Philosophiae Doctor - PhD (Earth Science)
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Item Application of geochemical characterization, multivariate statistics and geological modelling in assessment and prediction studies on selected coal and gold mine waste in South Africa(University of the Western Cape, 2023) Abegunde, Oluseyi Blessed; Opuwari, MimonituOver the years, South Africa has generated vast amounts of coal fly ash and gold slime tailings, constituting over 70% of the country's waste materials. These byproducts contain elevated levels of trace metals, posing a potential threat to the environment upon release. Addressing this issue requires a comparative study of the environmental impact of coal fly ash and selected mine tailings on water resources and land pollution. This research aims to investigate and compare leachability, metal release, oxidation effects, and environmental pollution between coal fly ash and gold tailings. By contrasting these aspects, the study seeks to enhance understanding of the potential risks associated with these materials, aiding informed decision-making for their management and regulation. Additionally, the research explores the correlation between gold tailings' acid potential generation and coal fly ash's alkaline potential generation in terms of leachability, metal release, oxidation effects, and environmental pollution. The research employed comprehensive laboratory experiments and analytical investigations, including leaching tests under simulated weathering conditions. A total of 51 gold tailings samples and 66 coal fly ash samples were analysed through SEM and XRD for mineralogical insights and ICP-MS and XRF for geochemical analyses. Statistical analysis revealed the significant roles of pH, Fe ions, Ca2+, and Mg2+ in metal extraction from both materials. Notably, the study identified key factors contributing to the environmental impact of coal fly ash and gold tailings. SEM imagery highlighted heterogeneous characteristics in gold tailings, while factor analysis indicated the potential release of ferrous ionic species, contributing to acidity. Trace elements like Ni, Zn, Pb, and Cu were predominantly associated with Fe/Mn oxides during leaching experiments, facilitating their mobilization with acid-generating ions.Item Rainfall induced transient pressure wave mechanisms and pore water pressure dynamics in tailings(University of the Western Cape, 2023) Theron, Charné; Yongxin, XuTailings Storage Facilities are some of the largest engineered structures responsible for the containment of mining waste, yet some physical/hydrological processes causing slope instability are still poorly understood. Previous studies conducted on the causes of failure of TSFs indicate rainfall-induced slope instability as the main trigger. However, the generation of certain physical/hydrological processes and the behaviour of soil hydraulic properties in the vadose zone when exposed to high intensity rainfall events, have only been considered on natural hillslopes. The purpose of this study is to investigate one such process resulting from high rainfall intensities on partially saturated conditions. In particular, it is hypothesised in this work that the wetting front advance from high rainfall intensities, anticipated under the force of climate change, may cause transient air pressure waves to change pore water suction and elevate the phreatic surface, subsequently impacting on the effective stress. The mechanisms that lead to the mobilisation of pre-event water through transient air pressure waves are known as Groundwater Ridging and the Lisse Effect. In this study, it was hypothesized that these phenomena contribute significantly to slope instability.Item An assessment of water use by riparian and non-riparian invasive alien plants and the effects on water resources at the catchment scale(University of the Western Cape, 2023) Mkunyana, Yonela Princess; Mazvimavi, DominicThe diversity and increasing extent of invasive alien plants (IAPs) are currently a global ecological and economic problem, especially in semi-arid regions. The introduction of IAPs worsens the strain in South Africa’s water resources by reducing the mean annual runoff by approximately 7%. Further work needs to be done to ensure that those IAPs that have the greatest impact receive priority. Effective management of IAPs promotes the conservation and sustainable use of the natural environment, the economies it supports, and the high quality of life in society. The monitoring of the distribution of IAPs is therefore an important consideration in catchment management. Remote sensing and cloud computing platform, Google Earth Engine (GEE) were used to map land use/landcover changes between the 1973 – 2021 period using Landsat imagery.Item Spatial and temporal dynamics of flows and pools along non-perennial rivers in arid and semi-arid areas, South Africa(University of the Western Cape, 2023) Maswanganye, Sagwati Eugene; Dube, TimothyThis study aimed to assess