Conference Abstracts

All Abstracts were presented at the Groundwater Conferences

Displaying 251 - 300 of 795 results

Title	Presenter Name	Presenter Surname	Area	Conference year Sort descending	Keywords
Estimation of representative transmissivities in heterogeneous aquifers	Fanie	de Lange		2015
Abstract The so-called apparent increase of transmisivity (T) or hydraulic conductivity (K) with scale is an artifact and does not exist in the field. The reason for the apparent increasing of T with scale is due to the use of the "not applicable" random log Gaussian stochastic models that are used by geohydrologists. In the petroleum field, which uses deterministic methods, the apparent increase of T with aquifer volume does not occur. Groundwater practitioners have to change their view and use models that do not show this effect. By using intuitive inspection of geological, fracture and connectivity data as well as real pumping test data, this paper shows that up-scaling must be performed with an exponential decaying function, where T always decreases with scale . Two types of heterogeneities exists namely a.) horizontal and b.) vertical. Connectivity between fractures is extremely important in both cases, but it is only in semi-confined and watertable aquifers that the vertical heterogeneities are really important (typical case of fracture dewatering) {List only- not presented}
Using gravity anomalies from GRACE to estimate changes in groundwater storage in the Vaal River Basin	Khuliso	Masindi		2015
Abstract The Gravity Recovery and Climate Experiment (GRACE) satellites detect minute temporal variation in the earth's gravitational field at an extraordinary accuracy, in order to make estimation of the total water storage (TWS). GRACE provides a unique opportunity to study and monitor real time water variation in the hydrologic stores (snow, groundwater, surface water and soil moisture) due to increases or decreases in storage. The GRACE monthly TWS data are being used to estimate changes in groundwater storage in the Vaal River Basin for a period (2002 to 2014). The Vaal River Basin has been selected, because it is one of the most water stressed catchments in South Africa; it is well-renowned for its high concentration of industrial activities and urbanized zones. Therefore, in order to meet future water demands, it is critical to monitor and calculate changes in groundwater storages as an important aspect of water management, where such a resource is a key to economic development and social development. Previous studies in the Vaal River Basin were mostly localised focusing mainly on groundwater quality and to a lesser extent groundwater assessment. Hydrological models have been generated for the whole of South Africa, but many of these models do not take into account the groundwater component. Thus, there is a significant gap in the understanding of surface and ground water dynamics in the Vaal River Basin. The paucity of data and monitoring networks are often the limitation in calculating changes in water storage over a large area, particularly in Africa. In this scenario GRACE is a good approach to estimate changes in hydrological storages as it covers large areas and generates real time data. It does not require information on soil moisture, which is often difficult to measure. The accuracy of calculating change in groundwater storage lies in the processing of GRACE data and smoothing radii. For this study, smoothing radii of 1500, 900, 500, 300, 150 and 1 km are used. Currently the associated error with different smoothing radii is unknown. The preliminary results indicate that the study area experienced a loss in TWS of -31.58 mm equivalent water height over a period of 144 months in TWS at 300 km smoothing radius. The change in groundwater storage is calculated by incorporating hydrologic components to the TWS (work in progress). The results obtained from this study will be compared to existing hydrological models and results generated from models applicable to the semi-arid region of South Africa. It is anticipated that this satellite observation technique, GRACE, will provide an accurate estimate of change in groundwater storage. Furthermore, it will show the usefulness of satellite based techniques for improving our understanding of groundwater dynamics, which will improve water management practices.
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.
Effects of Tidal Variation on LNAPL distribution in an aquifer	Willem J	van Biljon	Coastal Areas	2015	tidal influences, coastal aquifers
Abstract Collecting groundwater information close to the ocean often raises the question whether a tidal effect could be influencing the data. Sometimes this issue leads to speculation that is counterproductive and sometimes it is overlooked thereby causing judgement errors when interpreting data. This paper looks at the theoretical background of tidal influences in coastal aquifers to identify the screening factors to consider when deciding whether a contaminated site assessment needs to take tidal influences into account. The rising and falling of the tides cause a standing wave with varying frequency that is dampened by the neighbouring aquifer as the wave travels into it. Unconfined aquifers generally tend to be affected over a short distance, while the pressure wave can travel significant distances in a confined aquifer. There are indications that the rise and fall of the tides prevent discharge of the LNAPL, but it could cause lateral spreading due to the head changes in the aquifer. The tidal fluctuation also causes uncertainties in the LNAPL measurements. The case study presents data from a site where tidal variation directly influences the distribution of LNAPL in monitoring holes, while the variation in total fluid level is slight. In this specific case the tidal variation has to be accounted for, otherwise skewed measurement data will be collected.
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 effect of geology on the mobility and rebound of light non-aqueous phase liquids	Sedzani Elia	Muravha		2015	LNAPLS
Abstract Hydrogeological environments are commonly determined by the type of underlying geology; these environments may have a tremendous effect on the mobility and recovery of LNAPLs. Hydrogeological environment include intergranular sediments and bedrocks of contrasting permeability and porosity. This paper synthesizes several case studies and conceptual models of different hydrological environments and illustrates how they affect the flow characteristics and rebound of LNAPLs.
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.
