Conference Abstracts

All Abstracts were presented at the Groundwater Conferences

Displaying 601 - 650 of 795 results

Title	Presenter Name	Presenter Surname	Area	Conference year Sort ascending	Keywords
Petroleum Hydrocarbons Contamination in Soil and Groundwater: Case Study on the Coastal Tank Farm, Southern Africa	Erasmus	Chauke	Indian Ocean coastal zone	2015	tank farms, soil contamination
Abstract In this study, petroleum hydrocarbon contamination assessment was conducted at a cluster of petroleum products storage and handling facilities located on the Southern African Indian ocean coastal zone. The Port Development Company identified the need for the assessment of the soil and groundwater pollution status at the tank farms in order to develop a remediation and management plan to address hydrocarbon related soil and groundwater contamination. Previous work conducted at the site before consisted out of the drilling and sampling of a limited number of boreholes. The current investigation was triggered by the presence of free phase product in the coal grading tippler pit located ~350 m down gradient and south-east and east of the tank farms, rendering the operation thereof unsafe. The assessment intended identifying the source of product, distribution and mobility, the extent of the contamination, and the human health risks associated with the contamination. To achieve these, the investigation comprised site walkover and interviews, drilling of 76 hand auger and 101 direct push holes to facilitate vertical soil profile VOC screening and sampling (soil and groundwater) as well as granulomeric analysis to understand grain size distribution within the soil profile. The highest concentrations were associated with the coarse sand layers with the highest permeability. Free phase hydrocarbons product was found in holes adjacent to the pipeline responsible for the distribution of the product form the jetty to the different tanks farms. Of the 57 soil samples, 21 had high values of GRO and DRO, with 22 below Detection Limit and 14 can be described having traces of hydrocarbon. Both TAME and MTBE were detected in most of the water samples taken, including from wells located far down gradient. The groundwater sink, adjacent to the pipeline running from west to east, resulted in the limited lateral spread of MBTE in this area, with limited movement towards the sea. The depth of the soil contamination varies over the sites. Based on the site assessment results it was concluded that most of the groundwater contamination, which is a mixture of different product types, is associated with the pipeline responsible for transporting product from the jetty to the different petroleum companies. {List only- not presented}
Investigating groundwater governance arrangements for shale gas exploration and production in the main Karoo Basin, South Africa	Athenkosi	Matshini	Karoo	2015
Abstract South Africa relies on coal and imported crude oil for most of its energy demands. However, the current high demand for the coal and oil and other sources of energy threat the sustainability of such energy sources, hence, the need to diversity the energy sources. However, these energy sources (coal and oil) are non-renewable sources of energy and the production of energy from renewable sources is almost non-existent. Therefore, the production of shale gas in the main Karoo Basin of South Africa provides a potential and opportunity to diversify South Africa energy mix. In pursuing such an opportunity, one has to be mindful that shale gas is neither sustainable nor a green energy system. This study aims to improve knowledge on groundwater governance arrangements regarding shale gas exploration and production in order to inform the appropriate regulatory regime and best practices to protect groundwater resources. Although there has been much effort to understand the technical implications of shale gas exploration and production on groundwater, not much attention has been given to understanding the broader groundwater governance issues. Addressing groundwater governance issues is critical to effective regulation of unconventional gas exploration and production. This is because; failure of groundwater management often results from inadequate governance arrangements, rather than lack of knowledge about sustainable yield or pollution vulnerability of aquifers. It has been argued that, there exists a perpetual tension between viewing groundwater as a common-resource and the rights of private appropriation of groundwater for use. Thus, groundwater is inherently vulnerable to the "tragedy of the commons" in which actual users and potential polluters act solely in their individual short-term interest rather than taking into account long-term communal considerations. The study provides significant insights regarding appropriate and effective institutional arrangements for groundwater governance.
#GWD: The use of social media for science communication	Tercia	Strydom		2015
Abstract For a long time, professionals regarded social media as a superficial, unprofessional platform where internet users would submerge themselves in a virtual world, detached from real-life issues. Slowly, the myths and stigmas surrounding the use of social media has faded as more and more professionals and scientists have realized that these social platforms could be positively exploited in a professional manner which could be beneficial. In a digital age where information at our fingertips is the norm, professionals should co-evolve and ensure that their work is just as accessible and appealing, without the unnecessary jargon. Currently, science is mostly restricted to a very particular audience and conveyed in one direction only. Using a social media platform such as Twitter-which limits messages to only 140 characters-challenges scientists to convey their work in a very concise manner using simpler terminology. Furthermore, it dismisses the usual one-way form of communication by opening dialogue with fellow Twitter users. At conferences, Twitter can serve as a useful tool for active engagement which will not only "break the ice" between delegates but also ensure that important information is communicated to a much wider audience than only those in attendance. This idea was tested at the 2014 Savanna Science Network Meeting held in Skukuza, Kruger National Park, where the hashtag #SSNM was used. More than 63% of the Twitter users who participated in the #SSNM hashtag were actually not present at the conference. These external "delegates" were interested individuals from five different continents and in different professions besides Science. This highlights how social media can be exploited at conferences to ensure that key messages are conveyed beyond the immediate audience at the event.
Water Use Registration: A reflection of Groundwater Governance of the Verlorenvlei Catchment in the Sandveld	Imelda	Haines	Sandveld	2015	patato, RAMSAR, good governance
Abstract Introduction: Verlorenvlei catchment in the renowned potato Sandveld area is shared by three main towns where agriculture is a primary economic activity. This semi-arid catchment, receives low winter rainfall, but has a dynamic groundwater system providing almost all water services in the catchment and sustaining the acclaimed Verlorenvlei RAMSAR site. There have been recurring concerns of land use as a potential threat to water resources and the sustainability of Verlorenvlei RAMSAR site. The Minister of Water and Sanitation as custodian of water resources requires that surface water use less than 18 250 m3 and ground water use less than 3 650 m3/a to be granted under general authorization. All water use above such general authorization volumes is to be registered (Government Gazette No. 20526 of 1999). Water use registration, is identified as a tool used to achieve the effective management and governance of water resources. Water use above general authorization, is associated with larger scale land use activity, which may have an impact on water resources and the environmental at large. The following study, seeks to examine and compare catchment water use for land uses, to catchment water availability using water use registration data. Comparing water allocation and catchment capacity, this study further seeks to explore the effectiveness of water use registration in achieving good governance of water resources. Purpose: The purpose of this study was to determine effectiveness of water use registration in promoting good governance in the Verlorenvlei catchment Results: Of 124 registered water users identified in the Verlorenvlei catchment, only two of these water users are within the legislative limit outlined by Government Gazette No. 20526 of 1999. Overall, permissible water use is 447 547 259.5 m3/a, over 10 times the catchment capacity of 40 000 000 m3/a. Conclusion: Overall, excessive water use for land use activity is observed within the catchment, despite provision of legislature guiding against excessive water use. Increased water use registration, does however correlate with improved land use practices for agricultural production (Potato SA, 2014) suggesting probability of good governance. Lastly, there is a need for monitoring; improved water and land use efficiency, Integrated Water Resources Management and good governance in the catchment.
Groundwater chemical evolution at an underground coal gasification pilot plant in Majuba	Lehlohonolo	Mokhahlane	KwaZulu-Natal	2015
Abstract Underground coal gasification (UCG) is technology that aspires to exploit coal reserves using in-situ gasification. This mining method gasifies coal seams while extracting a syngas that can be used for electricity generation. Since the bulk of this process occurs in the subsurface, there is a possibility of impacting on regional groundwater quality. This paper seeks to assess this impact on groundwater across different aquifers while taking into account the chemical evolution of these aquifers. Three aquifer systems were identified namely the shallow, intermediate and the deep aquifer which comprises of the coal seam. The water chemistry was reviewed over a two year period during which the gasifier was still active. Alkaline conditions were prevalent across the three aquifers with minor seasonal changes. High levels of dissolved solids were observed especially in the deep aquifer but the quality of water was poor even in background samples. The impact of gasification does have small variation in already unusable water in the deep aquifer which was also characterized by low hydraulic conductivity. Higher hydraulic conductivity values were established in the shallow aquifer. No significant groundwater chemistry change was detected in this aquifer as a result of gasification process.
