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
The effects of land use change on surface water/groundwater interactions in the coastal lakes and wetlands of KwaZulu Natal	Jane	Tanner	KwaZulu-Natal	2015
Abstract The eastern coastal plain of South Africa has one of the outstanding natural wetland and coastal sites of Africa. The estuaries are complex and dynamic systems sustained by both groundwater and surface water. These systems are driven primarily by changing sea level and fluctuating climatic conditions, especially river runoff and sedimentation rates, which have been heavily affected by land use change. The largest lake, St Lucia, lies at the bottom end of several rivers, some of which have major afforestation within their catchments. Given that there is a strong connection between surface water and groundwater, a significant driver of the reduced river runoff constitutes reduced groundwater baseflows due to the lowering of groundwater levels in the upstream reaches of the lake's catchments. The remaining large lakes (Lake Sibaya and the Kosi Bay Lake system) are largely groundwater driven and are also affected by increasing impacts on the groundwater sustaining the lakes. There is an urgent need to quantify the impact of land use change, particularly increasing plantation forestry, on these coastal estuarine systems. While previous work has been undertaken to better understand the complex environment, this study examines the coastal environment (Lake St Lucia, Lake Sibaya and the Kosi Bay lakes) in an integrated manner and considers the impacts of various land use activities on the system, both in the 'buffer zone' surrounding the lakes and within the upstream reaches of the river catchments. The study builds on previous investigations and utilises results from existing models as well as available field data. The integrated Pitman Model is used to model the groundwater/surface water dynamics and will be validated using existing numerical model results, observed stream flow, groundwater levels and lake level information. While the model has been established at a quaternary catchment scale for the upstream reaches of the rivers, the downstream reaches have been modelled at smaller spatial scales dictated by groundwater flow directions. A wetland sub-model has been established to represent the numerous and varied wetlands while a specific sub-model has been developed to represent the hydrodynamics of Lake St Lucia and its complex connections to the sea. The currently ongoing study aims to quantify the current and future land use change impacts on the groundwater and surface water resources sustaining the lakes.
A review of groundwater resource protection measures in South Africa	Eberhard	Braune		2015

Managing Transboundary Groundwater Resources: The Case of the Ramotswa Aquifer	Nicole	Lefore	SADC	2015
Abstract What are the key institutions, both formal and informal, that determine actual groundwater use in the Ramotswa aquifer? Are current institutions at regional, national and sub-national levels adequate to collaborate for equitable benefit-sharing for the future? These are the questions that the paper will address based on early findings of a project aimed at determining the role the Ramotswa aquifer can play in addressing multiple-level water insecurity, drought and flood proneness, and livelihood insecurity. Groundwater resources are critical in the SADC region
Hydrogeochemical processes in the shallow aquifer of the Lubumbashi river basin: multivariate statistical approach	Lumu	Moussa Antoine		2015
Abstract Understanding the hydrogeochemical processes that govern groundwater quality is important for sustainable management of the water resource. A study with the objective of identifying the hydrogeochemical processes and their relation with existing quality of groundwater was carried processes in the shallow aquifer of the Lubumbashi river basin. The multivariate statistical approach includes self organizing maps (SOM'S) of neural networks, hierarchical cluster (HCA) and principal component analysis of the hydrochemical data were used to define the geochemical evaluation of aquifer system based on the ionic constituents, water types, hydrochemical facies and groundwater factors quality control. Water presents a spatial variability of chemical facies (HCO3- - Ca2+ - Mg2+, Cl- - Na+ + K+, Cl- - Ca2+ - Mg2+ , HCO3- - Na+ + K+ ) which is in relation to their interaction with the geological formation of the basin. The results suggests that different natural hydrogeochemical processes like simple dissolution, mixing, weathering of carbonate minerals and of silicate weathering and ion exchange are the key factors. Added to this is the imprint of anthropogenic input (use of fertilizers, septic practice poorly designed and uncontrolled urban discharges). Limited reverse ion exchange has been noticed at few locations of the study.
The importance of rainfall data in water resource planning and risk management	Nicolette	Vermaak		2015	rainfall data
Abstract Water resource management and risk management rely heavily on the availability of data and information. This includes the volumes of water needed, the volumes of water available, where the available water is and where it would be needed, etc. Historical records help to determine past use and gives a way to predict future use in the case of water resource planning while it helps to predict the possibility of floods and droughts when it comes to risk management. Rainfall data can provide valuable data for both water resource planning and risk management, since it is the input to the hydrologicalcycle. It is possible to determine dry and wet cycles using the cumulative deviation from mean that is calculated from the measured rainfall data. This was done for the Gnangara Mound in Australia, with the results giving a fair representation of the dry and wet cycles in the area. Data measured over a period of about 30 years for the Zachariashoek sub-catchment analyzed in the same fashion provided wet-dry cycles of about 8 years. The rainfall measurements had been taken at various settings around the catchment, and varied from place to place and differed from that measured at the WeatherSA stations in the vicinity. This article will draw a comparison between the Zachariashoek data and the WeatherSA data to determine whether the WeatherSA data followed the same patterns for the wet-dry cycles observed in Zachriashoek. It will then analyse the longer data record available for the WeatherSA data from 1920 to 2012. It is expected that the shorter wet-dry cycles seen in Zachariashoek will become part of longer wet-dry cycles that can be used in water resource planning and risk management. Rainfall is also dependent on a number of factors
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.