Hydrogeochemical Evolution of an Opencast Colliery After Decommissioning - Static vs. Dynamic Prediction	Altus	Huisamen	Mpumalanga	2015
Abstract Static indicator tests, such as acid-base accounting, are commonly used to provide an indication of ARD potential of backfill material in opencast coal mines. This potential for acidity is then commonly incorporated into numerical models, wrongfully, as a constant contamination source with the maximum possible sulphate being released from the pit, ad infinitum, which is, obviously, not the case. Dynamic tests on the other hand, are considered superior, but are expensive and time consuming. The proposed alternative approach is geochemical modelling, illustrated by a case study in the Mpumalanga coal fields. A decommissioned colliery near Carolina, Mpumalanga, was recently confronted with the prediction of the impacts that its backfilled opencasts might have on groundwater in the long term with regards to acid and contaminant generation, demanding a more realistic and well-defined conceptual and numerical approach than the simple minimum screening method. This study utilised the integration of a well-defined conceptual model, mineralogical data, acid-base accounting data, leaching test data, literature and groundwater monitoring data to address the long term hydrogeochemical evolution of groundwater at the colliery, using transiently calibrated geochemical and numerical flow models. Using the mineralogical data available from samples collected, as well as the sulphur content identified by ABA, a standard error was calculated for the abundances of all mineral phases present along with mean weight percentages, defining the likely boundaries of mineral abundances. Using these values along with reactive surface areas calculated from average grain sizes, using a collapsing core model, as well as rate constants from literature, the fluid rock interaction in the leaching tests was simulated and calibrated against leaching test results in the geochemical model, by varying mineral abundances, reactive surface areas and rate constants within the statistically acceptable boundaries. Once a calibrated mineral assemblage was identified using this method, the assemblage was geochemically modelled in the natural environment, after calculation of fluid to rock ratios, which in this case was purely potential backfill porosity vs. recharge due to the natural groundwater level being below the pit base, as well as potential oxygen fugacity. The calculated concentrations of constituents were then introduced into a transiently calibrated numerical flow and transport model via recharge concentrations, to also chemically calibrate this model. The chemical calibration was successful within a 20 mg/L range, illustrating the reliability of the conceptual and geochemical models, but also the reliability of predicted numerical modelling results. Based on the available data and modelling results, the colliery would not have a future impact on groundwater with regards to ARD and metals. However, elevated major cation and anion concentrations are expected, calculated within order of magnitude accuracy, and can be managed according to dynamic and realistic models, instead of a static worst case scenario.
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
Characterisation of submarine groundwater discharge into False Bay (Western Cape)	Eric	Petermann	Western Cape	2015
Abstract In this paper we present results of a field study that focused on the characterisation of submarine groundwater discharge (SGD) into False Bay (Western Cape) with emphasis on its localisation. SGD is defined here as any flow of water from the seabed to the ocean. Thus, it includes (1) advective flow of fresh terrestrial groundwater as well as (2) seawater that is re-circulated across the ocean / sediment interface. Groundwater discharge into the coastal sea is of general interest for two reasons: (i) it is a potential pathway of contaminant and nutrient flux into the ocean, and (ii) it may result in the "loss" of significant volumes of freshwater. In our investigation we applied environmental aquatic tracers, namely radionuclides of radon (222-Rn) and radium (223-Ra, 224-Ra), as well as physical water parameters (salinity and temperature). The concentrations of radon and radium can be used as tracers for groundwater discharge since radon and radium are highly enriched in groundwater relative to seawater. We conducted discrete point measurements of seawater and of terrestrial groundwater as well as continuous radon time-series measurements of near-coastal seawater. A large-scale survey was performed along the entire shoreline of False Bay and revealed distinct positive anomalies of radon in the area of Strand/Gordons Bay and a rather diffuse anomaly along the Cape Flats, which is indicating possible groundwater discharge in these areas. The location of these anomalies remained constant to a large extent throughout several surveys that were performed during different seasons, although these anomalies varied with regard to their magnitude and clearness. Further detailed studies were undertaken in the area of Strand/Gordons Bay including radon time-series measurements in the coastal sea at a fixed location in order to estimate the quantity of SGD and its variability on a tidal time scale. The results indicate that groundwater discharge rates are significantly elevated during low tide. Furthermore, the distribution of radium isotopes (224-Ra/223-Ra ratios) in the Strand/Gordons Bay area indicate a "groundwater" residence time of less than 10 days within a distance of 5 km from the shore. In summary, we found spatially considerable constant SGD locations during different field campaigns. Additionally, we gained a rough understanding of the SGD dynamics on a tidal time scale, its magnitude and groundwater residence time within the inner bay after discharge. These results can be beneficial to trace back contamination in near-coastal waters or to find potential locations for groundwater abstraction.
Assessing The Role Of Oxygen In The Attenuation Of Petroleum Hydrocarbon Vapours In The Vadose Zone	Samuel	Samuel M?hr		2015
Abstract Vapour intrusion (VI) is the term used to define the encroachment of vapour phase contaminants from subsurface sources into structures such as buildings and basements. It is widely recognized that VI often forms the principal risk of exposure to receptors at petroleum release sites. Petroleum VI (PVI) generally occurs where a release of petroleum hydrocarbon product migrates from its source (e.g. from a leaking underground storage tank) to the groundwater table at which point, given favourable conditions, the hydrocarbon plume may migrate laterally beneath an adjacent building or structure. Subsequent volatilisation of the petroleum product results in the upward diffusion of vapours towards the surface where the vapours may enter into the building or structure at concentrations which may be harmful to human health. The subject of PVI with regards to its fate and transport mechanisms, as well as associated mitigation measures is rapidly gaining attention on a global scale, although to date this exposure pathway remains largely un-assessed in South Africa, with no regulatory guidance currently available. In the late 1990's and early 2000's focus was placed on the development of VI screening criteria by which sites could be screened with respect to their hydrogeological conditions and contamination status so as to determine whether VI could be a potential exposure pathway of concern, with much of the early work being completed by the United States Environmental Protection Agency. For the past decade the majority of the available screening criteria and guidance has had a partially incomplete understanding of hydrocarbon vapour fate and transport processes associated with VI, which has led to doubt over the application of such screening criteria in many cases. Furthermore, recent research conducted abroad has highlighted the importance of the role of oxygen in the vadose zone in the natural attenuation of petroleum hydrocarbon vapours as they diffuse through the soil profile. This research is pointing towards the notion that currently applied screening criteria may be overly conservative, leading to many unnecessary PVI investigations being conducted to the disruption of occupants of the buildings, and at great cost. Over the last two years ERM has compiled a dataset of PVI results from numerous investigations it has conducted throughout Southern Africa and in this paper the authors present data that supports the growing global trend towards recognizing the role that oxygen plays in attenuating petroleum hydrocarbon vapours in the vadose zone. The data also supports the notion that confirmed cases of PVI into buildings have generally been found to be the exception to the rule and not the norm.
