DSpace Repository

Welcome to the NWU Repository, the open access Institutional Repository of the North-West University (NWU-IR). This is a digital archive that collects, preserves and distributes research material created by members of NWU. The aim of the NWU-IR is to increase the visibility, availability and impact of the research output of the North-West University through Open Access, search engine indexing and harvesting by several initiatives.

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Recent Submissions

An assessment of flood risk and vulnerability in coastal areas of KwaZulu-Natal
(North-West University (South Africa), 2026) Harripersadh, Amanda; Malherbe, C.W
Flooding is one of the most significant natural hazards affecting coastal regions worldwide, with increasing frequency and intensity driven by climate change, urbanisation, and environmental degradation. Coastal KwaZulu-Natal (KZN), South Africa, is particularly vulnerable due to its exposure to extreme rainfall events, storm surges, and densely populated river catchments. Despite recurring flood events, there remains limited spatially explicit information on flood-prone areas, vulnerability patterns, and associated risks. This study aimed to assess flood risk and vulnerability in the coastal regions of KwaZulu-Natal by integrating hydrological and hydraulic modelling with spatial and socio-economic analysis. The research focuses on key river systems, including the uMgeni, uMvoti, uMdloti, uMlazi, Mbokodweni, and uMkomazi catchments. Hydrological modelling was conducted using HEC-HMS to simulate rainfall-runoff processes, while hydraulic modelling using HEC-RAS was applied to determine flood depth, extent, and inundation patterns, consistent with integrated flood inundation modelling approaches described by Saksena et al. (2019).These outputs were integrated into a GIS environment (QGIS) to generate flood hazard maps. A vulnerability assessment was conducted using a Multi-Criteria Decision Analysis (MCDA) approach, incorporating socio-economic and environmental indicators such as population density, land use, settlement type, and proximity to rivers. The Analytic Hierarchy Process (AHP) was used to assign weights and develop a flood vulnerability index. The results indicate clear spatial variations in flood hazard and vulnerability across the study area. Larger river systems exhibited delayed but high-magnitude flood responses, while smaller, urbanised catchments showed rapid runoff and increased localised flood risk. Areas with high population density, informal settlements, and inadequate infrastructure were identified as the most vulnerable. The study highlights the importance of integrating hydrological modelling with socio-economic analysis to improve flood risk assessments. The findings provide valuable insights for disaster risk reduction, spatial planning, and climate adaptation strategies in KwaZulu-Natal. It is recommended that future efforts focus on improving data availability, strengthening early warning systems, and incorporating vulnerability assessments into policy and planning frameworks.
Evaluating the functionality of different kimberlite mine wastes as alternative to building material
(North-West University (South Africa), 2026) Du Plessis, Juan Crause; Koch, J; Boneschans, R.B
Kimberlite diamond mines tend to produce vast amounts of rock-derived waste that are ultimately stored and rehabilitated at high cost to the mining company. Diamond mine rock waste does not always contain the same cocktail of hazardous elements typically associated with other mining commodities' rock waste. Repurposing this material in a creative, optimised way could lead to value creation. Instead of rehabilitation, this project suggests that using various types of rock waste could replace aggregate or other components in the manufacture of building-related products. This could allow mining companies, building material manufacturers and the local community to work together to produce an environmentally friendly and economically viable product. Previous studies have found that kimberlite waste could be used in a range of products, from aggregates to cement to clinker bricks and more. The few studies that have been done have mostly concerned themselves with local bureau of standards requirements, using various testing methodologies. This project investigates mine rock waste from five Southern African sites, examining 25 different materials. The tests conducted followed the South African Board of Standards (SABS) and other key quality bureau methods to assess compliance for a safety-critical product, with a focus on aggregate compliance tests due to time constraints. Information from different textural tests, aggregate impact value (AIV), chemistry (XRF), and mineralogy (XRD) helps assess the potential usage of 25 different materials. Results showed that all materials met SANS 1083/1090 density requirements, but most tailings failed on grading, fineness modulus and dust content due to excessive fines. Waste rocks graded well and achieved acceptable Aggregate Impact Values. Mineralogy was the dominant limiting factor: high phyllosilicate and clay content made most tailings and waste rocks unsuitable for concrete aggregate. Only a dolomite-dominant group and a feldspar/pyroxene-rich Voorspoed group showed conditional potential. Unsuitable materials often contained clay or phyllosilicate minerals suited to light aggregate or clay brick production, a viable beneficiation pathway.
Evaluating the quality of water use licence application technical reports for solar power plants in the Free State Province
(North-West University (South Africa), 2026) Daniels, Earl Craig; Moolman, H.J
Globally, water resources are under pressure due to anthropogenic activities. One of the major contributors is the energy sector, driven by the increasing need for reliable electricity generation. In response to the environmental degradation of traditional electricity generation, renewable energy initiatives such as solar power plants are increasingly proposed in many countries, including South Africa. Semi-arid provinces in South Africa, such as the Free State province, have attracted solar power plant development due to abundant solar radiation resources. However, the province is known for threatened endemic biodiversity, protected areas, and stressed water resources. Despite the sustainable nature of solar power plants, they are not developed without environmental impacts, especially on water resources. The National Water Act (Act 36 of 1998) provides for the licensing of activities that may have negative impacts on water resources. This licensing process entails the submission of a Water Use Licence Application (WULA) technical report that is subjected to the scrutiny of the competent authority before the licensing of water uses. However, recently, the completeness and substantive quality of report content have been questioned. Therefore, this research aimed to evaluate