Browsing by Subject "Land use"

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    Estimating minimum thresholds of natural vegetation for the integrated management and protection of water quality in South African catchments
    (2025) Locke, Kent; Winter, Kevin
    Despite multi-level commitments to Integrated Water Resources Management (IWRM), many of South Africa's water quality problems are attributable to the negative impacts of anthropogenic land use on water quality. Academics and policymakers have warned that unless action is taken to improve water resources management through the implementation of coordinated, proactive, and data-driven strategies, the country faces a water crisis that will have severe socio-ecological consequences. As natural vegetation acts as a sink, thus protecting water resources from diffuse pollution, the preservation of an adequate amount within catchment areas is important. However, among several pertinent questions, it is not clear (1) how much natural vegetation cover is required, (2) at which scale(s) this would be most effective, (3) how natural vegetation should be classified, and (4) whether the fragmentation of natural vegetation is a significant factor. To answer these questions, regression analysis was used to model relationships between water quality (measured using a composite pollution index) and metrics of natural vegetation (estimated from national land cover maps) at multiple scales across a sample of sub-catchments located within South Africa's Berg-Olifants, Breede-Gouritz, and Mzimvubu-Tsitsikamma Water Management Areas. Across this sample, a statistically significant, nonlinear, and inverse relationship was found between proportions of natural vegetation cover and pollution levels. This relationship was strongest (1) when natural vegetation was defined as an aggregation of indigenous woody vegetation, wetlands, and forestry plantations, and (2) when measured across the whole catchment and within a 200 m riparian buffer zone. At both scales, however, fragmentation was not found to be significant. The models further indicated that approximately 82 to 90% natural vegetation cover was necessary at these scales to keep pollution scores within acceptable levels. Additional nonlinear thresholds estimated using breakpoint analysis also suggested that if proportions of natural vegetation fall below 45% (across the whole catchment) and 60% (within a 200 m riparian buffer zone) a dramatic increase in pollution levels can be expected. The study has direct relevance for IWRM in so far as these results demonstrate (1) the critical importance of preserving areas of natural vegetation for water quality management and (2) the possibility of providing actors with quantifiable and context-specific management targets which can inform multistakeholder decision-making processes at appropriate spatial scales.
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    Land-use planning in the Liesbeeck-Black River confluence area: management recommendations and land-use alternatives
    (1994) Wesemann, Harald; Meadows, Mike
    This dissertation is the individual analysis and evaluation of the baseline information on the Liesbeeck-Black River Confluence Area (hereinafter referred to as Confluence Area) gathered by the 1993-1994 Environmental and Geographical Science (EN GEO) Master of Philosophy (MPhil) class (see Appendix A). This dissertation is submitted to the examiners for evaluation as a partial requirement for the MPhil degree in Environmental Science. The baseline report (hereinafter BLR) is titled "Environmental Baseline Study for Land-Use Decision-Making in the Liesbeeck and Black River Confluence Area" (ENGEO Master's Class, 1994). It contains a comprehensive description, as well as preliminary analysis, of all the environmental components (socioeconomic and biophysical) that could be of relevance to land-use planning in the area. The overall need for this study, which comprises the group BLR and the individual dissertations, arises out of the fact that the Confluence Area with its river systems, is part of a "green, open space corridor" that is under pressure from development in a city needing to densify and contain urban sprawl. There is thus potential conflict between development and other environmental considerations including that of open space retention for conservation and recreation purposes. The Cape Town City Council (CCC) suggested this study but is not a "client". The study on the Confluence Area is intended to be of use to the CCC to enhance their ability to make sound land-use decisions for the area in the best interests of society at large. The CCC is also involved in numerous planning studies for the proposed redevelopment of a large tract of land adjacent to the study area, called the Culemborg-Black River area (hereinafter C-BR), and this study can feed into the overall planning process. This individual dissertation provides the CCC planning process with recommendations and land-use alternatives for the Confluence Area. Since the BLR forms the basis of this dissertation, they should be read in conjunction with each other.
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    The conservation worthiness of the environment of the Black and Liesbeeck River confluence area
    (1994) Tilanus, Edward Frank; Campbell; Heather
    This dissertation aims to interpret the environmental factors which will inform land use planning for the Liesbeek-Black River Confluence Area. It is in partial fulfilment of the academic requirements for a Master of Philosophy (M.Phil) in Environmental Science through the Department of Environmental and Geographical Science (ENGEO) at the University of Cape Town (UCT). This document follows on from the Baseline Information Document (BID) produced by the 1994 Masters students and should be read in combination with that document. This dissertation uses the information provided in that document, and with the support of other materials and insights, draws conclusions for the most appropriate land use for the study area. A Statement of the Problem, the Aim, Approach and Philosophy adopted towards the Study Area in this Dissertation. The problem is perceived to be the substantial public objection to recent proposed developments in the study area. These objections have revolved around the method of disposal of State land, the fragmentation of public open space and the apparent disregard of the authorities for the natural historical legacy of the Cape Peninsula. The aim of the study is to demonstrate that the study area holds potential as a public amenity. This could be self-supporting and of benefit to future generations in the region and is therefore worthy of conservation. The approach adopted in this dissertation is that the study area is unsuitable for any use other than as a conservation and recreational reserve. This could prove its value in a substantially more populated and informed future Cape Town. Urban open space, which constitutes wildlife habitat, is required locally to meet increased human population habitation needs. This need is perceived to be global phenomenon. There is concern that the accumulated consequence of these local demands, will result in a profound negative effect on the Biosphere.