Possible recharge areas for two of the Lower Berg aquifers units, Western Cape	Nicolette	Vermaak	Western Cape	2015	groundwater recharge
Abstract The question about the natural recharge areas for two of the Lower Berg river aquifers units, Elandsfontein Aquifer unit and Langebaan Road aquifer unit, has been keeping geohydrologists working in the area without a definite answer. Tredoux and Engelbrecht have postulated that it must be from the higher grounds around Hopefield, while Woodford hinted that an offshoot fault from the Coleso fault system could also cause the systems to be recharged from the Darling hills. Isotope studies had been done for the proposed Hopefield recharge area, but none has so far been done for the possible Darling recharge system. This paper will look at the studies done up to date and evaluate the data available for the boreholes drilled in the area in an attempt to get a clearer understanding of the two possibilities. It will also identify possible gaps in our knowledge of the area and the steps that would make it possible to fill in the gaps.
A predictive study to better protect groundwater at Underground Coal Gasification site	Venessa	Aphane		2015	underground coal gasification
Abstract Underground coal gasification (UCG) is considered a cleaner energy source as its known effect on the environment is minimal; it is cheaper and a lesser contributor to greenhouse gas emissions when compared to conventional coal mining. It has various potential impacts but the subsidence of the surface as well as the potential groundwater contamination is the biggest concerns. Subsidence caused by UCG processes will impact on the groundwater flow and levels due to potential artificial groundwater recharge. The geochemistry of the gasifier is strongly depended upon site specific conditions such as coal composition/type and groundwater chemistry. Independent of the coal rank, the most characteristic organic components of the condensates is phenols, naphthalene and benzene. In the selection of inorganic constituents, ammonia, sulphates and selected metals and metalloids such as mercury, arsenic, and selenium, are identified as the dominant environmental phases. The constituents of concern are generated during the pyrolysis and after gasification as dispersion and penetration of the pyrolysis take place, emission and dispersion of gas products, migration by leaching and penetration of groundwater. A laboratory-based predictive study was conducted using a high pressure thermimetric gasification analyser (HPTGA) to simulate UCG processes where syngas is produced. The HPTGA allows for simulation of the actual operational gasifier pressure on the coal seam and the use of the groundwater sample consumed during gasification. A gasification residue was produced by gasifying the coal sample at 800 °C temperature and by using air as the input gas. The gasification residue was leached using the high temperature experimental leaching procedure to identify the soluble phases of the gasified sample. The leachate analysis is used to determine the proportion of constituents present after gasification which will be removed by leaching as it is exposed to external forces and how it will affect the environment. The loading to groundwater for the whole gasifier is then determined by applying the leachate chemistry and rock-water ratio to the gasifier mine plan and volumes of coal consumed.
A Study Of Interaction Between Groundwater And Surface Water Using Environmental Isotopes, Hydrochemistry And Feacal Coliform BA	Bongizenzo	Nyawo		2015
Abstract The Table Mountain Group (TMG) Formation in the Uitenhage region, in the Eastern Province of South Africa, has many groundwater users, which could result in the over-exploitation of the underlying aquifer. Consequently, several investigations have been conducted to help in the planning and management of groundwater resources within the region. Traditionally, these investigations have considered groundwater and surface water as separate entities, and have been investigated separately. Environmental isotopes, hydrochemistry and feacal colifom bacteria techniques have proved to be useful in the formulation of interrelationships and for the understanding of groundwater and surface water interaction. The field survey and sampling of the springs, Swartkops River and the surrounding boreholes in the Uitenhage area have been conducted. After full analysis of the study, it is anticipated that the data from the spring, Swartkops River and the surrounding boreholes show interannual variation in the isotope values, indicating large variation in the degree of mixing, as well as to determine the origin and circulation time of different water bodies. ?D and ?18O value for the spring ranges from ?18.9? to ?7.4?, and 5.25? to 4.82?, respectively, while ?D values for borehole samples range from ?23.5? to ?20.0? and ?18O values range from ?5.67? to ?5.06?. In the river sample, ?D values ranges from ?12.1? to ?4.2?, ?18O from ?3.7? to ?1.13?, respectively. The entrobacter aerogen and E.Coli bacteria were detected in the samples. E. coli population for spring and the artesian boreholes indicated low value while the shallow boreholes had higher values are relatively closer to those of the middle ridges of the Swartkops River. The EC values for the spring samples averages at 14 mS/m, borehole samples ranges from 21 mS/m to 1402 mS/m, and surface water ranges from 19 mS/m to 195 mS/m. Swartkops River is an ephemeral, therefore it is expected that diffuse recharge occurs into the shallow aquifer.
Comparative use of groundwater by invasive alien PROSOPIS SPP and co-occurring indigenous V. Karoo in a semi-arid catchment	Sebinasi	Dzikiti		2015
Abstract Groundwater is a vital source of water for many communities in South Africa and elsewhere. Besides the changing climate, rapidly spreading invasive alien plants with deep roots e.g. Prosopis spp, pose a serious threat to this water source. Dense impenetrable thickets of Prosopis occur in the drier parts of the country mainly along river channels in the Northern, Eastern and Western Cape Provinces. Few studies have quantified the actual water use by this species outside of the USA where it is native. Consequently the impacts of Prosopis invasions on groundwater resources are not well documented in South Africa. The aim of this study was to quantify the actual volumes of water used by Prosopis invasions and to establish the effects on groundwater. Because deep rooted indigenous trees that normally replace Prosopis once it has been cleared also use groundwater, we sought to quantify the incremental water use by Prosopis over and above that used by indigenous trees in order to determine the true impacts on groundwater. The study was conducted at a site densely invaded by Prosopis at Brandkop farm near the groundwater dependent town of Nieuwoudtville in the Northern Cape. One in seven trees at the site is the Vachellia karroo (formerly A. karroo) which is the dominant deep rooted indigenous tree species. Actual transpiration rates by five Prosopis and five V. karroo are being measured using the heat pulse velocity (HPV) sap flow technique. Additional HPV sensors were installed on the tap and lateral roots to study the water uptake dynamics of the trees. Groundwater levels are being monitored in four boreholes drilled across the site while sources of water used by the trees (i.e. whether soil or groundwater) is being determined using O/H stable isotopes. For similar size trees, V. karroo had higher transpiration rates than Prosopis because of the larger sapwood to heartwood ratio in V. karroo than in Prosopis. However, at the stand level Prosopis consumed significantly larger amounts of water than V. karroo. This is because Prosopis invasions had a much higher tree density than V. karroo. From August 2013 to July 2014, annual stand transpiration for Prosopis (~ 372 mm) was more than 4 times higher than that of V. karroo (~ 84 mm). Tree water uptake was correlated to changes in groundwater levels (R2 ~ 0.42) with groundwater abstractions of ~ 2600 m3/ha/y by Prosopis compared to ~ 610 m3/ha/y for V. karroo. In addition, Prosopis showed evidence of hydraulic redistribution of groundwater wherein groundwater was deposited in the shallow soil layers while V. karroo did not. Results of this study suggest that clearing of Prosopis to salvage groundwater should target dense stands while less dense stands should be prevented from getting dense. {List only- not presented}
Aquifer Vulnerability Assessment Of The Federal Capital City, Abuja - Nigeria	Omogbemi O	Yaya	Nigeria	2015
Abstract Based on a modified DRASTIC model and GIS techniques, shallow groundwater vulnerability assessment was carried out in the Federal Capital City of Abuja, Nigeria. The results indicate that the studied area can be divided into three zones, namely: low groundwater vulnerability zone (vulnerability index <100) which covers about 60% of the City; moderate vulnerability zone (vulnerability indexes 100-140) which covers 35% of the City and high vulnerability zone (vulnerability index >140) which covers only 5% of the City. The highest groundwater vulnerability zone mainly locates in the central solid waste disposal site area in the outskirt of the City. The findings correlate well with the results of the physicochemical and microbiological investigation. The general low contamination vulnerability signature of the City may be attributed to absence of industries, limited agricultural activities, and preponderance of clayey top soil which effectively forms the first defence against contamination of the underlying aquifers as well as the presence of central sewage collection facility that covers about 25% of the City.
