Magister Scientiae - MSc (Environ & Water Science)

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A comparison of Brine evaporation rates under controlled conditions in a laboratory
(University of the Western Cape, 2018) Bent, Denzil; Petrik, Leslie
There are growing concerns around the environmental issues related to processed water as the demand for potable water is on the increase in South Africa. Effluents discharged from various sectors such as water treatment facilities pose a constant threat to the environment and natural water resources, including rivers and groundwater due to their poor chemical and physical composition. As a result, the demand for predicting the elevated concentrations of salts in a spatial and temporal dimension is constantly growing. The effluent at the eMalahleni water reclamation plant in Mpumalanga, South Africa, is being processed through a triple reverse osmosis that improves the water quality of the mine water to potable standards. Two water quality streams emerge from this process, i.e. a potable standard and the other a brine concentrate which is stored in ponds. Brine ponds are used for inland brine disposal in the eMalahleni water reclamation plant. The large volumes and limited capacity to store brines has placed great emphasis on enhanced evaporation rates to increase the efficiency of the ponds. In order to improve the rate of brine evaporation in the pond, an understanding of the effect of brine salt content and other parameters affecting the rate of evaporation is required. This study aimed at establishing the physical and chemical behaviour of the brine from the eMalahleni plant in a controlled environment. The investigation incorporated actual brine from the eMalahleni plant as well as synthetic salts typical of the major components of the eMalahleni brine.
An assessment of the contribution of surface and subsurface flows to river flows of the Sandspruit in the Berg River Catchment, South Africa.
(University of the Western Cape, 2018) Damons, Matthew; Mazvimavi, D
Studies have shown that the primary origin of salinity in river flows of the Sandspruit in the Berg Catchment located in the Western Cape Province of South Africa was mainly a result of atmospheric deposition of salts. The salts are transported to rivers through surface runoff and subsurface flow (i.e. through flow and groundwater flow). The purpose of this study was to determine the contributions of subsurface and surface flows to the total flows in the Sandspruit, Berg Catchment. Three rain events were studied. Water samples for two rain events were analysed for environmental tracers ?18O, Silica or Silicon dioxide (SiO2), Calcium (Ca2+) and Magnesium (Mg2+). Tracers used for two component hydrograph separation were ?18O and SiO2. The tracers, Ca2+ and Mg2+, revealed inconsistent contributions of both subsurface flow and surface flow. Two component hydrograph separations indicated is that groundwater is the dominant contributor to flow, while surface runoff mainly contributes during the onset of the storm event. Groundwater response to precipitation input indicated that boreholes near the river have a quicker response than boreholes further away from the river. Boreholes nearer to the river also indicate higher water levels in response to precipitation, in comparison to boreholes further from the river.
An assessment of wetland vulnerability to artisanal mining in Zimbabwe
(Universty of the Western Cape, 2024) Dube, Thandekile; Dube, Timothy
The preservation of wetlands and pristine riverine eco-hydrological systems in sub-Saharan Africa, is crucial for biodiversity, ecosystem stability, and water availability. These face escalating threats from factors such as rapid population growth, agricultural expansion, and, more importantly, emerging illegal artisanal mining. To address these challenges, this study comprehensively evaluates the impact of artisanal mining on wetland ecosystems in Zimbabwe and proposes possible management strategies for mitigating environmental degradation. To achieve this goal, the research begins with a comprehensive literature review focused on the impact of artisanal mining on wetlands in semi-arid environments of sub-Saharan Africa. The findings underscore the detrimental effects of artisanal mining on wetland ecosystems, including habitat loss, biodiversity decline, riverbed sedimentation, and heavy metal pollution. Subsequently, the study investigated in the Umzingwane Catchment, located in southern Zimbabwe as a case study, to analyse variations in water nutrient and metal concentrations in wetlands affected by illegal mining activities along riparian zones (wetland-dominated areas).
Analysis of monthly MOD16 evapotranspiration rates at sites with different climatic characteristics; Heuningnes and Letaba catchments in South Africa
(University of the Western Cape, 2017) Ndara, Nolusindiso; Mazvimavi D.; Jovanovic, N.
