Magister Scientiae - MSc (Environ & Water Science)

Permanent URI for this collectionhttps://hdl.handle.net/10566/17575

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Assessing the contribution and variations of spring discharges to river flows within the Nuwejaars Catchment, Cape Agulhas
(University of the Western Cape, 2025) Ajam, Mogamat Yaaseen
Water resource management in South Africa has not stressed the importance of springs as a water resource and fails to integrate surface water and groundwater as one essential resource functioning interchangeably. The investigation of springs as a water resource is a way of understanding the integrated manner in which groundwater interacts with surface water. Therefore, the protection of springs is imperative especially when it comes to active springs which may be contributing significantly towards river flows during the dry season. Previous studies have proven that springs are a significant source of water for many terrestrial and aquatic ecosystems. In addition, literature also highlights that springs are critical in sustaining domestic and agricultural water supplies. There are various factors that may influence spring discharge rates such as varying land cover type, topography, lithology, aquifer characteristics, hydrology and climatic conditions. As such, quantifying and understanding the hydrological effects of these factors is crucial for effective water resource management as it reflects changes in water fluxes and storages within the hydrological cycle. In order to manage these changes, the study made use of various methods such as the application of Mannings’ equation, flow measuring structures, manual flow measurements, hydrochemistry and isotope hydrology to examine the effects of rainfall on spring discharge rates across four experimental spring sites within the Nuwejaars Catchment. Objective 1 of the study was to locate the occurrences of springs and examine factors accounting for their locations within the Nuwejaars Catchment. This identification process took into account variables such as the type of land cover, topography, lithology, structural geology, hydrogeology and hydrology at each experimental site. Objective 2 of the study was to investigate the temporal variations in the quality and quantity of spring discharges and discern factors accounting for these variations. This was done in order to distinguish changes in spring discharges between the dry and wet seasons. Objective 3 of the study was to investigate the response of spring discharges to rainfall events. This response was determined by monitoring rainfall and spring discharges on multiple timescales to unravel spring flow dynamics at various rainfall intensities.
Impacts of land use land cover changes in mountainous catchments – a case study of Klaserie Catchment, Mariepskop Mountain
(Universty of the Western Cape, 2026) Yono, Anothando
Land use and land cover (LULC) change remains a central driver of ecological transformation, particularly in semi-arid mountainous catchments where terrain complexity, limited data availability, and climate variability intersect with increasing human population and activity. This study examines the drivers, spatial–temporal patterns, and hydrological implications of LULC change in the Klaserie Catchment, located in the semi-arid eastern region of South Africa, over a 34-year period (1990–2024). The study employed a remote sensing–based methodological framework integrating Landsat and Sentinel-2 imagery with machine learning algorithms, specifically Simple Non-Iterative Clustering (SNIC) and the Random Forest classifier, processed within Google Earth Engine (GEE). This approach was used to detect and delineate spatiotemporal changes across four major LULC categories: vegetation, bare land, built-up areas, and water bodies. Classification accuracies averaged (91–97%) with Kappa values of 0.84–0.94. Built-up areas increased by 199%, bare land declined by 30%, vegetation expanded slightly, and water bodies remained stable. The detected shifts in vegetation, bare land, and built-up areas further imply potential disruptions to hydrological processes in this mountainous catchment. Increased open surfaces and vegetation change may alter runoff generation, reduce infiltration, and affect baseflow regulation, with implications for streamflow variability, sediment transport, and water availability downstream. These findings underscore the urgent need for integrated land use planning, sustainable resource management, and climate-resilient policies to balance development pressures with the conservation of ecosystems and water security in semi-arid catchments.
