Application of environmental magnetism to trace sediment sources contributing to Kruger National Park reservoirs
- Authors: Miller, Jordan Katherine
- Date: 2021-10-29
- Subjects: Geomagnetism South Africa Kruger National Park , Sediments (Geology) South Africa Kruger National Park , Sedimentation and deposition South Africa Kruger National Park , Petrology South Africa Kruger National Park , Sediments (Geology) Magnetic properties South Africa Kruger National Park
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/192842 , vital:45269 , 10.21504/10962/192842
- Description: Sediment source fingerprinting using environmental magnetism has successfully differentiated between sediment sources in different regions of South Africa. The method was applied in the natural landscape of the Kruger National Park to trace sediment sources delivered to four reservoirs (Hartbeesfontein, Marheya, Nhlanganzwani, Silolweni) whose contributing catchments were underlain by a range of igneous, metamorphic, and sedimentary rocks. This research attempted to evaluate the impact of vegetation, lithology, and particle size controls on the ability of magnetic signatures to discriminate between lithology-defined potential sources. Potential source samples were collected from each lithology present in all catchments, except for the Lugmag catchment where the lithology was uniform, but the vegetation type varied significantly between woodland and grassland. One sediment core was taken in each of the four catchment reservoirs where there was more than one lithology present in order to unmix and apportion contributing sediment sources. Sampling time in the field was often restricted to short periods, dependent on anti-poaching activities and movement of free-roaming wildlife across the Park. This occasionally led to the sub-optimal collection of enough source samples to capture source signature variability. Mineral magnetic parameters were unable to discriminate between vegetation-defined sediment sources in the Lugmag catchment (homogenous underlying lithology) but were able to discriminate between lithology-defined sediment sources (to varying degrees) in the other four catchments. The contributions of each lithology-defined sediment source were estimated using a straightforward statistical protocol frequently used in published literature that included a Mann-Whitney U or Kruskal-Wallis H test, mass conservation test, discriminant function analysis, and an (un)mixing model. A contribution from each lithology source to reservoir sediment was estimated. Connectivity was a significant factor in understanding erosion in each of the catchments. Both longitudinal (e.g., drainage density) and lateral connectivity (e.g., floodplain - river) were important. Travel distance of eroded sediment to reservoirs was also an essential element in two of the four catchments. There are no defined floodplains, so channel bank soils are very similar to the catchment soils. Therefore, channel bank storage potential would be similar to the storage potential within the catchment. Vegetation played a crucial role in protecting soils, by reducing ii erosion potential as well as trapping and storing sediment, thereby interrupting lateral connectivity. Underlying geology and soils are determining factors of vegetation type and density. A published study estimated catchment area-specific sediment yields for different KNP catchments, including the Hartbeesfontein, Marheya, Nhlanganzwani and Silolweni catchments. The published data was used in combination with the (un)mixing model source contribution estimates of this thesis to determine specific sediment yields by lithology, i.e., for each catchment source. The polymodal particle size characteristics of the sample material led to an investigation into particle size controls on the ability of magnetic signatures to discriminate between potential sources. Due to time constraints, only the Hartbeesfontein and Marheya catchments were tested for grain size differences. For each catchment, one bulk sample was created for each lithology source. This bulk sample was divided into 10 subsamples. The samples were then fractionated into four particle size fraction groups: coarse (250 – 500 μm), medium (125 – 250 μm), fine (63 – 125 μm), and very fine (<63 μm). Reservoir samples were also bulked to create 10 down-core samples for each reservoir, and the samples were also fractionated into the four fraction groups. The same statistical protocol was applied to the fractionated samples and contribution estimates were obtained by lithology for each particle size fraction group. The goodness of fit and uncertainty of the (un)mixing model varied in each catchment, with the two measures of accuracy often showing an inverse relationship. The fractionated modelling estimated the same primary source in the two catchments as in the unfractionated modelling. However, additional information on the secondary and tertiary sources was obtained. Connectivity remained a significant factor in interpreting the results of the fractionated analysis. Specific sediment yields were estimated for each catchment source per particle size fraction group. These sediment yields provided a deeper understanding of sediment transport through a catchment and which particle size groups are most important in catchment erosion. An original contribution to research was made by estimating source contribution estimates for the four reservoirs, quantifying sediment yields for each catchment lithology and then for each catchment lithology by particle size. Mineral magnetic tracing of the catchments was applied for the first time in this region of South Africa. , Thesis (PhD) -- Faculty of Science, Geography, 2021
- Full Text:
- Date Issued: 2021-10-29
- Authors: Miller, Jordan Katherine
- Date: 2021-10-29
- Subjects: Geomagnetism South Africa Kruger National Park , Sediments (Geology) South Africa Kruger National Park , Sedimentation and deposition South Africa Kruger National Park , Petrology South Africa Kruger National Park , Sediments (Geology) Magnetic properties South Africa Kruger National Park
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/192842 , vital:45269 , 10.21504/10962/192842
