Conference Abstracts

All Abstracts were presented at the Groundwater Conferences

Displaying 51 - 100 of 795 results

Title	Presenter Name Sort ascending	Presenter Surname	Area	Conference year	Keywords
Investigation Of Possible Fluoride Source In Groundwater: A Case Study Of Siloam Village	Tobiloba	Onipe	Siloam Village	2019	Fluoride
Abstract Siloam, a village in the Northern province of South Africa (SA) has groundwater reportedly characterised by concentration of fluoride greater than the permissible limit of 1.5 mg/L by the World Health Organization (WHO). In response to reported high incidences (80%) of dental fluorosis in Siloam, sources of fluoride in the groundwater of Siloam village was investigated. Earlier hypothesis suggest that the source of fluoride could be fluorite. Physicochemical parameters were determined using a combined multimeter; while total fluoride (TF) was determined using Ion Chromatograph and Fluoride Ion Selective Electrode. Mineralogy of the rocks and soil in the village was determined using X-ray Fluorescence and X-ray diffraction, respectively. Results revealed that groundwater fluoride concentration ranged from 3.92 to 4.95 mg/L, which are far above the WHO permissible limit and South African National standard. Na-Cl water type was found to be dominant in the water samples which could be due to the heavy weathering of plagioclase present in the parent rocks. TF content of the rocks and soils of the village ranged from 10 to 2000 mg/L. Leachates were obtained by soaking the pulverised rocks and soil in de-ionized water over a period of 24 hours. TF in leachates ranged from 0.27 to 14.88 mg/L and 0.05 to 10.40 mg/L at induced, and non-induced temperature, respectively. Although, previous research hypothesize fluorite to be the possible source of fluoride in the village, this research shows that the main contributors of fluoride to groundwater in Siloam were smectite clays and the muscovite present in the sandstone, Investigation also revealed that the geothermal temperature of groundwater in the area is also a major factor enhancing the release of fluoride from the clay material into the groundwater.
The Use Of Derivative Analysis To Choose And Refine Conceptual Models Of Groundwater Flow Systems	Thokozani	Kanyerere	Western Cape	2019	modelling, flow systems
Abstract Groundwater flow system responses have been understood using derivative analysis. The argument is that the use of derivative analysis derived from pumping test data improves the understanding of aquifer types and curve matching in a hydrogeologic setting. The different aquifer systems encountered in Western Cape Government Business Continuity Programme (WCBCP) of South Africa was used as case study where the analysis of the time versus draw-down derivative plots were applied to validate the aquifer characteristics to explaining the groundwater flow systems. Key findings showed that analysis from the time versus draw-down derivative plots can be used to infer conditions within the wellbore, groundwater flow to boreholes and boundary conditions within the aquifer to provide insights. In addition, results confirmed that the archetypal time vs draw-down responses enabled characterizing the aquifer types and such analysis showed unique responses to the pumping. Lastly, long term operation of boreholes for water supply were ascertained when the analysis was interpreted. The analysis was enhanced when the geological information that was collected during drilling operations, were added to the conceptual understanding of groundwater flow studied aquifer system. However, due to costs implications of conducting long-term aquifer hydraulic pumping tests, deviations from the conventional draw-down responses are expected. In this study, it is suggested that due to complexities associated with heterogeneous flow in aquifer types, it is essential to combine derivative analysis with pumping methods to improve interpretation and assessing long term operation of boreholes for water supply
Using Hydrogeologic Conceptual Model To Implement A Successful Iwrm Approach In Limphasa River Catchment, Malawi	Thokozani	Kanyerere	Limphasa River Catchment, Malawi	2013	Hydrogeological, IWRM, conceptual model
Abstract This study examined the effective use of the hydrogeologic conceptual model (HCM) to implement the integrated water resource management (IWRM) approach. While research focuses on using hydrogeologic models in groundwater for planning, few studies show how to use HCM for a successful IWRM approach, especially in resource poor catchments. This is largely due to t he lack of adequate data to showcase such models. Despite the lack of numerical groundwater data, the HCM was used in this study and it provided the scientific and visual presentation of key issues for practical understanding by stakeholders. For the first time, HCM provided a practical understanding of t he groundwater system in the Limphasa River catchment. By using HCM and physical factors qualitatively, the study revealed that, apart from storage, abstraction mechanisms significantly contributes to regional initiatives of groundwater supply whose central objective is to utilise and manage such water sustainably. The model is based on the relationship between groundwater availability and its related hydrogeologic factors. Findings suggest improvement in quantifying the studied parameters through field experiments to provide a better estimation on storage and abstraction of groundwater in relation to impacts of a future changing climate. Since using HCM has shown practical usage, replicating it in catchments with similar physical and socioeconomic environments, would be desirable as refining the model progresses.
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
Investigating Risks To Groundwater Systems In The Main Karoo Basin Of South Africa	Thandokazi	Maceba	Karoo	2017	hydraulic fracturing, Shale gas, contamination, conceptual risk assessment, over-abstraction
Abstract The improvement in hydraulic fracturing techniques resulted in the exploitation of natural gas associated with low-permeability organic-rich shale formations in the United States. South Africa has prospective shale gas resources linked with the marine black shales of the Whitehill Formation found in the Karoo Basin. Plans exist to develop the Karoo shale gas resources to diversify the primary energy mix. However, concerns among stakeholders about groundwater contamination and source of water for hydraulic fracturing remain unresolved. Such concerns include the potential of spills, fugitive gases, mechanical well integrity, and water management practices individually and collectively to introduce methane, hydrocarbons, metals, radionuclides, or other chemicals in groundwater posing human and environmental health-related risks. However, such concerns have not been assessed to provide evidence-based results that can be used to develop either an early warning or mitigation or adaptive monitoring system for shale gas development activities. The study was designed to develop a conceptual risk assessment model of potential shale gas operations to provide insights for groundwater protection. The western part of Greater Karoo Basin was used as a case study area. Applying this model suggests that hydraulic fracturing itself will have low risks in contaminating groundwater resources. However, the risks for over-abstracting groundwater remain high. These results suggest that it is crucial to learn from countries which have practised hydraulic activities for long periods of time, especially countries where the environmental setting are similar to South Africa. These findings form the basis of designing field-based studies that will influence policy making for action planning.
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.
Validation of algorithms for estimating changes in groundwater storage from GRACE gravity satellite data for Poland	Tetyana	Solovey	Poland	2023	GRACE, groundwater storage assessment, validation
Abstract The development of satellite technologies creates more and more opportunities to build modern tools for monitoring the state of groundwater. The use of the GRACE satellites to monitor GWS changes has become widespread, but the degree of accuracy with which remote sensing data can estimate these changes is unclear. In this study, we quantified changes in the GWS in Poland from 2009 to 2022 using GRACE observations, in-situ data, and GLDAS. Long-term trends and seasonality were calculated and analysed for each time series. The correlation analysis between GRACE TWS, GWS obtained from GRACE and GLDAS, and GWS in situ was performed using linear regression. Pearson and Spearman’s methods show that GRACE performance is good in the region of shallow (up to 3 m) presence of thick (above 5 m) unconfined porous aquifers; however, performance is worse in a region with multiple aquifer systems, including fissured and karst aquifers. In addition, an unrepresentative groundwater GRACE signal is obtained in regions with surface water storage, such as the Baltic Sea area. It was also found that there is very high consistency between the GRACE observations and wells water level changes, while the GWS series obtained from GRACE and GLDAS do not provide adequate compatibility. According to the GRACE data, the results suggest that evapotranspiration and the hydrodynamic system have the greatest impact on the sensitivity of the GWS estimation. The results are important for better processing the GRACE data to obtain a representative signal for the GWS assessment.
GIS-Based Modeling Land-Use And Climate Variability Impacts On Groundwater Quality: Cape Flats Aquifer, South Africa	Tesfaye Tessema	Gintamo	Cape Flats Aquifer	2019	GIS, landuse, quality
Abstract Assessment of aquifer vulnerability to contamination is receiving renewed attention due to recent extreme events as demand for groundwater as alternative sources of water supply intensifies. In this study, GIS-based modeling of the impact of land-based activities and climate variability is employed to quantify the risk to quality deterioration of groundwater resource, delineate potential areas and highlight degree of vulnerability in the Cape Flats aquifer. The study used Scenariorcp85 CMIP5 AR5 climate change datasets downscaled from GCM using WaterWorld model. The WaterWorld is physically based global model for water balance includes all data required for application with a spatial resolution at 1-square km (Mulligan, 2009). The modeling results suggest that water balance for the predominantly low-lying flat central portion receives recharge ranges from 44 to 376 mm/yr. This reflects the area precipitation ranges from 500 to 800 mm/yr. Actual evapotranspiration (mm/yr) ranges from 92 to 1,200. The cmip5rcp85worldclimhe20412060 simulation main results indicate water balance (mm/yr) for the area predict to a minimum of -1,100 and maximum of 1,100. Actual evapotranspiration (mm/yr) ranges from 67 to 1,200. This led to an increase in evapotranspiration for the area of 13 mm/yr (2.5 %) that lead to an overall decrease in the water balance of -44 mm/yr (22 %). The human influence on water quality was simulated based on the human footprint index. The risk of contamination is largely attributed to the change in urban areas, pastures and cover of bare ground. In order to address the significant spatial variability of groundwater recharge and potential contamination risk occurring throughout the area, a GIS-based approach is used. The result underscores that GIS-based models are powerful tools to integrate spatiotemporal data and make assessment possible to improve understanding of water security in light of climate and land use change scenarios.