Modelling prospective future processes, sedimentation patterns and ecosystem service delivery of a wandering reach of the Olifants River floodplain, Western Cape
(University of the Western Cape, 2025-07) Morokong, Kamogelo Lesedi
Changes in river flow regimes driven by climate change or anthropogenic developments have the potential to alter flood and sediment dispersal patterns, and the delivery of ecosystem services. Climate change projections for the winter rainfall region of the Western Cape suggest warmer, drier conditions with more prolonged and intense drought periods, shorter duration but high intensity rainfall events, and overall increased inter-annual rainfall variability. Considering this, it can be expected that current processes of river flow, sediment dispersal patterns and the delivery of ecosystem services may be affected by these estimated climatic changes. This research therefore aimed to assess how sediment dispersal patterns and ecosystem service provision vary during periods of low, intermediate and high river flow scenarios, within a multi-thread wandering river reach of the Olifants River floodplain, Western Cape. The rationale for this approach is that, although it is difficult to predict the exact nature of future flow regimes, it is possible to evaluate how a river floodplain system may respond to different river flow patterns that have characterised a system in the recent past, and to use such insight to inform how the system may respond in the future if one type of flow regime becomes more dominant. The first objective was to develop representative flow time series for different flow scenarios representing low, intermediate, and high flow periods. This was achieved through collection and analysis of existing daily average river flow data and collected river flow data. The second objective was to evaluate the sediment dispersal patterns under the different flow scenarios. This was achieved by using the CAESAR-Lisflood landscape evolution model in reach mode. To address this objective the developed flow time series scenarios, field collected sediment data, a LiDAR-derived digital elevation model, and field estimates of the Manning’s roughness coefficient were used as the fundamental input parameters to run simulations for the above-mentioned flow scenarios. The last objective was to assess the implications of model output flow and sediment dispersal patterns on the potential delivery of flow and sediment-associated ecosystem services which are the flood attenuation, sediment trapping and phosphate assimilation services. The WET-EcoServices tool and output results from the CAESAR-Lisflood simulations were used to address this objective.
Flood risk modeling and impact assessment using google earth engine in Mpumalanga province, South Africa
(University of the Western Cape, 2025) Manyaka, Naledi
Flooding is one of the most devastating natural disasters globally, causing extensive damage to infrastructure, agriculture, and human settlements. In many regions, recurrent flood events continue to hamper disaster management programmes, largely due to the limited availability of near real-time monitoring systems and comprehensive risk assessment frameworks. This study aimed at addressing these challenges by developing an integrated spatial explicit flood risk assessment and monitoring framework using Google Earth Engine (GEE) cloud computing platform and multi-source spatial data (Sentinel-1 SAR, Sentinel-2 and CHIRPS). The study aimed to assess flood dynamics in the study area through two main components: a detailed assessment of flood events and an inter-annual analysis covering the period 2020-2024. Firstly, a flood event assessment was conducted (February 2023 flood) using threshold-based change detection methods applied to Sentinel-1 Synthetic Aperture Radar (SAR) data to map the spatial extent of inundation. The analysis revealed that the Ehlanzeni District experienced the highest level of flooding, covering approximately 17000 hectares, followed by the Gert Sibande District, where inundation ranged between 4300 and 8500 hectares. The inter-annual analysis further looked at temporal patterns and variability in flood occurrence over many years in the entire Mpumalanga province, providing insights into flood-prone areas. Overall, the results showed that Nkangala district experienced lower flood susceptibility. The inter-annual analysis showed substantial variability in flood extent, ranging from 30800 ha (2024) to 488100 ha (2021). The findings of the study further showed that the year 2021 and 2023 experienced severe flooding due to Tropical Cyclones Eloise and Freddy, respectively. Cropland impacts peaked at 39363 ha in 2023, while built-up area flooding reached 80711 ha in 2021. Rainfall threshold analysis identified optimal 7-day accumulation windows for flood prediction, with regional thresholds varying from 45 mm (Lowveld) to 65 mm (Highveld), providing empirical triggers for early warning systems. The integration of SAR data with optical imagery and weather data within the GEE platform proved effective for operational flood monitoring in data-scarce regions. The methodology provides a scalable, cost-effective framework that can be applied to similar contexts across Southern Africa.