Evapotranspiration (ET) is an important component of the water cycle that is estimated to return about 60% of precipitation back to the atmosphere. Actual ET can be estimated using remote sensing techniques and ground-based measurements. In recent years, a remote sensing product MOD 16 ET has been developed. The limited validation of this product done in South Africa showed that ET was underestimated at some sites. A comprehensive analysis of historic and seasonal trends in MOD 16 ET data in different climatic regions of South Africa has not been done. This study has the objective of evaluating if MOD 16 evapotranspiration estimates realistically represent the seasonal variations of ET on different land cover types in two different climatic regions; Mediterranean (Heuningnes catchment in Western Cape) and Sub-tropical (Letaba catchment in Limpopo) regions. Monthly MOD 16 ET maps for 2000-2012 for the Letaba catchment and Heuningnes catchment were created using ArcGIS. The results suggested that during the 2000 - 2012 period, ET was 438 - 753 mm/ year in the Letaba catchment and 432 - 458 mm/year in the Heuningnes catchment. The accuracy of MOD 16 ET was evaluated using estimates of actual ET from scintillometer data in Elandsberg (Western Cape) and flux tower data in Malopeni (Limpopo) and Skukuza (Limpopo). Monthly ET estimated using scintillometer and flux tower were calculated to coincide with the monthly MOD 16 ET data for a period of 1 year from Nov 2012- Oct 2013 in Elandsberg, 1 year 1 month from Mar 2009- Mar 2010 in Malopeni and 13 years from 2000- 2012 in Skukuza. In Elandsberg, the results showed that MOD 16 underestimated ET (R2 = 0.16, RMSE = 28.30 mm/month). In Malopeni, the results suggested that there is a strong relationship between ET estimated from flux tower data and MOD 16 ET (R2 = 0.77), but MOD 16 slightly overestimate ET (RMSE = 8.6 mm/month). MODIS ET estimates for Elandsberg had a poorer comparison with the results obtained at Malopeni and Skukuza.
Application of multivariate statistics and Geographic Information Systems (GIS) to map groundwater quality in the Beaufort West area, Western Cape, South Africa
(UWC, 2013) Solomon, Henok Goitom; Siad, Abdi Mohamoud
Groundwater in arid and semi-arid areas like the Karoo region of South Africa is an important source of domestic, agricultural and industrial source of fresh water. As a scarce resource, it requires extensive quality control and protection through innovative methods and efficient strategies. The town of Beaufort West and its vicinity use groundwater as a major source of municipal and private water supply. Forty nine groundwater samples were collected from spatially referenced boreholes located in and around the town of Beaufort West and were analyzed for EC, pH, TDS,TH, SAR, TA, Ca2+, Mg2+, Na+, K+, HCO3-, Cl-, NO3- and SO42- according to SANS 241 standards and tested for ionic balance. The groundwater of the study area was characterized using WHO and South African drinking water quality standards as well as TDS and Salinity hazard classifications. These comparisons and classifications characterized the groundwater of the study area as hard to very hard, with low to medium salinity hazard. These results are in accordance with the dominance of the ions Ca2+, Na+, HCO3 - and Cl- in the groundwater samples. Linear relationships between the hydrochemical variables were analysed through correlation and multiple regression analysis to relate the groundwater quality to the underlying hydrogeochemical processes. These linear relationships explained the contribution of the measured variables towards the salinity, hardness and anthropogenic contamination of the groundwater. The groundwater of the study area was also assessed using conventional trilinear diagrams and scatter plots to interpret the water quality and determine the major ion chemistry. The conventional methods highlighted the sources of the hydrochemical variables through analysis and interpretation of rock-water interaction and evaporations processes. To supplement these conventional methods and reveal hidden hydrogeochemical phenomenon, multivariate statistical analyses were employed. Factor analysis reduced the hydrochemical variables into three factors (Hardness, Alkalinity and Landuse) that characterize the groundwater quality in relation to the source of its hydrochemistry. Furthermore, combination of Cluster (CA) and Discriminant analyses (DA) were used to classify the groundwater in to different hydrochemical facies and determine the dominant hydrochemical variables that characterize these facies. The classification results were also compared with the trilinear diagrammatic interpretations to highlight the advantages of these multivariate statistical methods. The CA and DA classifications resulted in to six different hydrochemical facies that are characterized by NO3 -, Na+ and pH. These three hydrochemical variables explain 93.9% of the differences between the water types and highlight the influence of natural hydrogeochemical and anthropogenic processes on the groundwater quality. All the univariate, bivariate, multivariate statistical and conventional hydrogeochemical analyses results were analyzed spatially using ArcGIS 10.0. The spatial analysis employed the Inverse Distance Weighted (IDW) interpolation method to predict spatial distribution of unmeasured areas and reclassification of the interpolation results for classification purposes. The results of the different analyses methods employed in the thesis illustrate that the groundwater in the study area is generally hard but permissible in the absence of better alternative water source and useful for irrigation.