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.
Hydrogeology of the Cedarville Flats primary aquifer, Upper Umzimvubu River Basin, South Africa	Molla	Demlie	Eastern Cape	2015	Cedarville Flats alluvial aquifer, Environmental Isotopes, highland recharge, residence time
Abstract The Cedarville Flats aquifer located in the Upper Umzimvubu River Basin, Eastern Cape Province is a source of water supply for an important agricultural region in South Africa. The hydrogeology of this important aquifer is investigated to understand the occurrence, circulation, recharge and quality of groundwater. To this end, local and regional geology, borehole lithological logs, borehole yields, aquifer hydraulic characteristics (including aquifer thickness, water level, hydraulic conductivity, transmissivity and storage coefficient), hydrometeorological, hydrochemicaland environmental isotope data were collected and interpreted. The results show that the alluvial aquifer is made up of sand, gravel, boulders and clay and its thickness reaches 51 meters in places. Median hydraulic properties indicate that the Cedarville Flats primary aquifer is the most productive aquifer compared to the underlying Molteno and Burgersdorp Formations. It has an estimated median borehole yield in the order of 6 l/s as compared to 2 l/s for the Burgersdorp and 1.5 liters for the Molteno Formations. The aquifers in the area receive an estimated 7% of rainfall recharge. The groundwaters of the area are characterized by low ionic concentration with EC and TDS ranging from 235 to 285 ?S/cm and from 65 to 151 mg/l, respectively. The hydrochemical data further indicate a groundwater hydrochemical facies of either Ca-Na-Mg-HCO3 or Na-Ca-Mg-HCO3 highlighting a typically less evolved recharge area groundwater having short residence time and hence less water-rock interaction. Springs and artesian wells show a relatively depleted stable isotope and very low to dead tritium signals indicating high altitude recharge and longer circulation path and residence times compared to wells tapping the water table aquifer which indicate young water with recharge coming from the immediate surrounding area. Similarity in hydrochemical and stable isotope signatures between the streams that drain across the alluvial flats and the shallow groundwaters mean that there is a close interconnection between surface water and groundwater in the area.
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.
Hydrodynamic and Hydrochemical characterization of groundwater resources of a municipality in Switzerland	Cedric	Meier	Switzerland	2015
Abstract The study characterized the hydrodynamic and hydrochemical properties of the quaternary porous aquifer which supplies the municipality of Pont-en-Ogoz (Department of Fribourg in Switzerland) with drinking water. The hydrostratigraphic series is composed of a thin overburden material, a porous aquifer composed of gravel and sand, a thin silt-clay layer and sandstone that forms the deeper aquifer. Pumping tests of a borehole nearby the well PSG1 and well PSG1 itself was used to calculate a mean hydraulic conductivity of the aquifer. The hydraulic conductivity from the test varies between 7.4?10-7 m/s and 2.4?10-5 m/s. The values of hydraulic conductivities are typical for sedimentary rocks as silt, fine sandstone and fine sand. The main physical and chemical parameters like concentration in cations and anions, as well the pH, the dissolved oxygen, the electrical conductivity and the alkalinity were measured and saturation indices were calculated. The analysis of the physical and chemical parameters shows that the type of water is Ca-HCO3 and that it contain mixture of old water coming from a regional groundwater flow system, probably from the deeper aquifer, and from recently infiltrated water as local groundwater flow system. The quality of water is generally good, but the effect of the purification of it through the thin overburden layer is limited. An initial one dimension steady state models based on the hypothesis of Dupuits for an unconfined and confined aquifer was used to calculate the mean recharge. This model gives us a recharge values from 24.8 cm/year and 12.1 cm/year, respectively. A second, two dimensional, confined, homogeneous and isotropic model has been calibrated in order to represent the spatial distribution of the piezometric surface. All the models have been calibrated as a steady state. Two groups of predictive scenarios were done to evaluate the drawdown in the well PSG1 using the 2D model. The maximum drawdown calculated was 40 m for the first group of scenarios and 3-4 m for the second group. The second group of scenarios considered from the deeper sandstone aquifer contributing to the well PSG1. The results of the second group of scenarios fit the field results better and the capture zone is much smaller than the one from the first model. The reality is probably between those two models. In order to lower the uncertainty, spatial variation should be added
Arsenic in the west-African water reserves: Investigation into sources of the contaminant through case studies in the region	Andre	van Coller	West Africa	2015	Arsenic
Abstract The mineral rich basin of the West African region has vast reserves of gold, diamond as well as iron ore deposits. Throughout the regional geological setting characterised by structural variations and intrusive belts with metamorphic mineral rich sequences covered by saprolite soils, one common chemical constituent remains a constant in the water reserves. Arsenic is in high concentrations throughout the region with chemical ranges commonly above the various country guidelines as well as international IFC and WHO standards. The aqueous chemical species is associated with arsenopyrite rich mineralogy of the regional greenstone belts and highly weathered soils. This conference article and presentation investigates the natural source of the arsenic through baseline data as well as the effect of mining on the already high concentrations of arsenic in both the groundwater and surface water. Natural levels of various chemical species in the regional area are already high at baseline level. One of the main research questions is thus whether mining and other anthropogenic activities will have an impact on the environment or will the changes to concentrations be so insignificant to allow the ecosystems and water users to continue in their current ways without any effect. Various case studies in Burkina Faso, Liberia, Sierra Leone and other countries have been combined to investigate the arsenic-rich resources of the West African region through groundwater specialist investigative methods with emphasis on geochemical modelling of the fluid-rock and fluid-fluid interactions leading to the water quality in the region.