Validating Leaf Area Index (LAI) and canopy cover estimated from satellite imagery products with ground measurements in plum orchards, Western Cape
(University of the Western Cape, 2025) Nqumkana, Sinathi Yolanda
Sustainable fruit production increasingly depends on precise monitoring of crop performance, where accurate estimation of the Leaf Area Index (LAI) plays a central role in linking canopy structure to productivity. LAI is not only a key indicator of crop development and yield potential but also a critical input in biophysical and climatic models. However, direct measurement of LAI remains laborious, costly, and impractical for large or remote orchards, making remote sensing an attractive alternative for large-scale monitoring. The specific objectives were: (i) To recommend the best technique for measuring LAI and canopy cover with the LAI-2200 Plant Canopy Analyzer in plum orchards, (ii) To analyze LAI and canopy cover changes over time and during different ages of plum orchards, and different cultivars, and (iii) To validate satellite-derived LAI measurements with ground-based measurements. LAI ground data were collected using the LAI-2000 Plant Canopy Analyzer at the Wellington and Robertson plum orchards, with operators shielded using view caps to minimize sensor interference. Satellite data were sourced from FruitLook and Copernicus. Validation employed statistical metrics including the coefficient of determination (R²), Root Mean Square Error (RMSE), Mean Absolute Error (MAE), and Willmott’s Index of Agreement (d). Results showed that a single above-canopy reading effectively captured sky reference, while multiple below-canopy measurements improved precision. Measurements taken facing away from the sun at midday or in the afternoon minimized reflectance errors. ANOVA tests revealed no significant LAI and canopy cover differences between the two sites. In Wellington, FruitLook full-bearing orchards (R² = 0.49) performed better than non-bearing orchards (R² = 0.37), while Copernicus achieved R² = 0.40. In Robertson, correlations were lower (R² = 0.32 and R² = 0.23, respectively), though Fortune showed the highest cultivar correlation (R² = 0.42). Copernicus yielded moderate accuracy (RMSE = 3.54; MAE = 3.42). Mesh nets in orchards reduced measurement precision, contributing to weaker correlations. The study highlights that integrating ground-based and high-resolution satellite data, supported by improved algorithms to distinguish canopy and cover crops, can significantly enhance LAI monitoring accuracy. Such improvements will strengthen precision orchard management and contribute to sustainable fruit production.
Assessing the vertical distribution of microplastics in the sediments of a MAR basin
(University of the Western Cape, 2024) Stenzl, Sebastian Georg
Globally, cumulative plastic production since 1950 is estimated to have reached 2.5-8.3 billion tons of plastic. It is estimated up to 60% of this plastic is resting in landfills and the natural environment. Microplastics (MP) are small pieces of plastic ranging between 1μm - 5mm in size and have been found in every ecosystem and environment on the planet. Much of the available literature on microplastics is focused on biology and marine environments, with few in comparison focused on freshwater environments, and even fewer on groundwater settings. Therefore, the aim of this research was to determine if MPs are present in basin 7 of the AWSS, and if present to assess its distribution within the subsurface. To achieve this aim, three objectives were set. (1) Determine the vertical distribution of MPs and analyse correlation between this distribution and their physical characteristics. (2) Determine the particle size distribution of the subsurface and statistically analyse the relationship between MP abundance and D60 of sediments. (3) Examine and analyse the spatial distribution of sediments according to their D60, and the physical characteristics of MPs in the sediments of basin 7. 10 sediment cores 30cm in depth were collected from around basin 7. Post sampling, these cores were split into 6cm sections before undergoing pre-processing for organic matter removal. MPs were extracted from the sediment cores using ZnCl2 and filtered through 0.45μm fiberglass filters. The extracted MPs were then identified and characterized using a stereomicroscope and graticule. This data was then analysed and mapped using SPSS and QGIS software.