the use of multi-source remotely sensed data for monitoring the spatial distribution and dynamics of pools in two distinct sites (Touws and Molototsi) in South Africa. Various water extraction indices, including NDWI, Modified NDWI, and NDVI, were employed, along with a random forest classifier and Sentinel-1 SAR data, to map pools and their dynamics in both locations. The remote sensing methods effectively detected and mapped pools with satisfactory accuracy, except for small pools below 400 square meters. The study identified flow occurrences and rainfall as significant factors influencing changes in pool sizes. However, the interaction between pools and groundwater required further investigation and showed no conclusive evidence in this study.Item Hydro geochemical characteristics of the basement aquifers in namaqualand(University of the Western Cape, 2003) Titus, R.A; Xu, YAt the onset of this research programme it became apparent that there is a dearth of research studies focusing on the groundwater resources of the region. As a result, a conceptual representation of the hydrogeological system (i.e. specific aquifer systems, groundwater flow regime, etc.) for the perceived problematic aquifer systems in the Namaqualand region did not exist. The research project contributes significantly to conceptual representation of the aquifer system, in particular a quantitative understanding of the regions' groundwater resources in terms of its hydrochemical development and the construction of a groundwater flow model at regional scale as well as at a local scale. The groundwater resources for the Namaqualand region are developed predominantly in the basement rocks. The infiltration and flow of water is controlled by the prevailing complex fracture network and can vary in space and time. Such observations relate to structurally controlled flow systems and varying water chemistry amongst closely spaced fracture systems.Item A decision-making framework for groundwater management in arid zones (with a case study in Namaqualand).(University of the Western Cape, 2004) Pietersen, Kevin Claude; Xu,Yangwin and Green, George CliffordThe main aim of the work on which this thesis is based was to develop a framework for sustainable management of groundwater resources in arid zones with emphasis on Namaqualand in the north western region of South Africa. The first part of the thesis focuses on describing the groundwater resource base and legislative framework for groundwater management. Most aquifers in South Africa occur in fractured rock ranging in age from earliest Pre-Cambrian to Jurassic. Primary aquifers are mostly restricted to the coastal plains and river deposits. Characterisation of the fractured rock aquifers has been limited. Thus, an inadequate knowledge base exists in a number of hydrogeological domains to understand the attributes and dynamics of fractured rock aquifers. A serious shortcoming in our knowledge base is to understand the institutional arrangements necessary for proper resource management. This is particularly important in view of the National Water Act of 1998, where groundwater is subject to the same protection measures as surface water. These measures are sophisticated and require tools and technologies to be developed to support sustainable groundwater management and utilisation. The technical, economic, social, legal, political, and environmental issues affecting groundwater management of arid zones of South Africa were analysed. The objectives and appropriate measures to overcome the barriers for sustainable development were also presented. This was necessary to structure the decision problem and to generate and identify the decision alternatives. Thus decision alternatives have been formulated for the various elements of the objectives in order to achieve preferred scenarios. The main part of the thesis was the development of a decision-making framework for groundwater management in the arid zones of Namaqualand. A multiple criteria decision analysis (MCDA) approach was adopted to assist in the formulation of the decision-making framework. ln order to select the most appropriate MCDA technique, some background was required on the theoretical aspects. A value function method was selected, which provides decision support by interval SMART/SWING. This method incorporates informational uncertainty through interval judgements. The decision problem supported the selection of this method because of the discrete alternatives and uncertainty associated with groundwater management. Further, the method provided an interactive technique to interrogate various decision alternatives based on prior knowledge of the decision-maker. The software WINPRE was utilised in the value tree construction and analyses, A number of value trees and attributes were defined. These attributes were evaluated against the identified alternatives. This provided a systematic framework for the analytical understanding of the problem. As a result a number of preferred alternatives