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.
The use of chemistry, isotopes and gases as indicators of deep groundwater in the Main Karoo Basin	Ricky	Murray	Karoo	2015
Abstract Numerous environmental concerns have been raised with the possible exploration and development of shale gas in the Karoo. One such concern is that deep borehole drilling and the hydraulic fracturing process may create conduits through which deep-seated groundwater could migrate to shallow aquifers.This study set out to characterise deep Karoo groundwaters and identify indicators of deep flow. It was not possible to obtain groundwater samples from the deep-seated shales that are being considered for shale gas exploration and development because no suitable deep boreholes exist. Instead, samples from thermal springs and two deep boreholes that pass through the shales were obtained as the best approximation of deep-seated groundwaters in the Karoo. Deep and shallow groundwaters were characterised and determinands were identified to differentiate these waters. A provisional guide on the limits for these determinands was developed, and at this stage, this list can be used for guidance on differentiating deep form shallow waters. The determinands that appear to be most reliable in identifying deep groundwater were grouped and prioritised for future monitoring programmes.
Investigation of the probable infiltration from the wastewater ponds and its impact on the water quality of Pleistocene aquifer	EL-Said	Ahmed AL-Sayed Ragab	El Sadat	2015	Electrical Resistivity Tomography
Abstract 2-D Electrical Resistivity Tomography (ERT) and hydrochemical study have been conducted at El Sadat industrial city. The study aims at investigating the area around the waste water ponds to determine the possibility of water percolation from the wastewater (oxidation) ponds to the Pleistocene aquifer and to inspect the effect of this seepage on the groundwater chemistry. Pleistocene aquifer is the main groundwater reservoir in this area, where El Sadat city and its vicinities depend totally on this aquifer for water supplies needed for drinking, agricultural and industrial activities. In this concern, 7 ERT profiles were measured around the wastewater ponds. Besides, 10 water samples were collected from the ponds and the nearby groundwater wells. The water samples have been chemically analyzed for major cations (Ca+2, Na+, K+, Mg+2), major anions (Cl-, CO3-2, HCO3-, SO4-2), nutrients (NO2-, NO3-, PO4-3) and heavy elements (Cd, V, Cr, Zn, Ni, Cu, Fe, Mn, Pb). Also, the physical parameters (pH, Alkalinity, EC, TDS) of the water samples were measured. Inspection of the ERT sections shows that they exhibit lower resistivity values towards the water ponds and higher values in opposite sides. Also, the water table was detected at shallower depths at the same sides of lower resistivity. This could indicate a wastewater infiltration to the groundwater aquifer near the oxidation ponds. Correlation of the physical parameters and ionic concentrations of the wastewater (ponds) samples with those of the groundwater samples indicates that; the ionic levels are randomly varying and no specific trend could be obtained. Also, the wastewater samples shows some ionic levels lower than those detected in other groundwater samples. Besides, the nitrate level is higher in samples taken from the cultivated land than the wastewater samples due to the over using of nitrogen fertilizers. Then, we can say that the infiltrated water from wastewater ponds are NOT the main controller of the groundwater chemistry in this area, but rather the variable ionic concentrations could be attributed to local, natural and anthropogenic processes.
Modelling of Lake-groundwater interactions using a three-dimensional groundwater flow model for the Lake Sibayi catchment	Jannie	Weitz	KwaZulu-Natal	2015
Abstract Lake Sibayi (a topographically closed fresh water lake) and coastal aquifers around the lake are important water resources, which the ecology and local community depend on. Both the lake and groundwater support an important and ecologically sensitive wetland system in the area. Surface and subsurface geological information, groundwater head, hydrochemical and environmental isotope data were analysed to develop a conceptual model of aquifer-lake interaction which would later be integrated into the three dimensional numerical model for the area. Local geologic, groundwater head distribution, lake level, hydrochemistry and environmental isotope data confirm a direct hydraulic link between groundwater and the lake. In the western section of the catchment, groundwater feeds the lake as the groundwater head is above lake stage, whereas along the eastern section, the presence of mixing between lake and groundwater isotopic compositions indicates that the lake recharges the aquifer. Stable isotope signals further revealed the movement of lake water through and below the coastal dune cordon before discharging into the Indian Ocean. Quantification of the 9 year monthly water balance for the lake shows strong season variations of the water balance components. Based on lake volume and flow through rate, it was further noted that the average residence time for water in the lake was about 6 years. A recent increase in the rate of water abstraction from the lake combined with decreasing rainfall and rapidly increasing plantations in the catchment may result in a decrease in lake levels. This would have dramatic negative effects on the neighbouring ecosystem and allow for potential seawater invasion of the coastal aquifer.