Assessing effectiveness of groundwater remediation technologies to a coastal aquifer within an urban environment in South Africa
(University of the Western Cape, 2022) Kanyerere, Jessie Mzati; Clarke, Sumaya
The study aimed to assess the effectiveness of Reverse Osmosis technology as an example of ex-situ groundwater remediation technologies. The Cape Flats Aquifer System, an urban coastal system, was used as a case study. Globally, urban groundwater contamination remains a known problem for water users, hence the need to remediate such water. The study argues that effective technologies such as Reverse Osmosis to remediate groundwater contaminants exist. However, the effectiveness of such technologies is not demonstrated to inform the wider application. The question of how effective these technologies are in remediating groundwater contaminants is not fully understood.
Assessing groundwater-surface water interaction as a decision-making tool licensing water use South Africa : case study area of Gevonden farm
(University of the Western Cape, 2015) Biyela, Mfundi Cyril; Kanyerere, T.
Assessing groundwater-surface water interaction as a decision-making tool licensing water use South Africa: Case study area of Gevonden Farm is the title of the current study with the context that arises from the use of GRAII methodology which uses quaternary catchment boundaries for groundwater abstraction water use licence application assessment during decision making. The problem is that the quaternary catchment scale approach does not provide the scientific bases for site specific scale. The current study argues that such approach provides realistic, practical information at site specific scale and therefore informs the issuing of licences more accurately. The aim of the current study is to improve understanding of how the assessment of groundwater abstraction water use licence should be carried out at a site specific scale to improve decision making during licence issuance. The objective of the study is to outline the scientific study and demonstrate how the investigation that leads to the decision making can be conducted. The study was carried out using hydraulic methods such as pumping test and geochemical analysis method. Hydraulic properties were determined and chemical elements were analysed for and compared with the SANS 241 water quality standards for domestic and agricultural use. Hydraulic properties such as hydraulic conductivity (K), transmissivity (T), yield and storativity (S) were determined. Major and minor ions that are required to be analysed for domestic and agricultural water use were analysed. Piper diagrams and FC method were used to analyse data. The piper diagrams plotted indicated that surface water is mixing with groundwater and that means there is connection between groundwater and surface water. The chemical elements analysed for were compared with SANS 241 water quality standards for domestic and agricultural use. The water quality on the investigated site can be categorized as having good water quality. A sustainable yield estimated from the two boreholes (BH03 and BH05) which was 1.02 Ɩ/s. The available drawdown estimated with reference to the boreholes water strikes that were determined by EC profiling were 135 mbgl from both boreholes. The study recommends the issuance of water use licence with conditions that chemistry of water should be analysed for once a quarter and boreholes water levels should be analysed for once a month.