- Description: Sediment source fingerprinting using environmental magnetism has successfully differentiated between sediment sources in different regions of South Africa. The method was applied in the natural landscape of the Kruger National Park to trace sediment sources delivered to four reservoirs (Hartbeesfontein, Marheya, Nhlanganzwani, Silolweni) whose contributing catchments were underlain by a range of igneous, metamorphic, and sedimentary rocks. This research attempted to evaluate the impact of vegetation, lithology, and particle size controls on the ability of magnetic signatures to discriminate between lithology-defined potential sources. Potential source samples were collected from each lithology present in all catchments, except for the Lugmag catchment where the lithology was uniform, but the vegetation type varied significantly between woodland and grassland. One sediment core was taken in each of the four catchment reservoirs where there was more than one lithology present in order to unmix and apportion contributing sediment sources. Sampling time in the field was often restricted to short periods, dependent on anti-poaching activities and movement of free-roaming wildlife across the Park. This occasionally led to the sub-optimal collection of enough source samples to capture source signature variability. Mineral magnetic parameters were unable to discriminate between vegetation-defined sediment sources in the Lugmag catchment (homogenous underlying lithology) but were able to discriminate between lithology-defined sediment sources (to varying degrees) in the other four catchments. The contributions of each lithology-defined sediment source were estimated using a straightforward statistical protocol frequently used in published literature that included a Mann-Whitney U or Kruskal-Wallis H test, mass conservation test, discriminant function analysis, and an (un)mixing model. A contribution from each lithology source to reservoir sediment was estimated. Connectivity was a significant factor in understanding erosion in each of the catchments. Both longitudinal (e.g., drainage density) and lateral connectivity (e.g., floodplain - river) were important. Travel distance of eroded sediment to reservoirs was also an essential element in two of the four catchments. There are no defined floodplains, so channel bank soils are very similar to the catchment soils. Therefore, channel bank storage potential would be similar to the storage potential within the catchment. Vegetation played a crucial role in protecting soils, by reducing ii erosion potential as well as trapping and storing sediment, thereby interrupting lateral connectivity. Underlying geology and soils are determining factors of vegetation type and density. A published study estimated catchment area-specific sediment yields for different KNP catchments, including the Hartbeesfontein, Marheya, Nhlanganzwani and Silolweni catchments. The published data was used in combination with the (un)mixing model source contribution estimates of this thesis to determine specific sediment yields by lithology, i.e., for each catchment source. The polymodal particle size characteristics of the sample material led to an investigation into particle size controls on the ability of magnetic signatures to discriminate between potential sources. Due to time constraints, only the Hartbeesfontein and Marheya catchments were tested for grain size differences. For each catchment, one bulk sample was created for each lithology source. This bulk sample was divided into 10 subsamples. The samples were then fractionated into four particle size fraction groups: coarse (250 – 500 μm), medium (125 – 250 μm), fine (63 – 125 μm), and very fine (<63 μm). Reservoir samples were also bulked to create 10 down-core samples for each reservoir, and the samples were also fractionated into the four fraction groups. The same statistical protocol was applied to the fractionated samples and contribution estimates were obtained by lithology for each particle size fraction group. The goodness of fit and uncertainty of the (un)mixing model varied in each catchment, with the two measures of accuracy often showing an inverse relationship. The fractionated modelling estimated the same primary source in the two catchments as in the unfractionated modelling. However, additional information on the secondary and tertiary sources was obtained. Connectivity remained a significant factor in interpreting the results of the fractionated analysis. Specific sediment yields were estimated for each catchment source per particle size fraction group. These sediment yields provided a deeper understanding of sediment transport through a catchment and which particle size groups are most important in catchment erosion. An original contribution to research was made by estimating source contribution estimates for the four reservoirs, quantifying sediment yields for each catchment lithology and then for each catchment lithology by particle size. Mineral magnetic tracing of the catchments was applied for the first time in this region of South Africa. , Thesis (PhD) -- Faculty of Science, Geography, 2021
- Full Text:
- Date Issued: 2021-10-29
An investigation into the performance of smallholder irrigation schemes in Limpopo Province, South Africa: success factors, typologies and implications for development
- Denison, Jonathan Anthony Noel
- Authors: Denison, Jonathan Anthony Noel
- Date: 2019
- Subjects: Irrigation projects -- South Africa -- Limpopo , Farms, Small -- South Africa -- Limpopo , Land use -- South Africa -- Limpopo , Water-supply -- South Africa -- Limpopo
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/92317 , vital:30709