Numerical Modelling of Groundwater Flow Between a Complex Underground Mine and an Operational Opencast Mine	Altus	Huisamen	Mpumalanga	2015
Abstract The management of groundwater inflows into an opencast colliery in Mpumalanga is normally fairly easily achievable due to low inflow volumes and high evaporation rates. But, when flooded underground mine workings are encountered, groundwater inflow complexity increases dramatically. Understanding, predicting and managing groundwater inflow under these conditions can be challenging and highly complex. While normal opencast inflows are easily modelled these connected mines are pushing numerical models to their limits. This case study aims to illustrate an approach based on a finite difference model that has been used successfully in a South African coal mine. Based on a study at a colliery near Ermelo, Mpumalanga, the understanding and conceptualisation of the aquifer geometry, geological structures, hydrogeology, defunct underground mine geometry and interconnection between opencasts and the underground, proved to be vital, not only in calibration of the model, but also in the construction of the various layers and calculation of flow volumes between the various sources and sinks. This also aided greatly in constant source contaminant transport modelling to trace which mining areas may have a contamination effect on each other or the surrounding aquifer. In constructing the numerical flow model, the underground mine geometry was found to intersect various layers in the MODFLOW based model and pinching out in some areas. Due to the requirement of MODFLOW that layers should be continuous with no pinchouts to the model boundaries, this presented a notable challenge in the model construction. Therefore, mine geometry was divided into various slices, fitting within the hydrogeological layers, but still retaining the original geometry. The layers were then further divided laterally using different materials to represent the mine hydraulic properties and aquifer properties respectively, ensuring that the lateral distribution of materials also represents the underground mine geometry accurately. Using this model construction, the calculated mean residual head for the simulation of the current situation was found to be less than 3m while the simulation of the current mining situation with no underground mine present, yielded a mean residual head of approximately 10m. Additionally, inflows measured in the opencast penetrating the underground were measured at approximately 1000m3/d while the calibrated model calculated inflows of 1160m3/d, while simulating the current mining situation including the defunct underground. The current decant from the defunct underground, to the southeast of the site, was calculated as 1.9 L/s by the model while the measured rate was just over 1 L/s. Also, as expected, the dewatering of the opencast penetrating the flooded, defunct underground mine, was calculated to predominantly impact an underground mine compartment, isolated by underground seals, as opposed to the aquifer, which has a much lower hydraulic conductivity. {List only- not presented}
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}
Hydraulic fracturing and Water Resources: Separating fact from fiction	Lizanne	Bredenkamp	Karoo	2015	Shale gas, Dolerite Intrusions
Abstract Shale gas in South Africa can be a game changer for the Karoo and South Africa economy but it may have a devastating effect on the environment. The Karoo communities is highly reliable on groundwater for their stock, irrigation and also for domestic use. Knowing the process and the potential impacts of gas-well drilling and fracturing on shallow groundwater systems beforehand different appropriate studies can be done before any hydraulic fracturing can took place in South Africa. The biggest concerns with hydraulic fracturing is that the fracturing fluids will flow and discharge into shallow aquifers due to the high pressure used or the produced water mixed with deep saline water may discharge into the environment. This paper presents a baseline dataset that will be a reference point against which any future changes in groundwater concentrations can be measured. The Karoo basin with its numerous dolerite intrusions make it unique and different from other countries. These dolerite intrusions are associated with high yielding boreholes because of the fractured contact. The Karoo Basin may be under artesian conditions, which imply that any pollutant might migrate upwards in the Karoo. The understanding of key attributes for characterising groundwater of Karoo Aquifers is most importantly the depth to water level, the yield, and groundwater quality.. The understanding of these characteristics will help to close possible legislative loopholes regarding fracturing. This paper establish an interactive database to obtain full understanding of the hydrogeology of the Karoo to be able to quantify how much water is available in the Karoo and who is the users. Not only the quantity of the water in the Karoo, but also quality and age/origin by making use of different isotopes in conjunction with basic macro chemistry. This will allow for a broader picture before any unconventional gas mining in the Karoo takes place and it can be used to identify any future changes in groundwater quality and quantity of the Karoo aquifers.
Characterisation of a large LNAPL plume in Limpopo Province, South Africa	Mahlogonolo	Phahlamohlaka	Limpopo	2015
Abstract Work is being conducted in Limpopo province following a large volume spill of petroleum hydrocarbons that took place from a leaking underground pipeline, resulting in significant volume of groundwater contamination. This is by far the largest spillage to date in South Africa.10 million litres of jet fuel leaked for a 15 year period from an underground pipeline until its detection 13 years ago. The leak has since been repaired and bailing was the first method proposed and applied to the recovery of the free product, but due to its ineffectiveness the "quicker"pump-and-treat method replaced it. Due to complications caused by pum-and-treat, the process was stopped in 2007 and is about to be reinstated again in 2013. A village to the north of the spillage depends mostly on groundwater. Immediate remediation actions have to be established before the contaminant reaches their abstraction boreholes. This project aims to model the areal extent of this contaminant and eventually design a life cycle of remediation. This will be based on comparison between existing models dated 2002 and 2012 respectively for background information and to address the influence of ten years' bailing, pumping and natural attenuation. The new model will focus around implementing remedial measures to prevent further migration of the free phase or dissolved plumes in order to protect the water supply to the surrounding villages. The progress will be presented in this paper.
Numerical model simulation of underground mine to determine reliable groundwater inflow predictions	Brendon	Bredenkamp	Kalahari	2015	predictive simulations, groundwater moddeling system, dewatering measures
Abstract The proposed underground copper mine is one of the first Greenfield developments in the Kalahari Copper Belt. Groundwater resources in the region are scare and saline mainly due to minimal recharge. Management and simulations of groundwater inflows formed an integral part of the new mine design to reduce production losses caused by the inflows and to ensure a safe mining environment. The mine is located is a complex hydrogeological setting characterised by folding and deep water levels. Multiple fractured aquifers are associated with the mining area. Groundwater numerical modelling was performed in Groundwater Modelling System (GMS) using MODFLOW-NWT. Results of the scenarios were used as a management tool to aid in the potential inflow predictive simulations and dewatering management. The numerical model was calibrated by using field measured aquifer parameters and piezometric heads. Numerical simulations assisted in estimating average groundwater inflows at certain stages of the proposed mine development. The simulated mine groundwater inflow volumes were used as input into the design of the dewatering measures to ensure a safe mining environment.
