List of Titles

The effects of aspect, directional heating and depth on bedrock temperatures and the potential relationship with thermal fatigue weathering

- Breytenbach, Izak Johannes

Authors: Breytenbach, Izak Johannes
Date: 2021-04
Subjects: Weathering -- South Africa -- Karoo , Shields (Geology) -- South Africa -- Karoo , Shields (Geology) -- Thermal properties , Tillite -- South Africa -- Karoo
Language: English
Type: thesis , text , Doctoral , PhD
Identifier: http://hdl.handle.net/10962/177688 , vital:42847 , 10.21504/10962/177688
Description: Geomorphological weathering processes and their relationship with temperature fluctuations are frequently researched. These research efforts are mostly restricted to surface conditions where soils, loose-lying rocks or rock outcrops are assessed. However, there is a shortcoming in the understanding of the thermal properties in a rock mass, particularly in the upper metres below the surface, as this has not been investigated or researched in any great detail. The research reported here is unique in this regard as it exploited the use of rotary core boreholes in tillite bedrock in the Karoo (Western Cape, South Africa) which were drilled as part of an invasive materials investigation for a proposed new hard rock quarry to supply road stone. Temperature data were captured on a bedrock ridge hosting tillite outcrop with a strong east to west orientation. The site work was done in two separate phases. The initial phase of research saw data being captured for one year on two aspects (i.e. north and south) at a depth of 0.3 m. This was followed by the second (more detailed) phase, where three aspects were assessed (i.e. north, south and a flat crest), but at depths of 0.3 m, 2.0 m and 6.0 m, totalling nine data acquisition points. The second investigation phase gathered data for seven months. Supplementary weather data were also captured for the site. Subsequent data analyses revealed that there is much to learn about the thermal behaviour of bedrock in the upper metres below the surface, and that the temperature properties or thermal regimes are not as simple as often assumed. Temperature differences related to aspect are not only surficial, but are transmitted to underlying bedrock, and notable temperature differences were measurable to a depth of at least 6.0 m. Seasonal temperature fluctuations also have a pronounced effect on the rock mass temperatures and it was proven that deeper parts of the bedrock accumulate and dissipate heat at different (i.e. retarded) rates compared with shallower parts of the rock mass, creating suitable thermal conditions to induce thermal fatigue. Thermal properties were also proven to be non-linear. During analyses, the concept of temperature inversions was proven, whereby one part of the bedrock becomes hotter or cooler relative to another/adjacent part of the bedrock, compared with its earlier temperature state. It was argued that these temperature inversions may exacerbate thermal fatigue. This research proved that aspect (i.e. directional heating) and depth need to be considered when analysing thermal regimes in a rock mass, as these have a distinct influence. The effects which manifest themselves create suitable conditions for thermal fatigue, not only near the surface but also at depth in the bedrock. Lastly, the effects of meteorological conditions on shallow bedrock temperatures were assessed. Preliminary findings suggest that boundary conditions and meteorological processes may indeed affect shallow bedrock temperatures, but only under certain circumstances and not to the same extent as reported in the literature for conditions researched at the surface. Wind temperature relative to the rock temperature, as well as a combination of wind and rain were found to be the most significant factors. , Thesis (PhD) -- Faculty of Science, Geography, 2021
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Date Issued: 2021-04

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The further development, application and evaluation of a sediment yield model (WQSED) for catchment management in African catchments