Using geophysical applications for aquifer characterisation of paleowaters: a case study of the Bredasdorp basin, South Africa
(University of the Western Cape, 2024) Patel, Malikah
Reservoir depletion in the Bredasdorp Basin has come with many rising challenges, such as exorbitant decommissioning costs and deteriorating pipelines. However, a depleted offshore reservoir also has many opportunities that can be explored. This research study looks closely at offshore aquifers occurring in the Central Bredasdorp Basin, South Africa, as an alternative source of water. Groundwater usage accounts for 56% of South Africa’s population, either as sole or combined with surface water resources. Therefore, exploring different water sources is essential to the sustainability of our water resource management and security. Offshore aquifer research bridges the gap between two research groups, petroleum geology and hydrogeology, but is very rarely a reality, as data is not publicly available due to propriety rights restrictions. Integration of seismic and well log data acquired by the petroleum industry has demonstrated the effectiveness for offshore fresh groundwater modelling. Groundwater reserves below the seafloor are now becoming a common global phenomenon with brackish to low salinity water regarded as a substitute over sea waters, as the price of desalination processes rapidly decrease. This study focusses on the 14A aquifer, whereby water salinities measuring below a threshold of 30 ppt is regarded as fresh water. The aquifer was interpreted across an area of ~2300 km2 using a 3-dimensional seismic survey to map the aquifer boundaries, along with wireline data from twenty-two wells to extract critical aquifer parameters like porosity, water saturation, water salinity and permeability. The evaluation identified primarily sandstone and shale lithologies, with sand packages ranging from 4 m to 125 m of gross sand. Porosities in the aquifer range between 10-17% while core analysis indicated permeability values between 3mD and 639 mD in sandstone layers, suggesting good production potential in these intervals. The aquifer, measuring 18.72 km3 in size, is correlatable across a distance of ~ 35 km.
Spatial modelling of the hydrogeological connection between groundwater-dependent ecosystems and aquifers in the Kruger National Park, South Africa.
(University of the Western Cape, 2025) Msesane, Qawekazi
An improved understanding of the hydrogeological connection between aquifers and groundwater-dependent ecosystems (GDEs) is essential for an improved assessment and management of groundwater resources. In the Kruger National Park (KNP), which is also a prime conservation area of South Africa, groundwater plays the vital role of sustaining ecosystem functioning. Conducting hydrogeological assessments in this area will help to provide a robust methodological framework and a strategic tool for understanding groundwater flow and the influence of geology on groundwater occurrence and consequently the groundwater dependent ecosystems. This study therefore sought to assess the onnectivity between groundwater-dependent ecosystems and groundwater in the Kruger National Park, South Africa. Two specific objectives were set mainly focussing on the characterisation of the aquifers within the KNP and secondly the delineation of GDEs in the KNP using freely accessible remote sensing data coupled with cloud computing approaches. To achieve the objectives of the study, the first step was to develop an understanding of the aquifers in the area. This was accomplished by utilizing pre-existing pumping test data to estimate the hydraulic parameters of the aquifers, as well as constructing geological cross- sections and analyzing borehole lithological core logs to identify preferential groundwater flow paths. Groundwater recharge was estimated using the cumulative rainfall departure and rainfall infiltration breakthrough methods. The analysis of the pumping test data showed that transmissivity ranged from 0.5 m2 d -1 to 11.2 m2 d -1 , while storativity ranged from 1.28 × 10-6 to 4.38 × 10-4 . These results reveal that most of the selected boreholes have low transmissivity and storativity, as well as slightly high transmissivity for a few boreholes drilled into the hard granite/gneiss rock. This suggested a porous but low permeability weathered aquifer, which agrees with the observed borehole lithological logs. Groundwater recharge received in the area ranged between 20.55 Mm3 a -1 and 29.4 Mm3 a -1. . The results further showed that groundwater mainly occurs/stored in joints, fractures, faults, zones of weathering and structures such as dyke intrusions. The site-specific conceptual model of the southern part of the KNP showed the aquifer mostly fractures to various extents. The area mostly consists of weathered rock material. GDEs were delineated using the weighted overlay tool. The thematic output layer was spatially classified into four classes: poor, fair, good and excellent according to the likelihood of GDE occurrence in the area. The results showed that only 2.39% of the total area is characterized by excellent likelihood of GDEs occurring. Most II of these areas are around rivers and areas on gentle slopes. The findings of this study demonstrate the effectiveness of incorporating hydrogeological study in understanding the relationship between GDEs and groundwater. The study therefore underscores the relevance of hydrogeological analysis for improved conceptualization of GDEs, rather than relying on surface indicators which do not consider connectivity between underlying aquifers and potential GDEs