Assessing hydrogeological characteristics to establish influence of aquifer-river interaction in non-perennial river systems, Heuningnes catchment
(University of the Western Cape, 2019) Banda, Vincent Santos Dzulani; Mengistu, Haile; Kanyerere, Thokozani
Over half of total flows in the global river network are composed of non-perennial rivers. This indicates the importance of non-perennial river systems in supporting the biodiversity. It has been established that groundwater is one of the elements that control the flow regimes and classification (whether perennial or not) of a river system. However, the use of hydrogeological characteristics to establish the influence of groundwater on non-perennial river systems remain to be widely unpublished. This study, therefore, intends to conceptualize and explain the role of hydrogeological characteristics in non-perennial rivers, using the Heuningnes catchment in the Western Cape Province of South Africa as a case study. The study has argued that thorough characterization of aquifers is essential in order to adequately establish the extent of aquifer-river connectivity and how groundwater influences flows and chemical loading in non-perennial river systems. The study has three objectives namely: (i) to determine the aquifer characteristics (ii) to characterise the aquifer-river interaction and (iii) to conceptualize the groundwater flow system. Records review, field, analytical and laboratory-based methods were used to collect and interpret geological, groundwater level, pumping test, hydro-chemical and environmental stable isotopic data in order to characterise groundwater occurrence, flow system and its interaction with the rivers of the study area. Water samples were taken from groundwater, surface water and rainfall during both dry and wet periods. Results show that the study area has a topography-controlled water table with shallow depth to groundwater levels ranging on average from 3 - 10 m, which result into largely a local groundwater flow system. Transmissivity values determined from constant rate pumping test range between 0.17 and 1.74 m2/day. Results exhibit that the low transmissivity values are associated with the weathered nature of the Table Mountain sandstone and the unfractured Bokkeveld shale formations. Hydrochemical data results indicate that both groundwater and river samples in the upstream part of the study area are characterised as fresh water with TDS values of less than 1000 mg/l while the downstream part has saline waters with TDS ranging from 2000 – 35000 mg/l. Results also show that Na-Cl is the dominant water composition for both groundwater and river water. The order of major ion dominance is similar for the two water sources, with concentration ranges from high to low in the order of Na+>Mg2+>Ca2+>K+ and Cl->SO42->HCO3- for cations and anions respectively. The similar patterns and trends in salinity and major ion data suggest the connectivity between the aquifer and the river. Environmental stable isotope data indicate river samples in upstream areas having depleted δ18O (-4.3 to -5.12‰) and δ2H (-22.9 to -19.3‰) signatures similar to groundwater indicating a stable and continuous groundwater contribution to the river flows. Meanwhile, high evaporative enrichment of δ18O (1.13 to 7.08‰) and δ2H (38.8 to 7.5‰) is conceived in river samples from downstream areas. Ionic ratios and isotope-salinity relationships suggest that groundwater chemistry is derived from sea sprays, evaporation and dissolution of Bokkeveld shale host rock. Geological, hydrogeological, hydrochemical and environmental stable isotope data were used to develop a conceptual hydrogeological model which explains the role of groundwater in non-perennial river systems. Results indicate that the North East – South West fault on the north-eastern part of the study area seem to act as a conduit to groundwater flow thereby supplying water to the upstream rivers while the East -West fault in the northern part seem to act as a barrier to groundwater flow resulting into a hydraulic discontinuity between upstream and downstream areas. Meanwhile, the relatively low conductive formation in the downstream areas coupled with a relatively low hydraulic gradient (0.000843) suggests there is slow Darcian groundwater flows resulting in less flushing and high salinization of groundwater. Eventually, in the downstream part of the study area there is slow and minimal groundwater discharge to the rivers resulting into groundwater failing to maintain the river flows and pools. In general, rivers of the study area largely gain water from groundwater although the amount of groundwater discharge varies from one river segment to another in both upstream and downstream parts. The conceptual model has led to the development of a proposed optimum management of non-perennial rivers including the effects of groundwater abstraction on the river flows.