- Gwapedza, David

Authors: Gwapedza, David
Date: 2021-04
Subjects: Sedimentation and deposition -- South Africa , Sedimentation and deposition -- Zimbabwe , Watersheds -- South Africa , Watersheds -- Zimbabwe , Watershed management -- Africa , Water quality -- South Africa , Water quality -- Zimbabwe , Modified Universal Soil Loss Equation (MUSLE) , Water Quality and Sediment Model (WQSED) , Soil and Water Assessment Tool (SWAT)
Language: English
Type: thesis , text , Doctoral , PhD
Identifier: http://hdl.handle.net/10962/178376 , vital:42934 , 10.21504/10962/178376
Description: Erosion and sediment transport are natural catchment processes that play an essential role in ecosystem functioning by providing habitat for aquatic organisms and contributing to the health of wetlands. However, excessive erosion and sedimentation, mostly driven by anthropogenic activity, lead to ecosystem degradation, loss of agricultural land, water quality problems, reduced reservoir storage capacity and damage to physical infrastructure. It is reported that up to 25% of dams in South Africa have lost approximately 30% of their initial storage capacity to sedimentation. Therefore, excessive sedimentation transcends from an ecological problem to a health, livelihood and water security issue. Erosion and sedimentation occur at variable temporal and spatial scales; therefore, monitoring of these processes can be difficult and expensive. Regardless of all these prohibiting factors, information on erosion and sediment remains an urgent requirement for the sustainable management of catchments. Models have evolved as tools to replicate and simulate complex natural processes to understand and manage these systems. Several models have been developed globally to simulate erosion and sediment transport. However, these models are not always applicable in Africa because 1) the conditions under which they were developed are not as relevant for African catchments 2) they have high data requirements and cannot be applied with ease in our data-scarce African catchments 3) they are sometimes complicated, and there are little training available or potential users simply have no time to dedicate towards learning these models. To respond to the problems of erosion, sedimentation, water quality and unavailability of applicable models, the current research further develops, applies and evaluates an erosion and sediment transport model, the Water Quality and Sediment Model (WQSED), for integration within the existing water resources framework in South Africa and application for practical catchment management. The WQSED was developed to simulate daily suspended sediment loads that are vital for water quality and quantity assessments. The WQSED was developed based on the Modified Universal Soil Loss Equation (MUSLE), and the Pitman model is a primary hydrological model providing forcing data, although flow data from independent sources may be used to drive the WQSED model. The MUSLE was developed in the United States of America, and this research attempts to improve the applicability of the MUSLE by identifying key issues that may impede its performance. Assessments conducted within the current research can be divided into scale assessment and application and evaluation assessment. The scale assessment involved evaluating spatial and temporal scale issues associated with the MUSLE. Spatial scale assessments were conducted using analytical and mathematical assessments on a hypothetical catchment. Temporal scale issues were assessed in terms of the vegetation cover (C) factor within the Tsitsa River catchment in South Africa. Model application and evaluation involved applying and calibrating the model to simulate daily time-series sediment yield. The model was applied to calibrated and validated (split-sample validation) in two catchments in South Africa, two catchments in Zimbabwe and three catchments were selected from the USA and associated territories for further testing as continuous daily time-series observed sediment data could not be readily accessed for catchments in the Southern African region. The catchments where the model was calibrated and validated range in size from 50 km2 to 20 000 km2. Additionally, the model was applied to thirteen ‘ungauged’ catchments selected from across South Africa, where only long-term reservoir sedimentation rates were available to compare with long term model simulations converted to sediment yield rates. The additional thirteen catchments were selected from areas of different climatic, vegetation and soils conditions characterising South Africa and range in size from 30 km2 to 2 500 km2. The current research results are split into a) MUSLE scale dependency and b) WQSED testing and evaluation. Scale dependency testing showed that the MUSLE could be spatially scale-dependent, particularly when a lumped approach is used, resulting in simulations of up to 30% more sediment. Spatial scale dependence in the MUSLE was found to be related to the runoff and topographic factors used and how they are calculated. The current study resorted to adopting a reference grid in applying the MUSLE, followed by scaling up the outputs to the total catchment area. Using a reference grid resulted in a general avoidance of the problem of spatial scale. The adoption of a seasonal vegetation cover factor was shown to significantly account for temporal changes of vegetation cover within a year and reduce over-estimations in sediment output. The temporal scale evaluation demonstrated the uncertainties associated with using a fixed vegetation cover factor in a catchment with variable rainfall and runoff pattern. The WQSED model evaluation showed that the model could be calibrated and validated to provide consistent results. Satisfactory model evaluation statistics were obtained for most catchments to which the model was applied, based on general model evaluation guidelines (Nash Sutcliffe Efficiency and R2 > 0.5). The model also performed generally well compared to established models that had been previously applied in some of the study catchments. The highest sediment yields recorded per country were 153 t km-2 year-1 (Tsitsa River; South Africa), 90 t km-2 year-1 (Odzi River; Zimbabwe) and 340 t km-2 year-1 (Rio Tanama; Puerto Rico). The results also displayed consistent underestimations of peak sediment yield events, partly attributed to sediment emanating from gullies that are not explicitly accounted for in the WQSED model structure. Furthermore, the calibration process revealed that the WQSED storage model is generally challenging to calibrate. An alternative simpler version of the storage model was easier to calibrate, but the model may still be challenging to apply to catchments where calibration data are not available. The additional evaluation of the WQSED simulated sediment yield rates against observed reservoir sediment rates showed a broad range of differences between the simulated and observed sediment yield rates. Differences between WQSED simulated sediment and observed reservoir sediment ranges from a low of 30% to a high of > 40 times. The large differences were partly attributed to WQSED being limited to simulating suspended sediment from sheet and rill processes, whereas reservoir sediment is generated from more sources that include bedload, channel and gully processes. Nevertheless, the model simulations replicated some of the regional sediment yield patterns and are assumed to represent sheet and rill contributions to reservoir sediment in selected catchments. The outcome of this study is an improved WQSED model that has successfully undergone preliminary testing and evaluation. Therefore, the model is sufficiently complete to be used by independent researchers and water resources managers to simulate erosion and sediment transport. However, the model is best applicable to areas where some observed data or regional information are available to calibrate the storage components and constrain model outputs. The report on potential MUSLE scale dependencies is relevant globally to all studies applying the MUSLE model and, therefore, can improve MUSLE application in future studies. The WQSED model offers a relatively simple, effective and applicable tool that is set to provide information to enhance catchment, land and water resources management in catchments of Africa. , Thesis (PhD) -- Faculty of Science, Institute for Water Research, 2021
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Date Issued: 2021-04