Performance assessment of solar-powered groundwater pumping systems in rural areas of Greater Giyani Municipality (Limpopo, South Africa)
(University of the Western Cape, 2024) Shika, Seemole Sergio
The installation of solar-powered groundwater pumping systems in rural South Africa can mitigate the impacts of climate change by improving water security and agricultural productivity, which contributes to sustainable adaptive water management solutions for regions in drought conditions. The aim of the research was to assess the performance of solar-powered groundwater pumping systems at nine rural pilot sites in Greater Giyani Municipality: five small-holder farms and four villages supplied with drinking water. The objectives were: (i) to determine the water volumes abstracted and supplied from solar-powered groundwater pumping systems and evaluate the pump discharge rates; (ii) to analyze the longevity of the power supply system making use of solar panels; (iii) to evaluate the quality of groundwater distributed by solar-powered groundwater systems; and (iv) to assess the socio-economic benefits of the solar-powered groundwater pumping systems. The method entailed quantifying the following performance indicators: (i) weather conditions (acquiring daily weather data and rainfall); (ii) water abstraction (monitoring daily abstracted groundwater volumes, groundwater levels and pumping efficiency); (iii) solar power supply (measuring voltage from the control box weekly); (iv) source water quality (weekly and quarterly); and (v) socio-economic indicators (number of people supplied with water in villages; farm biophysical and economic water productivity). The results demonstrated no major groundwater drawdown, the discharge rates ranged between 0.355 – 2.54 L/s, the average daily volume abstracted ranged between 6- 55 m3; the power supply was 128 – 368 V and there were no major changes in groundwater quality over time with occasional naturally occurring elevated nitrate and electrical conductivity recorded across all pilot sites.
Groundwater numerical modelling for coupled hydrogeological – geochemistry analysis in an open pit mine of the Kalahari Manganese belt
(University of the Western Cape, 2024) Chaudhary, Preanna
Groundwater numerical modelling is used more and more in mining environmental applications, where contaminant plume development predictions at different phases of the operations, are required for various environmental applications. One such case is the application of numerical and mass transport modelling of an open pit mine in the Kalahari Manganese belt where a waste rock dump (WRD) is developed, as mining progresses. The numerical model was constructed and run using FEFLOW (DHI-Wasy). FEFLOW is a finite element numerical code, widely used for flow and mass transport modelling. FEFLOW was selected due to its flexibility and enhanced representation of geological and mining elements, enabling a full dynamic transient simulation of flow and mass transport. The historical monitoring data and rainfall (recharge) data were used for steady-state calibrations of the groundwater model.
Impact of wastewater treatment works discharges on surface water quality in Emalahleni Local Municipality, Mpumalanga Province
(University of the Western Cape, 2025) Mudau, Takalani Cicilia
This thesis reports the research work undertaken to evaluate the effects of Wastewater Treatment Works discharges on surface water quality in Emalahleni Local Municipality (ELM), Mpumalanga Province. Ferrobank and Riverview Wastewater Treatment Works (WWTWs) were identified for the research study. The study concentrated on assessing surface water quality by identifying the impact differences in water quality at the upstream and downstream sites of each WWTW effluent discharge point. The following physio-chemical and microbial water quality parameters (temperature, pH, turbidity, electrical conductivity, dissolved oxygen, phosphate, ammonia, nitrate, chemical oxygen demand, total suspended solids and Escherichia coli) were assessed. The water quality results were compared to the water use licence conditions for Ferrobank WWTW and the general limit values applicable to wastewater discharge into a water resource for Riverview WWTW respectively. The impact of these WWTWs was also assessed on the groundwater through one identified private borehole located within the vicinity of each WWTW mainly to identify any potential risk to the hydrogeological environment of the study area.