Groundwater Potential Evaluation Based On Integrated Gis And Remote Sensing Techniques, In Bilate River Catchment: South Rift Valley Of Ethiopia	Tesfaye Tessema	Gintamo	Ethiopia	2017	Bilate River, groundwater potential, spatial information system, thematic maps
Abstract The use of the integrated geographic information system and remote sensing technologies have not been widely demonstrated as one of the efficient techniques in facilitating better data analysis to enhance the interpretations of groundwater potential controlling parameters for sustained utilization and management of groundwater resources. This paper discuss the results of the study that aimed at showcasing the application of the integrated geographic information system and remote sensing techniques to delineate and classify possible groundwater potential zones in the Bilate River catchment, South Ethiopian Rift valley Escarpment. Thematic layers of lithology, geomorphology, drainage, lineament, rainfall, soil, slope and land use/land cover were prepared in Landsat ETM+ imagery and ArcGIS software. Weights assigned based on thematic layers relative importance in groundwater occurrence. In addition, corresponding normalized weights obtained based on the Saaty's analytical hierarchy process. Lastly, linear summation equation used weights to obtain a unified weight map containing due weights of all input variables. Thematic layers further reclassified to arrive at groundwater potential map using ArcGIS and IDRIS software. Key results included four different groundwater potential zones that classed as high, moderate, low and poor based on pair wise comparison of Satty’s importance scale criteria. The resulted groundwater potential zoning map validated based on existing water sources point data of the study area. The results provide important information, with the groundwater potential zone suitable for use by local authorities and decision makers responsible for groundwater resource management in the study area. Finally, integrated geographic information system and remote sensing technologies have provided an efficient tool for the identification of groundwater potential zones.
Geochemical Simulation of Drain Water Quality in Gold Tailings	Terry R	Harck		2017	geochemistry, modelling
Abstract This paper presents data obtained from sampling and geochemical analysis of gold tailings and associated pool and drain water. Inverse geochemical modelling using PHREEQC indicated geochemical processes operating in the tailings between the pool and drains. These included pyrite oxidation and dissolution of various minerals identified in the tailings. The processes were incorporated into an ensemble geochemical model to calculate post-closure sulphate concentration in tailings seepage. The ensemble model included a spreadsheet model to calculate oxygen flux at various depths in the tailings column, and a one-dimensional transport model in PHREEQC. The calculated oxygen flux was applied to each cell in the tailings column to determine the amount of sulphide oxidation and the release of acidity into the tailings pore water. The rate of vertical transport of pore water in the column was determined from physical characterisation of the tailings particle size and saturated hydraulic conductivity. The model results indicate elevated sulphate concentrations and acidity moving as a front from the top of the column downwards. The modelled sulphate concentration of 1 500 to 1 900 mg/L 8-16 years after closure compared well with measurements of drain water quality at a tailings dam decommissioned approximately 16 years ago. This provided some credibility to the modelled result of 2 300 mg/L sulphate up to 50 years post-closure. However, the tailings moisture content, infiltration rate, and pyrite oxidation rate in the model were based on literature values, rather than site-specific measurements.
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}
#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.
Connecting the dots: Groundwater / surface water interaction along the Letaba River, Limpopo	Tercia	Strydom	Limpopo	2015
Abstract The National Water Act (NWA) 36 of 1998 is regarded as providing a platform for an innovative way of managing the country's water resources. However, demands on the nation's water resources are intensifying as more and more catchments are coming under increasing stress. This may be attributed to significant changes in land-use and poor water resource governance which negatively affects the Environmental Water Requirement (EWR) flows of rivers in many catchments in South Africa. EWR refers to the flow needed by a river to sustain a healthy ecosystem. It is vital that the determined EWR flows are met and to ensure that all water-users receive their allocated water supplies. To ensure effective water management and water provision, it is critical to understand transmission losses considering that it is a key component of the water balance or hydrological budget. Quantitative investigations of transmission losses are necessary in order to calculate flows in a river and appropriately allocate water for different users. The Groot Letaba River situated in the north-eastern region of South Africa is a prime example of a river system where uncertainties in channel losses and gains are complicating effective water management. The Groot Letaba River is a model river where Strategic Adaptive Management (SAM) is currently being implemented to ensure adaptive and sustainable water resource management. This unique approach is facilitated by the institutional interaction between dam operators (from the upstream Tzaneen Dam) and stakeholders including Kruger National Park. However, there are huge uncertainties surrounding natural water losses (e.g. evapotranspiration) or gains (e.g. groundwater discharge) in the real-time model currently being used by dam operators. This study aims at attempting to narrow down the uncertainty by understanding and quantifying the natural hydrological processes between the two dominant land-uses along this river, i.e. agriculture and protected areas. In particular, the project will investigate the hydrological connectivity between groundwater and surface water along the Letaba River. This project will contribute significantly to management strategies by using a precise hydrological approach which will aid in improving estimates of water supply in the Groot Letaba River. Furthermore, this project could contribute to the development of appropriate water management strategies not only in the Letaba catchment but other similar Lowveld catchments as well.
Integrated System Approach To Evaluate Natural Processes And Hydrodynamics Linked To Groundwater-Surface Water Interaction	Teboho	Shakhane		2015
Abstract This study was aimed at developing an integrated groundwater-surface water interaction (GSI) model for a selected stretch of the Modder River by considering the following five different aspects of the GSI: 1) the distribution of different aquifer systems (structural connectivity) along the river 2) the hydraulic connectivity between the aquifer systems, 3) the volumes of water abstracted from the aquifers by streamside vegetation, 4) the volumes of water replenished to the groundwater system through rainfall recharge, and 5) the exchange fluxes between the various components of the groundwater-surface water system. The distribution of the aquifer systems was investigated by means of a) geo-electrical surveys, and b) in situ slug tests while their hydraulic connectivity was investigated by hydrogeochemical routing. The volumes of water abstracted by streamside vegetation were estimated by the quantification of the transpiration from individual plants and the groundwater recharge was estimated by a root zone water balance. The water exchange fluxes between the groundwater and surface water were determined from a simple riparian zone groundwater budget. The results of the geo-electrical surveys and slug tests allowed the delineation of the riparian area aquifers (RAA) and the terrestrial area aquifers (TAA) on both the south-eastern and north-western sides of the river. Based on the results of hydrochemical analyses, saturation indices and inverse mass balance modelling, the GSI involves flow of water from the TAA to the RAA, and finally to the river on the south-eastern side while it involves flow from the river into the RAA with a limited exchange with the TAA on the south-eastern side. The dominant vegetation on the study area was found to be the Acacia karroo and Diospyros lycioides. The close similarities in isotope compositions of the xylem sap and the borehole water samples suggested that the Acacia karroo sourced its water from the groundwater storage while differences in isotope compositions suggested that the Diospyros lycioides did not source water from the groundwater storage at the time of measurement. The results of groundwater recharge estimation in the study area highlighted the fact that both the antecedent moisture and the rainfall amounts determine whether recharge to the groundwater system will take place. Finally, the results of baseflow estimation indicated that the river is a gaining stream along the south-eastern reach while acting as a losing stream along the north-western reach.
Using Electrical Resistivity Tomography To Describe The Aquifer Architecture Linked To Groundwater And Surface Water Interaction	Teboho	Shakhane	Krugerdrift Dam, Free State	2013	Electrical Resistivity Tomography, aquifer, Groundwater, surface water
Abstract POSTER One of the critical elements of water resource management is the dynamic exchange between groundwater and surface water. Quantifying this exchange strongly relies on an adequate characterisation of the lithological architecture of the involved aquifer system. In the past, this characterisation often relied on lithological data obtained through invasive methods. However, given the spatial heterogeneity of the subsurface, these methods do not provide the density of sampling required for an accurate ‘‘image’’ of the large‐scale architecture of the aquifer system, leading to large uncertainties in the variations and continuities of subsurface structure. These uncertainties inevitably lead to inaccuracies in the conceptual geohydrological model, thereby diminishing the prospects of an accurate assessment of the groundwater–surface water interaction. In order to limit the uncertainties, the results of electrical resistivity tomography (ERT) surveys conducted on a site near the Krugersdrift Dam in the Free State Province of South Africa were used to make inferences regarding the prevailing geohydrological conditions. The resistivity models were compared to borehole logs from existing boreholes to produce a refined model of the subsurface architecture related to groundwater–surface water interactions.