An Acid Base Accounting study of the coal-bearing formations in the Waterberg coalfield	Lore-Mari	Deysel	Karoo	2015	coal mine, sulphur, acid base accounting
Abstract Coal constitutes 77% of the primary energy needs in the country, with the Waterberg Coalfield estimated to host about 40% of the remaining South African coal resources. The Karoo coals were deposited in a reduced environment that have the potential to produce sulphides within the sediments they are hosted. The sulphur content within the coal can range from 0.1 wt.% to as high as 10 wt.%. Mining generates a disturbance in the natural groundwater levels and affects the surrounding water chemistry when sulphate is produced as a result of pyrite oxidation. Acid base accounting (ABA) was used to determine the balance between the acid producing potential (AP) and acid neutralizing potential (NP). From the analysis the Net Neutralising Potential (NNP) classified samples as either acid or non-acid producing. ARD does not only result in the generation of acid but is accompanied by decreased pH and increased values of specific conductance, dissolved metals and sulphate. The ABA results showed that interburden and coal samples have higher risks of producing acid upon oxidation than overburden samples. Higher concentrations of neutralising minerals are present in overburden samples. ABA indicated that the material 60m below ground surface had a higher acid producing potential than the material above. The analysis from kinetic tests showed the long-term behaviour of different samples, with the electrical conductivity (EC) and pH changing over time. Samples with lower pH continued to produce more sulphate, while calcium continued to increase until it was depleted from the samples. Inductively coupled plasma analysis determined the release of the heavy metals which can be detrimental to the environment, such as As, Co, Ni and Pb. The water demand will increase as mining continues in the area, with inter-catchment transfers identified to overcome local water scarcity issues. ARD poses a big threat to both groundwater and surface water resources.
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
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.
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
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.
Characterization of the Pretoria Fountains East and Fountains West Karst Aquifer Compartments	Vevanya	Naidoo	Gauteng	2015
Abstract POSTER The Fountains East and Fountains West groundwater compartments (by means of the Upper and Lower Fountain springs) have been supplying the City of Pretoria with water since its founding in 1855. These adjacent compartments which are underlain by the Malmani dolomites of the Chuniespoort Group are separated by the Pretoria syenite dyke and are bounded to the north by the rocks of the Pretoria Group (Timeball Hill Formation). Swallow holes and paleosinkholes play important roles in recharge in karst environments. Available sinkhole data and geotechnical percussion borehole logs are being collated to compile a detailed conceptual geological model. Inorganic chemistry data (2007 - 2012) as well as spring discharge volumes (2011 - 2012) for the Upper and Lower Fountain springs, supplied by the City of Tshwane Municipality, is being used to characterise the two compartments. This is done by means of piper diagrams, stiff diagrams and temporal plots. Isotope data for the Upper and Lower Fountain springs are available for 1970 to 2007. ?D and ?18O data from the Upper and Lower Fountain springs are plotted against each other and the Global Meteoric Water Line. Other stable isotopes (including 14C and 3H) are also plotted as time trends and interpreted. Interpretation of the combined geotechnical, chemical and isotope data will aid in understanding the karst aquifer and the controls on groundwater system within and possibly between these compartments.
Characterise and quantify contamination within the Crocodile (West) and Marico Water Management Areas, South Africa	Chazanne	Allison	Hartebeespoort Dam	2015	Heavy metal, chemical fingerprint, geochemistry
Abstract Define chemical signatures from river waters collected in the Crocodile (West) and Marico Water Management Areas, South Africa. Samples were analysed for anion complexes using Ion Chromatography (IC) and major and trace element chemistry using quadrupole Inductively Coupled Plasma-Mass Spectrometry (q-ICP-MS). Results are used to define the various chemical signatures resulting from activities within the study area which include mining, agriculture, industry, residential and domestic, and recreational usage and to differentiate the 'background' that arises from the natural geological heterogeneity. The aim of this characterisation is to fingerprint the chemical signatures of various anthropogenic activities irrespective of background. Results from this investigation have been mapped using GIS to visualise the data across the study area. Based on the results, the contamination sources within the area can be identified and ranked in terms of their contribution to the total effective contamination received at Hartebeespoort Dam. {List only- not presented}
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
'Best Practice' Approach To Undertaking Detailed Groundwater Impact Assessment Studies For Proposed Solar Energy Plants	Sheila	Imrie	Jacobsdal, Free State	2015	Solar energy, EIA, best practice, groundwater management
Abstract South Africa is a country at the forefront of the solar energy revolution. Each solar energy plant implementation results in further supply of clean renewable energy to the South African electric grid, thus playing a part in helping South Africa meet its renewable energy targets, in addition to stimulating long-term economic development and creating new jobs. Active solar techniques include the use of photovoltaic systems, concentrated solar power and solar water heating to harness the energy. Particular focus has recently been on the use of concentrated solar power technology which is better able to address the issues of scalability and electric storage. The process includes the use of a liquid salt solution and also requires a reliable water source. When applying for a new solar energy plant, a geohydrological assessment is required to inform the Environmental Impact Assessment. SolarReserve South Africa (Pty) Ltd responsibly take this one step further by requesting detailed geohydrological assessments including drilling and field testing, numerical modelling and simulations, and detailed impact analysis. Of particular consideration in these assessments is the potential for groundwater to meet the plants water needs, as well as the assessment of risk and potential groundwater contamination impact from failure in the lining of the evaporation ponds. This paper describes the 'best practice' approach that has been formulated and undertaken for some previously proposed sites, and is now recommended for future use in the groundwater impact assessment of future proposed solar energy plants in South Africa. It makes use of a SolarReserve case study example, located at the farm Kalkaar near Jacobsdal in the Free State Province, to explain the main steps in the process and how the results of using this approach are important inputs in the assessment of impacts, decision-making regarding go/no-go, technology used, infrastructure and site layout, and responsible management and monitoring of the groundwater in the future.
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).
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.