Assessing hydrogeology of springs in Heuningnes Catchment in South Africa
(University of the Western Cape, 2022) Finini, Paula; Kanyerere, Thokozani
Springs have been a significant source of water for flora and fauna since the beginning of human history and, in some circumstances, the only source capable of supplying enough water to sustain domestic and agricultural water supplies. Research that expands our understanding of the potential and limitations of these resources has not focused much on springs that are located outside of karst environments. Groundwater discharge is part of the interaction that makes groundwater visible and sustains ecosystems. Groundwater discharges in rivers, springs, and wetlands forms groundwater-dependent ecosystems (GDEs). GDEs are often complex, and poorly understood component of the natural environment.
Assessing hydrogeology of springs in Heuningnes Catchment in South Africa
(University of the Western Cape, 2021) Finini, Paula; Kanyerere, Thokozani
Springs have been a significant source of water for flora and fauna since the beginning of human history and, in some circumstances, the only source capable of supplying enough water to sustain domestic and agricultural water supplies. Research that expands our understanding of the potential and limitations of these resources has not focused much on springs that are located outside of karst environments. Groundwater discharge is part of the interaction that makes groundwater visible and sustains ecosystems. Groundwater discharges in rivers, springs, and wetlands forms groundwater-dependent ecosystems (GDEs). GDEs are often complex, and poorly understood component of the natural environment. For example, identifying actual spots for spring discharges and validating previously mapped springs remains a challenge; hence, the focus of the current study, which, argues that if spring hydrogeology is not characterized first, then the influence of such springs on the environment and human needs cannot inform their action. This study aimed at providing improved knowledge and understanding of spring hydrogeology. Heuningnes catchment in South Africa was used as a case study. Three specific objectives were set as follows: 1] spring hydrogeology was characterized where new springs were identified, and old springs were validated/crosschecked. A springs map was produced and overlaid on a conceptual model of groundwater flow to describe subsurface conditions for spring occurrence; 2] Flow dynamics of springs were determined where spring flows were measured to estimate discharge rate; 3] the hydrogeochemistry of springs was assessed with hydrogeochemical processes responsible for temporal and spatial changes in the quality of spring waters were established for suitability of water for use by the environment and people. Results showed that the validated springs existed in upland, middle, and lowland within the study catchment. Most springs were associated with Table Mountain Group and Bokkeveld formations with fractures, lithological contacts, and faults that influenced the main flow paths for springs.
Assessing river-aquifer interaction for sustained water abstraction, Lower Vaal Catchment, South Africa
(University of the Western Cape, 2022) Baloyi, Lucky; Kanyerere, Thokozani
Several methods are available in the literature for the estimations of river-aquifer interactions. However, the selection of which depends on available data, local geographic and topographic conditions, the spatial and temporal scale required, and the reliability of results obtained by different methods. This study was caried out to assess the river-aquifer interaction for sustained water abstraction using the Lower Vaal River catchment as an example. The study aimed to improve knowledge and understanding of using multi-methods for the assessment of river-aquifer interactions. To achieve this, the study had three objectives namely, 1.) to investigate areas where river recharge aquifers exist (focussed recharge area), 2.) to determine areas where aquifer recharge river exist (aquifer discharge areas), and 3.) to develop a conceptual model of the groundwater process that explains interactions.
Assessing Rural domestic water demand and use for local groundwater governance during drought, Halambani area, South Africa
(University of the Western Cape, 2017) Lebese, Ally Hanyani; Kanyerere, T
Groundwater demand (abstraction) and use during drought continues to be a vital aspect in rural areas. However, the lack of systematic data to assess the availability, demand and use of such resource in addition to lack of having appropriate implementation plan for governing such resources at local scale especially in unmetered areas remain a problem. The argument in this study was that designing appropriate implementation plan that considers local context, informs the basis for implementing local groundwater good governance practice that would sustain utilisation and management of groundwater resources. The Ha-Lambani Village in Limpopo Province of South Africa was used as case study. The aim of this study was to assess rural domestic water demand and use that would inform a basis for designing an appropriate implementation plan for local groundwater good governance as an intervention during drought in rural unmetered areas. To achieve such an aim, i), physiographic factors that influence groundwater availability were explained to establish availability of groundwater; ii), rural domestic water demand and use were assessed to showcase the procedure of generating quantitative data on groundwater abstraction and consumption; iii), factors that determine rural domestic water demand and use were established; iv), appropriate implementation plan for local groundwater governance was designed with evaluation indicators built in. The capability, resilience and sustainable livelihoods approaches were applied as theoretical and conceptual frameworks for the study which informed better understanding of coping strategies during drought.