Determining the socio-economic value of groundwater: Franschhoek case study
(2011-12-01) Pearce, Darian; Xu, Yongxin; Brendonck, Luc
The Western Cape, a province of South Africa is facing increased pressure to develop new supplies of fresh water to cater for the regions rapidly growing demand. Groundwater is being explored as a possible contributor to the freshwater supply. Development of the resource has been slow despite the existence of significant potential groundwater resources in the form of several shallow primary aquifer systems and an extensive secondary aquifer formation known as the Table Mountain Group (TMG) Aquifer. This slow development may be attributed primarily to a lack of awareness amongst key stakeholders and general ignorance in the water market with regards to the potential of this resource.
Geophysical, technical, and engineering feasibility assessment of solar-powered groundwater abstraction in rural areas of Greater Giyani Municipality, Limpopo
(University of the Western Cape, 2024) Willoughby, Alana; Jovanovic, Nebo
Extreme climate events, such as tropical cyclones, wildfires, and droughts play a role in increased water scarcity. These events may pose severe impacts and effects on communities and ecosystems over many years. Rural communities in Limpopo need more access to energy and water that may be used for agricultural irrigation. Solar-powered irrigation for agriculture is a desirable use of renewable energy. However, for the system to be practical, it must be technically and economically feasible. This study assesses the geophysical, technical, and engineering feasibility of using solar-powered irrigation systems in Greater Giyani Municipality, Limpopo. The geophysical objective is to evaluate the conditions of the site, the yield of the boreholes as well as their characteristics. The technical-engineering objective is to determine the design of the system and how many solar panels and pumps are required, power and capacity of the pump and the pipes and fittings that are required. A toolbox created by GIZ (German Corporation for International Cooperation), and FAO (Food and Agriculture Organization of the United Nations) was used to aid in the design of the solar-powered system. Various toolboxes were used to design, set up, safeguard, and maintain the solar-powered irrigation system. These toolboxes are comprised of modules that contain user-friendly software tools in the form of calculation sheets, checklists and guidelines. Data were collected on climate, soil, geohydrology, land use, borehole characteristics, and farming practices.
Quantification of consumptive water use of full-bearing, high-yielding Japanese Plum trees with the HYDRUS-2D model
(University of the Western Cape, 2024) Mathews, Ubaidullah; Jovanovic, Nebo
In South Africa, the Japanese plum industry peaked at 87,746 metric tons in 2016 and recently produced 65,258 tons in 2020, with 73% of this output aimed at the export market. Despite its importance, there is a significant lack of data on the water requirements for Japanese plum cultivation, impeding effective water management strategies. This study addresses this gap by analyzing the crop water needs of the 'African Delight' and 'Fortune' cultivars in Robertson and Wellington using the HYDRUS-2D model. Data, including weather conditions, soil properties, and various field measurements, were collected over two seasons. The model's accuracy, with mean absolute errors of 1.45 mm in Wellington and 4.01 mm in Robertson, was evaluated against observed soil water content. Results showed varying water requirements: 'African Delight' in Wellington needed 980 - 1000 mm and in Robertson 1018 - 1030 mm, while 'Fortune' in Robertson required 1017 - 1038 mm. Orchard-specific details include planting densities and yields, with 'African Delight' in Robertson yielding up to 52 t/ha-1, outperforming other sites. Basal crop coefficients (Kcb) ranged from 0.97 to 1.18, and LAI values from 0.54 to 3.19, consistent with international data for high-density plum orchards.