Incorporating participation in groundwater decision support systems for water scarce rural areas: Siloam Village case study	John Ogony	Odiyo	Limpopo	2015
Abstract A groundwater decision support system (DSS) that incorporates stakeholder participation has been developed for Siloam Village in Limpopo Province, South Africa. Residents of Siloam Village are dependent on groundwater to augment inadequate pipe borne water supply. This creates the need for a DSS that ensures efficient and sustainable management and utilization of water. Such a DSS is constituted of both quantitative and qualitative components. The study further proposes framework for implementation of the DSS which incorporates community participation. This will act as a tool for empowering and educating the communities in rural villages so that they can be able to manage their water resources. The developed DSSs will make it possible for Siloam community to operate their water supply systems efficiently taking into account environmental needs and water quality
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}
Radon-222 in Thermal Springs of Limpopo Province, South Africa	Humberto	Saeze	Limpopo	2015
Abstract Studies have shown that the use of natural water (drinking and bathing) with high level of 222Rn concentration may contribute to negative health effect in human beings. Thermal springs located in Limpopo province were sampled for the determination of 222Rn concentration by gamma ray spectrometry. The spring water has been used for domestic purposes: drinking and bathing, and for recreation bathing mainly. 19 samples were collected between thermal springs emanation points and swimming facilities (out and in doors). Radon-222 concentration found in these water ranges from 0.2 to 624 Bq/l. These results indicate that 7 thermal springs may represent increasing risk on bathing or inhalation of radon gas, leading to an increased risk of healthy.
Development of regional groundwater flow models for the Vaal Gamagara well fields	Martin	Holland	Northern Cape	2015	flow models
Abstract The increasing water demand for the Northern Cape Province initiated the feasibility study to augment and/or upgrade the Vaal Gamagara Water Supply (VGWS) scheme. The study completed in 2011, recommended the upgrade of the total VGWS scheme to supply the water demand of users for the planning horizon to 2030. However, short term water demand and to augment the water from the Vaal River could also be sourced from groundwater and/or mine dewatering. This resulted in the detailed assessment of the exploitation potential of three groundwater development target areas namely SD1, SD2 and SD4, largely underlain by karst aquifers. The intrusive work done on the Vaal Gamagara target areas is arguably one of the largest groundwater investigations of modern time for South Africa. This paper describes the development of the 3-dimensional groundwater flow models for the three target areas as part of this investigation. The software code chosen for the modelling work was the program SPRING which uses the finite-element approximation to solve the groundwater flow equation. Each conceptual groundwater model developed was converted into a multi-layer numerical flow model for each groundwater development area and calibrated against observed heads, spring flows and long term water level monitoring data. Once the models demonstrated to reasonably reproduce past behaviour, they were used to forecast the outcome of future groundwater behaviour (i.e. abstraction from the well fields). Three large scale transient groundwater models have been built to analyse regional flow systems, to simulate water budget component changes, and to optimize groundwater development on a ‘sustainable’ basis. Different scenarios were developed for each target area to study the impact of different recharge scenarios and variable abstraction rates on the groundwater development of the area. Several simulations were carried out iteratively to identify the necessary number, optimal pumping rates and the temporal variability of the withdrawal period. While the proposed abstraction rates for all three groundwater regions (SD1, SD2 and SD4) of 13 million m3 / annum are considered as ‘sustainable’, by definition ‘sustainability’ has so determine the balance between economic, social and environmental interest. Perhaps a more applicable term for the long-term abstractions rates for the SD well fields is the maintainable aquifer yield which simply refers to a yield (volume/ time) that can be maintained by reduced discharge or enhanced recharge, without continually mining the aquifer or depleting aquifer storage.
Integrated Modelling: A Tool For Urban Groundwater Management On The Cape Flats, Cape Town	Benjamin	Mauck		2015
Abstract There is growing concern that South Africa's urban centres are becoming increasingly vulnerable to water scarcity due to stressed surface water resources, rapid urbanisation, climate change and increasing demand for water. Given South Africa's water scarcity, global trends for sustainable development, and awareness around the issues of environmental degradation and climate change, there is a need to consider alternative water management strategies. Water Sensitive Urban Design (WSUD) is an approach to sustainable urban water management that attempts to achieve the goal of a 'Water Sensitive City'. The concept of a Water Sensitive City seeks to ensure the sustainable management of water using a range of approaches such as the reuse of water (stormwater and wastewater), exploiting alternative available sources of supply, sustainable stormwater management and improving the resource value of urban water through aesthetic and recreational appeal. Therefore, WSUD attempts to assign a resource value to all forms of water in the urban context, viz. stormwater, wastewater, potable water and groundwater. However, groundwater is often the least considered because it is a hidden resource, often overlooked as a form a water supply (potable and non-potable) and it is often poorly protected. The management of urban groundwater and understanding the impacts of WSUD on groundwater in South African cities is challenging, due to complex geology, ambiguous groundwater regulations and management, data limitations, and lack of capacity. Thus, there is a need for an approach to assess the feasibility of management strategies such as WSUD, so that the potential opportunities and impacts can be quantified and used to inform the decision making process. An integrated modelling approach, incorporating both surface and subsurface hydrological processes, allows various urban water management strategies to be tested due to the complete representation of the hydrological cycle. This integration is important as WSUD is used to manage surface water, but WSUD known to utilise groundwater as a means of treatment and storage. This paper assesses the application, calibration and testing of the integrated model, MIKE SHE, and examines the complexities and value of establishing an integrated groundwater and surface water model for urban applications in South Africa. The paper serves to demonstrate the value of the application of MIKE SHE and integrated modelling for urban applications in a South African context and to test the models performance in Cape Town's unique conditions, accounting for a semi-arid climate, complex land use, variable topography and data limitations. Furthermore, this paper illustrates the value of integrated modelling as a management tool for assessing the implementation of WSUD strategies on the Cape Flats, helping identifying potential impacts of WSUD interventions on groundwater and the potential opportunities for groundwater to contribute towards ensuring to Cape Town's water security into the future.
