Developing a form-process framework to describe the functioning of semi-arid alluvial fans in the Baviaanskloof Valley, South Africa
- Authors: Bobbins, Kerry Leigh
- Date: 2012
- Subjects: Alluvial fans -- Research -- South Africa Sedimentation and deposition -- Research -- South Africa Geomorphology -- Research -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4825 , http://hdl.handle.net/10962/d1005500
- Description: The Baviaanskloof catchment is a semi-arid catchment located in the Cape Fold Mountains of South Africa. Little is known about the functioning of the complicated Baviaanskloof fluvial system and the role alluvial fans in the fluvial landscape. This thesis will contribute to field of geomorphology and, more specifically, to the field of fan morphometry by producing a standalone fan framework outlining methods to investigate the influence of external and internal control variables on alluvial fans. In this thesis, outcomes of the applied framework and case study are used to develop fan restoration guidelines for the Baviaanskloof Valley. The framework incorporates external and internal fan control variables at a valley-wide and local fan scale. External control variables include accommodation space, base-level change, and drainage basin inputs. Internal control variables include fan style, morphometry and fan channels. In order to apply the framework, fan morphometry data was required. This data was collected by creating a spatial plan of fans and basins in the valley. Outcomes of the applied framework include; an understanding of baselevel change on fans, relationships between fan basin characteristics and the fan surface and insight into fan channel processes. Results of the applied framework are investigated further using bivariate (correlation matrix) and multivariate (principle component analysis and regression analysis) analysis techniques. Significant relationships identified are: drainage basin area versus fan area, fan area and fan slope and drainage basin ruggedness and basin size. The primary outcomes of this thesis include an alluvial fan form-process framework, key considerations to be included in alluvial fan restoration projects and fan restoration guidelines. Contributions of this thesis to broader alluvial fan morphology science includes new insights into general fan literature by compiling a form-process alluvial fan classification framework to identify external and internal fan control variables and identify fan form. Additions have been made to Clarke’s (2010) evolutionary stages to describe stages 4 and 5 of fan evolution that has been adapted to describe fan evolution and differentiate between stages of mature fan evolution. This thesis has also contributed to the study of alluvial fans in South Africa, particularly in the Baviaanskloof Valley. The layout of the procedural guidelines and key considerations for an alluvial fan project provides a guide for rapid fan assessment for maximum cost and time benefits for stakeholders.
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Rivers as borders, dividing or uniting? : the effect of topography and implications for catchment management in South Africa
- Authors: Smedley, David Alan
- Date: 2012
- Subjects: Rivers -- South Africa , Water-supply -- Management -- South Africa , Water-supply -- Management -- Orange River Watershed , Watershed management -- South Africa , Watershed management -- Orange River Watershed , South Africa -- Boundaries , Water-supply -- Management -- Citizen participation , Water-supply -- Government policy -- South Africa , Water-supply -- Political aspects -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4851 , http://hdl.handle.net/10962/d1005527 , Rivers -- South Africa , Water-supply -- Management -- South Africa , Water-supply -- Management -- Orange River Watershed , Watershed management -- South Africa , Watershed management -- Orange River Watershed , South Africa -- Boundaries , Water-supply -- Management -- Citizen participation , Water-supply -- Government policy -- South Africa , Water-supply -- Political aspects -- South Africa
- Description: South Africa's water resources are unequally distributed over space and time to a high degree and our already stressed water resources situation will only be exacerbated by climate change if current predictions are correct. The potential for conflict over increasingly strained water resources in South Africa is thus very real. In order to deal with these complex problems national legislation is demanding that water resource management be decentralized to the local level where active participation can take place in an integrated manner in accordance with the principles of IWRM. However, administrative and political boundaries rarely match those of catchments as, throughout South Africa, rivers have been employed extensively to delineate administrative and political boundaries at a number of spatial scales. The aim of this research is to determine if rivers act as dividing or uniting features in a socio-political landscape and whether topography will influence their role in this context. By considering sections of the Orange-Senqu River, some of which are employed as political or administrative boundaries, this project furthermore aims to consider the implications of this for catchment management in South Africa. South Africa's proposed form of decentralized water management will have to contend with the effects of different topographies on the way in which rivers are perceived and utilized. The ability of a river to act as a dividing or uniting feature is dependent on a number of interrelated factors, the effects of which are either reduced or enhanced by the topography surrounding the river. Factors such as the state of the resource, levels of utilization, local histories and the employment of the river as a political or administrative border are all factors that determine the extent to which a river unites or divides the communities along its banks, and are all influenced by topography. The implications of this for the management of catchments in South Africa are significant. Local water management institutions will have to contend with a mismatch in borders and in many cases bridge social divides that are deeply entrenched along the banks of rivers. Importantly, the need for a context specific approach to catchment management is highlighted.
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