were elicited. The analyses resulted in a model for groundwater management in arid zones. The ideal state for groundwater management was presented, but in practice this is difficult to implement, mainly because of human and financial resources. As a result, a critical path was established based on the analyses done in this thesis. This was applied to the Namaqualand example. ln this example the activities to support a Catchment Management Strategy was identified. This means that the decision-maker is able to focus on issues that are deemed important. More importantly, the method allows the decision-maker to develop the various consequences of the alternatives with stakeholders. As a result of the decision model a number of strategies were proposed for sustainable groundwater management in arid zones with a case study in Namaqualand. A consequences table were developed which could be used for M&E purposes.Item Applicability of big data analytics to support groundwater management in Southern Africa(University of the Western Cape, 2022) Gaffoor, Zaheed; Kanyerere, ThokozaniGroundwater is a vital resources for member states in the Southern African Development Community (SADC). However, sustainable managing groundwater resources in SADC is a challenge. Amongst the many issues facing groundwater managers in SADC, limited access to high fidelity data, as well as a poor understanding of the techniques needed to transform the data into information, has hampered the decision making process. Big data relates to large, voluminous and heterogenous datasets which are being generated through numerous activities, such as computer simulations, remote sensing, commercial transactions, internet activity, monitoring networks, IoT sensors, historical documents, social media and many others.Item Developing an integrated remotely sensed framework for the detection and monitoring of seasonally-flooded wetlands in semi-arid environments of southern Africa(University of the Western Cape, 2022) Gxokwe, Siyamthanda; Dube, TimothyWetlands are among the most important ecosystems on earth; they cover approximately 4-6% of the earth’s surface and offer critical eco-hydrological services. However, these ecosystems are under threat from anthropogenic activities, droughts and climate variability, as well as from global environmental change. It is estimated that over 60% of the world’s wetlands have been lost due to climate change and variability, as well as other anthropogenic influences. There is, therefore, a need for their routine monitoring and assessment to ensure the sustainable use and management of these systems on a national, regional and local scale, and prevent their further degradation and loss. This study aimed at developing an integrated cloud-computing-based, remotely-sensed framework for the detection and monitoring of small and seasonally-flooded wetlands along the semi-arid Limpopo Transboundary River Basin of southern Africa, which was previously a challenging task when using the traditional assessment and monitoring methods.Item Streamflow generating mechanisms in a mountainous Jonkershoek catchment, South Africa(University of the Western Cape, 2022) Mokua, Retang Anna Lapalemabu; Mazvimavi, DominicThe Jonkershoek valley catchment in a mountain region that forms the headwaters of the Eerste River, which contributes water to the Cape Winelands District Municipality and parts of the City of Cape Town in the Western Cape Province, South Africa. These areas include highly urbanized and agriculturally advanced regions, which are vulnerable to occasional water shortages. Understanding the processes and factors accounting for the spatial and temporal variations of streamflow in this area is critical. This information can be used to build appropriate conceptual models of this catchment’s functioning to support the management of water resources.Item Geological and hydrgeological characteristics of acid mine drainage from an abandoned coal mine: A case study of Shandi coal mine in Niangziguan spring catchment, Shanxi(University of Western Cape, 2022) Wang, Zhaoliang; Xu, YongxinAs Shanxi Province is rich in coal resources, the output of raw coal approximately accounts for one quarter of China's production. It is one of the most important energy and heavy chemical bases and plays a significant role in the sustainable development of the national economy and energy security. With the continuing exploitation of coal resources in Shanxi, water environmental problems such as the destruction of water resources and deterioration of water quality have become increasingly prominent. Especially with the closure of many depleted coal mines, water pollution caused by acid mine drainage (AMD) has become more and more serious, which aggravated the shortage of water resources and threatens the safety of local drinking water supply. Since 2008, more than 100 coal mines have been abandoned in the Yangquan coalfield of Shanxi, and the AMD has polluted the surface water and groundwater in the