Groundwater and mining on the West African shield: application of mineralogical and weathering profiling	David	Love	West Africa	2015
Abstract The Birimian and Tarkwaian rocks of the Paleoproterozoic West African Shield host some of the most important gold reserves in the world, with Ghana the world's 10th largest gold producer and the region collectively producing more gold than all but five countries in the world. The gold was deposited during successive hydrothermal sulphide alteration events, which were channelled by shear zones and thrusts formed during the regional progressive Eburnean tectono-thermal deformation event. The hydrothermal fluids were auriferous and sulphide-rich, resulting in two distinct types of gold and sulphide mineralisation: (1) gold-bearing quartz- and quartz-ankerite veins, occurring in NNE-SSW trending shear zones or thrust folds, usually in Birimian metasediments, with associated sulphides deposited on the fragmented wall rock and (2) disseminated gold-bearing pyrite and arsenopyrite, occurring in halos within the same shear zones or thrust folds as the quartz veins. The sulphidic nature of the gold deposit leads to a high risk of acid rock drainage (ARD). During operations, inflowing groundwater may carry the ARD into underground workings and opencast pits. Post-closure, as the groundwater rebounds, there is a risk of acidic pit lakes forming or acidic decant of underground mines. However, the occurrence of ARD in such systems can be predicted by a combination of weathering profiling, mineralogical profiling and conventional acid base accounting (ABA). The weathering profile can be divided into three zones, readily distinguishable in borehole core: (i) Oxide Zone, from which both the acid-generating sulphide minerals and the acid-neutralising carbonate minerals have been largely leached, (ii) Transitional Zone, from which the carbonate minerals have been largely leached but the sulphide minerals remain, (iii) a Fresh/Primary Zone, where both sulphide and carbonate minerals occur. The Oxide Zone is generally non acid-generating, the Transitional Zone is acid-generating and the Fresh Zone is potentially acid-generating, depending upon the balance of sulphide vs carbonate minerals. Mineralogical profiles can be prepared from the relative abundance of macroscopic sulphide and carbonate minerals in the borehole core, again providing an assessment of ARD risk. Combined logs can then be prepared from these profiles with acid-generation and neutralisation data from ABAs, illustrating in space where the highest ARD risk zones are located. Using this information, groundwater and mine water management options can be developed for operations and closure, such as prioritisation of open pit backfilling or which levels of an underground mine water should be preferentially excluded from.
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.
Interannual variability in rainfall isotope composition as a tracer of spring water flow.	Roger E	Diamond	Western Cape	2015	Table Mountain Group, springs, rainfall isotopes
Abstract Table Mountain reaches 1086m elevation, the upper half of which comprises Table Mountain Group (TMG) quartzite with extensive fracture porosity. The lower half of the mountain comprises a mixture of Cape Granite intruded into Malmesbury Group metapelites, both of which are poor aquifers, but are in places overlain by scree slopes predominantly composed of TMG quartzite boulders. The region experiences a Mediterranean climate with warm, dry summers and cold, wet winters, with rainfall ranging from 600-1600mm/a depending largely on proximity to the mountain. Several springs issue from the slopes of the mountain, ranging in elevation from 15-410masl and in flow from non-perennial to 30L/s. Water chemistry reveals very little about spring water flow, as the waters have very low dissolved solids. Samples of 10 of these springs were taken twice per year for 3 years while rainwater was sampled at 120masl at the University of Cape Town (UCT) and at 1074masl at the Upper Cableway Station. These samples were analysed for oxygen and hydrogen stable isotope composition, mostly by mass spectrometer, but also by laser spectroscopy. The isotope results reveal an altitude gradient between the two rainfall stations of -0.075?/100m for ?D and -0.48?/100m for ?18O. Employing this isotope gradient, the average recharge altitude for the springs is 304masl, compared to an average discharge altitude of 156masl. Using this difference in altitude and the average slope of the terrain, a typical flow path of 1km from recharge to discharge point can be derived. Additionally, there are shifts in the weighted annual mean isotope composition of rainfall at UCT. For the years 2010-2012, the shifts are paralleled by similar shifts in the mean isotope composition at the springs for each of those years. This suggests rainfall discharges in the same winter season it has been recharged. In combination with the evidence for long term reliability of some of the springs over the dry season and during droughts, this suggests a layered flow of groundwater in the scree aquifer, allowing both long term steady discharge of deeper groundwater, as well as short term discharge of recently recharged rain. In combination with the flow path derived above, hydraulic conductivities in the realm of 10-20m/d can be calculated for the scree aquifers.
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.
Using Gravity Anomalies from Grace to Estimate Changes in Groundwater Storage In The Vaal River Basin	Khuliso	Masindi	Gauteng	2015	GRACE
Abstract The Gravity Recovery and Climate Experiment satellites detect minute temporal variation in the earth’s gravitational field at an unprecedented accuracy, in order to make estimation of the total water storage (TWS). GRACE provides a unique opportunity to study and monitor real time water variation in the hydrologic stores( snow, groundwater, surface water and soil moisture) due to increase or decrease in storage. The GRACE monthly TWS data are used to estimate changes in groundwater storage in the Vaal River Basin. The Vaal River Basin has been selected because it is one of the most water stressed catchment in South Africa; it is well-renowned for its high concentration of industrial activities and urbanized zones. Therefore, in order to meet future water demands it is critical to monitor and calculate changes in groundwater dynamics as an important aspect of water management, where such a resource is a key to economic development and social development. Previous studies in the Vaal River Basin, where mostly localized focusing largely on groundwater quality and to a lesser extent groundwater assessment. Hydrological models have been generated for the whole of South Africa, many of this models does not take into account the groundwater. Thus, there is a significant gap in our understanding of surface and ground water dynamics in the Vaal River Basin. The paucity of data and monitoring networks is often the limitation in calculating changes in water storage over a large area, particularly in Africa. In this scenario GRACE is the only approach to estimate changes in hydrological stores as it covers large areas and generate real time data. It does not require information on soil moisture, which is often difficult to measure. The preliminary results indicate that the change in TWS anomaly derived from GRACE data is - 12.85 mm of vertical column of water at 300 km smoothing radius. The change in groundwater storage is calculated by incorporating hydrologic components to the TWS (work in progress). The results obtained from this study will be compared to existing hydrological models and results generated from models applicable to the semi-arid region of South Africa. It is anticipated that this satellite observation technique, GRACE, will provide an accurate estimate of change in groundwater storage. Furthermore, it will show the usefulness of satellite based techniques for improving our understanding of groundwater dynamic, which will improve water management practices.