A Decision Support System to Assess Climate Change Impacts on Rural Communities	Musiiwa	Luruli		2015
Abstract Climate change contributes to the way in which people live. Natural resources such as groundwater, wood and surface water form a great part of livelihood in rural communities and are used extensively in rural areas where basic services have not yet been provided. The effect of climate change to all these natural resource may impact the lives of those in rural communities. Climate change is already starting to affect some of the poor and most vulnerable communities around the world. The aim of the dissertation is to develop a framework to assess the vulnerability of rural communities to climate change, with a specific focus groundwater and issues relating to gender. A questionnaire and interviews were used to collect data about rural communities' level of awareness climate change, their attitudes toward coping with climate change impact, level of education, income scale and how does this affect their security. Hyrodocensus was taken around the village to determine the rivers, dams, boreholes, abandoned boreholes and wells. Water samples were collected and analysed. The response rate was higher in females than in male's stakeholders (54% vs 46%).the results show that woman were mostly doing the hard work to complete daily basic activities. Education was found to be of high school level and incomes were low. The framework was developed with basic need showed that the area was at risk of poverty .Boreholes was found and water quality was analysed to be adequate for drinking water purpose. More information will be discussed on presentation.
Investigation of possible contaminant plumes emanating from residual mine deposits in the Limpopo Province of South Africa	Emmanuel	Chirenje	Mpumalanga	2015
Abstract Acid mine drainage (AMD) has lately received considerable media coverage in South Africa. This has caused considerable increase in researchers most of them with emphasis on decantation of contaminated water from the old gold mines in Witwatersrand basins and fewer on mine residue contamination from Coal and Gold mines in Mpumalanga and Limpopo provinces. The paper outlines results of ground geophysical surveys that were carried out along the perimeter of two mine dumps in the Barberton Greenstone belt in the Mpumalanga Province, South Africa. The aim of the study was to generate a 3D geo-electric model of the subsurface showing possible acid mine drainage contaminant pathways. Two geophysical methods namely Frequency Domain Electromagnetic profiling (FDEM) and electrical resistivity tomography (ERT) were applied in order to investigate the variation of electrical conductivity in the subsurface. ERT method was done over frequency domain electromagnetics anomalies to further investigate depth extent of the anomalies. {List only- not presented} On the resistivity section ERT1 of Dump 1, a discontinuity in the bedrock was identified. The FDEM survey identified an area with high conductivity values to the north of Dump 1. The ERT results show a shallow plume at 20m depth, which is consistent on two parallel sections on Dump 1. The area could be a possible pathway of mine dump residue (AMD) to a stream in the north. The bedrock is generally characterized by high resistivity values; a break in the bedrock exists on this high resistivity zone on ERT 6. The identified breaks in the bedrock in terms of resistivity could be a fault zone which can act as possible pathway of mine dump residue (AMD) to a shallow aquifer. Potential contaminant recharge pathways were delineated using geophysical electrical and electromagnetic methods. Potential groundwater recharge pathways and sub-vertical low resistivity zones with values <100 Ohm.m were delineated using the ERT method. Investigation of contaminant plume migration is recommended over the anomalies that were generated from geophysics data in the Barberton areas. KEYWORDS Acid mine drainage, Frequency Domain Electromagnetic profiling and electrical resistivity tomography
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.
Groundwater Protection Zoning- A case study of the Rawsonville research site.	Shuaib	Dustay		2015	groundwater protection zones
Abstract Currently limited progress is made in South Africa (and Africa) on the protection of groundwater used for drinking water. To achieve the objective of water for growth and development and to provide socio-economic and environmental benefits of communities using groundwater, significant aquifers and well fields must be adequately protected. Groundwater protection zoning is seen as an important step in this regard. Till today, limited case studies of groundwater protection zoning exists in Africa. A case study at the Rawsonville research site is conducted in this research project. Generic protection zones can be delineated at the site using published reports and database data. However, due to the complexity of the fractured rock at the research site, these would be of limited value and would not provide adequate protection for the well field Baseline data was collected by conducting a hydro census and through aquifer tests. An inventory of the activities that can potentially impact water quality was done and aquifer characteristics such as transmissivity and hydraulic conductivity were determined through various types of aquifer testing. Fracture positions were identified using fluid logging and fracture flow rates were also measured using fluid logging data. A conceptual model and preliminary 3D numerical model were created to try to understand groundwater movement at the research site. The knowledge gained will be used to guide information gathering and monitoring that can be used to build a more detailed numerical model and implement a trustworthy groundwater protection plan at a later stage. The expected results will have applicability to groundwater management in general. The protection plan developed during this project can be used as a case study to update and improve policy implementation. {List only- not presented}
Parameter estimation for artesian aquifer in Table Mountain Group Aquifer by analytical and numerical simulation methods	Xiaobin	Sun	Western Cape	2015
Abstract Accurate parameter estimation for fractured-rock aquifer is very challenging, due to the complexity of fracture connectivity, particular when it comes to artesian flow systems where the potentiometric is above the ground level, such as semi-confined, partially confined and weak confined aquifers in Table Mountain Group (TMG) Aquifer. The parameter estimates of these types of aquifers are largely made through constant-head and recovery test method. However, such a test is seldom carried out in Table Mountain Group Aquifer in South Africa due to a lack of proper testing unit made available for data capturing and appropriate method for data interpretation. An artesian borehole of BH 1 drilled in TMG Peninsula Formation on the Gevonden farm in Western Cape Province was chosen as a case study. The potentiometric surface is above the ground level in rainy season, while it drops to/below ground level during the dry season. A special testing unit was designed and implemented in BH 1 to measure and record the flow rate during the free-flowing period, and the pressure changes during the recovery period. All the data were captured at a function of time for data interpretation at later stage. Curve-fitting software developed with VBA was adopted for parameter estimation based on the constant-head and recovery tests theories. The results indicate that a negative skin zone exists in the immediate vicinity of the artesian borehole, and the hydraulic parameters estimates of transmissivity (T) ranging from 6.9 to 14.7 m2/d and storativity (S) ranging from 2.110-5 to 2.110-4 appear to be reasonable with measured data collected from early times. However, due to formation losses, the analytical method failed to interpret the data collected at later times. Consequently the analysed results by analytical solution with later stage data are less reliable for this case. The MODFLOW-2000 (Parameter Estimation) package developed by USGS was also adopted to determine these parameters for the same aquifer. It approves that there exist formation losses, which leads to the aquifer response distinctly different at later stage of overflow and recovery tests. The aquifer parameter estimates with early time data of tests by analytical and numerical methods show that there is generally good agreement. However, significant errors could be generated by analytical method applied where there is occurrence of well or formation losses, while these restrictions could be overcome by applying a numerical method.