- Description: The research aimed to determine the factors that contribute to the success or failure of smallholder irrigation schemes in the Limpopo Province. It focussed on public-schemes where farmers share the water system Limpopo Province has more than half of the smallholder irrigation schemes in the country with an equipped area of approximately 28 000 ha. The main aims of the research were to identify key factors that explain performance and to develop a contemporary irrigation scheme typology. The research intended to provide a better perspective on how to focus investments across the multiple thematic areas that are associated with sustained and profitable irrigation farming activity. A survey of 102 irrigation schemes was conducted, comprising 82% of the population of schemes greater than 20 ha in Limpopo Province. The quantitative survey complemented prior in-depth qualitative research undertaken on Limpopo schemes. Data was consolidated into five performance indicators and 13 characteristic factors that impact performance. Schemes were viewed as technical and socio-biological systems where performance was determined by the dynamic interaction of multiple factors. The analysis was done in a complex systems framework using correlation, cluster and principle component analysis. It was postulated that over-arching concepts of productivity, profitability and manageability would explain why schemes succeed or fail. The schemes were found to be relatively very small in size with three quarters (74.8%) of them falling in the 50 to 250 ha size range, and only 11 schemes larger than 250 ha. Average plot sizes were 1.34 ha with a wide range between 0.18 and 16.25 ha. There were 65 operational schemes (equivalent to 63.7%), and 37 had failed (equivalent to 36.3%). Using a criterion for success of greater than 50% cropping intensity (to align with other studies and below which schemes can be considered to have failed), the success rate of the Limpopo schemes was 58%. The result was similar to the rest of South Africa and the same as the average rate for SADC identified in other studies using the same criterion. The schemes exhibited a mixed production purpose on average, with a significant market emphasis indicating these schemes have largely evolved from ‘food schemes’ to partly market-farming. Main crops grown were summer-maize and winter fresh-vegetables and cropping intensities on operational schemes ranged widely from 10% to 175%, with an average of 94%. Failure was associated with three dominant factors: energy type; infrastructure condition; and water resource constraints. The first two factors showed that manageability of technology was important. There is strong empirical evidence that pumped smallholder schemes are vulnerable in their physical form, prone to functional and financial failure, live much shorter lives, and perform no better than gravity-canal schemes. Out of the 37 schemes that failed, 34 (91.8%) were pumped. Pumped schemes tend to collapse suddenly while young and exhibit lower cut-off thresholds in productivity that, when crossed, trigger collapse. They also have much lower resilience to factors such as water stress or low farm-profitability. Pumped schemes need higher levels farm sophistication, market-oriented farming, and operational capability to keep the pumping pressure up. Water resource constraints were widespread, considerably more so on gravity schemes. Commercialising farmers were inhibited by lack of access to knowledge. Success was associated with numerous factors, but two findings stand out; the performance of gravity systems and the prevalence of land-exchange activity; the latter enabled by institutional flexibility and reflecting a process of ‘bricolage’ at play. Increased plot size was associated with increased commercialisation and, when larger than 1.8 ha, only commercialised farming was pursued. Market proximity seemed to play a role in increased longevity and to market access in commercialisation. These findings highlighted the importance of productivity and profitability in explaining success. Gravity schemes performed much more strongly in terms of longevity (nearly four times longer-lived) and similarly to pumped schemes in terms of cropping intensity. This was achieved under much greater water stress and with considerably worse infrastructure condition. Water efficiency was determined to be high on half of the schemes that were using short-furrow irrigation; equivalent, in a basin perspective, to drip irrigation. Two of the three top performing schemes (>150% intensity) were old gravity schemes. Farmers on approximately 75% of Limpopo smallholder schemes are currently engaging in land exchange transactions in a highly insecure and un-formalised institutional setup. Land exchange prevalence longer than two years was moderately associated with cropping intensity and strongly associated with commercialisation. This result has three important implications. First, it suggests that more land is utilised on the schemes when there is vibrant land-leasing activity. Secondly, schemes with a higher prevalence of long-term leasing seem to have a strong tendency to be more commercialised. Thirdly, the duration of the lease is significant, as neither single-season, nor annual leases yielded any positive associations, while those exchanges that were two years or longer, were associated with increased performance. These findings highlight the potential for longer-term land-exchange interventions to address the widespread low land utilisation on smallholder schemes, and to catalyse more commercially-oriented farming. An irrigation scheme typology was derived from the cluster analysis and was aligned to a contemporary irrigation farming typology. The key descriptors included technology type, purpose of farming and scheme management type. By matching scheme type to the farmer typology (or typologies), strategic decisions regarding technology choices for infrastructure, land, and water institutional interventions can be better informed. All schemes demand attention to the multiple factors required to achieve performance, not least water-tenure security, irrigation management organisational development, and infrastructure modernisation. Complexity was demonstrated by the finding that multiple factors contribute to success, and that there are many dimensions that change independently and have a cascading effect through the system in ways that are difficult to predict. Agricultural systems support to achieve productivity and profitability are essential for success. The research findings lead to the recommendation that, in addition, strategic planners must also consider the implications of the dominant factors of water-technology choices so that these are manageable, and the dynamics of farm-size change based on land exchange processes, in order to harness new opportunities to maximise irrigation scheme performance in future.