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.
eSymon - An Innovative Solution to Monitoring Data Management	Tarika	Isaac	South Africa various	2021	eSymon, Monitoring, data management, data visualization, data security
Abstract The year 2020 will forever be synonymous with the Covid-19 pandemic and the immeasurable impact it has had on all our lives. During this time, there was one avenue that reigned supreme: technology. Whether it was Zoom calls or Netflix, online consultations or video conferencing at work, technology took charge. In light of this, GCS (Pty) Ltd started exploring ways that technology could assist with the most common problem identified in the Water and Environmental sectors, which is the management of large volumes of geodata. Thus, the invention of eSymon. Monitoring of the environment usually generates a significant amount of data. If this data is not systematically stored, problems often arise with: • Limited access to historical data due to poor storage; • Different formats of stored data (if they are kept in digital form at all); • Continuity and integrity of the data; and • Security of the data. Therefore, years of historical data cannot be used or trusted. The solution was to develop eSymon, which is an acronym for Electronic Data Management System for Monitoring. eSymon is primarily designed to: • Systematically import, store, view and manipulate large volumes of monitoring data; • Provide remote and instantaneous access to site-specific information; • Allow data visualization using an interactive GIS interface; and • Create various outputs such as time series graphs, geochemical diagrams and contour maps. The main idea of the software is to have all historical data for a site on one platform and have it be accessible and functional at the touch of a button. This results in several key benefits, including saving time, providing accurate and up to date information, not having to wait for technical reports to assess trends and compliance, providing several means of data visualization and, most importantly, ensuring data security.
Hydrogeochemical Footprint As A Result Of Mining Activities In The Johannesburg Area	Tamiru	Abiye	Johannesburg	2013	hydrochemical
Abstract The water quality in the crystalline rocks of the Johannesburg and its environs has been severely altered by the mining activity. Due to freshwater scarcity and dependency of the people on the groundwater, it is important to understand the extent of hydrogeochemical footprint in the area. The water quality characteristic has been thoroughly assessed in the crystalline aquifers based on the input from hydrogeochemical characteristics and environmental isotopes. The results show that the calculated dilution factor for acid-mine decant is in the range of 68% as a result of interaction with surrounding fresh water. The SO4/Cl ratio has a wide range of values that falls between 0 and 306.37, while that of Fe/Ca ratio falls between 0 and 5.59. High SO4/Cl values potentially indicate the interference of acid-mine decant with the groundwater system traced through sulphate concentration. Similarly, a high Fe/Ca ratio also indicates the impact of acid-mine decant on the groundwater system where iron is traced with respect to calcium concentration. In this regard the ratios above 0,25 (with the assumption of 1 to 4 natural abundance for Fe:Ca in water in the area) could potentially represent acid-mine decant source.The results confirm that most of the water- supply wells have heterogeneous chemistry with distinctive hydrogeochemical footprint represented by abnormally high Fe, SO4 and Si as a result of acid-mine decant.
Fluoride challenge in groundwater of the Ethiopian Rift Valley and adjacent highlands	Taddesse M	Bollollo	Ethiopia	2015	Fluoride
Abstract The urban and rural communities sources of water for domestic and other uses come from groundwater in most parts of Ethiopia. But the groundwater is not free from challenge. Fluoride is one of those critical problems which are affecting the health of inhabitants of this corridor. There are places where the fluoride contents reach more than 10mg/l. groundwater Treatment plants, changing the water scheme source from surface water and related efforts have been made so far to alleviation such challenges. Fluoride affects bones and teeth by changing its color and easily affected to a number of health complication in the rift valley of Ethiopia. {List only- not presented}
Developing And Optimising Conditions For Bioflocculation Of Bacillus Sp.Isolated From The Estuary On The Umlalazi Catchment At Mtunzini, KZN Province	TM	Kubhayi	KwaZulu-Natal	2017	Bioflocculant, flocculating activity
Abstract Synthetic flocculants are widely used in water treatment for their efficiency when it comes to flocculation but pose a risk to the environment and human health. The need for an alternative flocculant was investigated in this study. Bioflocculants which are produced by microorganisms have the potential to flocculate fine suspended particles. The bioflocculant production by Bacillus sp. isolated from Umlalazi Estuary in Mtunzini, KwaZulu-Natal Province was evaluated. Optimum flocculation conditions were obtained with an inoculum size of 1% v/v (89%), carbon source which was glucose with a flocculating activity of 88%, a multiple nitrogen source with a flocculating activity of 88%, an optimum temperature of 400C with 95% flocculating activity, shaking speed of 120 rpm with 95% flocculating activity, K+ for the cations was optimum at 95% flocculating activity and the pH of 7 had the flocculating activity of 94%. In the time course assay optimum conditions were reached after 84 hours with the flocculating activity of 92% at pH 5.29 using 0.4% (w/v) kaolin suspension. After extraction and purification, a bioflocculant yield of 2.1g/L was recovered from a 1L fermentation broth. Water treatment without the risk to human health is now a reality.
Optimizing managed aquifer recharge in coastal dunes by extracting brackish groundwater: results of a field pilot in the Netherlands	T	van Dooren	Netherlands	2023	Brackish groundwater extraction, Managed aquifer recharge, drinking water production, field pilot, coastal dunes
Abstract Faced with climate change and population growth, Dutch drinking water company Dunea is looking for additional water resources to secure the drinking water supply for the coastal city of The Hague. One of the options is to enhance the existing managed aquifer recharge (MAR) system in the coastal dunes by extracting brackish groundwater. Extracting brackish groundwater provides an additional drinking water source, can protect existing production wells from salinization, and can effectively stabilise or even grow the freshwater reserves in the coastal dunes, according to numerical groundwater modelling. To test this concept in the field, a three-year pilot commenced in January 2022 at Dunea’s primary drinking water production site, Scheveningen. Brackish groundwater is extracted at a rate of 50 m3 /h with multiple well screens placed in a single borehole within the brackish transition zone (85-105 meters below sea level). The extracted groundwater is desalinated by reverse osmosis, whilst the flow rate and quality of extracted groundwater are continuously monitored. The hydraulic effects and the dynamic interfaces between fresh, brackish and saline groundwater are monitored with a dense network of piezometers, hydraulic head loggers and geo-electrical measurement techniques. At the IAH conference, the monitoring results of the pilot will be presented. Based on the results of the field pilot and additional numerical modelling, the feasibility of upscaling and replicating the concept of brackish groundwater extraction to optimize MAR and increase the availability of fresh groundwater in coastal areas is reflected.
Risk-corrected contaminant detection probability of monitoring well networks for flow towards pumping wells in heterogeneous aquifers	T	Sarris	New Zealand	2023	Contaminant transport, Dispersion, Groundwater Contamination, Heterogeneity, monitoring networks, Risk corrected detection rate
Abstract A groundwater monitoring network surrounding a pumping well (such as a public water supply) allows for early contaminant detection and mitigation where possible contaminant source locations are often unknown. This numerical study investigates how the contaminant detection probability of a hypothetical sentinel-well monitoring network consisting of one to four monitoring wells is affected by aquifer spatial heterogeneity and dispersion characteristics, where the contaminant source location is randomized. This is achieved through a stochastic framework using a Monte Carlo approach. A single production well is considered, resulting in converging non-uniform flow close to the well. Optimal network arrangements are obtained by maximizing a weighted risk function that considers true and false positive detection rates, sampling frequency, early detection, and contaminant travel time uncertainty. Aquifer dispersivity is found to be the dominant parameter for the quantification of network performance. For the range of parameters considered, a single monitoring well screening the full aquifer thickness is expected to correctly and timely identify at least 12% of all incidents resulting in contaminants reaching the production well. Irrespective of network size and sampling frequency, more dispersive transport conditions result in higher detection rates. Increasing aquifer heterogeneity and decreasing spatial continuity also lead to higher detection rates, though these effects are diminished for networks of 3 or more wells. Earlier detection, critical for remedial action and supply safety, comes with a significant cost in terms of detection rate and should be carefully considered when a monitoring network is being designed.