Assessing the effect of the Kars Wetland on flow attenuation in the Cape Agulhas, South Africa
(University of the Western Cape, 2019) Hans, Damian Trevor; Mazvimavi, Dominic
The Kars has a well-defined channel along the 62 km stretch from its sources in the Bredasdorp Mountains. After entering the Agulhas plain which has a very low gradient, this river changes into a triangular shaped wetland. This wetland is 7 km in length with no defined channel running through it. The wetland then discharges into another 7 km long channel that joins the Heuningnes River with its mouth at the Indian Ocean. The presence of the wetland causes frequent flooding which affects cultivated lands and a major highway linking towns on the coastal Cape Agulhas area with the rest of the country. Before this study, there was no monitoring of flows along the Kars River including water levels within the wetland. Consequently, the conditions leading to flooding of the wetlands were unknown. This study is aimed at understanding how the combination of local rainfall, Kars River inflow into the wetland, soil characteristics, and the morphology of the wetland influence flooding/inundation. The study monitored river inflows into and outflows from the wetland. A soil survey was conducted within the wetland using the augering method and an infiltrometer to determine soil type and infiltration rates. This was done to assess the hydrological characteristics of the wetland. Using the collected climate data and river flow data, a conceptual model was developed for predicting downstream outflows and possible flood events on a daily timescale. The results indicated that the Kars wetland comprises soil with high silt and clay content, and low infiltration capacity. The wetland causes flood attenuation and diffuse surface flows. Low infiltration rates result in ponding of local rainfall which can contribute to flooding.
Assessing the influence of groundwater recharge mechanism on non-perennial river systems, Tankwa Karoo, South Africa
(University of the Western Cape, 2019) Mqondeki, Phumlani; Kanyerere, Thokozani
In South Africa and neighbouring countries such as Zimbabwe, Botswana, Angola, and Namibia, most river systems are non-perennial due to semi-arid or arid climatic characteristics. In such river systems, the interaction between groundwater and surface water is of significance in terms of developing appropriate methods for determining ecological water requirements among others. However, the interaction is not well understood in terms of the influence on the volume and quality of water on the gaining and losing water bodies. In past research, the importance of non-perennial rivers (NPRS) was neglected because these river systems were considered as systems of low ecological importance and economic value. However, an improved understanding of these systems illustrated that they provide habitat for diverse and unique flora and fauna. Therefore, the main research question that was posed for the study was what is the influence of river-aquifer interactions in non-perennial river systems in the semi-arid environment? The central argument was that unless we assess the interaction between surface water and groundwater in NPRS, we cannot improve on understanding of the role of groundwater on the NPRS. The aim of the study was therefore, to assess surface water-groundwater (river-aquifer) interactions in non-perennial river systems to provide an insight regarding how these water resources interact in semi-arid environments. To achieve the aim, three specific objectives were formulated, namely, to establish the groundwater contribution to the river system, to investigate the role of the river in recharging the underlying aquifer, and to develop a regional hydrogeological conceptual model of recharge mechanisms. To achieve the objectives of the study, samples were collected from boreholes, a dug well, springs, surface water and cumulative rainfall collectors during the summer and winter seasons. The samples were analysed for hydrochemistry and stable isotopic signatures (δ2H and δ18O). The intention was to identify where and when do river-aquifer interactions occur in the study area. Secondary data from records review and field data from hydrometric methods, ERT geophysical surveys and tracer techniques were also used to address the third objective.