the quality of WULA technical reports for solar power plants in the Free State province and to offer recommendations to improve their quality. The evaluation followed a case study approach in which a sample of eight WULA technical reports was evaluated against the criteria of an adapted review package. The evaluation results revealed an overall satisfactory performance (A-C=51%; D-F=49%) with omissions identified in certain subcategories. Review area 1 (description of the development) and review area 2 (specialist assessment of impacts) performed predominantly satisfactorily in their sub-categories. Whereas review area 3 (alternatives and impacts) performed average, and review area 4 (communication of results) displayed unsatisfactory performance. Overall, subcategories that performed unsatisfactorily include the baseline conditions, waste, alternatives, public participation, the inclusion of non-technical summaries, assessment of impact significance, commitment to mitigation, report layout, presentation, and emphasis of information. The satisfactory performing categories are site description, environmental description, definition of impacts, identification of impacts, prediction of impact magnitude, scope and effectiveness of mitigation, and report emphasis. To address the gaps in quality of the WULA technical reports, it is recommended that Environmental Assessment Practitioners (EAPs) be provided with the final project designs to understand the project holistically and scope in all possible potential impacts into the WULA for all relevant specialist studies to be submitted. The appointed EAPs and specialists should adopt a project life cycle approach in their assessments of water-related impacts. The Department of Water and Sanitation (DWS) should continually conduct workshops in the water sector related legislation for applicants to include all legal requirements, climate change, and emergencies in their WULAs. The required DWS Risk Assessment Matrix must be templated to include wasterelated impacts and impacts on Interested and Affected Parties.
Reviewing the quality of Environmental Impact Assessment reports for development projects affecting wetlands in the Amathole District Municipality of the Eastern Cape
(North-West University (South Africa), 2026) Buso, Lulama
Environmental Impact Assessment (EIA) is an essential environmental management tool that promotes sustainable development by identifying, assessing, and mitigating the impacts of proposed developments. Despite South Africa's legislative framework under the National Environmental Management Act (NEMA) EIA Regulations, 2014 (as amended in 2017), challenges such as weak compliance monitoring, increasing development pressures, and inadequate consideration of wetland ecological functions continue to undermine the effectiveness of wetland-related EIAs. This study assessed the quality of Environmental Impact Assessment Reports (EIARs) for development projects affecting wetlands in the Amathole District Municipality, Eastern Cape, South Africa. The study aimed to (i) review the quality of EIARs and (ii) evaluate the extent to which recommendations from Wetland Specialist Impact Assessment (WSIA) reports were incorporated into EIARs using an adapted Lee and Colley Review Package. A qualitative descriptive research design was adopted, with document analysis conducted on 15 EIARs and their associated WSIA reports selected through convenience sampling. The findings showed that 93% (n = 14) of the EIARs were of satisfactory quality (Grades A-C), with Review Areas 1 and 2 performing the best, while Review Areas 3 and 4 required improvements. All WSIA reports achieved satisfactory overall grades, although most were boundary cases, indicating inconsistent substantive quality and integration of specialist recommendations. Overall, the study found that EIARs generally comply with the procedural requirements of the NEMA EIA Regulations but require improvements in analytical quality, mitigation measures, and the incorporation of wetland specialist recommendations. The study contributes new knowledge by providing a systematic quality review of wetland-related Specialist Impact Assessment reports within the South African EIA context and offers recommendations for Environmental Assessment Practitioners, Competent Authorities, policymakers, and future research to improve wetland conservation and EIA practice.
Dehydrogenase-linked metabolic markers of changes in the mitochondrial redox status
(North-West University (South Africa), 2026) Ally, Momina; Pretorius, M; Guarnieri, J.W; Williams, A.A
Mitochondria are essential to normal cellular function due to their production of adenosine triphosphate (ATP), which serves as the primary energy source for most biochemical and physiological processes. Dysfunction of the mitochondrion is commonly characterised by impaired oxidative phosphorylation (OXPHOS) and altered redox status. Redox status regulates a plethora of biological processes, including cellular signalling pathways, regulation of antioxidant defence systems and metabolic pathways, therefore maintenance of it is essential for normal cellular function. Metabolic investigations conducted in the past consistently indicated that a disruption in redox status contributes to cellular adaptations observed in both patients with mitochondrial diseases and animal models. However, due to the challenges in directly measuring NAD+/NADH ratios in cells and tissues, indirect measurements are primarily utilised, particularly the ratios between the substrate and product pairs of dehydrogenase-catalysed reactions. To validate whether these metabolite ratios accurately reflect changes in redox status, it is necessary to compare them with direct measurements of NAD+/NADH ratios. Therefore, this study aimed to determine whether dehydrogenase-linked metabolite ratios can serve as valid indicators of mitochondrial redox state status (NAD+/NADH ratio) at different stages of mitochondrial dysfunction. This aim was achieved through the generation of SoNar- and mtLbNox-expressing cell models, followed by investigating the relationship between m.3243A>G heteroplasmy, dehydrogenase-linked metabolite ratios and NAD+/NADH balance, as well as the evaluation of mtLbNox expression on these factors. The results demonstrate that increasing m.3243A>G heteroplasmy induces compartment-specific changes in NAD+ levels and variable changes in metabolite ratios, while mtLbNox intervention confirmed that pyruvate/lactate, oxaloacetate/malate, and 2-ketoisocaproate/2hydroxyisocaproate ratios consistently reflected changes in redox state. Other metabolite ratios did not respond proportionally to altered redox state and therefore require further investigation. The results of this study demonstrate that while dehydrogenase-linked metabolite ratios can reflect aspects of redox-associated metabolic adaptation, their relationship with redox state is complex, compartment-dependent and not consistent across all pathways.