Case Study: Groundwater Exploration in the Basement Granites of the Kraaipan Group using Aeromagnetic Surveys	Marius	Terblanche	North-West	2015
Abstract Aurecon was appointed to conduct groundwater exploration for production well fields in the towns of Setlagole and Madibogo. These towns are located in an arid part of the North West province on the edge of the Kalahari. The landscape is flat and covered by aeolian sand underlain by basement granite of the Kraaipan Group Geology. Historically groundwater exploration consisted of reconnaissance geophysical surveys followed by detail ground surveys. Where no potentially water bearing geological structures are shown on geological maps & aerial photos, the project area would be divided into a grid on which the ground geophysical survey would be done. This type of exploration is time consuming and expensive. In some cases the terrain or cultural noise prohibits the use of conventional geophysical methods, with only more expensive and time consuming methods being left as an option. This is where the high resolution airborne magnetic survey excels. The results obtained from this type of survey are of such nature that only a small amount of ground geophysics is necessary to locate drilling targets. This survey method is also cost effective allowing a larger area to be covered in a short amount of time as compared to conventional ground techniques. This paper will discuss successes achieved using high resolution aeromagnetic surveys as the basis for groundwater exploration in traditionally low-yielding igneous geology.
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}
Stampriet Transboundary Aquifer System	Joyce T	Leshomo	SADC	2015	IAH, Unesco-IHP, transboundary aquifers
Abstract The International Association of Hydrogeologists and UNESCO's International Hydrological Programme have established the Internationally Shared (transboundary) Aquifer Resource Management (ISARM) Programme. This multiagency cooperative program has launched a number of global and regional initiatives designed to delineate and analyze transboundary aquifer systems and to encourage riparian states to work cooperatively toward mutually beneficial, sustainable aquifer development and management. The Stampriet Transboundary Aquifer System was selected as one of the three case studies funded by UNESCO. The Stampriet Aquifer System is located in the arid part of the countries (Botswana, Namibia and South Africa) where groundwater is a sole provider for water resource. The area is characterised by the Kalahari (local unconfined aquifer) and Nossob confined aquifer
Integration of geophysical and well monitoring techniques in the evaluation of the groundwater potential for the Urban Bulawayo	Innocent	Muchingami	Zimbabwe	2015
Abstract POSTER Most developing urban areas in semi-arid regions of Sub Saharan Africa are often forced to utilise groundwater as an alternate source of domestic water supplies. As such groundwater evaluations strategies often face dual challenges in terms of resource quantification and their quality evaluation. However, groundwater potential assessment and aquifer yield evaluations often present a challenge when the system is of crystalline basement nature where groundwater potential is highly spatially variable and cases of dry holes and seasonal wells have been reported. This study demonstrate the integrated combination of geophysical techniques, (namely, vertical electrical sounding, electrical resistivity tomography, magnetic mapping, and seismic refraction tomography) with both borehole monitoring and infiltration techniques in the groundwater prospecting and spatial yield analysis of the Urban Bulawayo crystalline basement aquifer. The Bulawayo Metropolitan Province of Zimbabwe is located in the semi-arid region of Zimbabwe with an average annual rainfall of below 500 mm and has had a prolonged dry spell has resulted in the dwindling of the existing surface water resources. The aquifer system consists of syenite granite and fractured basaltic greenstone crystalline basement complexes. Provisional geophysical results have shown that the thickness of the fractured zone sharply varies in terms of spatial distribution and often some sections are characterized by shallow surface fractured zone that may only be 20-30 m thick and some sections have a reported regolith of up to 60m in thickness. Borehole yield assessments and chemical analysis techniques will be done on drilled wells in order to come out with detailed spatial variation in the borehole yield and water quality variations across the aquifer system. All the technical evaluations are then integrated to produce a detailed hydro-geophysical map of the system that can be used in the technical groundwater management of the urban Bulawayo aquifer.
The most valuable resource	Nicolette	Vermaak	West Coast, Western Cape	2015	resource economics
Abstract Mining is becoming a problem in the Western Cape - different kinds of mining and other resources, different problems than in other parts of the country. The West Coast had been declared a development corridor and a mining priority area. It is an arid to semi-arid area, where surface water is scarce, and rainfall relatively low and decreasing as one moves north. Some areas have significant volumes of good quality groundwater available, with potential impacts by the mining activities. This would play the importance of different resources off against the other. Most see resources as minerals, such as gold, silver, phosphate, and others where the value of these resources is measurable. Resources are also human capital, time, water, air, a healthy environment. It is more difficult to measure the value of the second group, as some of them have more than just a Rand and cent value. The value of resources is mostly done by measuring its monetary value, i.e. how much you will get when you sell the resource to a customer, providing the way the value of most resources is measured, i.e. resource economics. Economics is an area that most scientists are not familiar with as it contains a way thinking, of rules and laws unrelated to the way they have been taught. Supply and demand determines the value of a commodity, with scarce resources normally fetching higher prices. The value of the second group of resources is more difficult to determine. When does a resource become a strategic resource? This would be a resource that has a limited supply, does not get regenerated through natural processes and that is needed for defence, energy supply and others important for the stability of a country. There are also a category of resources we cannot live without such as water, and air - pure, fresh air and water. Without it life on this planet will cease to exist. This could be termed critical resources. What do you do if the occurrence of two very important critical resources overlaps, where the extraction of the one will lead to irreparable damage to the other? This article will look at one site where a strategic resource occurs at the same site as an important water resource. It will compare the potential value of the mineral resource with the value of the water resource in the aquifer measured at the current value of water as available to the public. It will also take into account the value of the water resource from the perspective of a healthy functioning ecosystem and a RAMSAR site. This analysis becomes more valuable when considering the potential effects of climate change in the area and the cost of desalination.