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The impact of translanguaging and acculturation towards implementation of the Incremental Indigenous African Languages programme in former Model-C schools (Alfred Nzo West District, Eastern Cape)

- Lepheana, Jeremia

Authors: Lepheana, Jeremia
Date: 2021-04
Subjects: Translanguaging (Linguistics) , Acculturation -- South Africa -- Eastern Cape , Model C schools (South Africa) , Multilingual education -- South Africa -- Eastern Cape , Multicultural education -- South Africa -- Eastern Cape , Incremental Indigenous African Languages Programme
Language: English
Type: thesis , text , Doctoral , PhD
Identifier: http://hdl.handle.net/10962/177236 , vital:42802 , 10.21504/10962/177236
Description: This thesis explores the possibilities of multilingual language instruction within multi-ethnic classrooms in former Model-C schools shaped by multiple discursive practices. The researcher reviews current research on multilingualism and teaching and proposes strategies for overcoming the English prescriptivism, and monolingual mind-set in education. The research reported in this dissertation is both a qualitative and quantitative study, which sought to investigate the patterns of translanguaging in classrooms in five primary schools in Alfred Nzo West district (Maluti sub-district). In quantitative research, questionnaires were used to gather data from teachers and learners. In the qualitative research methodology, document analysis method of collecting data was employed. Purposive sampling was the major sampling method to ensure that relevant data was collected. Language in Education Policy formed the major analytical framework for this study. The aim of the study was to investigate the impact of translanguaging as it is used by teachers and learners in the class in selected primary schools in Alfred Nzo West district. The research focuses on how primary school learners and their teachers engage with teaching and learning, and the strategies that teachers use to promote the use of two or three languages in classrooms to help learners to understand content and concepts in English, Sesotho and isiXhosa as there are multi-ethnic classrooms in the district. The dissertation concludes with some reflections on the findings, implications of the findings for future research and training, and recommendations to use the languages of school children as rich resources for teaching and learning. The Socio-cultural theory formed the theoretical framework that guided this study. According to Vygotsky’s theory of cognitive development, children learn through social interaction that includes collaborative and cooperative dialogue with someone who is more skilled in tasks they are trying to learn. The findings of this study show the misunderstandings of the LiEP, translanguaging and multilingual education. The study also shows the lack of confidence in the ability of African languages to provide quality education. , Thesis (PhD) -- Faculty of Humanities, School of Languages, 2021
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Date Issued: 2021-04

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The Influence of Clientelism on the Informal Sector in Zimbabwe : a Case Study of Glen View 8 Complex, Harare