Geochemical reaction modelling as a tool to quantify gold mining impacts on shallow groundwater resources in the East Rand Basin	Robert	Hansen	Witwatersrand	2015
Abstract In recent years acid mine drainage (AMD) has become the focus on many mine sites throughout the world. The Witwatersrand gold mines have been the main focus of AMD in South Africa due to their extensive impact on especially groundwater resources. The Witwatersrand Basin is a regional geological feature containing the world-famous auriferous conglomerate horizons. It is divided into sub-basins and the East Rand Basin is one of them. Due to the regional scale of the East Rand Basin AMD issues, a systems approach is required to provide a useful tool to understand the pollution source term and fate and transport dynamics and to aid in environmental decision making and to evaluate the geochemical impact of mitigation measures and evaluate future scenarios. The numeric geochemical models, using a systems perspective, show that the mine waste facilities, specifically the tailings dams are significant contamination point sources in the East Rand Basin, specifically for acidity (low pH), SO4, Fe, Mn, U, Ni, Co, Al and Zn. When the AMD solution enters the soil beneath the tailings, ferrous and SO4 concentrations remain elevated, while Mn, U, Ni and Co and perhaps other metals are adsorbed. After ~50 years the pollution plume starts to break through the base of the soil profile and the concentration of the adsorbed metals increase in the discharging solution as the adsorption capacity of the soil becomes saturated. The pollution pulse then starts to migrate to the shallow groundwater where contamination of this resource occurs. Toe seepage from the tailings either first reacts with carbonate, where acidity is neutralised to a degree and some metals precipitated from solution, where after it reaches the surface water drainage, such as the Blesbokspruit, where it is diluted. Some evaporation can occur, but evaporation only leads to concentration of acidity and dissolved constituents, thereby effectively worsening the AMD solution quality. The mixing models have shown that the dilution factor is sufficient to mitigate much of the AMD, although seasonal variability in precipitation and evapotranspiration is expected to have some influence on the mixing ratio and some variability in the initial solution will also be reflected in variation in surface water and groundwater quality. {List only- not presented}
The use of Hydrogeochemical Analysis Model to assess groundwater quality for drinking and agricultural use in Heuningnes Catchment	Portia Leah	Mokoena	Western Cape	2015
Abstract POSTER The study aims at using hydrogeochemical model to establish groundwater quality in shallow and deep aquifers in Heuningnes Catchment which is located within Bredasdorp in the Western Cape Province. The catchment is positioned at latitude of 34o42'50"S and longitude 20o07'13"E. The area is about 1400km2 has vleis, lakes and pans and its predominant formation is sedimentary rocks of Table Mountain and Bokkeveld Groups sitting on a crystalline basement of the Malmesbury granites. Comprehensive characterisation of the hydrogeochemical evolution is lacking and the current study argues that the use of hydrogeochemical Analysis Model (HAM) has potential to establish water-type, water source, water mixing/rock-water interactions, salinity, saturated adsorption ratio and hardness-softness of that predominant hydrochemical facies in the study area in addition to assessing the compliance of such water to WHO and South Africa water quality guidelines for drinking and agricultural use. Groundwater samples will be collected in 45 different locations (wellpoints/shallow wells, boreholes and wetland as end member) using in-situ sampling techniques to measure pH, electrical conductivity, total dissolved solids and temperature. Turbidity, total hardness, calcium, chloride and bicarbonate will be analysed using analytical chemistry methods including titrimetric method. Magnesium, potassium, sodium, nitrate and phosphate analysed by Atomic Absorption Spectrophotometer whilst sulfate will be analysed using spectrophotometer. Graphical methods such as piper diagram will be used to present the results to determine water-type, water freshness/hardness, water source, water mixing/rock-water interactions, salinity, saturated adsorption ratio and hydrogeochemical processes. The results from the present study are envisaged to inform formulation of science-based interventions strategies that will lead to sustainable utilization and management of the water resources in the area to improve the livelihoods of people and environmental integrity. Key words: Groundwater quality, Heuningnes Catchment, hydrogeochemical Analysis Model, Piper diagrams, Hydrogeochemistry
Investigating Deep Basin Groundwater Flow Systems In The Main Karoo Basin Of South Africa	Thandokazi	Maceba	USA	2015
Abstract POSTER The improvement in horizontal drilling and hydraulic fracturing techniques has resulted in the exploitation of gas associated with low-permeability organic-rich shale formations in the United States of America (USA) to become one of the most important energy resources. The USA experience has resulted in renewed exploration interest in the shale formations in the main Karoo Basin. The basins consist of sediments of the Karoo Supergroup, which were deposited during the Late Palaeozoic-Early Mesozoic. Typically, South Africa has been heavily reliant on coal for its primary energy supply, but currently, the country is seeking to develop alternative sources in order to diversify its energy sources. In the Karoo basin, the Whitehill Formation is the most prospective shale gas target. The neighbouring shales such as the Prince Albert Formation are of commercial interest, particularly if the Prince Albert Formation is exploited as an extension of the Whitehill play. Water management has emerged as being crucial for the sustainable development of unconventional gas resources in particular the risks to groundwater resources. This study attempts to develop a conceptual model of deep basin groundwater flow systems in the main Karoo Basin. The conceptual model aims to inform possible solution to protect groundwater resources. This will be done by investigating possible scenarios for interaction between deep and shallow aquifers as to establish possible migration pathways of flowback and produced water that would lead to possible pollution to shallow Karoo aquifers during and/or after the hydraulic fracturing process or activities in the main Karoo Basin.
The National State of Water in South Africa - the Annual Reporting	Kwazikwakhe	Majola		2015
Abstract POSTER The Department of Water and Sanitation (DWS) is the custodian of South Africa's water and thus is imperative that it reports on its state as the National Water Act of 1998 requires regular reporting to Parliament by the Minister. Hence, the annual compilation of report entitled "The National State of Water in South Africa." This report aims to give an overview of the status and trends of water quality and quantity, further assisting with international water reporting obligations to SADC Region, African Continent, and Globally e.g. the United Nations Commission on Sustainable Development. This information empowers the public and provides knowledge to water managers for informed decision-making. The main purpose is to enhance quality, accessibility and relevance of data and information relating to the goal of Integrated Water Resource Management towards attaining holistic Integrated Water Management, and Integrated Water Cycle Management in future. Three distinct requirements for collecting data by DWS are: (i) assessing and comparing the status and trends for both quantity and quality; (ii) monitoring for water use and (iii) monitoring for compliance to licence conditions. Such information is further used to assess the effectiveness of policies implemented and identify the existing gaps. Various challenges to the country's water demand proper integrated water resources planning and management. The report is divided into Themes such as, Resource Management, Water Services/Delivery, Water Development and Finance, based on selected indicators. The indicators are strategically selected to provide a representative picture of the state, as well as the changes over time to the drivers, pressures, impacts and responses related to the chosen themes. These Indicators include: Climatic Conditions, Water Availability, Water Use, Water Protection, Water Quality, Water Service Delivery, Water Infrastructure, Water Finance, and Sanitation. The report for Hydrological Year 2013/2014 has been completed and it shows that the amount of water available varies greatly between different places and seasons, and from one year to another. The average total storage was around 85% of full supply capacity in September 2014. Surface water quality is generally facing a threat from eutrophication and microbial pollution emanating mainly from mismanaged water (and waste) treatment plants and related landuse activities. Groundwater quality is generally good except in some localised areas where mining and industrial activities are prevalent. With regards to infrastructure; vandalism, lack of maintenance & management skills reflect on/as non-revenue water, highlighting the need for more funding towards maintenance, especially in groundwater which is normally wrongly deemed as an unreliable resource. In the past 20 years, water services delivery to communities has improved as the Millennium Development Goals have been met and surpassed, while the sanitation access goals were likely to be met.
Groundwater dependency and the plight of Loeriesfontein	Dale	Barrow	Northern Cape	2015	mini-wellfield, mixing model
Abstract The town of Loeriesfontein, situated in the northern Cape, is entirely groundwater dependent, and is currently facing a serious water shortage. Low rainfall and the lack of storm events have resulted in groundwater levels dropping drastically. The current supply boreholes have been over abstracted and cannot meet the required demand. Water levels are close to pump depth for some of the municipal boreholes, and yields are decreasing. The town at one stage was trucking in water in order to supply its residents. Additional supplies are therefore urgently required. A number of measures were implemented to monitor and manage the current demand and the limited supply. Thereafter GEOSS investigated the occurrence of groundwater within a 20 km radius of Loeriesfontein, and found that dolerite represents the primary target formation for groundwater exploration. Groundwater occurrence is found at the lower dolerite contact with the host rock, or in fractures in the dolerite itself. Based on an extensive hydrocensus, geophysical surveys, drilling and yield testing, the Rheeboksfontein area was identified as a suitable water source. Initially water was being trucked into Loeriesfontein from Rheeboksfontein and later an innovative arrangement of solar driven borehole pumps and reservoir pumps resulted in water being transported much closer to Loeriesfontein, reducing the transportation distances and costs. During this first Phase of exploration the projected supply still did not meet the water demand and water quality targets. A number of high yielding boreholes were drilled, however the water quality was such that it would have required treatment and disposal of brine in that area is problematic. The extent of the exploration was then increased to a distance of 40 km from Loeriesfontein. A detailed hydrocensus was completed, followed up with further geophysical surveys, drilling and yield testing. Successful boreholes were drilled and the required demand and water quality standards could just be met. This finding is being verified with numerical modelling. A process is underway to develop a mini-wellfield and then the environmental processes are being followed so that a pipeline can be built delivering water directly into the reservoirs at Loeriesfontein. On-going monitoring and maintenance is crucial to the long-term success of the groundwater supply.