An 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
Groundwater Vulnerability Assessment Of A Sedimentary Basin In South Western Nigeria	Saheed	Oke	Nigeria	2015
Abstract The Dahomey Basin is a transboundary sedimentary basin with its eastern half in south western Nigeria. The vulnerability assessment of the basin was carried out to ascertain the degree of the shallow unconfined aquifers sensitive to groundwater contamination through the investigations of the intrinsic properties of lithology over the unconfined aquifer systems. The basin is a multi-layered aquifer system hosting large population densities particularly in Lagos where nearly half of the population rely on the groundwater for domestics and industrial purposes. The vulnerability evaluation involves determining the protective cover and infiltration condition of the unsaturated zone in the basin. This was achieved using the PI vulnerability method of the European vulnerability approach. The PI method specifically measures the protection cover and the degree to which the protective cover is bypassed. Intrinsic parameters assessed were the subsoil, lithology, topsoil, recharge and fracturing for the protective cover. While, the saturated hydraulic conductivity of topsoil, infiltration processes and the lateral surface and subsurface flow were evaluated for the infiltration bypassed. The results were depicted in vulnerability maps. Map of the protective cover ranges from high to very high. This means a very effective cover over the groundwater resources. The I map revealed a low to very low degree of bypass. The final vulnerability map shows that the Dahomey Basin vulnerability ranges from moderate to very low vulnerability areas. Low vulnerability areas were characterised by lithology with massive sandstone and limestone, sub soils of sandy loam texture, high slopes and high depth to water table. The moderate vulnerability areas were characterised by high rainfall and high recharge, low water table, unconsolidated sandstones and alluvium lithology. The vulnerability map was validated with hydrochemical properties of the groundwater. Chloride and TDS concentration of the groundwater reveals high chloride concentration for low groundwater vulnerability areas while low chloride concentrations were observed for moderate vulnerability areas. Low to moderate groundwater vulnerability areas show low TDS concentrations according to the WHO standards except for the coastal areas with relatively higher TDS concentrations. The groundwater vulnerability maps will be a useful tool for planning land use activities which will minimise groundwater contamination and enhance the protection of the Dahomey Basin groundwater resources. {List only- not presented} Keywords: PI method, Dahomey Basin, aquifer vulnerability, protective cover, groundwater resources.
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.
Steytlerville Bulk Water Supply	CJ	Roets	Eastern Cape	2015
Abstract The continuous increase in demand for water from a growing population and associated additional housing projects in the town of Steytlerville in the Eastern Cape Province has resulted in a shortage in water supply from the existing boreholes. In order to supplement the additional demand, a bulk water augmentation scheme using surface water from the Groot Rivier at a point immediately east of the Hadley crossing was implemented. This was done by drilling two large diameter production boreholes vertically into the alluvium and underlying bedrock of the river to a depth of intersecting the entire thickness of the mapped alluvium. Two boreholes were connected to a network of subsurface drains that allowed for recharge from the open channel to flow into the production boreholes. In addition to the sub-surface drain system connecting the sump boreholes, three recharge drains were constructed upstream of the abstraction boreholes. The purpose of these drains were to recharge the underlying paleo-channel to improve the water quality and yield from the paleo-channel. This was achieved by connecting the sub-surface drainage pipe to a vertical screened recharge borehole. The end result of the study was the successful implementation of a alternate borehole yield of 14l/s from the production wells to the Steytlerville town water reticulation supply.
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.
Supervised committee artificial neutral network in groundwater exploration in granitic and metamorphic terrains of South Africa	Emmanuel	Sakala	Northern Cape	2015
Abstract POSTER The areas studied in this paper are situated in semi-dry regions of Limpopo and Northern Cape Provinces of South Africa. Groundwater is the only dependable source of water for many local users and farming communities. The growing population is putting immense pressure in the current water resources, hence a need to find new groundwater resources. The areas are most dominated by fractured rock aquifers which accounts to over 90% of South African aquifers. Finding sustainable sources of groundwater in these regions is often a challenge due the complex nature of the fracturing network system of fractured aquifers. This study uses a supervised committee learning with artificial neutral network (SCLANN) model to improve the regional groundwater exploration in granitic basement terrains and valley controlled aquifers in metamorphic terrains of South Africa. The data used in the study was obtained from the national groundwater archive and interpretation of high resolution aeromagnetic data, ground surveys and remote sensing datasets. The artificial neural network (ANN), Fuzzy (F) and Neuro-fuzzy (NF) unsupervised models whose input were groundwater controlling parameters like regolith thickness, lithology, relief, faults, lineament density, lengths of lineaments was used. The results from the ANN, F and NF models were used as inputs to a nonlinear supervised SCLANN framework with the borehole yield as the training and validation outputs. Borehole yield was used as it is one of the measurable parameter that directly related to productivity of groundwater resources. The use of the unsupervised models improved the results significantly as the SCLANN model results as a combined advantage of the individual models to achieve the optimal high performance. The results show that the three models used to build a SCLANN model was able to improve the identification of potential groundwater targets at regional scales. This approach can be incorporated in regional groundwater exploration programs to improving drilling success rate on granitic basement and metamorphic terrains in South Africa. The results show that the SCLANN outperforms individual unsupervised models. However the SCLANN results for granitic basement terrains were far much better than the metamorphic terrains probably showing the limitation of the approach in metamorphic terrains.
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}
Groundwater and Surface Water Interaction Study for the Ingula Wetland	Christie	Terrell		2015
Abstract The Bedford Dam is the upper storage dam for the Ingula Pumped Storage Scheme and is situated in the Ingula/Bedford Wetland. This wetland has a high structural diversity which supports a unique assemblage of plants and invertebrates. The flow regulation and water purification value is of particular importance as the wetland falls within the Greater Vaal River catchment. Concern was raised with respect to the potential negative impact of the newly constructed dam on the dynamic water balance within the wetland. An assessment of the extent to which groundwater drives / sustains the wetland systems and the water requirements needed to sustain the wetland processes was determined. This includes establishing the impact of the Bedford Dam on the groundwater and wetland systems as well as providing recommendations on management and monitoring requirements. The hydropedological interpretations of the soils within the study area indicate that baseflow to the wetland is maintained through perennial groundwater, mainly recharged from infiltration on the plateau, and was confirmed through isotope sampling and hydrometric measurements. It is apparent that the surface flows in the main wetland are fed by recent sources, while the subsurface layers in the wetland are sustained by the slower moving near-surface and bedrock groundwater. The movement of groundwater towards the wetland is hindered by the numerous dykes creating a barrier to flow. Nevertheless, there seems to be a good connection between the groundwater sources in the upland and the surface drainage features that conduct this water to the contributing hillslopes adjacent to the main wetland. The surface flows of the main wetland are sustained by contributions from tributary fingers. The discharge out of the wetland is highly seasonal
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.