Investigating the role of groundwater - surface water connectivity in supporting non-perennial river systems, Sandveld, Western Cape, South Africa
(University of the Western Cape, 2021) Pietersen, Raven Jesse; Kanyerere, Thokozani
Non-perennial rivers are characterised by a discontinuous and variable hydrological flow regime which may retreat to form isolated pools along the watercourse during prolonged dry periods. The resulting spatio-temporal variability in hydrological characteristics provides support for a variety of ecological habitats which promote species richness and biodiversity. It is well established that groundwater may offer flow supplementation to perennial river flow throughout the year as baseflow, while fewer authors have unpacked the nuances of the importance of groundwater in dynamics of water persistence and the conditions that determine non-perennial pool reoccurrence. This study explores river-aquifer interaction of the Verlorenvlei catchment within the Western Cape Province of South Africa as a case study in order to create an improved hydrogeological understanding of groundwater’s role in non-perennial rivers to improve of water management practices. A multi-method approach was designed to fulfil this aim. In addition to desktop literature review and in-field sampling of water for environmental tracers, a water presence, groundwater level, and geophysical survey was conducted in order to develop a conceptual understanding of the multi-scale interaction occurring within the Verlorenvlei basin. Results of the isotopic and chemical analysis of water sources revealed the water origin and groundwater flow dynamics for the Verlorenvlei. The contribution of groundwater from Table Mountain Group related, fault-driven flow to the groundwater balance of the Verlorenvlei creates regional gaining conditions. Local gaining conditions within the Verlorenvlei river are created through lateral input of upwelling groundwater which moves downgradient with the topography as evidenced by the hydrogeological and geophysical survey. Using the Verlorenvlei as a case study, a contribution is made to the knowledge of the role of groundwater in non-perennial rivers. The results presented in this study indicate that where basin hydrogeology allows, groundwater may play an important role in the supply of water to non-perennial pools, especially during periods of minimal rainfall. The interaction mechanisms of this groundwater contribution within non-perennial rivers are site specific and spatially variable. Basin hydrogeology, subsurface stratigraphy and water availability are key limiting factors to interaction in non-perennial rivers. Future research aimed at generating robust information on discrete zones of water presence along non-perennial rivers may allow for better assessment of the potential vulnerability of these areas to water loss. Where these areas are fed by groundwater, to accommodate for their vulnerability, groundwater capture maps may allow for investigation of the local impact of groundwater use on these areas.
Investigation of the carbon storage potential of the Sundays River Trough in the Algoa Basin
(University of the Western Cape, 2023) Moleele, Tshiamo; opuari, Mimonitu
Algoa Basin, South Africa, was extensively studied using data from three selected wells: AL 1/69, CK 1/68, and NA 3/70. These wells were chosen due to their positioning within tThe storage potential for carbon dioxide (CO2) within the Sundays River Trough, located in the he Sundays River The storage potential for carbon dioxide (CO2) within the Sundays River Trough, located in the Algoa Basin, South Africa, was extensively studied using data from three selected wells: AL 1/69, CK 1/68, and NA 3/70. These wells were chosen due to their positioning within the Sundays River Trough and the availability of geophysical wireline logs, conventional core analysis, geological well completion reports, and 2D seismic lines. Physical rock properties, such as lithology and reservoir zones, were identified, and quantitative parameters like volume of clay, porosity, and water saturation were determined. Permeability was calculated using basic log functions. The storage potential of CO2 was assessed by employing CO2SCREEN, and the total estimated storage potential for the Sundays River Trough was obtained. The 'Geological Storage of Carbon Dioxide' Atlas, published by the Council of Geosciences, provides estimates of the potential CO2 storage capacity in geological formations across the entire country. Previous studies have focused on investigating CO2 storage in geological formations, particularly saline aquifers, at a regional scale, with a primary focus on the Zululand Basin region. This research aims to enhance the ongoing understanding of CO2 storage potential, enabling the development of pilot programs and subsequent injection initiatives. By doing so, South Africa can actively contribute to the reduction of carbon emissions and effectively mitigate climate change. The total expected storage potential in the Sundays River Trough, considering the three selected areas surrounding wells AL 1/69, CK 1/68, and NA 3/70, amounted to P10= 13.37Mt, P50= 54.22Mt, and P90= 160.26Mt in the Sundays River formation and P10= 12.52Mt, P50= 50.45Mt, and P90= 147.97Mt in the Wood Beds formation withWell CK 1/68 exhibiting no storage potential, Based on the acceptable storage estimates of the Sundays River & Wood Beds formation and factoring in Smith et al. (2011) site screening criteria, the Sundays River Trough does have potential for CO2 storage. However, it leans towards negative site screening criteria due to low permeability and low porosity. The presence of old 2D seismic lines also plays a major role in determining that the Sundays River Trough may not be entirely suitable for storage.