Assessing the surface water - groundwater interaction and its influence on the water quality from headwaters to lowlands
(University of the Western Cape, 2023) Cornelius, Aneeqah; Clarke, S
The connections between surface water and groundwater systems remain poorly understood in many catchments throughout the world and yet they are fundamental in effectively managing water resources. Managing water resources in an integrated manner is not straightforward, particularly if both resources are being utilized. Groundwater-surface water interactions are difficult to observe, measure, and have commonly been ignored in water management considerations and policies. Thus, it is important to understand the interaction between the two water bodies as it can have significant impacts on both water quantity and quality. The current study assessed groundwater – surface water interaction in order to understand how the interaction influences the available water resource in the Nuwejaars Catchment
An assessment of factors influencing the spatial variability of iron concentrations in groundwater in selected areas of the Western Cape Province.
(University of the Western Cape, 2023) Bissonram, Presanta; Clarke, Sumaya
Groundwater in South Africa, and more specifically the Western Cape Province (WCP), has become of major interest in recent years due to the unpredictable climatic conditions and the uncertainty of surface water to continuously meet the current and future water demands. With the exploration of groundwater (through the drilling of boreholes) to meet the current water demand and to ensure water security there comes the related problem of iron (Fe) and Manganese (Mn) oxidation and precipitation. The precipitation of Fe and Mn in boreholes reduce the yield and quality of the water, resulting in borehole clogging. This study took place in the WCP and the sites sampled at were hospitals as part of the business continuity project that was initiated during the drought in that took place in Cape Town in 2017. There are 4 objectives for this study which are to assess spatial variations in Fe and Mn concentrations, to establish site-specific processes controlling the concentration of Fe and Mn in groundwater, to model the likelihood of precipitation of Fe and Mn based on detected solution composition and to assess the best practice method/techniques for sampling Fe and Mn. This research project made use of quantitative and qualitative research methods. The first two objectives was addressed by using historical data which included groundwater chemistry data, pumping test data and geological data of the WCP. In addition to the historical data being used sampling was done at selected sites to understand the current groundwater chemistry, while interviews were conducted with site maintenance personnel to further understand the management of the boreholes. The third objective made use of the PHREEQC software to determine the saturation indices of samples collected and modelling of the effect of change in Fe, Mn, redox potential, pH and temperature has on the precipitation of Fe and Mn minerals. The last objective was achieved through the sampling conducted which provided the opportunity to test the best practice sampling methods of Fe and Mn in groundwater.
Assessment of groundwater level fluctuation trends in Grootfontein dolomite Aquifer, North West Province, South Africa
(University of the Western Cape, 2022) Rananga, Thomas Hulisani; Kanyerere, Thokozani
Groundwater level decline is a problem experienced in aquifers with more than one groundwater user such as the Grootfontein dolomite aquifer in the North West Province of South Africa. This study assessed groundwater level fluctuation trends for monitoring boreholes within municipal and irrigation groundwater abstraction areas. The study also determined the influence of rainfall and municipal groundwater abstraction as the dominant factors responsible for groundwater level fluctuation in the area. The study further recommended possible interventions for declining groundwater levels within the Grootfontein dolomite aquifer study area. Analysis of groundwater level fluctuation trend was conducted from 1980 to 2020 using Mann-Kendall and Sen's slope statistical tests. The results showed that groundwater levels in the study area had a declining trend. Spearman rank correlation was used to determine the influence of rainfall and municipal groundwater abstraction on groundwater level fluctuation within the study area.
An assessment of river and wetland morphology dynamics using geospatial techniques
(University of the Western Cape, 2023) Mbambi, Yamkela; Dube, Timothy
Land surface modification has intensified in recent years, and it continues to be an ongoing process. This raises serious concerns about changes in land use and land cover (LULC) since some of these changes have led to catchment degradation. The degradation of catchments has been observed to have adverse effects on natural resources, such as water bodies, resulting in food insecurity, water scarcity, and the degradation of ecosystems and the environment. Therefore, to effectively sustain life and the environment, it is crucial to monitor LULC changes for sustainable development and planning that can help alleviate pressures on water resources. This study aims to assess the impacts of LULC changes on the morphology dynamics and area changes of water resources in the Heuningnes catchment in South Africa. The findings from this assessment can offer valuable insights for water resource conservation in this catchment. Remote sensing and GIS techniques were employed to map and detect LULC changes, morphology dynamics, and area changes of water resources from 1990 to 2020.