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).
A numerical simulation of solute transport in dry coal ash dumps with a case study in South Africa	Innocent	Muchingami		2015
Abstract An understanding of the movement of moisture fluxes in the unsaturated zone of waste disposal sites play a critical role in terms of potential groundwater contamination. Increasing attention is being given to the unsaturated or vadose zone where much of the subsurface contamination originates, passes through, or can be eliminated before it contaminates surface and subsurface water resources. As the transport of contaminants is closely linked with the water ?ux in through the unsaturated zone, any quantitative analysis of contaminant transport must ?rst evaluate water ?uxes into and through the this region. Mathematical models have often been used as critical tools for the optimal quantification of site-speci?c subsurface water ?ow and solute transport processes so as to enable the implementation of management practices that minimize both surface and groundwater pollution. For instance, numerical models have been used in the simulation of water and solute movement in the subsurface for a variety of applications, including the characterization of unsaturated zone solute transport in waste disposal sites and landfills. In this study, HYDRUS 2D numerical simulation was used to simulate water and salt movement in the unsaturated zone at a dry coal ash disposal site in Mpumalanga, South Africa. The main objective of this work was to determine the flux dynamics within the unsaturated zone of the coal ash medium, so as to develop a conceptual model that explains solute transport through the unsaturated zone of the coal ash medium for a period of approximately 10 year intervals. Field experiments were carried out to determine the model input parameters and the initial conditions, through the determination of average moisture content, average bulk density and the saturated hydraulic conductivity of the medium. A two dimensional finite-element mesh of 100m x 45m model was used to represent cross section of the ash dump. Two dimensional time lapse models showing the migration of moisture fluxes and salt plumes were produced for the coal ash medium. An explanation on the variation of moisture content and cumulative fluxes in the ash dump was done with reference to preexisting ash dump data as well as the soil physical characteristics of the ash medium. {List only- not presented}
Mountain Catchment Studies and Catchment Management	Nicolette	Vermaak	Western Cape	2015	catchment management
Abstract The mountain catchments of the Western Cape winter rainfall area were identified as areas needing more study in the early 1960s and so the Mountain Catchment studies were born. A number of study areas were suggested for these studies, but it was finally narrowed down to three sites. The studies in Jonkershoek had already started in 1935, with Zachariashoek and Jakkalsrivier added on in the 1960s. The Zachariashoek site was the only one that included groundwater as part of the experimental setup. A number of publications had been written about the work done in Zachariashoek. Most of the publications focused on changes in runoff after deforestation and fires, as well as the recovery patterns of the vegetation. The studies in Zachariashoek were done from 1964 till its termination in 1991 because of a lack of funding. The groundwater component consisted of 14 boreholes, with recorders on the five boreholes near the five weirs. The Zachariashoek area is made up of three catchments, Zachariashoek, Bakkerskloof and Kasteelkloof. It is adjacent to the Wemmershoek catchment. Bakkerskloof was the control catchment, while different burn cycles were part of the experimental setup of the two other catchments. The vegetation of Kasteelkloof was burned every 6 years with a 12 year cycle for Zachariashoek. Monitoring of the 5 weirs, 14 boreholes and the 9 rain gauges was done every week, with recorders on all five weirs, five of the 14 boreholes and at least 4 of the rain gauges. This data was entered into the data bases of the Department of Water and Sanitation, stretching from 1964 to 1986, with a complete record contained in 10 small field books. In this publication, we will look at the experiments done in Zachariashoek to see how this long term monitoring data can assist in managing the water resources within a catchment, taking into account the effects of deforestation and fires on surface water, groundwater and recharge to groundwater, the interaction between groundwater and surface water, as well as climate change.
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.
Variability In Kd And How It Relates To The New Guidelines For Contaminated Land	Michelle	Papenfus		2015
Abstract Globally, a growing concern have been that the heavy metal contents of soil are increasing as the result of industrial, mining, agricultural and domestic activities. While certain heavy metals are essential for plant growth as micronutrients, it may become toxic at higher concentrations. Additionally, as the toxic metals load of the soil increases, the risk of non-localized pollution due to the metals leaching into groundwater increases. The total soil metal content alone is not a good measure of risk, and thus not a very useful tool to determine potential risks to soil and water contamination. The tendency of a contaminant to seep into the groundwater is determined by its solubility and by the ratio between the concentration of the contaminant sorbed by the soil and the concentration remaining in solution. This ratio is commonly known as the soil partitioning or distribution coefficient (Kd). A higher Kd value indicate stronger attraction to the soil solids and lower susceptibility to leaching. Studies indicate that the Kd for a given constituent may vary widely depending on the nature of the soil in which the constituent occurs. The Kd of a soil represents the net effect of several soil sorption processes acting upon the contaminant under a certain set of conditions. Soil properties such as the pH, clay content, organic carbon content and the amount of Mn and Fe oxides, have an immense influence on the Kd value of a soil. Kds for Cu, Pb and V for various typical South African soil horizons were calculated from sorption graphs. In most cases there were contrasting Kd values especially when the cations, Cu and Pb, had high contamination levels, the value for V was low. There is large variation between the Kds stipulated in the Framework for the Management of Contaminated land (as drafted by the Department of Environmental Affairs) and the values obtained experimentally in this study. The results further indicate that a single Kd for an element/metal cannot be used for all soil types/horizons due to the effect of soil properties on the Kd. The results for Cu and Pb indicated that the Kds can range in the order of 10 to 10 000 L/kg for Cu and 10 to 100 000 L/kg for Pb. The variation in V Kd was not as extensive ranging from approximately 10 to 1 000 L/kg. {List only- not presented}
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.