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).
Quantifying the consumptive water use of Japanese plum orchards in the Western Cape province using the SEBS and SEBAL models
(Universty of the Western Cape, 2024) Motsei, Nonofo; Jovanović, Nebojša
Japanese plums form part of a multi-billion-rand deciduous fruit industry in South Africa. As with other dry countries, South Africa faces several water-related challenges, namely increasing water scarcity driven by a high population growth rate, rising intersectoral competition for water resources and climate change. Due to the low and erratic rainfall in the country, plums are grown under irrigation. As such the availability of water is crucial for the sustainability and growth of the South African fruit industry. Previous studies have successfully determined the water requirements of various fruit crops (e.g., apples, oranges), however, the water use requirements of plum orchards have not been sufficiently investigated. This paucity of knowledge forms the baseline of this study which aims to quantify the seasonal water use of high performing full-bearing Japanese plum orchards. To address this aim, the study was divided into two sections. In the first section, the water use of optimally irrigated, full bearing and high performing Japanese plum orchards planted to mid and late maturing Fortune and African Delight cultivars was estimated using the SEBS model and Fruit Look (SEBAL).
Environmental and socio-economic feasibility of solar powered groundwater pumps in drought affected areas of giyani Limpopo.
(University of the Western Cape, 2023) Mpambo, Mandelwa; Jovanovic, Nebojsa
In the South African context, large portions of rural population do not have access to water supply. Shallow groundwater in alluvial aquifers of ephemeral (or dry sand bed) rivers can potentially be an alternative sustainable source of water for multiple uses. Solar-powered groundwater pumps could be suitable to reduce abstraction costs in rural areas that are often far from national grid connections. The objectives of this study were to conduct an environmental and socio-economic feasibility assessment of using solar-powered groundwater pumps in rural villages of Greater Giyani Municipality (Limpopo). The environmental assessment dealt with environmental issues associated with the use of solar pumps by analysing their emission of CO2 as compared to alternative energy supply options such as fuel and electricity. The socio-economic aspects dealt with the capital and maintenance costs associated with the system as compared to alternative sources of energy. A cost-benefit analysis was conducted in order to determine financial benefits, returns on investment and payback periods of using solar powered groundwater pumps. A life cycle analysis of the solar powered system was conducted. The results indicated a great market strength exists for these solar powered systems and even though they have high initial costs, their running costs are lower compared to alternative sources (diesel and grid). The life cycle analysis done using OPENLCA software showed that solar powered water pumps have environmental impacts especially during their manufacturing phase.
Using stable isotopes and hydrochemistry to quantify end-member source dynamics in the Berg River of the Franschhoek and Paarl Valley
(University of the Western Cape, 2023) Meyer, Celine; Clarke, Sumaya
The Berg River is a main source of freshwater in South Africa's Franschhoek-Paarl valley for domestic use, industry, and agriculture, but climate change or variability and poor management threaten its quality and quantity. A theoretical understanding of the basin's runoff processes, including the balance between groundwater and precipitation inputs in the river system, is crucial for meeting ecological reserve requirements and preserving ecosystems. By comprehending the dynamics and relationship between the river and its end-member sources by evaluating the contributions of groundwater and precipitation to the streamflow and the seasonal behaviour of solutes, the ecological health and functioning of the river and its associated ecosystems can successfully be managed and maintained. This study involved 25 sampling campaigns conducted between 2020 and 2021 along the Berg River in the Franschhoek and Paarl valley at 40 locations to sample precipitation (n=3), groundwater (n=15), and main river and major tributaries (n=22). The aim was to assess the temporal and spatial variations of the isotopic and hydrochemical compositions to quantify the river’s end-member source dynamics.

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