Niangziguan spring catchment.Item GIS and remote sensing-based integrated modelling of climate and land use change impacts on groundwater quality: Cape Flats Aquifer, South Africa(University of Western Cape, 2021) Gintamo, Tesfaye Tessema; Kanyerere, ThokozaniThe need to ensure groundwater security is vital, particularly in urban areas. Assessing the impact of land use and climate variables on groundwater quality can help improve sustainable management. The vulnerability mapping of groundwater contamination identifies high-risk areas. Using models and technologies that forecast the distribution of contamination risk over time and place can help prioritize groundwater monitoring. Based on such needs, the Cape Flats aquifer in Cape Town, South Africa, was chosen as the case study for assessing the potential for groundwater contamination risk in urban and coastal hydrogeological settings. The Cape Flats aquifer has been highlighted as an alternate water supply source to augment current supply sources in Cape Town. However, the shallow aquifer is under pressure from agricultural and industrial activities and long-term climate variables, among other factors.Item Hydraulic properties of the Table Mountain group (TMG) aquifers(University of the Western Cape, 2006) Lin, Lixiang; Xu, YongxinThe Table Mountain Group (TMG), located at the southmost cape of African Continent, is one out of three major regional aquifer systems in South Africa, which has a potential of bulk water supply to meet the requirements of irrigation and local municipalities in the Western and Eastern Cape provinces. The TMG aquifers comprising a thick sequence of hard sedimentary rocks dominated by fractured sandstones have the outcrop area of 37000 km2, the deposit area of 248000 km2 and the thickness ranging from 900m to 4000m. Large-scale distribution of the TMG over various geological structures leads to a big diversity in its hydrogeological properties, especially the hydraulic properties which are critical in determining the aquifers’ abstraction potential and sustainable yield. A proper estimation of hydraulic properties, with focus on the investigation of aquifer porosity, permeability and storativity, is important for the sound evaluation and sustainable utilization of the groundwater resource in the TMG area. Data from previous studies and current research have been collated and analyzed to help establish conceptual models of the TMG aquifers and to quantify the intrinsic aquifer properties − hydraulic properties. Based on the study of hydrogeological settings and aquifer types, combined with the interpretation of aquifer hydraulic tests, it is realized that the hydraulic properties of the TMG rocks are strongly controlled by fractures regarding the groundwater flow path within the TMG rocks. Media study on the nature of the fractures or fracture networks therefore is conducted in detail. Subsequently, the establishment of the fractured-media conceptual models on the basis of stochastic analyses is helpful for the better understanding of groundwater behaviors in the TMG aquifers. With the data derived from field measurements and interpretation of remote sensing data, the fractured rock hydraulic conductivities are estimated by using a hydraulic conductivity tensor approach. Considering the influential factors such aperture, roughness, stress condition, and most importantly the connectivity of fractures, the tensor model is accordingly modified to meet different boundary conditions for the estimation of the hydraulic conductivities on the surface and at depth. As a result, the estimated hydraulic conductivities at most sites fall in the range of 10-2~10-3 m/d that is roughly consistent with site pumping test results. However, it decreases with depth following a negative power law, which implies that the majority of fractures tend to be closed at depth. Site hydraulic tests also show the similar tendency of vertically spatial variation of the hydraulic conductivities. The study of fracture connectivity shows another hydrogeological significance. Fracture networks on the measurement scale present the feature of various fracture blocks in the system rather than they are well connected. The 3-D model demonstrates that very few fractures in the TMG sandstones are competent for groundwater flow. With this regard the computation of hydraulic conductivities is hence calibrated Multiple approaches are employed to estimate porosity and associated aquifer storativity. Results show that porosity of the TMG sandstones is strongly scale-dependent, of which the value of core sample laboratory tests yield a upper limit of 1.0%~3.6%. The porosity of pumping tests and in-situ fracture measurements fall in the middle rang of 0.05%~0.6%, whilst the application of lineament interpretation from remote sensing data produce its lower limit of 1.2×10-8. Assuming the TMG rocks are homogeneous media, the storativity value should have the same trend at various scales. These results indicate that the TMG