Feasibility of iron and manganese removal by in-situ ozonation - Atlantis Aquifer Case Study	Kate	Robey	Western Cape	2015
Abstract The development of groundwater supply schemes is on the increase in South Africa. However, the sustainability of many of these wellfields is threatened due to the presence of iron (Fe2+) and manganese (Mn2+) ions in the groundwater. Their occurrence can manifest in problems with water quality and supply to consumers. The World Health Organisation recommends the removal of iron and manganese to below 0.3 mg/? and 0.1 mg/? respectively, to circumvent water quality risks. However, production borehole clogging is of greatest concern in the operation of wellfields due to the severe cost implications associated with reduced production. Clogging is caused by the precipitation of iron- and manganese-oxides at the borehole screen initiated by biogeochemical processes. Since Fe2+ and Mn2+ ions and the bacterial populations are naturally present in anoxic/anaerobic aquifer systems and the ingress of oxygen through pumping cannot be entirely prevented. The only approach to controlling borehole clogging is through management and rehabilitation procedures. Locally, these procedures have been implemented and in severe clogging cases the Blended Chemical Heat Treatment method has been applied. However, the effectiveness of rehabilitation has been limited. This can be ascribed to factors such as the incorrect production borehole design
Observations on seepage from platinum tailings	Terry	Harck		2015	platinum tailings
Abstract Tailings storage facilities are significant contributors of dissolved solids to underlying aquifers and adjacent watercourses. Salt balances indicate estimated seepage loads of the order of 1 500 tonnes of chloride per year. Actual seepage loads will be determined by the hydraulic conductivity of the tailings and mechanisms of flow within the tailings. Field observations and sample analytical results from several platinum tailings facilities are presented. These indicate the development of lenses of clay sized material within coarser silty material and suggest a tortuous seepage flow path, perhaps characterised by zones of preferential flow. The implications of seepage modelling and geochemical data on the salt loads mobilised from tailings are discussed. Results suggest that tailings facilities are effective at retaining salts and that release of accumulated salts after closure may take place at long time scales. {List only- not presented}
Refinement of a 3D Finite Element Mesh Model, Bela-Bela, South Africa	Tshegofatso	Mophatlane	North West	2015
Abstract This paper follows on current research taking place in the Springbok Flats Basin focusing on Carbon Dioxide Geological Sequestration within coal seams. The research, commissioned by ESKOM, began in 2012 and has a primary aim of producing a hydrogeological risk assessment for carbon dioxide geological sequestration operations scheduled for national pilot testing within the basin. One of the fundamental tools used in the assessment has been finite element mesh modeling. A 3D finite element mesh model of the study area, that has 11307 nodes, has been generated using FEFLOW algorithms. Portions in the study area without linear and point physical features have been modeled with the Advancing Front Algorithm, while the Grid Builder Algorithm has been used to model portions with linear and point features. This paper has investigated the node angle accuracy and precision of the mesh model by generating a map of the maximum interior angle of triangles. Approximately 70 % of the triangles have equilateral angles, while the remainder triangles have obtuse angles. The majority of the equilateral triangles occur within the portions modeled with the Advancing Front Algorithm. Half of the obtuse triangles have been refined to equilateral triangles with the FEFLOW refinement tools while the other half has been refined manually with the node digitizing features. FEM models perform better with dense triangle matrices with equilateral angles, as they influence the accuracy of the FEM.
Groundwater governance: where science, economics and politics meet	Nicolette	Vermaak		2015	groundwater governance
Abstract POSTER Researching a subject on the internet the slogan "Water flows upstream to money" popped up. The context was drought, and the meaning clear. If politics come into play as well, it would seem that science is relegated to a distant third place. The proclamation of the National Water Act, of 1998 (Act 36 of 1998), recognized the importance of groundwater and its role in the hydrological cycle and water supply issues. Groundwater governance has grown since then and is becoming increasingly important. One of the most important tenets on which groundwater based is the concept of sustainability. Various definitions of sustainability is used with the best know being "?development which meets the needs and aspirations of the present generation without compromising the ability of future generations to meet their own needs." Even though the basic understanding of sustainability may have been around for much longer than the term, it is the application of the theory in our current context that present us with challenges. Concepts like the precautionary principle, corporate governance and other buzz words that is being used does not always ensure good groundwater governance. One of the greatest problems is often the lack of scientific understanding and knowledge. Groundwater systems tend to be more complex and thus more difficult to manage than surface water. Understanding how groundwater and surface water interact, and that it is actually a linked water resource adds to the complexity. Add to this its importance in the functioning of groundwater dependent ecosystems that is still poorly understood. This article will look at principles for good groundwater governance and the tools that are needed to achieve it. It will finally look at real case studies where scientific considerations fall by the wayside for the requirements of the economy and political goals.
The use of boreholes for the infiltration of treated effluent - Pearly Beach Waste Water Treatment Works - A case study.	Dale	Barrow	Western Cape	2015	monitoring network
Abstract A Waste Water Treatment Works (WWTW) is being constructed at Pearly Beach. A geohydrological assessment was conducted to assess the potential discharge of treated effluent above and below the subsurface calcrete layers. A hydrocensus has been completed of the area to confirm there is no use of groundwater down-gradient of the WWTW and there is no likely impact on ecosystem functioning. Based on existing boreholes, infiltration above the calcrete layer in the vadose zone was found to be more efficient. A geophysical study was conducted to determine the optimal locations of boreholes for disposal of the treated effluent. The geophysics included an extensive electromagnetic (EM) survey. Resistivity data were acquired along a single resistivity profile to use as calibration for the EM data. This information has been correlated with borehole information from the monitoring boreholes that were drilled at the proposed WWTW site. From this information it would seem that the areas with higher conductivity (lower resistivity) can be targeted for drilling boreholes to dispose of the treated effluent. Also, the higher conductivity areas are interpreted as the areas with increased porosity. However, the change in conductivity could result from an increase in salinity or changes in calcrete content in the subsurface. The expected depth of the unconsolidated sand formations is generally less than 10 m based on the interpreted depth of the saturated formation from the resistivity data. Drilling will target the unconsolidated sands, as well as potential higher porosity zones beneath the calcrete. The geophysics data should then be calibrated with the information obtained from drilling the first borehole. The other sites can then be confirmed or reviewed based on the information. The boreholes are to be drilled soon and pump tested. The obvious concern is that the boreholes may clog, however measures will be put in place to minimise this risk. A detailed monitoring network will also be established. On-going monitoring is crucial to ensure the success of the scheme. The full conference paper will include the drilling and pump testing results and infiltration tests. This method of disposal needs to be taken into consideration especially if such schemes can be run successfully so that another option is available for the disposal of treated effluent. {List only- not presented}
An investigation into the effectiveness of underground water pollution mitigation policies	Sibanda	Kin		2015
Abstract Pollution of underground water is fast becoming a global problem and South Africa is not immune to this problem. The principal objective of this paper is to investigate the effectiveness of laws and policies put in place to mitigate underground water pollution. The paper also seeks to examine the causes and types of underground water pollution followed by a closer look into the laws and policies in place to mitigate the pollution levels. Finally, the paper seeks to ascertain whether the current policies are properly implemented. The paper follows content analysis (desk research) to achieve the objectives. Policy recommendations are given based on the findings. {List only- not presented}
Identification and Assessment of LNAPL Hydrogeological Conditions to Refine Conceptual Site Models.	Adolf	October		2015
Abstract LNAPL present in a monitoring well forms part of the broader groundwater system and is effectively influenced by hydrogeological conditions, which are always changing. Monitoring of LNAPL is therefore of utmost importance to identify and assess the LNAPL hydrogeological conditions. Both groundwater and LNAPL can exist as unconfined and confined. Groundwater is unconfined when the upper boundary is the water table and is confined as a result of the presence of a confining layer with a relatively low vertical hydraulic conductivity that inhibits the flow of all liquids. LNAPL becomes unconfined when the apparent free product thickness increases with a decreasing groundwater elevation and confined when apparent free product thickness increases with an increasing groundwater elevation. The LNAPL is confined as a result of the difference between the capillary properties of the mobile LNAPL zone and its confining layer. Specifically, LNAPL is confined when it cannot overcome the pore entry pressure of the confining unit. Consequently, LNAPL may be confined when groundwater is not. The paper attempts to describe the hydrogeological conditions in case histories of both primary and fractured aquifers and illustrate how to identify and assess the conditions. Data such as free phase and groundwater level monitoring, well logs, sieving of soil and LNAPL bail tests are used as assessment tools. The additional required data is gathered and integrated in the conceptual site model, followed by a revision of the CSM and a refinement of decision goals over time. Thus the CSM matures and enables an improved understanding of the site characteristics and the re-adjustment of decision criteria. {List only- not presented}
Complementary use of electromagnetic frequency domain and electroseimic survey methods in groundwater exploration in Zimbabwe.	Joseph M	Zulu	Zimbabwe	2015
Abstract Complementary use of electromagnetic frequency domain and electrosiesmic geophysical exploration methods in groundwater exploration in Zimbabwe. Joseph M Zulu, Josrum Enterprises No. 129 A Fort Street, Albion Flats, 2nd Floor, Office Suite 5 Room 3, Bulawayo, Zimbabwe. Email Address: [email protected]. Abstract Geophysical survey methods and divining are commonly used in groundwater exploration. In view of the current costs of drilling boreholes and fear of drilling a dry borehole, most people prefer the use of geophysical survey methods to have their boreholes sited. Some prefer the use of diving methods for initial siting and then confirmation of the identified site using geophysical survey methods. The key principle being complementarity of the methods to confirm the presence of water at the identified site. Electrical resistivity method and electromagnetic frequency domain methods are popular in ground water exploration in Zimbabwe, with electrical resistivity being the method of choice by many investigators. A new approach in groundwater exploration is proposed where complementarity of geophysical methods is exploited. A complementary approach of using geophysical methods in conjunction with geology, where two methods are used in investigating a site is proposed. In the study the latest technology in groundwater exploration, electrosiesmic survey method was used to complement the electromagnetic frequency domain method in various geological environments. Electromagnetic profiles were carried out on the target areas. Inversion was done on the collected and results presented as a pseudo section. Anomalies identified were further investigated using electrosiesmic sounding. The results of the sounding were presented in the form of a sounding curve. The subsurface layer thicknesses were calculated using forward modelling assuming the typical seismic velocity values of waves generated when passing through geological formations in the areas under investigation. The geology of areas studied include granite, greenstone, Kalahari sands, sandstones, mudstones and basalt of the Karoo stratigraphy. The approach produced impressive results. High yielding borehole sites were identified and successfully drilled in areas where it had been accepted that it was difficult to get water or in areas where it had been accepted there was no groundwater. Comparison of driller's log with models generated from geophysical survey results was also done. Key words: electromagnetic, electroseismic, geology, complementarity, groundwater. I acknowledge that this work has not been published elsewhere.
