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Doctoral Degrees (Agricultural Engineering)

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Browsing Doctoral Degrees (Agricultural Engineering) by Author "Jewitt, Graham Paul Wyndham."

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    The development of the Water-Energy-Food Nexus Index and its application to the Southern African Development Community.
    (2020) Simpson, Gareth Beresford.; Jewitt, Graham Paul Wyndham.
    This thesis commences with a review of the development and relevance of the water-energy-food (WEF) nexus as a framework for achieving resource security. Based on academic and grey literature it includes an assessment of what the WEF nexus is, a review of its novelty (or lack thereof), and describes the challenges associated with integrating and optimising the WEF nexus. The criticism that several WEF nexus conceptualisations neglect distributional justice is considered, followed by a reflection on governance aspects associated with the approach. Four short WEF nexus case studies illustrate nexus considerations. The research subsequently assesses the status quo of opinion within the WEF nexus fraternity. The approach is not yet a decade old, and several practitioners have called for a shift in focus from ‘nexus thinking’ to ‘nexus doing.’ Various research tools to support nexus action are presented. Next, a comprehensive WEF nexus case study that includes indicators and GIS-base maps is offered. The case study is the Mpumalanga Province in South Africa, which represents a melting pot for the WEF nexus. Within this province is a strategic water area, extensive coal mining for energy generation and a considerable portion of the nation’s high potential agricultural land. This nexus assessment yields a radar chart that represents a visualisation of six water-, energy- and food-related indicators. An anthropogenic WEF nexus framework is subsequently motivated and presented. This framework has been utilised to develop the core output of this research project, namely, the development of a country-level composite indicator that has been established for 170 nations. Following an assessment of 87 globally applicable water-, energy- and food-related indicators, 21 were selected to constitute the WEF Nexus Index. This index provides a quantitative perspective of this multi-centric lens for evaluating trade-offs necessary to achieve sustainable development. To this end, it can be utilised for assessing national progress relating to integrated resource management as well as supporting decision making and policy development. The relevance and usefulness of the outcomes are demonstrated through a detailed discourse of the findings for selected regions and countries. An extended analysis is provided for the Southern African Development Community (SADC). WEF nexus assessments in the decade leading up to the 2030 Sustainable Development Goal (SDG) target year must be more comprehensive. Qualitative studies must be conducted in parallel with quantitative assessments. There is no one-size-fits-all method for integrated resource management utilising the WEF nexus. Instead, the approach must be tailored for each unique situation, and the WEF Nexus Index can be a catalyst and entry-point for such studies. By evaluating a subset of the SDGs, the index is complementary to the SDGs. The WEF Nexus Index is not a silver bullet that will solve all the significant development or environmental challenges facing humanity. This approach can, however, be added to the sustainability toolbox that is being utilised to engineer ‘the future we want’.
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    Flood disaster preparedness and impacts on rural households: a comparative study of Mwandi District of Zambia and Eastern Zambezi Region of Namibia.
    (2019) Mabuku, Monde Patrina.; Senzanje, Aidan.; Mudhara, Maxwell.; Jewitt, Graham Paul Wyndham.; Mulwafu, Wapulumuka O.
    The Zambezi Basin is considered vulnerable to climate variability as evidenced by the recurrent floods. The increased occurrence and severity of floods in recent years in areas previously not flooded has inundated parts of Eastern Zambezi Region of Namibia and Mwandi District of Zambia. The magnitude and frequency of these floods, coupled with poor disaster preparedness and lack of effective adaptation strategies, is believed to have negative impacts on rural households. Therefore, a cross country case study was carried out in order to assess the impacts of floods on income, crop production and livestock ownership; to determine the level of flood disaster preparedness; to assess coping and adaptation strategies undertaken by the rural households, and to develop a Household Flood Disaster Resilience Framework (HFDRF). Furthermore, the factors influencing the choice of different adaptation strategies and preparedness level were determined. Data were collected through structured and semi- structured questionnaire survey, focus group discussions, literature reviews and observations. The results indicated that floods had statistically significant impacts on income, crop production and livestock ownership of flooded rural households in both Namibia and Zambia. Rural households depended on both short-term coping and long-term adaptation strategies in order to minimize the negative impacts of floods and flood disasters. Households coped with floods through charcoal production, sale of firewood, sale of grass and reeds, collection of wild food and receipt of food aid. Long-term adaptation strategies included planting trees, fish farming, and flood water harvesting, temporary relocation to higher ground, and changing planting dates, among others. A majority of the households were well prepared (52%) for flood hazards in Namibia, whilst a minority were well prepared (9%) in Zambia. Furthermore, flood preparedness was influenced by sense of community, risk perception, self-efficacy, responsibility efficacy, outcome expectancy, education level, marital status, access and size of land. The study concludes that a variety of factors influence level of flood preparedness and adaptation strategy choices. For policy purposes, this suggests that relevant stakeholders’ interventions should consider these factors in order to enhance the rural households’ adaptive capacity to flooding. Furthermore, results on the impacts of floods on rural households could help in targeting the most vulnerable households in responding effectively to food disasters. This study informs decision makers and practitioners who aim to strengthen disaster risk reduction and management in the two countries and under similar environments, on the status quo of flood impacts, adaptation, and preparedness. The Household Flood Disaster Resilience Framework can be used as a tool for monitoring rural households’ flood resilience.
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    Object-orientation and integration for modelling water resource systems using the ACRU model.
    (2018) Clark, David John.; Smithers, Jeffrey Colin.; Jewitt, Graham Paul Wyndham.
    Water is a limiting resource in South Africa, with demand in many catchments exceeding supply, necessitating transfers of water between catchments. This situation requires detailed and integrated management of the country’s water resources, considering environmental, social and economic aspects as outlined in the National Water Act (Act 36 of 1998). Integrated water resources management (IWRM) will require better data and information through monitoring and integrated water resources modelling. The ACRU hydrological model is an important repository of South African water research and knowledge. In recent years there have been technological advances in computer programming techniques and model integration. The thesis for this study was that the valuable knowledge already existing in the ACRU model could be leveraged to provide a better hydrological model to support IWRM in South Africa by: (i) restructuring the model using object-oriented design and programming techniques, and (ii) implementing a model interface standard. Object-oriented restructuring of the ACRU model resulted in a more flexible model enabling better representation of complex water resource systems. The restructuring also resulted in a more extensible model to facilitate the inclusion of new modules and improved data handling. A new model input structure was developed using Extensible Markup Language (XML) to complement the object-oriented structure of the ACRU model. It was recognised that different models have different purposes and strengths. The OpenMI 2.0 model interface standard was implemented for ACRU, enabling ntegration with other OpenMI 2.0 compliant specialised models representing different domains to provide a more holistic IWRM view of water resource systems. Model integration using OpenMI was demonstrated by linking ACRU to the eWater Source river network model. A case study in the upper uMngeni Catchment in South Africa demonstrated: (i) the benefits of the object-oriented design of the restructured ACRU model, in the context of using ACRU to create modelled catchment-scale water resource accounts, and (ii) the integration of ACRU with another model using OpenMI. The case study also demonstrated that despite the improvements to the ACRU model, the simulations are only as good as the model input data.