract With the revision of the European Drinking Water Directive (Directive on the quality of water intended for human consumption 2020/2184) in December 2020, the preparation of Water Safety Plans (WSP) is foreseen according to the guidelines of WHO. Within the EU Interreg Adrion MUHA project, a decision support tool (DST) has been developed to provide a holistic approach to drinking water infrastructure risk analysis. The project mainly addresses four water-related risks: accidental pollution, floods, droughts and earthquakes. The core of the DST is the inventory of hazardous events (causes, their consequences and impacts) for each component of the drinking water supply chain: (1) drinking water source - catchment area, (2) water supply system, and (3) domestic distribution system. For each identified potential hazard, the type of hazard was determined (e.g., biological, chemical, radiological, or physical hazard (including turbidity), inadequate availability of water supplied to customers, safety to personnel, external harm to third parties, including liability). The DST was tested in the partner countries (Italy, Slovenia, Croatia, Serbia, Montenegro and Greece) to verify the resilience of the measures and elaborate the WSP. In the end, the REWAS-ADRION strategy was elaborated, aiming to increase the resilience of drinking water supplies to floods, droughts, accidental pollution, and earthquake-related failures by improving the water safety planning mechanism based on the concept of inter-agency cooperation to support water utilities, civil protection organizations, and water authorities.
Investigation The Effect Of Excess Pumping On The Groundwater Salinity In Semi-Arid Aquifers Using Predicted Future Scenarios	Mohammed	Seyam	2019	Hydrological Modeling, Groundwater Quality, Salinity, Prediction scenario
Abstract The groundwater quality in semi-arid aquifers can be deteriorated very rabidly due to many factors. The most important factor affecting the quality of groundwater quality in Gaza Strip aquifer is the excess pumping that resulting from the high population density in the area. The goal of this study to investigate the future potential deterioration in groundwater salinity using scenario analysis modeling by artificial neural networks (ANN). The ANN model is utilized to predict the groundwater salinity based on three future scenarios of pumping quantities and rates from the Gaza strip aquifer. The results shows that in case the pumping rate remains as the present conditions, chloride concentration will increase rapidly in most areas of the Gaza Strip and the availability of fresh water will decrease in disquieting rates by year 2030. Results proved that groundwater salinity will be improved solely if the pumping rate is reduced by half and it also will be improved considerably if the pumping rate is completely stopped. Based on the results of this study, an urgent calling for developing other drinking water resources to secure the water demand is the most effective solution to decrease the groundwater salinity.
The UNESCO IHP project "Groundwater Resources Governance in Transboundary Aquifers" (GGRETA) - Legal and Institutional Aspect	Ramogale	Sekwele	2015
Abstract This study intent to share the legal and institutional analysis of the UNESCO IHP project "Groundwater Resources Governance in Transboundary Aquifers" (GGRETA) project for the Stampriet Transboundary aquifer. The Intergovernmental Council (IGC) of the UNESCO International Hydrological Programme (IHP) at its 20th Session requested the UNESCO-IHP to continue the Study and Assessment of Transboundary Aquifers and Groundwater Resources and encouraged UNESCO Member States to cooperate on the study of their transboundary aquifers, with the support of the IHP. The GGRETA project includes three case studies: the Trifinio aquifer in Central America, the Pretashkent aquifer in central Asia and the Stampriet aquifer in southern Africa. This study focuses on the Stampriet Transboundary Aquifer System that straddles the border between Botswana, Namibia and South Africa. The Stampriet system is an important strategic resource for the three countries. In Namibia the aquifer is the main source of water supply for agricultural development and urban centers in the region, in Botswana the aquifer supplies settlements and livestock while in South Africa the aquifer supplies livestock ranches and a game reserve. The project methodology is based on UNESCO's Shared Aquifer Resources Management (ISARM) guidelines and their multidisciplinary approach to transboundary aquifers governance and management, addressing hydrogeological, socio-economic, legal, institutional and environmental aspects. The GGRETA builds recognition of the shared nature of the resource, and mutual trust through joint fact finding and science based analysis and diagnostics. This began with collection and processing of legal and institutional data at the national level using a standardized set of variables developed by the International Groundwater Resources Assessment Center (IGRAC). This was followed by harmonization of the national data using common classifications, reference systems, language, formats and derive indicators from the variables. The harmonized data provided the basis for an integrated assessment of the Stampriet transboundary aquifer. The data assisted the case study countries to set priorities for further collaborative work on the aquifer and to reach consensus on the scope and content of multicountry consultation mechanism aimed at improving the sustainable management of the aquifer. The project also includes training for national representatives in international law applied to transboundary aquifers and methodology for improving inter-country cooperation. This methodology has been developed in the framework of UNESCO's Potential Conflict Cooperation Potential (PCCP) program. The on-going study also includes consultation with stakeholders to provide feedback on proposals for multicountry cooperation mechanisms. It is anticipated that upon completion of the study, a joint governance model shall have been drawn amongst the three countries sharing the aquifer to ensure a mutual resource management.