groundwater resource at a larger scale may be overestimated if use the aquifer parameters derived from a smaller-scale study. Research findings in current study provide a new insight into the fractured rock aquifers in the TMG area. Some of the results will have wide implications on the groundwater management and forms a solid basis the further study of the TMG aquifers.Item Integrated approach to solving reservoir problems and evaluations using Sequence Stratigraphy, Geological Structures and Diagenesis in Orange Basin, South Africa"(University of the Western Cape, 2010) Adekola, Solomon Adeniyi; Akinlua, AThe use of integrated approach to evaluate reservoir rock quality and source rock potential is becoming increasingly important in petroleum geology. This approach was employed to unravel the reason for variable reservoir quality of sandstones and evaluation of source rock potential of shale intervals of Orange Basin, SW, South Africa. The data sets acquired for this study include 783.63 km digital 2D seismic lines cutting across the 5 blocks of the basin, digital wireline logs (gamma ray, resistivity, density and neutron), core (sidewall and core) and ditch cutting samples from 10 wells of interest. The digital seismic section and wireline logs were subjected to manual and computer interpretation using specialized softwares (FastTracker, PETREL 2008, and SMT 8.2). The wireline logs of the 10wells were broken to depositional sequences and systems tracts: lowstand, transgressive and highstand systems tracts. The seismic section was analysed for depositional sequences, systems tracts and structures. Growth faults that are listric and normal were found localized in the basin. The faults are flank faults, erestal faults as well as antithetic faults. Sandstone and shale samples were selected within the systems tracts for laboratory analyses. The sidewall and core samples were subjected to petrographic thin section analysis, mineralogical analyses which include x-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and stable carbon and oxygen isotopes geochemistry to determine the diagenetic alteration at deposition and post deposition in the basin. The shale samples were subjected to Roek-Eval pyrolysis and accelerated solvent extraction (ASE) prior to gas chromatographic (GC) and gas chromatographic-mass spectrometric (GC-MS) analyses of the rock extracts, in order to determine the provenance, type and thermal maturity of organic matter present in sediments of the Orange Basin. The results revealed a complex diagenetic history of sandstones in this basin, which includes compaction, cementation/micritization, dissolution, silicification/overgrowth of quartz, and fracturing. The Eh-pH shows that the cements in the area of the basin under investigation were precipitated under weak acidic and slightly alkaline conditions. The 0 80 isotope values range from -1.648 to 10.054 %, -1.574 to 13.134 %, and -2.644 to 16.180 % in the LST, TST, and HST, respectively. While 03e isotope values range from -25.667 to -12.44 %, -27.862 to -6.954% and -27.407 to -19.935 % in the LST, TST, and HST, respectively. The plot of 0180 versus 0J3e shows that the sediments were deposited in shallow marine temperate conditions. The consistency of abundance of 0J3e isotope across the stratigraphic sequences indicates that the burial diagenesis has no significant effect on geochemical pattern of occurrence of ()J3e isotope in the sandstones under investigation. The authigenic minerals precipitated blocked the grain interspaces and interlayers and with continued burial, compaction impeded the development of secondary porosity resulting in the poor reservoir quality. The origins of the cementing materials are both autochtonous and allochtonous. The Roek-Eval pyroysis and Toe results of the shale samples revealed that LST is characterised by mainly marginally organic rich shale samples with a few organic rich rocks, variable organic matter types ranging from Type II to Type IV, and a few samples are thermally mature but have low organic matter quality. Four samples from two wells (A_Fl and a_AI) in the LST have good petroleum generative potential but not sufficiently mature for petroleum generation. TST is characterised with a few samples being marginally organic rich with only one being organic rich, mainly Type III kerogen with few Type IV kerogen, and only a few samples are thermally mature that has low organic matter quality. HST is characterised by many marginally organic rich rock samples, mainly Type III and a few mixed Type IIIIII kerogen, and only a few samples are thermally mature. The results of this study show that the LST has the best prospect in terms of petroleum generation potential, followed by HST and TST has least petroleum generation potential. The study also reveals that limited petroleum source rocks exist, which are also impacted by low thermal maturity levels. The basin is more gas prone than oil The shale samples were further analysed by Rock-Eval-Pyrolysis and for