Source protection zone delineation: Numerical insights on the effect of heterogeneity	T	Sarris	New Zealand	2023	Drinking water, Flow and transport modelling, Heterogeneity, Source protection zone delineation, Transition probability
Abstract Source protection area delineation has evolved over the last decades from fixed radius, analytical and numerical methods which do not consider uncertainty to more complex stochastic numerical approaches where uncertainties are often considered in a Monte Carlo framework. The representation of aquifer heterogeneity in these studies is typically based on a geostatistical representation of hydraulic properties. This presentation compares results from complex stochastic flow and transport simulations, simple homogeneous models, and existing analytical expressions. As a case study, we use the existing drinking supply wells in West Melton located Canterbury’s Selwyn District in New Zealand. Monte Carlo realisations are parameterised in MODFLOW6 so that the prior knowledge of the aquifer’s effective, large scale flow characteristics is honoured. Homogenous simulations are based on the same grid, using the aquifer’s effective properties to parameterise the numerical flow model. In both cases, conservative transport of pathogens is undertaken using Modpath7, using both forward and backward particle tracking. The numerical results are compared with analytical expressions from the international literature. Our results suggest that aquifer heterogeneity needs to be explicitly addressed in all cases. Homogeneous simulations almost certainly underestimate contamination risk and produce unrealistically small source protection areas. Parameterisation of the stochastic heterogeneous realisations also affects the size and extent of the source protection area, suggesting that these need to be carefully considered for practical applications.
Upscaling Preferential Flow in Heterogeneous Porous Media from the Laboratory to the Field	T	James Oudega	Austria	2023	Heterogeneity, preferential flow, upscaling
Abstract ue to public health or environmental concerns, performing tracer tests in the field by injecting pathogenic microorganisms or contaminants of emerging concern into groundwater is not permitted. Therefore, examining the effects of preferential flow processes on these contaminants under controlled saturated conditions must be done in the laboratory, but the resulting transport parameters cannot be directly applied to field-scale groundwater models. This research considers how an upscaling relationship can be found using a colloidal tracer and three different scales: small laboratory columns (0.1 m scale), a large intact core (1 m scale), and a real-world gravel aquifer (10 m scale). The small columns were filled with gravel from boreholes at the field site, an alluvial gravel aquifer close to Vienna, Austria. The mesoscale consists of an undisturbed gravel column from a gravel pit near Neuhofen an der Ybbs, Austria. Results showed that a certain pattern emerges after an initial scale-dependent threshold, regardless of differences due to the small columns being repacked with aquifer material and the large column and field site being “undisturbed”. In this way, the mesoscale column allows us to gain insight into upscaling processes by incorporating an in-between step when comparing groundwater transport at the column- to the field scale.
Transboundary groundwater flows between Poland and Ukraine: The role of joint assessments and international frameworks on water resources management	T	Solovey	Poland, Ukraine	2023	Cross-border groundwater flow, numerical modelling, Sustainable exploitation, Transboundary aquifer, Mine water management
Abstract There is a transboundary groundwater reservoir on the Polish–Ukrainian borderlands, which is of key importance in shaping strategic groundwater resources. Due to the particular importance of this reservoir, the two neighbouring countries are obliged to undertake joint actions to protect it. One of the main difficulties in building a common platform for the management of TBAs in the Polish-Ukrainian border area is the differences in the approach to the identification of GWB, monitoring methodologies and assessment of the condition of GWB, and the inconsistent hydrogeological databases between the two countries. A transboundary numerical groundwater flow model was developed to support internationally integrated management. The model research helped diagnose potential problems by determining the scope of the area with cross-border flows and quantifying the flows between Poland and Ukraine. In addition, the numerical model was used to define the optimal cross-border management unit and the conditions needed to exploit the Lublin–Lviv Reservoir sustainably. Abstraction on a current level slightly increased the transboundary groundwater flow from Poland to Ukraine and minimally reduced the flow in the opposite direction but did not reverse the direction of water flow at the border. The simulated drawdowns do not have a transboundary range, but negative effects on surface water resources are noticeable. Joint management should focus on a broader legal consensus, improvement of institutional relations, and integration of monitoring and groundwater status assessment systems.
Assessment Of The Spatial Coverage Of Groundwater Dependent Ecosystems In A Semi-Arid To Arid River Gouritz River Basin	T	Mbandezi	Western Cape	2017	Shallow groundwater, groundwater dependant ecosystems, remote sensing
Abstract The presence of shallow groundwater at locations with limited spatial coverage in drylands have since time immemorial supported plant and animal communities. These locations often have in comparison to the surrounding dry landscapes high biomass production and biodiversity. The presence of groundwater makes these locations attractive for development of groundwater dependent human activities such as irrigated crop production, and livestock production. Groundwater abstractions from locations that are not necessarily close to these plant and animal communities, but tapping into the same aquifer systems have also a potential to affect the availability of water to these ecosystems which is critical for their existence. The importance of these groundwater dependent ecosystems is not well understood due to limited knowledge about their spatial coverage. Some of the groundwater dependent ecosystems occur in areas that are not accessible such as mountain slopes, or in remote areas. The long-term impact of groundwater usage on some of these ecosystems has not been evaluated, with most of the knowledge about these impacts being based on anecdotal information obtained from the respective land owners. Remote sensing offers an opportunity to map the spatial coverage of groundwater dependent ecosystems in drylands. A distinguishing characteristic of these systems is the active plant growth especially during periods when throughout the landscape, there is limited or no water to support plant growth. Monitoring plant growth during the dry season using indices such as the NDVI enables detection of groundwater dependent ecosystems. Knowledge about the rates of actual evapotranspiration at locations with these ecosystems enables an estimation of the amount of water required to support them during the dry season. The MODIS 16 actual evapotranspiration rates (ETA) which are globally available can be used for evaluating water use by groundwater dependent ecosystems. This paper explores the mapping of the spatial coverage of groundwater dependent ecosystems using remote sensing based vegetation indices in parts of the Gourizt River basin in South Africa. The rates of waters use by the identified groundwater dependent ecosystems are estimated using actual evapotranspiration rates based on MODIS 16. The paper also examines possible long-term changes to the spatial coverage of groundwater dependent ecosystems.
Fracking regulations to protect groundwater resources during unconventional oil and gas extraction: Getting it right.	Surina	Esterhuyse	National	2021	Fracking, Regulations, enforcement
Abstract The South African government is actively pursuing unconventional oil and gas (UOG) extraction to augment energy supplies in South Africa, but it risks damaging water quality. The Department of Water Resources and Sanitation recently released regulations to protect water resources during UOG extraction for public comment. Regulations are one of the main tools that can be used to minimise UOG extraction impacts on water resources and enhance an environmentally sustainable economy. This tool must however be used correctly. Many states in the US and Canada have extensive regulations to protect water resources during UOG extraction but they are often ineffective, either because they were poorly drafted or because they are not properly enforced. Since South Africa is a water-scarce, groundwater-dependent country, we asked South African groundwater experts what regulations are needed and how to enforce them. Focusing on the interface between science and public policy, we critically analyse and recommend the most appropriate fracking regulations to protect groundwater resources. Additionally, we consider the enforcement mechanisms required to ensure the proper regulation of fracking. The results from this study can assist the government in ensuring that regulations that they are currently drafting and finalising, are appropriate to protect groundwater resources, and that they would be able to enforce them effectively.
Towards The Effective Management Of Groundwater Resources During Unconventional Gas Mining	Surina	Esterhuyse	National	2013	Unconventional gas
Abstract Unconventional gas mining is a new and unprecedented activity in South Africa that may pose various risks to groundwater resources. According to legal experts, South Africa does not currently have the capacity to manage this activity effectively due to various lacunae that exist in the South African legislation. The possible impacts of unconventional gas mining on groundwater, as well as governance strategies that are used in countries where unconventional gas mining is performed; have been analysed and will be discussed. Based on possible impacts and strategies to manage and protect groundwater internationally, possible governance options for the management of South Africa’s groundwater resources are proposed
Towards The Effective Management Of Groundwater Resources During Unconventional Gas Mining	Surina	Esterhuyse	South Africa	2013	Unconventional gas
Abstract Unconventional gas mining is a new and unprecedented activity in South Africa that may pose various risks to groundwater resources. According to legal experts, South Africa does not currently have the capacity to manage this activity effectively due to various lacunae that exist in the South African legislation. The possible impacts of unconventional gas mining on groundwater, as well as governance strategies that are used in countries where unconventional gas mining is performed; have been analysed and will be discussed. Based on possible impacts and strategies to manage and protect groundwater internationally, possible governance options for the management of South Africa’s groundwater resources are proposed.