Application of GIS Mapping Techniques to Classify Karoo Aquifers	Mildred	Goes	2015
Abstract POSTER As the National Water Act has evolved to provide for more effective and sustainable management of our water resources, there has been a shift in focus to more strategic management practices. With this shift come new difficulties relating to the presentation of sensitivity issues within a spatial context. To this end it is necessary to integrate existing significant spatial layers into one map that retains the context, enables simple interpretation and interrogation and facilitates decision making. This project shows the steps taken to map and identify key groundwater characteristics in the Karoo using Geographic Information Systems (GIS) techniques. Two types of GIS-based groundwater maps have been produced to assist with interpretation of existing data on Karoo Aquifer Systems in turn informing the management of groundwater risks within Shell's applications for shale gas exploration. Aquifer Attribute and Vulnerability maps were produced to assist in the decision making process. The former is an aquifer classification methodology developed by the project team, while the latter uses the well-known DRASTIC methodology. The overlay analysis tool of ESRI's ArcGIS 10.1 software was used, enabling the assessment and spatial integration of extensive volumes of data, without losing the original detail, and combining them into a single output. This process allows for optimal site selection of suitable exploration target areas. Weightings were applied to differentiate the relative importance of the input criteria. For the Attributes maps ten key attributes were agreed by the project team to be the most significant in contributing to groundwater/aquifer characteristics in the Karoo. This work culminated in the production of a series of GIS-based groundwater attributes maps to form the Karoo Groundwater Atlas which can be used to guide groundwater risk management for a number of purposes. The DRASTIC model uses seven key hydrogeological parameters to characterise the hydrogeological setting and evaluate aquifer vulnerability, defined as the tendency or likelihood for general contaminants to reach the watertable after introduction at ground surface.
Generation Of Multi-Site And Multi-Variate Stochastic Inputs To Support Improved Groundwater Resource Assessment	John Ogony	Odiyo	2019	resource assessment
Abstract In South Africa, the use of stochastic inputs in surface water resources assessments has become the norm while this is rarely done for groundwater resources. Studies that have applied multi-site and multi-variate methods that incorporate stochastic generation of groundwater levels are limited. Stochastic based inputs account for uncertainties attributed to inherent temporal and spatial variability of hydrologic variables and climatic conditions. This study applied variable length block (VLB) stochastic generator for simultaneous generation of multi-site stochastic time series of rainfall, evaporation and groundwater levels. In the study, 100 stochastic sequences with record length of 34 years (1980-2013), similar to the historic one were generated. Performance of VLB was assessed by comparing single statistics of historic time series located within box plots of the 100 annual and monthly stochastically generated time series. The statistics used include mean, median, 25th and 75th percentiles, lowest and highest values, standard deviation, skewness, and serial and cross correlation coefficients. Majority (9 out of 10) of the historical statistics were mostly well preserved by VLB, except for skewness. Historic highest groundwater levels were mostly underestimated. Historic statistics below interquartile range (overestimation) is a common problem of weather generators which can be reduced by including additional covariates that influence atmospheric circulation. The generation of multi-site stochastic sequences support realistic assessment of groundwater resources and generation of groundwater operating rules.
An investigation into the effectiveness of underground water pollution mitigation policies	Sibanda	Kin	2015
Abstract Pollution of underground water is fast becoming a global problem and South Africa is not immune to this problem. The principal objective of this paper is to investigate the effectiveness of laws and policies put in place to mitigate underground water pollution. The paper also seeks to examine the causes and types of underground water pollution followed by a closer look into the laws and policies in place to mitigate the pollution levels. Finally, the paper seeks to ascertain whether the current policies are properly implemented. The paper follows content analysis (desk research) to achieve the objectives. Policy recommendations are given based on the findings. {List only- not presented}
A Decision Support System to Assess Climate Change Impacts on Rural Communities	Musiiwa	Luruli	2015
Abstract Climate change contributes to the way in which people live. Natural resources such as groundwater, wood and surface water form a great part of livelihood in rural communities and are used extensively in rural areas where basic services have not yet been provided. The effect of climate change to all these natural resource may impact the lives of those in rural communities. Climate change is already starting to affect some of the poor and most vulnerable communities around the world. The aim of the dissertation is to develop a framework to assess the vulnerability of rural communities to climate change, with a specific focus groundwater and issues relating to gender. A questionnaire and interviews were used to collect data about rural communities' level of awareness climate change, their attitudes toward coping with climate change impact, level of education, income scale and how does this affect their security. Hyrodocensus was taken around the village to determine the rivers, dams, boreholes, abandoned boreholes and wells. Water samples were collected and analysed. The response rate was higher in females than in male's stakeholders (54% vs 46%).the results show that woman were mostly doing the hard work to complete daily basic activities. Education was found to be of high school level and incomes were low. The framework was developed with basic need showed that the area was at risk of poverty .Boreholes was found and water quality was analysed to be adequate for drinking water purpose. More information will be discussed on presentation.