- Tandire, Justin

Authors: Tandire, Justin
Date: 2021-04
Subjects: Patron and client -- Zimbabwe -- Harare , Informal sector (Economics) -- Zimbabwe -- Harare , Informal sector (Economics) -- Political aspects -- Zimbabwe -- Harare , Patronage, Political -- Zimbabwe -- Harare , ZANU-PF (Organization : Zimbabwe) , Zimbabwe -- Social conditions , Glen View Complex 8 (Zimbabwe)
Language: English
Type: thesis , text , Doctoral , PhD
Identifier: http://hdl.handle.net/10962/177986 , vital:42896 , 10.21504/10962/177986
Description: This study focuses on the influence of clientelism in the informal sector of Zimbabwe in Glen View 8 (Complex). The study used the case of Glen view 8 (complex) in Harare Province. The study focused on political dynamics in the informal sector; livelihood strategies employed by informal sector operators; manifestation of “Big Men”, social networks in the informal sector; and different strategies employed by operators to overcome the problems of political manipulation, clientelism and patronage. It employs a qualitative research methodology to enable a nuanced comprehension of the clientelistic relationships that take place in the informal sector of Zimbabwe. Through in-depth interviews, focus group discussions, narratives and in-depth interviews with key informants, the study explored the clientelistic nature of the informal sector. The major findings of the study are that the informal sector in Zimbabwe is influenced by political patronage. It was established that patronage influences the informal sector in Zimbabwe in general and at Glen View Complex 8 in particular. Some of the operators revealed that patronage negatively affects their business as they are sometimes forced to attend political party meetings either at the complex or at ZANU-PF star rallies in town. The operators experience a plethora of problems such as lack of security, poor sanitation, stiff competition, poor infrastructure, lack of insurance and fire outbreaks. It has been revealed that most of the problems experienced at the complex are a result of the politicisation of the informal sector particularly by the ZANU-PF party. Operators at the complex have described the politicisation of the informal sector as a major drawback to their efforts of realising maximum benefits from their work. Therefore, the thrust of this thesis is premised on the de-politicisation of the informal sector as the starting point in the transformation of the activities of the operators. , Thesis (PhD) -- Faculty of Humanities, Sociology, 2021
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Date Issued: 2021-04

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The role of open government data in the repurposing of land administration in postapartheid South Africa : an exploration

- Manona, Siyabulela Sobantu

Authors: Manona, Siyabulela Sobantu
Date: 2021-04
Subjects: Transparency in government -- South Africa , Land reform -- South Africa , Qualitative research -- Methodology , Postcolonialism -- South Africa , Post-apartheid era -- South Africa , South Africa -- Economic conditions -- 1991- , South Africa -- Social conditions -- 1994- , South Africa -- Politics and government -- 1994- , Open Government Data (OGD)
Language: English
Type: thesis , text , Doctoral , PhD
Identifier: http://hdl.handle.net/10962/178397 , vital:42936 , 10.21504/10962/178397
Description: Almost three decades after the official end of the apartheid, South Africa has been on a sturdy path that is characterised by deepening spatial economic inequalities. A plethora of policy instruments unleashed since 1994 had not only failed to stem the tide of poverty and inequality, but had deepened them. As part of this, South Africa’s most ambitious social engineering programme – land reform -- had disappointing outcomes. Premised on a view that these apartheid continuities were embedded in South Africa’s land administration system – which was incoherent and fragmented and requiring a systemic overhaul -- the study sought to explore the potential role of Open Government Data (OGD) in the repurposing of land administration system in the post-apartheid South Africa. To achieve this goal, the study was guided by the following objectives: to explore the ontology and the state of land governance and administration in the context of the post-apartheid South Africa; to undertake an evaluation or assessment of South Africa’s land data ecosystem; and to explore the potential role of OGD in the repurposing of land administration system in the postapartheid of South Africa. This study was steeped in qualitative research methods, underpinned by primary and secondary literature review. While the study was primarily pitched on a national scale – the combination of the systems and multiple scales approaches – yielded results which dislodges solutions that are required outside of the domain of a single state. This is one glaring example of land governance complexities that straddle beyond national scale – specifically in respect of new policy trajectories on trans-national boundaries and governance of water resources. Based on the holistic ontology of land, this study concludes that land administration and land governance overarching conceptual orientation -- concerned with land use decisions made by humans at various scales from a praxis and policy perspective –constitute two sides of the same coin, the former steeped towards practice and the latter steeped towards policy. Drawing from decolonial theories the study concludes that land does not only have multiple dimensions, but it also has multiple meanings, in a manner that calls for an ontological shift away from the western ontology, towards an inclusive and holistic conceptualisation. Historiography that is anchored in de-colonial thinking of South Africa’s land governance helps us understand how and why – colonial/apartheid norms acrimoniously found their way into the post-apartheid order -- the post-apartheid institutions of modernity rest on the same hierarchies of identities, classification and pathologisation. The study concludes that, while the colonial/apartheid administration may be gone, it’s underlying power matrices continue -- i.e. capitalism/European/patriachal/white – in a manner which explains the continuities of South Africa’s spatial inequalities and the associated economic inequalities. The organising principle for land relations (including opportunities) continues to be underpinned by gender, race and class, in ways that expose the mythical dimensions of the 'post-apartheid' underbelly. While identifying the need for homogenisation and rationalistion of colonial, apartheid and post-apartheid institutions (on a national scale) that is insufficient for the transformation of the colonial situation of what is in essence a part of the global system, the study advocates for the ‘repurposing of land governance and administration’ – underpinned by de-colonial thinking. Repurposing is seen as political imaginary that would entail uncoupling thought processes and praxis from the colonial matrices of power. The study goes on to conclude that there is a definite role for Open Government Data in repurposing of land administration in the post-apartheid South Africa – as a necessary, though in and of it’s own it is an insufficient condition to achieve that ideal -- but presents an opportunity to enhance transdisciplinarity approaches and efficiencies in internal government functioning and evidence-based decision making and policy formulation processes. , Thesis (PhD) -- Faculty of Science, Geography, 2021
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Date Issued: 2021-04