Successful field pilot scale nitrate removal using low technology methods	Sumaya	Israel		2015
Abstract Decades of monitoring, characterising, and assessing nitrate concentration distribution and behaviour in the soil profile and it's pathway into groundwater have resulted in a good understanding of its distribution in the country. While the national distribution is of great importance, site specific conditions determine fate, transport, and ultimately concentration in a specific area. Field experimental work included installation of a barrier containing a cheaply available carbon source to treat groundwater. The "reactor"/ tank with dimensions- 1,37m height, 2.15m diameter used for the experiment was slotted for its entire circumference by marking and grinding through the 5mm thick plastic material. The top section was left open to allow for filling and occasional checking of filled material during the experiment. The tank was packed with Eucalyptus globulus woodchips which was freely available at the site. Concentrations of groundwater nitrate at the site were well over what could be expected in any naturally occurring groundwater systems, and would result only by major anthropogenic activities in unconfined aquifer areas of South Africa. The changes in parameter concentrations with time were measured in order to determine the efficiency and life span of the carbon source used for the experiment. This paper considers 35 months of monitoring at a site where a low technology method was implemented. Field implementation was tested at a site which previously experienced some NH4NO3 spills. Main results from the field work showed that nitrate was totally removed at the treatment zone and surrounding boreholes, and even sulphate and NH4+ were removed during the experiment. This shows that the woodchips were successful in affecting denitrification for 35 months. Data also shows that boreholes further downstream from the tank had reduced NO3-, SO42- and NH4+ levels. Using the available biodegradable carbon for the woodchips based on its composition, a barrier lifespan could be determined. The results of calculations showed that the barrier would be effective for at least another 6.9 years from the period of the last sampling date. A total lifespan of about 10 years can thus be estimated.
Western Cape Coastal Groundwater Resources: Potential For Artificial Recharge And Conjunctive Use	Sumaya	Israel	Western Cape	2017	groundwater potential, artificial recharge, mixed use
Abstract Western Cape groundwater resources are often considered in isolation, per quaternary or aquifer depending on the level of management. This is an attempt to look at groundwater resources in its entirety for the major aquifer areas of the Western Cape. Atlantis in the Western Cape has been successfully operating for about 4 decades using artificial recharge, recycling of treated waste water and storm water. It is currently under used due to clogging of borehole screens and pumps with iron. However, there is no question of the potential for use and the volumes of water that the aquifer is able to supply. The Cape Flats Aquifer (CFA) has been identified in the past as a potential source to augment Cape Town’s municipal water supplies. Studies to assess the viability of the aquifer as a water supply to the Cape Metropolitan area all concluded that the CFA is a viable resource that can supply a projected sustainable yield of about 18 Mm3/a of bulk water. Artificial recharge was tested in the Cape Flats and showed great promise. The Langebaan area along the West Coast has an existing well field supply, which is able to supply the town. Artificial recharge was tested in Langebaan Road during 2009, and showed promise for the Langebaan area. In essence, the Western Cape has a large volume of untapped resources which could improve the water situation. Climatic data, groundwater levels, and chemistry for these areas are explored to consider the potential for artificial recharge, abstraction and use and the extent to which artificially recharged and existing resources can supply the coastal areas of the Western Cape.
The Role Of High Resolution Site Characterisation In Informing Remediation Decisions At A Petroleum Release Site Overlying A Fra	Steve	McKeown		2015
Abstract Inadequate characterization of petroleum release sites often leads to the design and implementation of inappropriate remedial systems, which do not achieve the required remedial objectives or are inefficient in addressing the identified risk drivers, running for lengthy periods of time with little benefit. It has been recognized that high resolution site characterization can provide the necessary level of information to allow for appropriate solutions to be implemented. Although the initial cost of characterization is higher, the long-term costs can be substantially reduced and the remedial benefits far greater. The authors will discuss a case study site in the Karoo, South Africa, where ERM has utilized our fractured rock toolbox approach to conduct high resolution characterization of a petroleum release incident to inform the most practical and appropriate remedial approach. The incident occurred when a leak from a subsurface petrol line caused the release of approximately 9 000 litres of fuel into the fractured sedimentary bedrock formation beneath the site. Methods of characterization included: - Surface geological mapping of regionally observed geological outcrops to determine the structural orientation of the underlying bedding planes and jointing systems; - A surface electrical resistivity geophysics assessment for interpretation of underlying geological and hydrogeological structures; - Installation of groundwater monitoring wells to delineate the extent of contamination; - Diamond core drilling to obtain rock cores from the formation for assessment of structural characteristics and the presence of hydrocarbons by means of black light fluorescence screening and hydrocarbon detection dyes; - Down-borehole geophysical profiling to determine fracture location, fracture density, fracture dip and joint orientation; and - Down-borehole deployment of Flexible Underground Technologies (FLUTe?) liners to determine the precise vertical location of light non-aqueous phase liquid (LNAPL) bearing joint systems and fracture zones, and to assist in determining the vertical extent of transmissive fractures zones. ERM used the information obtained from the characterization to compile a remedial action plan to identify suitable remedial strategies for mitigating the effects of the contamination and to target optimal areas of the site for pilot testing of the selected remedial methods. Following successful trials of a variety of methods for LNAPL removal, ERM selected the most appropriate and efficient technique for full-scale implementation. {List only- not presented}
Optimizing borehole performance through dynamic flow and chemistry profiling	Steve	Kalule		2021	Drinking water standards, Groundwater Quality, supply boreholes, remediation system, optimised well design, well profiling
Abstract Stringent drinking water standards for constituents like chromium, arsenic, and nitrates, combined with continually higher demand for groundwater resources have led to the need for more efficient and accurate well characterization. Many boreholes are screened across multiple aquifers to maximize groundwater production, and since these aquifers can have different water qualities, the water produced at the wellhead is a blend of the various water qualities. Furthermore, the water entering a well may not be distributed equally across the screened intervals, but instead be highly variable based on the transmissivity of the aquifers, the depth of the pump intake, the pumping rate, and whether any perforations are sealed off due to physical, chemical, or biological plugging. By identifying zones of high and low flows and differing water qualities, well profiling is a proven technology that helps optimize operational groundwater production from water supply boreholes or remediation systems. This frequently results in increased efficiencies and reduced treatment costs. By accurately defining groundwater quantity and quality, dynamic profiling provides the data needed to optimize well designs. Conventional exploration methods frequently rely on selecting well screen intervals based on performing and analyzing drill stem tests for one zone at a time. Using dynamic flow and water quality profiling, the transmissivity and water quality can be determined for multiple production zones in a matter of one to two days. It also allows the location and size of the test intervals to be adjusted in the field, based on real-time measurements. In this paper we discuss dynamic well profiling techniques with project case examples of characterization different types groundwater boreholes for a variety of applications and industries resulting in significant cost saving and sustainable water abstraction.
The Role Of High Resolution Site Characterisation In Informing Remediation Decisions At A Petroleum Release Site Overlying A Fractured Rock Aquifer In South Africa	Steve	McKeown	National	2013	remediation, petroleum, fractured rock, aquifer
Abstract Inadequate characterisation of petroleum release sites often leads to the design and implementation of inappropriate remedial systems, which do not achieve the required remedial objectives or are inefficient in addressing the identified risk drivers, running for lengthy periods of time with little benefit. It has been recognised that high resolution site characterisation can provide the necessary level of information to allow for appropriate solutions to be implemented. Although the initial cost of characterisation is higher, the long-term costs can be substantially reduced and the remedial benefits far greater. The authors will discuss a case study site in the Karoo, South Africa, where ERM has utilised their fractured rock toolbox approach to conduct high resolution characterisation of a petroleum release incident to inform the most practical and appropriate remedial approach. The incident occurred when a leak from a subsurface petrol line caused the release of approximately 9 000 litres of fuel into the fractured sedimentary bedrock formation beneath the site. Methods of characterisation included: Surface geological mapping of regionally observed geological outcrops to determine the structural orientation of the underlying bedding planes and jointing systems. A surface electrical resistivity geophysics assessment for interpretation of underlying geological and hydrogeological structures. Installation of groundwater monitoring wells to delineate the extent of contamination. Diamond core drilling to obtain rock cores from the formation for assessment of structural characteristics and the presence of hydrocarbons by means of black light fluorescence screening and hydrocarbon detection dyes. Down-borehole geophysical profiling to determine fracture location, fracture density, fracture dip and joint orientation. Down-borehole deployment of Flexible Underground Technologies (FLUTe®) liners to determine the precise vertical location of light non-aqueous phase liquid (LNAPL) bearing joint systems and fracture zones, and to assist in determining the vertical extent of transmissive fractures zones. ERM used the information obtained from the characterisation to compile a remedial action plan to identify suitable remedial strategies for mitigating the effects of the contamination and to target optimal areas of the site for pilot testing of the selected remedial methods. Following successful trials of a variety of methods for LNAPL removal, ERM selected the most appropriate and efficient technique for full-scale implementation.