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}
Groundwater and surface water interaction in farming areas in the Rawsonville area of the Western Cape.	Siphumelelo	Mbali	Western Cape	2015
Abstract The understanding of groundwater and surface water interaction is important for the planning of water resources in particular for farming areas. The interactions between groundwater and surface water are complex. To understand the relationship of groundwater and surface water interactions it is important to have a good understanding of the relation of climate, landform, geology, and biotic factors, a sound hydrogeoecological framework. Surface-water and groundwater ecosystems are viewed as linked components of a hydrologic continuum leading to related sustainability issues. In this study the Gevonden farm in Rawsonville will be used as the study site. This study site forms part of the Table Mountain Group (TMG). The methods to establish the relationship of groundwater and surface water interaction are collection of rainfall data monthly, river channel parameters at the farm such as the discharge on a monthly bases, chemistry of the water in the stream and groundwater were also be analyzed and pumping tests will be conducted twice to get the hydraulic parameters of the aquifer. The aquifer parameters will be analyzed using the Theis and Cooper-Jacob methods. The river has lower water levels in the summer months and this is also the case in the water levels in the boreholes on the farm, however in winter the opposite is true. The chemical analyses which are identical indicate that there is groundwater and surface water interaction in the farm. The degree of the interaction differs throughout the year. The results show that the interaction is influenced by the rainfall. The results clearly suggests that the farmers need to construct dams and drill pumping borehole in order to have enough water to water their crops in the summer season as by that time the river is almost dry. {List only- not presented}
'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.
Flow Test Analysis And Monitoring Of The Deep Confined Peninsula Aquifer In Blossoms (Oudtshoorn), Western Cape, South Africa	David	McGibbon	Western Cape	2015
Abstract The Oudtshoorn Groundwater Project aims to target deep groundwater as a long-term option to augment the water supply to the greater Oudtshoorn Local Municipality. Located 15 km south of Oudtshoorn towards the Outeniqua Mountain range, the Blossoms Wellfield lies within a potentially high-yielding artesian basin. The Peninsula Formation (of the Table Mountain Group (TMG), hydrostratigraphically known as the Peninsula Aquifer, is exposed in the Outeniqua Mountains (high rainfall recharge area), and is deeply confined northwards by the overlying Bokkeveld Group. The project is currently emerging from an exploration phase, with eight existing boreholes that target the deep confined Peninsula Aquifer, and three boreholes that monitor the shallower Nardouw (Skurweberg) Aquifer. Estimation of the aquifer's productive and sustainable groundwater potential involves determining its hydraulic properties by stressing the aquifer through flow and pumping tests and accurately monitoring flow rates, the potentiometric surface level (PSL) during flow, and PSL recovery thereafter. Free-flow and pumping tests were carried out on four boreholes between the 12th May 2014 and the 29th June 2014. The boreholes were all equipped with data-loggers to record pressure and flow-meters to determine the flow-rate. Recovery of the aquifer after the testing is still being continuously monitored. Results from the month and a half flow-test show that there is no interaction between the deep confined Peninsula Aquifer and the shallower Nardouw Aquifer beneath the southern part of the wellfield. Because the water-use licence stipulates that there can be no negative impact from Peninsula Aquifer abstraction on the Nardouw Aquifer, which is utilised by farmers in the region, this issue is of paramount importance. The hydrochemical signature of the two aquifers is also different. Recovery monitoring emphasised that the northern block is better inter-connected through fracture systems than the southern block, because those boreholes recovered to their original potentiometric surface almost immediately, whereas the southern boreholes took days for recovery. Two boreholes in the south are still recovering eight months later, which is most likely due to their being drilled into the limb of folded rock systems and not the more fractured hinge zone (as with the more connected boreholes). Using the drawdown and recovery curves ('Horner plots'), the transmissivity and storativity of the aquifer is calculated analytically by the Theis equation. The results show a large variation in storativity (1.0E-1 to 1.46E-4) and transmissivity (9-20 m2/day) between the various boreholes, emphasising the heterogeneity of the aquifer. The aquifer properties gained from this testing are essential in better understanding the aquifer system, and developing numerical models for future wellfield testing and model simulation.
Multi-data Integration Approach in Groundwater Resource Potential Mapping: A case study from the North West Province, South Afri	Abera	Tessema	North-West	2015
Abstract Multi-data integration approach was used to assess groundwater potential in an area consisting crystalline basement and carbonate rocks that are located in the North West Province of South Africa. The main objective of the study is to evaluate the groundwater resource potential of the region based on a thorough analysis of existing data combined with field observation. Integration of six thematic layers was supplemented by a statistical analysis of the relationship between lineaments density and borehole yield. Prior to data integration, weighting coefficients were computed using principal component analysis. The resulting thematic layer derived from integration of the six layers revealed a number of groundwater potential zones. The most probable groundwater potential zones cover ~14% of the entire study area and located within carbonate rocks consisting limestone and dolomite. The presence of pre-existing structures together with younger and coarse sedimentary rocks deposited atop the carbonate rocks played a significant role in the development of high well fields in the southern part of the area. Moderate-to-high groundwater potential zones within Ventersdorp lava coincide with maximum concentrations of fractures. The results of statistical correlation suggest that 62% of high borehole yield within the Ventersdorp lave can be attributed to fracture density. In general, the present approach is very effective in delineating potential targets and can be used as a sound scientific basis for further detailed groundwater investigation. KEY WORDS:- Multi-data, thematic layers, groundwater, carbonate rocks, structures
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.
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.