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}
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.
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.
Monitored Natural Attenuation of Inorganic Constituents: A Case Study in a Karoo Aquifer	Vevanya	Naidoo	Karoo	2015
Abstract Natural attenuation describes a set of natural processes which decrease the concentrations and/or mobility of contaminants without human intervention. In order to evaluate and demonstrate the effectiveness of natural attenuation, regular long term monitoring must be implemented. This entire process is called Monitored natural attenuation (MNA). The focus of MNA is generally placed on hydrocarbons and chlorinated solvents but according to the United States Environmental Protection Agency (USEPA) MNA can be used for various metals, radio nuclides and other inorganic contaminants. MNA was deemed the best method to reduce the concentration and mobility of contaminants impacting the groundwater environment, at a fertiliser plant in the Free State. A number of improvements in infrastructure were made in 2013which were assumed to have prevented further release of contaminants into the groundwater system, from the source areas on site. MNA was also considered to be the most effective affordable solution for the site as groundwater in the vicinity is not used for domestic purposes (low risk). Cl, NO3 and NH4 were used to monitor the movement of the contamination off site and the effectiveness of MNA. With regards to the inorganic contaminants emanating from the site, sorption, dispersion, dilution, and volatilization are the main attenuation mechanisms. These mechanisms are considered to be non-destructive attenuation mechanisms. Denitrification, nitrate reduction through microbial processes, may also facilitate in the attenuation of the in organic constituent nitrate. Denitrification is considered a destructive mechanism. Classed posts and temporal graphs of the Cl, NO3 and NH4 concentrations between 2008 and 2014 were utilised to show the movement and change in size and shape of the contamination plumes and subsequently, monitor MNA. The data indicates that the NO3, Cl and NH4 contamination plumes from the various source areas on the site have detached from the site and are currently moving down gradient along the natural drainage. Contaminant concentrations at the site have generally decreased in recent monitoring events while concentrations downstream of the site have remained stable. This indicates that MNA is currently an effective method of remediation for the site and monitoring should be continued to ensure that it remains effective.
Waste Management in Nigeria: A paradigm Shift	Akobundu	Amadi	Nigeria	2015	waste management, environmental pollution, Modern sanitary landfill
Abstract The manner in which municipal and industrial wastes generated are disposed in the urban areas in Nigeria is worrisome. The practice of dumping solid wastes in abandoned burrow-pits or valley and the discharge of liquid wastes directly on soils or surface water without any form of treatment has resulted in soil and water pollution. The continuous release of dangerous gases into the atmosphere by industries unabated has contributed to air pollution. These inadequate waste disposal techniques have created serious environmental and health challenges. Due to increasing population growth rate, urbanization, industrialization and economic growth, there has been a phenomenal increase in the volume of wastes generated daily and handling of these wastes have constituted an environmental problem. The need to manage these wastes in an environmentally-friendly manner that will guarantee safety of the soil and water resources lead to the present study. The newly designed waste management landfill incorporates advanced features such as complex multiple liner construction to facilitate organic decomposition and maintain structural integrity. The multiple protective layers and regular monitoring ensure that the waste management landfills exist in harmony with their surrounding environments and communities. These features that enhances maximum protection of soil and water from contamination by plume by decaying waste is lacking in the un-lined open waste dumps been practiced in the country. Pollution abatement, waste reduction, energy saving, health and economic benefits are some of the advantages of the newly designed sanitary landfill system.
Groundwater Exploration And Monitoring At Selected Western Cape Schools	Candice	Lasher	Western Cape	2015
Abstract POSTER The Department of Transport and Public Works has been involved with the building and upgrading of schools in the Western Cape, as well as providing green areas for sports fields. Due to the excessive costs of using municipal water the option of using groundwater for irrigation was investigated by SRK Consulting. A number of successful boreholes have been scientifically sited, drilled and tested since 2011. The boreholes have been equipped with pumps and data loggers have been installed in several. These data loggers measure time-series water levels and temperature while the flow meters measure the discharge rate and the quantity of groundwater used. Currently groundwater is being abstracted to irrigate the sports fields. Initially some problems were encountered. Boreholes were not operating optimally due to incorrect pump sizes resulting in water levels to be at pump inlet depths and pumps were not being switched off for recovery. However, due to continuous monitoring, the pumping rates and times were adjusted accordingly. It is imperative that all boreholes are equipped with loggers and continuously monitored to ensure that the boreholes are being optimally and sustainably used. Monitoring groundwater abstraction and aquifer water levels provides critical information for proper groundwater resource management. It is envisaged that schools will become proactive and participate in the groundwater monitoring. The latter will assist with groundwater awareness and assist in the use of alternative water sources and ease the burden on already stretched conventional sources.
Fluoride challenge in groundwater of the Ethiopian Rift Valley and adjacent highlands	Taddesse M	Bollollo	Ethiopia	2015	Fluoride
Abstract The urban and rural communities sources of water for domestic and other uses come from groundwater in most parts of Ethiopia. But the groundwater is not free from challenge. Fluoride is one of those critical problems which are affecting the health of inhabitants of this corridor. There are places where the fluoride contents reach more than 10mg/l. groundwater Treatment plants, changing the water scheme source from surface water and related efforts have been made so far to alleviation such challenges. Fluoride affects bones and teeth by changing its color and easily affected to a number of health complication in the rift valley of Ethiopia. {List only- not presented}
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.
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.