The Structural Hydrogeology Of A Gold Mine In Mali	Stephen	Fonkem	Mali	2013	Hydrogeology, gold mining
Abstract The occurrence of groundwater around a mined-out open pit, connected to an active underground working is not completely understood, but it is fascinating. It has been established that gold mineralisation in study area was structurally controlled. The geomorphology of the local drainage system is highly controlled by the fold or fault architecture. Surface water flowed through, and eroded open fractures in exposed damaged zones (zone of subsidiary structures surrounding a fault). Previous conceptual hydrogeological models of groundwater system suggested is a two-aquifer system, consisting of a fractured aquifer overlain by a weathered aquifer, where groundwater flow mimics surface topography. Based on recent drilling and reassessment of historic geological and hydrogeological data, the groundwater system around the mine could not only be described in terms of an elevation or stratigraphic units, as traditional aquifers are. The weight of the study was placed on accurately understanding the groundwater system in the deposit area by using structural hydrogeology as a best tool in the hydrogeological tool box. From a hydraulic head point of view, in addition to the weathered groundwater system, there are as many bedrock aquifers and aquitards as there are major structures in the pit area.
Modelling Mine Water Rebound With MODFLOW	Stephen	Fonkem		2015
Abstract A review from international literature discredits the capability of MODFLOW to simulate mine water rebound, due to the nonstandard hydrogeology of underground mine systems. The conceptual understanding is that, after cessation of dewatering, mine water inflow rates and hydraulic heads are related to the void-volume, the differences in head between the water in the mine void and head dependent source, plus natural recharge to the mine voids. The flooded mine voids in the study area are partially underlain by a dolomitic aquifer. The other head dependent source of inflow into the mine voids are the surrounding and overlying Karoo aquifers. Head independent inflow rates into the mine voids, using the long term decant rates, was estimated to be 0.2% of rainfall. During mining, dewatering occurred at approximately 3 to 6 Ml/d. The objective of the model was therefore to simulate the changes head-dependent inflow rates during the rebound period. Analysis of the water level recovery data depicted that once the mine filled up with water, the hydraulic head of the mine rose with the elastic storage coefficient value of the mine void and not the specific retention as conditions changed from unconfined to confined. A three layer model was setup, to represent the two seams mined, separated by a deep Karoo aquifer. The presence of the dolomite on the mine floor was incorporated using the general head boundary package. Head dependent influx from overlying shallow and intermediate Karoo aquifers were simulated using the river package. All model layers were simulated as confined, initially to avoid model convergence issues. The confined setup proved to be the core in simulating mine water rebound with MODFLOW. The modelling exercise showed that storage during rebound is a boundary condition. This simply means that the complexity of mine water rebound can only be achieved in MODFLOW by proper time stepping and dividing the model into different stress periods to represent the changes in storage. Rebound in the study area, modelled with 21 stress periods produced a perfect water level recovery data for the different mine compartments. This was achieved by applying storage capacities of between 0.3 to 0.006 to simulate rebound during unconfined conditions, and values of between 10-4 and 10-5 when the mine void is flooded. The results showed that the inflow from the dolomitic aquifer steadily decreased from 4121 m3/d to 0 m3/d as the mine hydraulic head increased and rose over the head in the dolomitic aquifer. During the same period, inflow from the surrounding Karoo aquifers decreased from 2422 m3/d to less than 10 m3/d. The results of the model were very important in determining the volumes of water to be abstracted from the mine voids for ash-backfilling. {List only- not presented}
Vapour Intrusion Risk Assessment: Case Studies using Modelling and Direct Measurement from Contaminated Sites in South Africa	Stephen	McKeown		2015
Abstract Vapour intrusion (VI) is recognized to drive human health risk at numerous sites that have been contaminated by petroleum products and other volatile contaminants. The risks related to VI are typically evaluated using direct measurement (vapour sampling) or modelling methods. ERM has developed a toolbox approach using a combination of exclusion distance criteria, direct measurement and modelling methods to assess risks and achieve closure. For direct measurement, samples of vapour are taken beneath the floor slab of buildings (sub-slab sampling) or from the air inside the buildings (indoor air sampling). Modelling methods are often used to estimate the partitioning of volatile contaminants from soil or groundwater sources into the vapour phase and the subsequent transport of vapours from the subsurface environment into habitable buildings. A limitation of modelling approaches is that they are designed to be conservative to be adequately protective of sensitive receptors. VI models also do not typically take into account the degradation of hydrocarbon vapours in the presence of oxygen, which has been found to be a significant process for petroleum hydrocarbons. The authors have compiled a dataset of petroleum vapour and groundwater results from over 50 petroleum release sites in southern Africa. These data were used to develop exclusion distance criteria for vapours emitted from contaminated groundwater sources (i.e. distance from the source at which sufficient aerobic attenuation has occurred for the VI risk to be negligible). A standard "lines of evidence" approach has been applied to the assessment of VI risk by firstly applying the exclusion distance criteria to sites with groundwater contaminant plumes beneath buildings, and if these are met, the sites are considered to have no unacceptable VI risk. Where exclusion screening criteria are not met, risk is estimated using modelling, and if a potential risk is predicted, then direct sub-slab measurements are taken to more accurately assess the risk. Lastly, where sub-slab assessment predicts a potential VI risk, indoor vapour measurement are taken to evaluate actual risk, taking into account interferences from other sources and background levels of contaminants. Mitigating measures can then be applied as appropriate. Various case studies will be presented including direct measurements at industrial and residential sites overlying contaminant plumes and modelling methods at residential properties adjacent to service station sites. A risk-based approach to the assessment of contaminated land provides a sustainable and cost effective methodology, and also avoids unnecessary remediation. The results show that VI risks can be adequately addressed with a toolbox approach using multiple lines of evidence.
The Structural Hydrogeology Of A Gold Mine In Mali	Stephen	Fonkem	Mali	2013	Hydrogeology, gold mining
Abstract The occurrence of groundwater around a mined-out open pit, connected to an active underground working is not completely understood, but it is fascinating. It has been established that gold mineralisation in study area was structurally controlled. The geomorphology of the local drainage system is highly controlled by the fold or fault architecture. Surface water flowed through, and eroded open fractures in exposed damaged zones (zone of subsidiary structures surrounding a fault). Previous conceptual hydrogeological models of groundwater system suggested is a two-aquifer system, consisting of a fractured aquifer overlain by a weathered aquifer, where groundwater flow mimics surface topography. Based on recent drilling and reassessment of historic geological and hydrogeological data, the groundwater system around the mine could not only be described in terms of an elevation or stratigraphic units, as traditional aquifers are. The weight of the study was placed on accurately understanding the groundwater system in the deposit area by using structural hydrogeology as a best tool in the hydrogeological tool box. From a hydraulic head point of view, in addition to the weathered groundwater system, there are as many bedrock aquifers and aquitards as there are major structures in the pit area.
Simulation of Underground Mine Flooding with EPANET and MODFLOW	Stephen	Fonkem	Free State	2015	mine shaft, flooding, modelling, MODFLOW
Abstract Underground mine water rebound prediction in its simplest form can be simulated linearly by comparing the volume of the mined ore with long-term average recharge rate to obtain an estimate of the time which will elapse before the workings are full to their decant elevation. This type of linear interpolation of rising water levels can lead to an over estimation or an underestimation of the date when mine voids will flood to the critical levels. This is due to the fact that this method cannot account for the variability and interconnection between different mine voids and also does not consider the change in storage over time which is an important factor. In an abandoned underground water environment, water is stored in flooded mine stopes (tanks) and flows through a network of haulages (pipes). Due to the dip and strike of the ore body, the mined stopes are extensively interconnected on multiple levels and bounded by faults and dykes, so that water rising within any one tank will display a common level throughout that tank. At certain elevations, adjoining tanks may be connected via a discrete "overflow point", which may be a holding or permeable geological features. Water level rise during flooding is a function of head-dependent inflows from adjoining mine aquifers and/or other tanks, and the distribution of storage capacity within the tank. The process of flooding occurs independently in two (or more) adjoining tanks until such time as the water level in one or more of the tanks reaches an overflow point. Inter-tank transfers of water will then occur until the difference in head between the two tanks either side of each overflow point is minimised. To apply the conceptual model stated above, EPANET 2 was used to predict the risk of flooding of a mine shaft, in the Free State Goldfields, if dewatering is discontinued. Considerations on stope volumetric calculations, haulage interconnections, modelling assumptions and predictions, are presented.