The Groundwater Data Acquisition and Management Strategy for the Department of Water and Sanitation	Mxolisi	Mukhawana		2015
Abstract Data acquisition and Management (DAM) is a group of activities relating to the planning, development, implementation and administration of systems for the acquisition, storage, security, retrieval, dissemination, archiving and disposal of data. Data is the life blood of an organization and the Department of Water and Sanitation (DWS) is mandated by the National Water Act (No 36 of 1998) as well as the Water Services Act (No 108 of 1997), to provide useful water related information to decision makers in a timely and efficient manner. In 2009 the DWS National Water Monitoring Committee (NWMC) established the DAM as its subcommittee. The purpose was to ensure coordination and collaboration in the acquisition and management of water related data in support of water monitoring programs. The DAM subcommittee has relatively been inactive over the years and this has led to many unresolved data issues. The data extracted from the DWS Data Acquisition and Management Systems (DAMS) is usually not stored in the same formats. As a result, most of the data is fragmented, disintegrated and not easily accessible, making it inefficient for water managers to use the data to make water related decisions. The lack of standardization of data collection, storage, archiving and dissemination methods as well as insufficient collaboration with external institutions in terms of data sharing, negatively affects the management water resources. Therefore, there is an urgent need to establish and implement a DAM Strategy for the DWS and water sector, in order to maintain and improve data quality, accuracy, availability, accessibility and security. The proposed DAM Strategy is composed of the six main implementation phases, viz. (1) Identification of stakeholders and role players as well as their roles and responsibilities in the DWS DAM. (2) Definition of the role of DAM in the data and information management value chain for the DWS. (3) Development of a strategy for communication of data needs and issues. (4) Development of a DAM life Cycle (DAMLC). (5) Review of existing DAMS in the DWS. (6) Review of current data quality standards. The proposed DAM Strategy is currently being implemented on the DWS Groundwater DAM. The purpose of this paper is to share the interesting results obtained thus far, and to seek feedback from the water sector community.
Mapping irrigation potential from renewable groundwater in Africa - a quantitative hydrological approach	Karen	Villholth	Africa	2015
Abstract Groundwater provides an important buffer to climate variability in Africa. Yet, groundwater irrigation contributes only a relatively small share of cultivated land, approximately 1% (about 2 mill. ha) as compared to 14% in Asia. While groundwater is over-exploited for irrigation in many parts in Asia, previous assessments indicate an underutilized potential in parts of Africa. As opposed to previous country-based estimates, this paper derives a continent-wide, distributed (0.5 degrees spatial resolution) map of groundwater irrigation potential, indicated in terms of fractions of cropland potentially irrigable with renewable groundwater. The method builds on an annual groundwater balance approach using 41 years of hydrological data, allocating only that fraction of groundwater recharge that is in excess after satisfying other present human needs and environmental requirements, while disregarding socio-economic and physical constraints in access to the resource. Due to high uncertainty of groundwater environmental needs, three scenarios, leaving 30, 50 and 70% of recharge for the environment, were implemented. Current dominating crops and cropping rotations and associated irrigation requirements in a zonal approach were applied in order to convert recharge excess to potential irrigated cropland. Results show an inhomogeneously distributed groundwater irrigation potential across the continent, even within individual countries, mainly reflecting recharge patterns and presence or absence of cultivated cropland. Results further show that average annual renewable groundwater availability for irrigation ranges from 692 to 1644 km3 depending on scenario. The total area of cropland irrigable with renewable groundwater ranges from 44.6 to 105.3 mill. ha, corresponding to 20.5 to 48.6% of the cropland over the continent. In particular, significant potential exists in the semiarid Sahel and eastern African regions which could support poverty alleviation if developed sustainably and equitably. The map is a first assessment that needs to be complimented with assessment of other factors, e.g. hydrogeological conditions, groundwater accessibility, soils, and socio-economic factors as well as more local assessments.
TEMPEST for groundwater exploration	Odirile	Dingoko	Australia	2015	Airborne electromagnetic surveys
Abstract In recent years there has been renewed interested in identifying and understanding groundwater resources. Airborne electromagnetic (AEM) surveys can provide useful, cost effective information about the geometry of aquifers and their host rocks. TEMPEST is a fixed wing AEM system which has been used extensively for groundwater applications. The system possesses many attributes which aid in groundwater exploration including: broad operational bandwidth; multifaceted software approach; and, a distinctive calibration technique. These features allow both shallow and deep subsurface features to be imaged which aid in mapping groundwater aquifers along with the broader groundwater subsystem. This paper will review TEMPEST surveys flown for the Western Australian Department of Water (DoW) for the purpose of groundwater characterisation. The surveys were focussed on the identification of geological contacts, subsurface aquifers and seawater intrusion extents. The survey data was interpreted using an integrated approach which involved reviewing the newly acquired geophysical data, identifying contacts and anomalous features in the acquired data, reviewing existing geological and geophysical data in the area and correlating features identified in acquired data to known geology. The first case study was flown over the North Gnangara area of the Perth Basin with the primary aim of defining the spatial distribution of clay and silty layers that impede recharge to the groundwater table. The survey succeeded in achieving its primary aim of identifying the distribution of clay layer targets. Through the integrated interpretation approach it was also successful in achieving its secondary aims by clearly defining the contact between superficial units and the underlying stratigraphy, identifying key structures within the basin, outlining the top of the seawater intrusion, and mapping confining strata within the deeper aquifer systems in the Perth Basin. The second case study was flown over the lower reaches of four river systems in the North Pilbara coast with the aim of understanding the aquifer geometries and groundwater salinity distribution within the region. The primary aims of the survey were achieved and provided a basement geology map, relative porosity maps, approximate weathered and unweathered bedrock surfaces as well as the approximate geometry of the seawater intrusion within all survey areas. It was also possible to map the interpreted extents of alluvial aquifers within two of the river systems as well as the contact between two sandstone aquifers present in one of the river systems. These case studies show that the TEMPEST AEM system can provide valuable information about the geometry of aquifers and their host geology. AEM surveys should be used as an initial method for determining broad aquifer geometry and the identification of priority areas prior to further less cost effective water bore drilling.