n-alkanes, aliphatic isoprenoid hydrocarbons and biomarkers (steranes and hopanes) by gas 2 chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). For most of the shale samples from the different stratigraphic sequences from Aptian to Campanian age Roek-Eval data (hydrogen (HI) and oxygen index (Ol)) and biomarker parameters (oleanane/hopane ratio, proportions of steranes, pristaneln-heptadecane vs. phytanelnoctadecane) point to mainly Typ III terrestrial organic matter. Only a few samples of Turonian age reveal a higher proportion of marine organic matter being classified as Typ IIIIII or Typ II. Biomarker parameters also suggest that the samples are deposited under suboxic to oxic environmental conditions. Roek-Eval data and biomarker maturity parameters assign for most of the samples a maturity level at the beginning of the oil window with some more mature samples of Aptian, Albian and Cenomanian age. The hydrocarbon generation potential is for most of the samples low as indicated by the S2/S3 ratio and HI values, exceptions are samples from Turonian and Aptian ageItem Assessing land use-land cover changes and their effects on the hydrological responses within the Nyangores River Catchment, Kenya(University of Western Cape, 2021) Ndungo, Margaret Njoki; Mazvimavi, DominicThis thesis aimed at contributing knowledge on how the widespread changes in land use/cover resulting from increasing human population and their associated activities, are influencing hydrological responses in a sub-humid catchment. The study therefore hypothesised that reduced forest cover over time in favour of agricultural activities is altering hydrological processes of the catchment which is affecting the flow characteristics in a sub-humid catchment. The sub-humid catchment selected to investigate these issues is the Nyangores River Catchment in Kenya.Item Characterization of flowpaths to improve the prediction of vegetation impacts on hydrological processes in semi-arid mountainous catchments of the Cape Fold Belt(University of Western Cape, 2021) Jumbi, Faith Tatenda; Mazvimavi, DominicMountainous areas are important water sources in many landscapes. An understanding of how mountainous catchments function is important particularly in semi-arid areas, where water shortages are prevalent. In addition to climate and physiographic factors, the hydrological responses of mountainous catchments can be influenced by land uses and land cover types. Although the general effects of land use and land cover types on hydrological processes are known, prediction of the specific effects in a given catchment is still problematic. This study characterized flowpaths, and hydrological responses to different land cover types in a semi-arid, mountainous Kromme River catchment (Eastern Cape province of South Africa), located in the Cape Fold Mountains of the Table Mountain Group (TMG) geological region.Item The partitioning of evapotranspiration in apple orchards from planting until full-bearing age and implications for water resources management(University of Western Cape, 2021) Ntshidi, Zanele; Mazvimavi, DominicOrchard evapotranspiration (ET) is a complex flux which has been the subject of many studies. It often includes transpiration from the trees, cover crops and weeds, evaporation from the soil, mulches, and other orchard artefacts. Studies of evapotranspiration in orchards often quantify tree water use and soil evaporation, treating the water use from the understorey vegetation on the orchard floor as negligible. Therefore, there is a paucity of information; first about the water use of cover crops in general, and secondly about the contribution of cover crops to whole orchard ET. This information is important, especially in semi-arid regions like South Africa where water resources are already under great strain and the situation is predicted to worsen in future due to climate change.Item Spatial and temporal variations of inundation and their influence on ecosystem services from a shallow coastal lake. A case study of Soetendalsvlei in the Nuwejaars catchment, South Africa(University of Western Cape, 2021) Carolissen, Mandy; Mazvimavi, DominicEnhancing our understanding of wetland properties and the ecosystem services provided by wetlands within a dynamic landscape, is fundamental to ensuring appropriate management strategies for enhanced biodiversity and ecosystem benefits. With increased anthropogenic activities and the impacts of climatic variability, a better understanding of the factors influencing the water balance dynamics of wetlands can provide insight into how wetlands respond to change. The main aim of the research was to improve the understanding of the spatial and temporal availability of water and storage of a depression wetland in a semi-arid climate, and to relate these to ecosystem functions. As ecosystems are intricately connected to society, a secondary aim of the research was to gain insight to how wetland ecosystems, within a changing climate and landscape, provide benefits