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Former farm workers of foreign descent in communal areas in post-fast track Zimbabwe : the case of Shamva District

- Chadambuka, Patience

Authors: Chadambuka, Patience
Date: 2021-10-29
Subjects: Migrant agricultural laborers -- Zimbabwe -- Shamva District , Agricultural laborers, Foreign -- Zimbabwe -- Shamva District , Land reform -- Zimbabwe , Belonging (Social psychology) -- Zimbabwe -- Shamva District , Social integration-- Zimbabwe -- Shamva District , Fast Track Land Reform Programme (FTLRP)
Language: English
Type: thesis , text , Doctoral , PhD
Identifier: http://hdl.handle.net/10962/178420 , vital:42938 , 10.21504/10962/178420
Description: Land and ethnicity continue to condition contestations in relation to belonging amongst rural Zimbabweans. The colonial era defined Zimbabwe’s land politics in a highly racialised and ethnicised manner. Racially, the colonial era gave birth to white-owned fertile farm lands, while blacks (or Africans) were resettled in agriculturally-unproductive Reserves, later referred to as communal areas in the post-colonial era. Though they were initially created with a segregatory and oppressive intent bent on disenfranchising native Africans, the Reserves became a definitive landscape embedded in ethnic and ancestral belonging for the autochthonous Natives. The Reserves were created exclusively for autochthonous Africans, and the colonial administration ensured that foreign migrant Africans recruited mainly as covenanted labour from nearby colonies would not be accommodated and consequently belong in Reserves. Migrant Africans were instead domiciled in white commercial farms, mines and urban areas, and deprived of land rights accorded to the autochthones. In the case of white farms specifically, the labourers experienced a conditional belonging (to the farm). This overall exclusionary system was later inherited and maintained by the post-colonial Zimbabwean government, up until the year 2000. Zimbabwe’s highly documented Fast Track Land Reform Programme (FTLRP) from the year 2000 did away with the entrenched racial bifurcations of land, as white commercial farms became fast track farms. However, it did not undercut the existence of communal areas. The FTLRP had a profound effect on the lives of commercial farm workers, particularly those of foreign origin who had no other home or source of livelihood to fall back on after fast track displacements. Some though sought to move into communal areas, from which they had been excluded previously. Within this context, most scholarly studies of the post fast track period ignore the plight of former farm workers especially those that moved to, and into, communal areas. This ethnographic study, specifically of former farm workers of foreign origin in Shamva communal areas, therefore seeks to contribute to Zimbabwean studies in this regard. It documents and examines the perceptions, practices and lived experiences of former farm workers of foreign origin now residing in the Bushu communal areas of Shamva, and how they interface with Bushu autochthones in seeking to belong to Bushu. This is pursued by way of qualitative research methods (including lengthy stays in the study sites) as well as through the use of a theoretical framing focusing on lifeworlds, interfaces, belonging, othering and strangerhood. Key findings reveal that belonging by the former farm workers in Bushu entails a non-linear and convoluted process characterised by a series of contestations around for instance land shortages, limited livelihood strategies and cultural difference. This project of belonging does not entail assimilation on the part of the former farm workers, as they continue to uphold certain historical practices, leading to a form of co-existence between the autochthones and allochthones in Bushu. In this way, the former farm workers seem to develop a conditional belonging in (and to) Bushu, albeit different than the one experienced on white farms in the past. , Thesis (PhD) -- Faculty of Humanities, Sociology, 2021
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Date Issued: 2021-10-29

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