The Structural Hydrogeology of a Gold Mine	Stephen	Fonkem	South Africa	2015	gold mining, fractures, hydrogeological models
Abstract Gold mineralization in study area is structurally controlled. The geomorphology of the local drainage system is highly controlled by the fault architecture. Surface water flowed through, and eroded open fractures in exposed damaged zones (zone of subsidiary structures surrounding a fault). Previous conceptual hydrogeological models of groundwater system suggested is a two-aquifer system, consisting of a fractured aquifer overlain by a weathered aquifer, where groundwater flow mimics surface topography. Based on recent drilling and reassessment of historic geological and hydrogeological data, the groundwater system cannot only be described in terms of an elevation or stratigraphic units, as traditional aquifers are, but instead in relationship with the folds and faults. The fractured aquifer system around the mine pit is structurally compartmentalized both laterally and vertically, as depicted by the variance in static hydraulic heads and borehole yields over short distances. The un-fractured mass has very low drainable porosity. Virtually all water is contained in fractures. The main fracture zones north and west of the pit typically yield 1.3 to 2 L/s
Using geophysics to detect water-hosting fractures in the Vredefort Dome: A training opportunity	Stephanie	Enslin	Vredefort Dome, Gauteng	2021	Field School, fractures, geophysical methods
Abstract Tamilo, T; Webb, S.J. The Vredefort Dome 120 km southwest of Johannesburg is a meteorite impact crater that formed at approximately 2 Ga. The region hosts farmland, and the town of Parys is situated in the northwestern part of the dome. The dome is the location of the annual Wits University/AfricaArray Geophysical Field School. The aim of the field school is to teach geoscience students several geophysical techniques while conducting scientific research in the area. A geophysical survey during the 2019 field school over an open field just outside of Parys revealed a buried fracture that hosts ground water. A 150 m long magnetic profile over the fractures shows a magnetic low (approximately 500 nT) that correlates with a low resistivity region on the inverted electrical resistivity data (dipole-dipole method). Euler deconvolution depth estimates and magnetic modelling estimate an overburden thickness of around 10 m and a similar fracture thickness. The magnetic low of the fracture is due to weathering and removal of any magnetic material in the granites in the region. Two existing boreholes that lie 618m due south and at a 10 m lower elevation have water levels of around 6.4 m. Both boreholes lie near a riverbed and vegetation, and appear to lie along an extension to the fracture. This fractures detected using geophysical methods seems to form part of a larger fracture system within the Vredefort Dome, that is linked to the formation of the dome. These fractures provide a vital source of water for the local farming community.
Water resource management in tectonically active volcanic regions: Towards an in-depth understanding of Mt. Fuji’s hydrogeology	Stephanie	Musy		2023	SW-GW interactions; tracers; modelling
Abstract Mt. Fuji is the iconic centrepiece of a large, tectonically active volcanic watershed (100 km2 ), which plays a vital role in supplying safe drinking water to millions of people through groundwater and numerous freshwater springs. Situated at the top of the sole known continental triple-trench junction, the Fuji watershed experiences significant tectonic instability and pictures complex geology. Recently, the conventional understanding of Mt. Fuji catchment being conceptually simple, laminar groundwater flow system with three isolated aquifers was challenged: the combined use of noble gases, vanadium, and microbial eDNA as measured in different waters around Fuji revealed the presence of substantial deep groundwater water upwelling along Japan’s tectonically most active fault system, the Fujikawa Kako Fault Zone [1]. These findings call for even deeper investigations of the hydrogeology and the mixing dynamics within large-scale volcanic watersheds, typically characterized by complex geologies and extensive networks of fractures and faults. In our current study, we approach these questions by integrating existing and emerging methodologies, such as continuous, high-resolution monitoring of dissolved gases (GE-MIMS [2]) and microbes [3], eDNA, trace elements, and integrated 3-D hydrogeological modelling [4]. The collected tracer time series and hydraulic and seismic observations are used to develop an integrated SW-GW flow model of the Mt. Fuji watershed. Climate change projections will further inform predictive modelling and facilitate the design of resilient and sustainable water resource management strategies in tectonically active volcanic regions
Using Citizen Science Approach to Design Implementation of Science-Policy Interaction Plan for Optimal Use and Protection of Groundwater Resources at Quaternary Scale, South Africa	Stanley	Nzama	South Africa	2017	Citizen-science, ecological model, adaptive management, groundwater resource directed measures, resource directed measures, science-policy interaction
Abstract Using citizen science approach to influence implementation of science-policy interface concept leads to optimal use and protection of groundwater resources that ensures sustained research for practical policy dialogue. Mere determination of water resource classes, the reserve and resource quality objectives within the resource directed measures (RDM) concept for protection of groundwater water resources without considering implementation aspects, propels for defiance in policy implementation at local scale. Although water resource classes and resource quality objectives have not yet been implemented at any catchment at this stage, however findings indicate that in some areas challenges have been experienced with preliminary Reserve implementation at local level, especially in water use license applications. There is a need for an orthodox link between RDM and Source Directed Controls (SDC) to complement current methods used and processes followed in GRDM projects for uncontested RDM implementation to ensure sustainable groundwater resource protection especially at local site where the resource reside. The argument in this paper is that a feasible implementation for GRDM at local level provides science-policy interface platform for the sustained operation of the science-citizen approach. The objective of study was to design a field-tested conceptual model of science-policy interaction that monitors and evaluates GRDM intervention. How policy implementation and evaluation utilizes scientific research outputs at local level were examined using ecological model. Key findings indicated that (i) systems analysis approach was lacking at local level (ii) practical assessments of GRDM at local specific quaternary catchment scale was not adequate (iii) optimal reserve determination methodology for uncontested water utilisation was not clear to provide proper guidance for water use license application (iv) Reflective operational plan (GRDM monitoring) to enhance science-policy interaction was not available at quaternary catchment scale (v) Best practices of adaptive management principle to sustain groundwater resource protection were limited at local level. From these results, it can be said that the up scaling of the current approach for RDM especially GRDM requires refinement for practical uptake of scientific results. The study recommended that a feasible implementation plan for GRDM at local level that provides science-policy interface platform for the sustained operation of the science-citizen approach need to be designed, implemented, monitored and evaluated with citizens to inform reflective policy implementation. Although, the results of this study are not conclusive, the insights as a starting point for proactive buy in approach is provided to ensure that science-policy interaction remain practical and relevant to scientists and policy makers as well as society.
Science-Policy Nexus: Assessing role of groundwater resource directed measures in water resources protection practice, case of Schoonspruit-Koekemoerspruit River Catchment, South Africa	Stanley	Nzama	Gauteng, North West	2021	RDM, aquifer protection, knowledge sharing, policy implementation
Abstract The argument in this paper is that improved understanding of science-policy integration, where physical bases of natural science is combined with practice in managing water resource challenges, becomes critical in translating scientific knowledge into effective and sustainability solutions linked to groundwater resource protection. Such hypothesis should be attested at locally relevant scale where water resources reside and where water utilization takes place. This paper provides a practical case-study of how science-policy integration can directly impacts groundwater resource protection practice from a local, and national perspective using strategies of groundwater resources directed measures. A combination of literature surveys, and desktop record review methods were used for the purpose of data collection from published literature and publicly accessible national databases of the Department of Water and Sanitation (DWS). Collected data were analysed using document analysis, descriptive statistics, and case study analysis methods. Based on the analysis, three types of science-policy nexus theoretical models exist in practice, namely, 1) science-policy integration, 2) policy-science integration, and 3) mixed integration. From a national perspective, the analysis showed that South Africa is able to practically apply science-policy nexus in policy implementation practice for water resources protection, and that such practice depicts a mixed integration model of the nexus. Case study analysis of the Schoonspruit-Koekemoerspruit River Catchment provided insight on how localized operationalization of groundwater resource directed measures facilitates sustained groundwater resources protection for water availability and sustainable utilization. This study provides an exemplary for collaborations between researchers and/or scientists and policy makers to ensure that science research is answering policy-relevant questions and that results from scientific work are readily available for policy implementation. In addition, there is adequate evidence to indicate that science-policy nexus can be designed and prioritized to support sustainable development agenda on groundwater resilience, and visibility at various levels.