Policy and pragmatism in South African groundwater management	Jude	Cobbing	South Africa	2015	policy, water management organisations
Abstract Changes to South African water law and policy since the mid-90s have promoted integrated water resource management (IWRM) and the wider application of the principle of subsidiarity (decentralization), underpinned by the Constitutional emphasis on equity, human rights and redress. New water management organisations aim to promote equity, universal access to water, economic prosperity and gender equality but the reality, especially for groundwater, is less inspiring. The Water Act of 1998 envisages new organisations including Catchment Management Agencies (CMAs), Water User Organisations (WUAs) and Water Service Authorities (WSAs), but in many cases these organisations have inadequate capacity or do not exist at all. Only two of the nine (formerly nineteen) CMAs have been formed in more than fifteen years, and neither is yet financially self-reliant. The onerous process necessary to found a WUA and other disincentives have meant that fully-fledged WUAs as envisaged by the Water Act are rare. Hydrogeologists are unusual at Water Service Authority level, and the Department of Water and Sanitation (DWS) still assesses most groundwater resources. This has stoked argument between DWS and WSAs over long-term sustainable municipal water supplies. Our mandated organisations are not delivering the outcomes for groundwater that policy makers envisaged. Municipalities campaign for surface water instead of groundwater, yet groundwater is still the mainstay of rural water supply and has the most promise for underserved areas. Intractable problems with operation and maintenance are wrongly blamed on the primary groundwater resource, or on "shortages" of one kind or another. There is a need to emphasise function and outcomes rather than trust that these will follow automatically once "the right" organisations are in place. A hybrid of top-down expertise with a genuine focus on local outcomes is called for. We currently pay a considerable opportunity cost for delays, turf-wars and finger pointing - including reputational damage to groundwater as well as less reliable water supplies for the poorest South Africans.
In situ iron removal: Innovative option for preventing production borehole clogging	Kate	Robey	Karoo	2015
Abstract Worldwide many aquifer systems are subject to hydrochemical and biogeochemical reactions involving iron which limit the sustainability of groundwater schemes. This mainly manifests itself in clogging of the screen and immediate aquifer with iron oxyhydroxides resulting in loss of production capacity of the borehole. Clogging is caused by chemical precipitation and biofouling processes which also manifests in South African wellfields such as the Atlantis and the Klein Karoo Rural Water Supply Scheme. Both wellfields have the potential to provide a sufficient, good quality water supply to rural communities, however clogging of the production boreholes has threatened the sustainability of the scheme as quality and quantity of water is affected. Repeated rehabilitation of the affected boreholes using techniques such as the Blended Chemical Heat Treatment (BCHT) method does not provide a long term solution. Such treatments are costly with varying restoration of original yields achieved and clogging recurs with time. Currently, the research, management and treatment options in South Africa have focused on the clogging processes which are complex and site specific making it extremely difficult to treat and rectify. This project attempts to eliminate the cause of the clogging which is elevated concentrations of dissolved iron. High iron concentrations in groundwater are associated with reducing conditions in the aquifer allowing for dissolution of iron from the aquifer matrix. These conditions can be natural- and/or human-induced. Attempts to circumvent iron clogging of boreholes have focussed on increasing the redox potential in the aquifer to prevent dissolution and facilitate fixation of the iron in the aquifer matrix. Various in situ treatment systems have been implemented successfully overseas for some time. However, in South African in situ treatment of iron has only been a theoretical approach. Based on experience from abroad the most viable option to research and apply elimination of ferrous iron in South African aquifer systems would be through the in situ iron removal treatment The objective of this paper is to set out the experience from abroad and to outline the initial results of this treatment. A pilot plant for testing the local applicability of this method was constructed at the Witzand wellfield of the Atlantis primary aquifer on the West coast of South Africa.
Acid mine drainage in the Witwatersrand: Unanswered questions	Henk	Coetzee	Witwatersrand	2015
Abstract Since the first decant of acid mine drainage in the West Rand in 2002, a great deal of effort has gone into researching the challenges which it poses there and in the adjacent Central Rand and East Rand Gold Fields. Short-term interventions have been implemented to maintain water at conservatively-determined safe levels and remove the worst contaminants from the water pumped from the mined. A feasibility study, looking at the long-term options has proposed treatment of water to a much higher standard, identifying a number of potential end-users of the treated water and highlighted the extremely high costs involved in responsible management. During the second half of 2010, a team of experts was convened to assess problems related to acid mine drainage in the Witwatersrand and propose solutions. A number of recommendations were made and the most urgent - the need for a short-term intervention to bring things under control and the the feasibility study for long-term management of the problems were undertaken. Nevertheless, despite the intense focus on the problem, a number of questions have remained unanswered. Throughout the period of min flooding, no detailed systematic monitoring of surface water flow has been undertaken, preventing the detailed apportionment of pollution between underground and surface sources. Ingress control measures have been proposed, but funding mechanisms, regulatory hurdles and challenges relating to long-term management have not all been comprehensively addressed. On a more positive note, the installation and operation of pumps to control the water level in the Western and Central Basins will start to provide valuable data regarding the response of the flooded mine workings to pumping, assisting in the characterisation of the hydraulic properties and behaviour of the large voids. This will facilitate the optimisation of pumping strategies and the refinement of environmental critical levels and assist in the development of more sustainable management options.
Estimating groundwater availability at catchment scale using streamflow recession and instream flow requirements of rivers	Girma Yimer	Ebrahim		2015	streamflow, RDM
Abstract Groundwater is an important resource for multiple uses in South Africa. Hence, setting limits to its sustainable abstraction while assuring basic human needs is required. Due to prevalent data scarcity related to groundwater replenishment, which is the traditional basis for estimating groundwater availability, the present article presents a novel method for determining allocatable groundwater in quaternary catchments through information on streamflow. Using established methodologies for assessing baseflow, recession flow, and instream ecological flow requirement, the methodology develops a combined stepwise methodology to determine annual groundwater storage volume using linear reservoir theory, essentially linking low flows proportionally to upstream groundwater storages. The approach was trialled for twenty-one perennial and relatively undisturbed quaternary catchments with longterm and reliable streamflow records. Using the Desktop Reserve Model, maintenance low instream flow requirements necessary to meet present ecological state of the streams were determined, and baseflows in excess of these flows were converted into allocatable groundwater storages on an annual basis. Results show that groundwater development potential exists in nineteen of the catchments, with upper limits to allocatable groundwater volumes (including present uses) ranging from 0.02 to 2.60 Mm3/a over the catchments. With a secured availability of these volumes 75% of the years, variability between years is assumed to be manageable. A significant (R2 = 0.86) correlation between baseflow index and the drainage time scale for the catchments underscores the physical basis of the methodology and also enables the reduction of the procedure by one step, omitting recession flow analysis. The method serves as an important complementary tool for the assessment of the groundwater part of the Reserve and the Groundwater Resource Directed Measures in South Africa.