Assessment of the contributions of water allocation reforms to achieving equitable access to water by smallholder emerging farmers in the Breede-Gouritz catchment management agency
(University of the Western Cape, 2018) Mnyaka, Sinazo; Mazvimavi, Dominic
The National Water Act of (1998) of South Africa has a goal of achieving equitable access to water resources, as well as achieving environmental sustainability and efficient use of water. Consequently, water resources management is being reformed to ensure the achievement of these principles. Allocation of water through granting of licenses for abstraction and storage of water has been implemented to ensure that historically disadvantaged individuals (HDIs) have access to water and to promote sustainable, efficient and beneficial use of water resources for the whole country. The Water Allocation Reform Policy is a tool that is used to implement the goal of the National Water Act and it is guided by the set objectives, which are to allocate 30% of all water to previously disadvantaged individuals by 2014, 45% by 2019 and 60% by 2025. Despite these efforts, there is evidence that smallholder emerging farmers who are part of the disadvantaged groups do not have access to water for productive use. Many studies conducted so far have shown that equitable, sustainable and efficient water allocation has not been achieved in South Africa. It is not very clear why this trend is continuing despite all efforts to the contrary. The aim of the study was to assess the contribution of the reforms of water allocation systems towards increasing access to water by historically disadvantaged groups in Barrydale area in the Western Cape Province, South Africa. Interviews were conducted to determine how the reforms have influenced access to water for productive use by smallholder emerging farmers. Document review was undertaken to determine the progress in the implementation of the water allocation reform by the Breede-Overberg Catchment Management Agency (BGCMA). The results indicated that small-scale farmers do not have access to water for agricultural activities in Barrydale due to lack of components, which include financial funding, access to farming infrastructure and skills. The BGCMA has not completed the implementation of the Water Allocation Reform and as a result, mechanisms initiated by the BGCMA have not resulted in improved access to water by HDIs. The outcome of the study indicated a lack of implementation of the water allocation reforms by the BGCMA, hence there is still no increase to water access for agricultural use by HDIs.
Characterizing water quality of rivers and underlying aquifers in the Nuwejaars Catchment, South Africa
(University of Western Cape, 2020) Malijani, Errol Masuzyo; Kanyerere, T; Day, J
Non-perennial rivers are the main source of surface water in drylands. These rivers are unpredictable and highly variable in terms of flow regime and water quality. Despite their abundance, and importance in the landscape, non-perennial rivers still remain under- studied. The functioning of non-perennial rivers seems to be strongly dependent on groundwater, especially during dry seasons when pools develop, but the relationship between surface water and groundwater has seldom been established and quantified. Many of these systems are ungauged and hydrological and chemical data are available for very few systems in South Africa. The present study falls under the Non-perennial Rivers Project, and aimed to characterize the water quality of rivers and aquifers in the Nuwejaars Catchment, located in Cape Agulhas, near the southern-most tip of Africa. To achieve this aim, a quantitative approach that provides the ability to assess relationships between variables both spatially and temporally was applied. Field visits were conducted on four occasions during July 2017 and July 2018, to characterize the chemistry of surface water and groundwater during dry and wet seasons. Physical parameters were measured in situ, while water samples were collected from boreholes, piezometers, springs, artesian boreholes and selected points along the river for laboratory analysis of major ions, nutrients and stable isotopes. Descriptive and bivariate statistical methods were used to summarise and evaluate the strength of the relationship between variables, while multivariate statistical methods were applied to group similar samples based on their chemical compositions. Piper diagrams were generated to characterize water type based on the proportions of cations and anions, while correlation and stoichiometric analysis was applied to identify hydrogeochemical processes influencing groundwater chemistry. Stable isotope compositions were presented on a graph, along with the global meteoric water line (GMWL) and local meteoric water line (LMWL) to establish similarities between isotope signatures of groundwater and surface water.