to society, and add value to human-wellbeing. Soetendalsvlei, a shallow freshwater depression, and one of the few coastal freshwater lakes of South Africa, was the focus of the research.Item Developing a citizen science framework for water resources protection to facilitate operationalization of resource directed measures at catchment level, South Africa(University of Western Cape, 2021) Nzama, Stanley Mvuselelo; Kanyerere, ThokozaniMaintenance of water resources protection practice for water availability, uninterrupted water utilization, and for ecosystem integrity is critical for sustainable achievement of resource security for all. Therefore, operationalization of water resource protection strategies such as resource directed measures, especially at catchment level where water resources utilization takes place is critical. The main aim of the current study was to develop a citizen science framework for operationalization of resource directed measures at catchment level. Such a framework used a nexus approach, and its development was guided by the principles of socio-ecological model from a systems thinking perspective. This demonstrated importance of resource directed measures which are accepted as relevant policy implementation strategies towards improved and integrated water resources management practice at catchment level, where local citizens become part of such practice.Item Developing a citizen science framework for water resources Protection to facilitate operationalization of resource Directed measures at catchment level, South Africa(2021) Nzama, Stanley Mvuselelo; Kanyerere, ThokozaniMaintenance of water resources protection practice for water availability, uninterrupted water utilization, and for ecosystem integrity is critical for sustainable achievement of resource security for all. Therefore, operationalization of water resource protection strategies such as resource directed measures, especially at catchment level where water resources utilization takes place is critical. The main aim of the current study was to develop a citizen science framework for operationalization of resource directed measures at catchment level. Such a framework used a nexus approach, and its development was guided by the principles of socio-ecological model from a systems thinking perspective. This demonstrated importance of resource directed measures which are accepted as relevant policy implementation strategies towards improved and integrated water resources management practice at catchment level, where local citizens become part of such practice. Local operationalization of resource directed measures provides a basis for practical policy implementation at catchment level, thereby informing decisions taken on water resources protection and sustainable water use for several purposes. It provides an understanding of how policies which are formulated for water resources protection purposes influence land use activities and other non-land use activities to ensure water availability for current and future generations. Furthermore, localized operationalization of resource directed measures facilitates ecological ecosystems protection such that goods and services derived from such ecosystems are sustained. The research problem of the current study was a lack of available and feasible plan for resource directed measures practice at catchment level which has a direct influence on the continued water quality deterioration and unsustainable utilization of water resources. This study argued that a citizen science framework needed to be developed and such a plan must be informed by science-policy interface that is practical, reflective and must consider the nexus approach using the concept of citizen science in order to improve the practice of resource directed measures at local level in an acceptable manner by practitioners.Item The impact of land use and land cover changes on wetland productivity and hydrological systems in the Limpopo transboundary river basin, South Africa(University of Western Cape, 2021) Thamaga, Kgabo Humphrey; Dube, TimothyWetlands are highly productive systems that act as habitats for a variety of flora and fauna. Despite their ecohydrological significance, wetland ecosystems are under severe threat as a result of environmental changes (e.g. the changing temperature and rainfall), as well as pressure from anthropogenic land use activities (e.g. agriculture, rural-urban development and dam construction). Such changes result in severe disturbances in the hydrology, plant species composition, spatial distribution, productivity and diversity of wetlands, as well as their ability to offer critical ecosystem goods and services. However, wetland degradation varies considerably from place to place, with severe degradation occurring particularly in developing regions, such as sub-Saharan Africa, where Land Use and Land Cover changes impact on wetland ecosystems by affecting the diversity of plant species, productivity, as well as the wetland hydrology.