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.
Transport and Fate of chemical and microbial tracers at UWC campus site, Cape Flats aquifer of South Africa	Erin	Haricombe	Western Cape	2015	biological tracers, chemical tracers
Abstract Different biological and chemical transport results are evaluated in this study. Ecoli and PDR1 were selected as the biological tracers with salt and rhodamine as chemical tracers. The transport experiments were evaluated through the primary aquifer material found at the University of the Western Cape research site. A series of controlled experiments under laboratory and field conditions was conducted. Each provides a different kind of data and information. The results from laboratory studies could be used to better design the field studies. In both cases, the data collected was to provide information on fate and transport of microbes in groundwater. The field design phase of the experiment was an up-scaling of the laboratory phase of this project. The amount injected into the aquifer was increased in proportion to the size of the research site. Tracer tests using chemical and microbial tracers were carried out simultaneously. Results of laboratory tests show a 5 times slower transport of microbes, compared to salts.. The salts at field scale show a breakthrough occurring after 2 days whereas the microbes never managed to breakthrough with the experiment stopped after 45 days. A new borehole was drilled closer to reduce distance/ travel time, but this had no effect on field results for the microbes. {List only- not presented}
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
"Deriving groundwater recharge using Stronium isotopes: Oshivelo Aquifer, Namibia" - A step towards groundwater management	Henry	Beukes	Namibia	2015	Isotopes
Abstract In order to obtain a better understanding of a groundwater system, it is very important to understand the recharge mechanisms of such a system. Several intensive investigations have been done, documenting the different methodologies to derive recharge. Most of these studies have been centred on the detailed analysis and description of isotopes, which are either a characteristic of the water, the rock, or both. The isotopes of strontium, in particular the isotopic 87Sr/86Sr ratio, is one of such methodologies applied to drive the sources of recharge. The Oshivelo management area is part of the greater Owambo Basin, with no major rivers flowing through the project area, while the Omuramba Owambo, which crosses the area from east to west, bears water only rarely. This rural area therefore heavily relies on groundwater resources. Towards the end of the 20th century, through exploratory drillings an artesian aquifer in the southern part of the Owambo basin was discovered. Several investigation and water supply boreholes have been drilled, with the major findings summarised: - In the late 1990s DWA (DWA, 1999) drilled 12 exploration boreholes and six observation boreholes, showing high yields ranging between 40 and 200 m?/h. One of the boreholes yielded saline water, classified under the Oshivelo Artesian Aquifer and it was recognized that there may be a risk of saltwater intrusion when beginning to exploit the aquifer. It was assumed that the aquifer receives local recharge from the Etosha Limestone Member aquifer in the order of 3.75 MCM/a and additional unquantified recharge from the Otavi Dolomite Aquifer. - In the early 2000s KfW funded a study of the Tsumeb area, including the development of a groundwater flow model according to which an amount of 31 MCM/a would be leaving the Tsumeb area at the northern model boundary, i.e. flow into the Oshivelo Region. - The DWA plans to supply the north-western Oshikoto Region with water from the KOV2 aquifer via a pipeline in order to overcome water shortages there and to become more independent from surface water supplies from Angola. Though, through the groundwater model, a first estimate of groundwater resources availability has been established, the source of recharge is yet to be determined, including the flow mechanisms. Without, this vital piece of information, a valuable groundwater resource may be eventually utilized unsustainably. This presentation will focus primarily on the determination of groundwater recharge mechanisms, which would produce additional input to refine the existing groundwater flow model, concentrating on the Oshivelo Aquifer system. Upon the successful completion of this investigation, the next step would then be to evaluate the groundwater flow model and use it for a proper groundwater management plan. {List only- not presented}
An Investigation Of Groundwater Recharge And Residence Time Using Noble Gases, Tritium, And Terrigenic Helium	Hugh	Klein	Utah, USA	2015
Abstract Noble gases are used in this study to investigate the recharge thermometry and apparent groundwater residence time of the aquifers on the eastern slope of the Wasatch Mountains in the Snyderville Basin of Summit County, Utah. Recharge to and residence time for the basin aquifer in the Salt Lake Valley, Utah, from the western slope of the Wasatch Mountain range by 'mountain-block recharge' (MBR), is a significant source of subsurface flow based on noble gas and tritium (3H) data. The Snyderville Basin recharge thermometry from 15 wells and 2 springs indicates recharge temperatures fall within the temperature "lapse space" defined by the recharge thermometry determined in the study of MBR for the Salt Lake Valley and the mean annual lapse rate for the area. Groundwater residence times for the Snyderville Basin were obtained using tritium and helium-3 (3He). The initial 3H concentrations calculated for the samples were evaluated relative to the 3H levels in the early 1950s (pre-bomb) to categorize the waters as: (1) dominantly pre-bomb; (2) dominantly modern; or (3) a mixture of pre-bomb and modern. Apparent ages range from almost 6 years to more than 50 years. Terrigenic helium-4 (4He) is also used as a groundwater dating tool with the relationship between terrigenic 4He in Snyderville Basin aquifers and age based on the apparent 3H/3He ages of samples containing water from only one distinct time period. The 4He is then used to calculate groundwater residence times for samples that are too old to be dated using the 3H/3He method. The mean groundwater residence times calculated with both methods indicate the water yielded by wells and springs in the Snyderville Basin generally ranges from 6 to more than 50 years. In addition, the calculated terrigenic 4He age for the pre-bomb component of many samples was found to exceed 100 years. While terrigenic 4He residence times are not as definitive as those calculated with the 3H/3He method, or chlorofluorocarbons (CFCs), age dating with terrigenic 4He allows initial estimates to be made for groundwater residence times in the Snyderville Basin, and is an important tool for establishing groundwater residence times greater than 50 years. Historic water levels from production wells indicate a declining water table. This trend in conjunction with precipitation data for the area illustrates the decline in the water levels to be a function of pumping from the aquifers. Groundwater residence times in the Snyderville Basin and declining water levels support the need for a groundwater management program in the Snyderville Basin to effectively sustain the use of groundwater resources based on groundwater age. {List only- not presented}
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
Knowledge comes with trial, error and time: The Langebaan Road story	Nicolette	Vermaak	Western Cape	2015
Abstract When planning an experimental setup in the laboratory, it is very important and possible to control all the variables so that one can manipulate particular variables at a given time. Experimental setups under natural conditions could be a challenging task. The success of an experiment depends to a large extent on the correct understanding of the functioning of a natural system. If the conceptual understanding of the natural system is erroneous, it is likely that unexpected results could be achieved. This was the case with the artificial recharge pilot project that was done in 2008 and 2009 at the Langebaan Road wellfield just outside Hopefield in the Western Cape. Years of research gave scientists a fairly good idea of the way in which the aquifer system functioned, especially since the establishment of the well field. This provided information of the response of the aquifer unit to large scale abstraction. The Langebaan Road aquifer unit is a multilayered system with a lower aquifer composed of Elandsfontyn gravel overlaying a bedrock layer of either granite of the Vredenburg or Darling plutons of the Cape Granite Suite or Malmesbury shale. The bedrock was considered impermeable. The upper aquifer layer was composed of mostly the Varswater Formation with peat and clay of the Elandsfontyn Formation forming the confining layer between the two aquifer layers. The extent of the different layers of the aquifer unit was plotted with a fair amount of accuracy and the clay layer was considered to be continuous between the two aquifer layers. Monitoring data for the area was done since 1974 with a gap in data-set between 1991 and 2001. Despite all the data from geophysical work, boreholes drilled, and the monitoring record, the research done prior and during the artificial recharge pilot project in 2008 and 2009 the aquifer units did not respond quite as anticipated. The Artificial Recharge (AR) pilot project team concluded that the aquifer units responded in a particular manner as opposed to the expected response according to the data and conceptual model at hand. It was thus clear that there are gaps in the conceptual model of the aquifer systems in the bigger Lower Berg River Valley that include the Langebaan Road, Elandsfontein and other aquifers that needed to bridge before another pilot test is attempted. Although the artificial recharge pilot project did not yield the expected results, valuable lessons were learned. This article will look at the conclusions and recommendations of the research done on the pilot project and attempt to evaluate the monitoring data (water levels, chemistry and rainfall) from the period just before the beginning of the AR pilot project. The monitoring data would be manipulated using the following techniques