Hydrogeological Characterization Of The Pietermaritzburg Formation, Ecca Group: Case Study At The Ukulinga Research Farm, Pietermaritzburg.	Sphindile	Mtshali	Pietermaritzburg Formation, Ukulinga Research Farm	2019	Aquifer characterization, Environmental Isotopes, Groundwater level monitoring, Hydrochemistry, Ecca Group
Abstract Continued population growth, economic development and climatic change have increased the demand for water supply in South Africa. As a result, most surface water systems have been exhaustively developed, increasing dependency on groundwater, including on meager aquifers during dry spells. This study aims to characterize the hydrogeology of the Pietermaritzburg Formation, a poorly productive aquifer that has been targeted for borehole sitting during drought years though with poor success rate. Pumping test analyses, monthly monitoring of groundwater level, electrical conductivity (EC), pH, water temperature and environmental isotopes (?2H, ?18O) were undertaken in 2018. Analyses of the pumping test data of the pumping well using the Theis and Cooper-Jacob method has returned hydraulic conductivity (K), transmissivity (T) and storativity (S) values of 4.1210-6 m/day, 1.5610-4 m2/day and 1.5210-4, respectively. Analyses of observation well data located west 20 m from the pumping well gave K, T and S values of 1.7910-7 m/day, 6.9510-6 m2/day and 2.810-10, respectively. A second observation well located 33 m north from the pumping well did not show any water level response to the pumping. Additionally, the rate of water level recovery was very slow both in the pumped well and one of the observation wells. These test results indicate that the investigated aquifer is not only poorly productive but also heterogeneous, compartmentalized in nature and not feasible for sitting water supply wells. Rainfall recharge estimated using the water table fluctuation method (WTF) based on monitored groundwater level data is about 28 mm/a or 3.5% of mean annual precipitation (MAP). The groundwater level, temperature and EC monitoring indicate that as new rainfall recharge reaches the aquifer, the groundwater level and temperatures increases while the EC decreases as a result of salinity reduction because of dilution. Similarly, as the groundwater level declines as a result of prolonged dry seasons, the groundwater temperature drops, while EC increases due to increased salinity. Furthermore, monthly environmental isotope monitoring shows that all the samples plot along the local meteoric water line (LMWL) indicating that groundwater is recharged from local precipitation. The groundwater at the studied site is characterized by Ca-Na-HCO3 hydrochemical facies indicating an early stage of rock-water interaction
Assessment Of Groundwater Potential Using The Wetspass Model	Sophia	Rwanga	National	2013	groundwater potential, Hydrogeological, GIS
Abstract Quantification of hydrological processes is required for many projects related to potential groundwater recharge. Thus, investigation on various hydrogeologic conditions is paramount. Changes of climate can affect the hydrological cycle by altering groundwater recharge. As a result, an understanding of the hydrological conditions is essential to make sensible predictions of the possible groundwater recharge. Thus WetSpass, which yields spatially varying groundwater recharge using hydrological inputs, can be used together with a geographical information system to quantify the environmentally acceptable flow regime of the catchment area. This paper presents an overview on the use of WetSpass in combination with GIS on quantification of groundwater potential which will assist to sustainable groundwater development in the catchment area. Previous applications are presented.
HALF FULL OR HALF EMPTY ? Groundwater surface water interactions – An ever-increasing focus for water resource management.	Sonia	Veltman	South Africa various	2021	Gw-Sw interaction, wellfield testing, resource management, numerical model
Abstract More often these days we hear concerns from water users regarding “how much water is the newly drilled borehole of a neighbor extracting from “their” river water”. These are serious question with serious repercussions for sustainable use and economic development. No one wants to lose what they have invested in. On the other hand, from a groundwater perspective, this is very one sided. Numerical modelling solutions are often proposed to clients as a more accurate method of determining the groundwater surface water interaction, with the addition of volumes removed from the modelling domain, to present to decision makers the changes in volumes of discharge into streams or volumes of infiltration of stream water into the aquifer. However, this is an expensive and time-consuming exercise, and will most likely incur additional costs to accumulate sufficient meaningful data sets for input into these detailed models. A robust combination of analytical and numerical solutions is proposed, while keeping aquifer assumptions conservative, where a lack of regional data exist. This is useful in quantifying this interaction and associated volumes better without the full time and cost associated with calibrated regional flow and transport models. Analytical calculations assist in the quantification of the aquifer’s hydraulic and physical properties and is used to conceptualize flow better and determine the inputs for a conservative well field scale numerical model, in which the change in flow between groundwater and surface water system are also evaluated. The well field scale model is calibrated in a fraction of the time as a conventional flow model (less than 20%), while volumes derived is defendable and based on measurable data. This combination is viewed to be a critical step in providing time effective solutions
Groundwater In Sustainable Development Goal 6: The South African Case Study	Sivashni	Naicker		2019	Domesticate, South Africa, United Nations
Abstract South Africa has committed to achieving the United Nations Sustainable Development Goals (SDG's) by 2030. But what does this mean and how does groundwater fit in to this? SDG 6 in particular focuses on ensuring universal access to safe and affordable drinking water for all by 2030. SDG 6 requires that the country protects and restores water-related ecosystems such as forests, mountains, wetlands, aquifers and rivers which are essential if we are to mitigate water scarcity. To accomplish this, South Africa has proceeded to align various plans, strategies, and policies to encompass the targets of the SDG's. This paper will focus on SDG sub-goal 6.3 which incorporates improvement of water quality and sub-goal 6.6 which involves protection and restoration of ecosystems. The methodology given by the UN for the groundwater in indicator 6.3.2 stipulates that countries are required to report on "proportion of water with good ambient water quality", in South Africa however we had to domesticate the indicator i.e. render it suitable for South African conditions so we changed the methodology to "proportion of water the conforms to the Water Quality Objectives (WQO's)" but there are virtually no WQO's developed for groundwater. Four core groundwater quality parameters (Electrical Conductivity, pH, Nitrate and Sulphate) are available through ZQM stations categorized through 65 hydrogeological (Vegter) regions. Groundwater water quality baseline is calculated as a reference period/range per hydrogeological region. For SDG 6.6, the indicator required for groundwater is "Quantity of groundwater within aquifers" The methodology received by the UN for "Quantity of groundwater within aquifers" required a baseline (average reference period of five years) in meters per hydrogeological region. This indicator is again domesticated for South Africa and based on the 40-60 percentiles of groundwater levels per hydrogeological region. There are a number of future indicators that can be included for aquifers under SDG 6.6, but the groundwater sector needs to come together and decide what is important to report on. These SDG targets reporting has given the Water and Sanitation sector a new look at data. It has forced us to critically think of concepts such as baseline and performance monitoring. We now know where our data gaps and targets are, and we have to provide an action plan to address these.
Development of an Aquifer Management Plan for the Polokwane Urban Complex	Sivashni	Naicker	Limpopo	2021	NWA 1998, wellfields, Aquifer management plan
Abstract The National Water Act, 1998 (Act 36 of 1998) requires water resources management be driven at a local level, in keeping with the local nature of water systems. Polokwane Local Municipality (PLM) as the Water Services Authority, is responsible for supplying adequate domestic water to 16 Rural Water Schemes and Groundwater Schemes. The Department of Water and Sanitation (DWS) Masterplan highlighted that the DWS, Catchment Management Agencies and Water Boards need to develop wellfields and management plans to ensure sustainable use of aquifers. The Aquifer Management Plan (AMP) for the Polokwane Urban Complex (PUC) within the Olifants-Sand Water Supply Scheme was developed with an overall aim of achieving integrated and adaptive management of the aquifer. This is to assist in confronting climate change challenges and water security at local level. The AMP forms part of the Integrated Water Resource Management and should be seen in the context of other related guidelines and activities, such as catchment management, water conservation and demand management, waste water management, and water resource planning and management. Extensive consultation with PLM and various other stakeholders as part of the Aquifer Management Plan was meant to foster a groundwater management relationship between the Department, PLM and other stakeholders to create an enabling environment for implementation of the Aquifer Management Plan. A set of goals, targets and actions were developed for the Aquifer Management Plan These goals and targets serve as steps that allow for ‘zooming’ into the more specific actions. During consultations with the PLM, relevant Professional Service Providers, the DWS Limpopo Provincial Office and numerous other stakeholders, 75 actions within the 10 goals were identified. Ultimately, an Aquifer Management Plan had to identify actions that can improve groundwater resource management within the Polokwane Urban Complex and develop a supportive cross-institutional relationship in which to pursue them.
Measuring Hydraulic Conductivity Across Different Scales Using Varying Methods To Develop A Hydraulic Conductivity Model	Sispho	Dlakiya	Cape Town	2021	Poster, hudraulic conductivity, methods, scales, infiltrometer, vertical infiltration
Abstract This paper describes the calibration and testing processes of three methods of measuring hydraulic conductivity (slug test, mini disk infiltrometer and particle size distribution (sieves)) across varying scales (field and lab). The methods used in the field are the slug test and sieves which were used in four different wells of the Rietvlei wetland in Cape town and the mini disk infiltrometer was used in a grid developed in one of the Nelson Mandela University Reserve salt pans. The mini disk infiltrometer and the slug test are used to determine the saturated hydraulic conductivity (Ks) of altered or unaltered soil samples under controlled conditions in a laboratory, and that is a key parameter to understand the movement of water through a porous medium. The mini disk infiltrometer requires a small volume of water and has a compact size which makes it convenient for laboratory soil specimens, especially when studying vertical infiltration. Infiltration shows a dependence on the compaction and saturation of soil while hydraulic conductivity increases with depth in a simulated aquifer.