Effects of Urbanization and Agricultural activities on Aquifer storage and Groundwater quality	Athenkosi	Matshini		2015
Abstract POSTER Aquifer stress arising from urbanization and agricultural activities, these two factors affect aquifer properties when prolonged. Increase in urbanization especially those situated on top unconfined or semi-confined aquifer results in pressure on natural resources, this includes water resources, and changes of land use for agricultural purposes with high economic benefits has an effect on groundwater quality to due to application of Nitrogen- fertilizers during crop rotation and this is largely experienced in developing countries. The effects ranges from groundwater quality to aquifer storage as prolonged aquifer withdrawals due to irrigation, construction, manufacturing affects groundwater storage. Assessment of urbanization and agricultural effects on groundwater requires a complex analysis as integration approaches needs to be discovered for a better analysis of the two more specially when assessing groundwater pollution. The study was conducted to assess the impacts of urbanization and agricultural activities on aquifer storage and groundwater quality: by (a) determining the relationship between the occurrence of contamination due to urbanization by assessing contaminants present in the study area (b) develop groundwater protection, and if any offer recommendation for groundwater management. Multiple-well tests were conducted observing the behavior of drawdown and recovery for assessing groundwater storage. Two aquifer properties were observed to yield information about any changes in aquifer storage (transmissivity and storage coefficient) and groundwater quality lab test focusing on TDS, nitrate and pH were conducted. Historical results reflect that before industrial and urban revolution the groundwater contained small amounts of TDS compared with the present results. Increase in nitrate and pH concentrations observed in location closer to agricultural areas. Prolonged aquifer withdrawals increases expansion of cone of depression and therefore increases aquifer vulnerability and the risk of aquifer being polluted, and this increases storage coefficient. This study can be used to formulate protection zones for water resources and practice towards groundwater management.
Developing Groundwater Supplies To Supplement The Water Supply Of Ladismith, Western Cape Province	Roger	Parsons	Western Cape	2015
Abstract Ladismith was established in 1852 at a point where freshwater springs discharge from the Swartberg mountains. Growth of the town required building of the Goewerments Dam in 1920 and the Jan F le Grange Dam in 1978. However, water demand now matches supply, and water shortages are being experienced. Poor management and recent droughts exacerbated the situation. A project was initiated to address problems with the existing water supply and identify additional sources of water. Groundwater is an obvious option, with the regionally extensive Cango-Baviaanskloof fault being located directly north of the town. The west-east trending fault juxtaposes the highly productive Table Mountain Group aquifer with less productive argillaceous rocks of the lower Witteberg Group. This paper presents the results of initial geohydrological exploratory work and examines the role groundwater can play in the future water supply to the town. {List only- not presented} KEYWORDS groundwater, exploration, water supply, Ladismith
A framework for conjunctive use at local government level	Kornelius	Riemann		2015	Conjunctive use, IWRM, framework
Abstract Conjunctive use of surface water and groundwater resources offers huge advantages to municipalities. It can significantly increase the resilience of the municipal water supply to drought situations. Optimal use and integration of different sources would result in a yield of the total system that is higher than the combined yield of each source separately. However, integrated water resource management (IWRM) in general and planned conjunctive use of both groundwater and surface water resources in particular have not been successfully implemented yet in South Africa. Six selected case studies of municipalities across South Africa, which utilize both surface water and groundwater for the water supply to specific towns, have undergone a review of their current water governance provisions wrt groundwater, surface water and conjunctive use. The review has been based on a questionnaire for direct interaction with the local government officials, supported by other readily available documents such as municipal Integrated Development Plan (IDP) and Water Services Development Plan (WSDP), municipal websites, Blue Drop and Green Drop Assessment Reports, Municipal Strategic Self-Assessment (MuSSA) and the All Towns Reconciliation Strategy reports. These case studies reveal the different institutional arrangements for water resource management and water supply services that exist in municipalities. The advantages and disadvantages of the institutional arrangements for each case study have been determined. Problem areas identified include split of responsibilities for surface water and groundwater resources between different institutions, lack of financial and HR support within the government spheres, lack of formal and structured stakeholder engagement, insufficient monitoring for both sources, inter alia. Based on this comparative study of different municipalities, a draft framework of optimal institutional arrangements and governance provisions at local government level is developed to support the integration and optimisation of surface water and groundwater supply. The proposed framework is based on three pillars; viz. leadership and clear structures within the responsible local government institution, formal engagement with all relevant internal and external stakeholders and a sufficient monitoring network that supports the stakeholder engagement and decision making.
Hydraulic tests of strong artesian boreholes; wellhead construction and test design	Kornelius	Riemann		2015
Abstract Artesian boreholes are a common feature worldwide in confined aquifers, but the hydraulic testing of these boreholes, and estimation of aquifer properties from such tests, still poses a challenge for hydrogeologists. Common hydraulic tests, such as step-drawdown or constant-discharge rate tests require a static water level at the start of the test, and the measurement of drawdown (increasing over time) and abstraction rate (fixed for a period of time). Usually, when undertaking a pumping test in an artesian borehole, the drawdown is measured from ground level, and the drop in hydraulic head between static pressure and ground level is often ignored. This procedure also implies that the starting time of the test is not at the static water level. A constant-head test, set at ground level, is the other option. However, the decrease in flow rate is not only dependent on the hydraulic properties of the aquifer, but also masked by pipe hydraulic effects within the well. This kind of test would also limit the available drawdown to be utilized for the test. Hence, it was required to develop a method for undertaking hydraulic tests in strong artesian boreholes, allowing for the drawdown to fluctuate between levels both above and below ground and avoiding the pitfalls described above. The solution is a specially designed and constructed wellhead for the installation of the pump and monitoring equipment prior to the hydraulic test. The standard tests are slightly modified and are only undertaken after sealing the wellhead and reaching static hydraulic pressure. The recommended wellhead construction and subsequent hydraulic tests were implemented at a strong artesian borehole in the Blossoms Wellfield, south of Oudtshoorn in the Western Cape province of South Africa.
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.
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.