Spatial and temporal assessment of groundwater-surface water interaction, Skoonspruit River catchment, North West, South Africa	Thokozani	Kanyerere	North-West	2015
Abstract POSTER The poster presents the spatial-temporal assessment of groundwater-surfacewater (GW-SW) aspects in Skoonspruit River catchment, North West of South Africa. Despite the common use of quantitative methods to assess various aspects of GW-SW interaction, the use of qualitative methods remains poorly understood in assessing aspects of GW-SW interaction especially in the context of developing countries such as South Africa. While quantitative methods are envisaged to provide reliable and valid results,the use of qualitative methods are exploratory, site specific and more revealing to provide insights for more robust confirmatory methods. Such approach remains fundamental to comprehensive assessments that facilitate relevant generation of information to decision makers to enable them develop and improve interventions for the desired water utilization and management practice. However, the use of such qualitative methods in GW-SW interaction studies has not been applied, a situation which limit the basis for applying quantitative methods and that make quantitative methods not yield the desired results in most studies. The current study argues that the use of quantitative methods should be informed by the results from the qualitative methods and that the poor results from the GW-SW interaction studies is partly due to lack of implementing the qualitative methods prior to using the quantitative methods, especially in the context of developing countries such as South Africa. The current study established spatial variation in the water-type of the upper and lower catchment for both groundwater and surface water. Characterized water-type for several site specific reaches and determined the temporal trends for GW-SW interaction process in order to produce a comprehensive scenario for spatial-temporal pattern for GW-SW interaction in the Skoonspruit River catchment of North West to inform desired interventions for water use and management. Key Words: Qualitative methods, Quantitative methods, Spatial-temporal assessment, GW-SW interaction, Water use and management, Skoonspruit River catchment, North West
Application of multivariate statistical analysis to investigate the hydrochemistry of groundwater Upper Berg River Catchment, We	Tebogo	Madlala	Western Cape	2015
Abstract The present study applied multivariate statistical analysis (MSA) to investigate the status of the hydrochemistry of groundwater Upper Berg River Catchment, Western Cape, South Africa. Factors that influence the quality of groundwater are well established. The aim of the present study was to characterize groundwater quality in the Upper Berg River Catchment, using multivariate statistical analysis methods in order to establish the evolution and suitability of such waters for agricultural use in addition to confirming major factors that explain groundwater quality in the study area. Principal Component Analysis (PCA) and Hierarchical Cluster Analysis (CA) were applied to groundwater physicochemical data that were collected from 30 boreholes. Data collection and analysis followed standard procedure. The use of a Piper Diagram showed that Na-Cl water types were the predominant groundwater facies. Furthermore, PCA extracted five major factors that explained 83.11 % of the variation in the physicochemical characteristics of groundwater. Using Varimax rotation, two main factors, namely, surface water recharge and rock-water interactions, were extracted which collectively explained 60.81% of the variation in the groundwater physicochemical data. The two factors indicate that the predominant factors affecting groundwater quality in the study area are natural (biochemical) processes in the subsurface as well as interactions between the rock matrix and passing water. Cluster Analysis extracted three major groundwater clusters based on dissimilarities in groundwater physicochemical characteristics in different sites. The first cluster included 7 borehole sites located in the Franschhoek Valley area and 14 borehole sites located in the Robertsvlei Saddle area as well as the upper catchment (behind the Berg River Dam). The second and third clusters collectively included 9 groundwater sites within the Franschhoek Valley area. These sites were located on agricultural land where extensive vineyard and orchid cultivation is done. Groundwater quality in the Upper Berg River Catchment mainly reflects the influence of natural process of recharge, rock-water interactions and microbial activity. The quality of groundwater fell within Target Water Quality Guidelines for agricultural water use published by the Department of Water and Forestry Affairs meaning such waters are suitable for agricultural use. Key words: Dendrogram, Groundwater quality, Hierarchical Cluster Analysis, Principal Component Analysis, Physicochemical, Spatial.
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
Oudtshoorn Groundwater Project: Exploratory drilling results from the Blossoms Wellfield	Dylan	Blake	Eastern Cape	2015
Abstract {List only- not presented}
The North Lee County Reverse Osmosis Water Treatment Plant Injection Deep Injection Well Project	Hugh	Klein	Florida, USA	2015
Abstract The way in which groundwater is utilized and managed in South Africa is currently being reconsidered, and injection wells offer numerous possibilities for the storage, disposal and abstraction of the groundwater resource for municipalities, rural communities, mining, oil and gas, and a multitude of other industries. This presentation is about the North Lee County Reverse Osmosis Water Treatment Plant Injection Deep Injection Well project in southwest Florida in the United States. Water is plentiful in Florida, but it is not drinking water quality when it comes out of the ground. As such, treating water from wells is an important part of water supply in the coastal regions of the state. One form of treatment is reverse osmosis (RO), which generates a brine concentrate waste. The concentrate must then be disposed of, and a preferred method of disposal is an injection well because the disposal is not visible to the general public. The injection well project was associated with the construction of a large water treatment plant. The emphasis of this presentation is on the drilling and technical work in the field for this injection well, and to illustrate the rigorous requirements of drilling, constructing and testing a Class I injection well. Class I injection wells are permitted by the United States Environmental Protection Agency (US EPA) for injecting hazardous waste, industrial non-hazardous liquid, and/or municipal wastewater beneath the lowermost Underground Source of Drinking Water (USDW). Aquifer storage and recovery (ASR) wells are permitted as Class V injection wells by the US EPA. The permitting of an injection well is rigorous and requires state and federal approval before, during and after the field portion of the project. {List only- not presented}
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.
Geohydrological update and numerical modelling of the Langebaan and Elandsfontein Aquifer Systems	Julian E	Conrad	Western Cape	2015	Elandsfontyn Aquifer System, Langebaan Road Aquifer Systemaquifer systems, numerical modelling
Abstract The Saldanha / Langebaan area is expanding at a significant rate, increasing the water demand for the area. The expansion comes from the industrial, residential and tourism sector. In addition there are economically viable deposits of silica and phosphate in the area. Ecosystem functioning in the area is also to a degree dependent on groundwater. All of these factors require an improved understanding of the geohydrology of the area. The geology of the area consists of basement Cape Granite and Malmesbury Group rocks that underlie the sediments of the Sandveld Group. The unconsolidated formations present, are (in order of oldest to youngest) as follows: - Elandsfontyn Formation (oldest): This formation overlies the bedrock in depressions and palaeo-channels in the bedrock. This formation is about 40 m thick and is composed of upward fining quartz sediments. - Varswater Formation: This formation is composed of marine deposits and is restricted to the western (seaward) parts of a bedrock depression to the east of the Langebaan Lagoon and Saldanha. The formation is characterized by rounded quartz grains. - Langebaan Formation: This formation consists of calc-arenites. The sediments are generally grey to cream coloured and consist of quartz and shell fragments, the grain size ranges from coarse to fine and the consolidation is variable. - Witzand Formation (youngest). This formation consists of light-coloured, calcareous, coastal dune sand that can be distinguished from the underlying consolidated Langebaan Formation. The Elandsfontyn Aquifer System (EAS) and the Langebaan Road Aquifer System (LRAS) are the main aquifer systems in the area. These aquifer systems are defined by palaeo-channels that have been filled with gravels of the Elandsfontyn Formation and represent preferred groundwater flow paths. Within each of these aquifer systems (EAS and LRAS) two aquifer units are present. Namely, the confined Lower Aquifer Unit (LAU) geologically consisting of the basal gravels of the Elandsfontyn Formation and the Upper Aquifer Unit (UAU) composed of consolidated sands and calcrete. The two units are separated by a clay aquitard. A numerical model has been established for the area, and extends from the Berg River to the Langebaan Lagoon. Granite outcrop and river system define the other boundaries of the model. Extensive logging of groundwater levels by the Department of Water and Sanitation (DWS) has enabled the accurate establishment of a model. In addition extensive field work and a detailed hydrocensus, as well as the capture of a lot of historical information has resulted in a comprehensive GIS which assists with the refinement of the numerical model. The model provides a valuable tool in modelling potential impacts whether they been from planned groundwater abstraction or artificial recharge. {List only- not presented}
Stampriet Transboundary Aquifer System	Kwazikwakhe	Majola		2015

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.
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}