- Full Text:
- Date Issued: 2019
- Authors: Denison, Jonathan Anthony Noel
- Date: 2019
- Subjects: Irrigation projects -- South Africa -- Limpopo , Farms, Small -- South Africa -- Limpopo , Land use -- South Africa -- Limpopo , Water-supply -- South Africa -- Limpopo
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/92317 , vital:30709
- Description: The research aimed to determine the factors that contribute to the success or failure of smallholder irrigation schemes in the Limpopo Province. It focussed on public-schemes where farmers share the water system Limpopo Province has more than half of the smallholder irrigation schemes in the country with an equipped area of approximately 28 000 ha. The main aims of the research were to identify key factors that explain performance and to develop a contemporary irrigation scheme typology. The research intended to provide a better perspective on how to focus investments across the multiple thematic areas that are associated with sustained and profitable irrigation farming activity. A survey of 102 irrigation schemes was conducted, comprising 82% of the population of schemes greater than 20 ha in Limpopo Province. The quantitative survey complemented prior in-depth qualitative research undertaken on Limpopo schemes. Data was consolidated into five performance indicators and 13 characteristic factors that impact performance. Schemes were viewed as technical and socio-biological systems where performance was determined by the dynamic interaction of multiple factors. The analysis was done in a complex systems framework using correlation, cluster and principle component analysis. It was postulated that over-arching concepts of productivity, profitability and manageability would explain why schemes succeed or fail. The schemes were found to be relatively very small in size with three quarters (74.8%) of them falling in the 50 to 250 ha size range, and only 11 schemes larger than 250 ha. Average plot sizes were 1.34 ha with a wide range between 0.18 and 16.25 ha. There were 65 operational schemes (equivalent to 63.7%), and 37 had failed (equivalent to 36.3%). Using a criterion for success of greater than 50% cropping intensity (to align with other studies and below which schemes can be considered to have failed), the success rate of the Limpopo schemes was 58%. The result was similar to the rest of South Africa and the same as the average rate for SADC identified in other studies using the same criterion. The schemes exhibited a mixed production purpose on average, with a significant market emphasis indicating these schemes have largely evolved from ‘food schemes’ to partly market-farming. Main crops grown were summer-maize and winter fresh-vegetables and cropping intensities on operational schemes ranged widely from 10% to 175%, with an average of 94%. Failure was associated with three dominant factors: energy type; infrastructure condition; and water resource constraints. The first two factors showed that manageability of technology was important. There is strong empirical evidence that pumped smallholder schemes are vulnerable in their physical form, prone to functional and financial failure, live much shorter lives, and perform no better than gravity-canal schemes. Out of the 37 schemes that failed, 34 (91.8%) were pumped. Pumped schemes tend to collapse suddenly while young and exhibit lower cut-off thresholds in productivity that, when crossed, trigger collapse. They also have much lower resilience to factors such as water stress or low farm-profitability. Pumped schemes need higher levels farm sophistication, market-oriented farming, and operational capability to keep the pumping pressure up. Water resource constraints were widespread, considerably more so on gravity schemes. Commercialising farmers were inhibited by lack of access to knowledge. Success was associated with numerous factors, but two findings stand out; the performance of gravity systems and the prevalence of land-exchange activity; the latter enabled by institutional flexibility and reflecting a process of ‘bricolage’ at play. Increased plot size was associated with increased commercialisation and, when larger than 1.8 ha, only commercialised farming was pursued. Market proximity seemed to play a role in increased longevity and to market access in commercialisation. These findings highlighted the importance of productivity and profitability in explaining success. Gravity schemes performed much more strongly in terms of longevity (nearly four times longer-lived) and similarly to pumped schemes in terms of cropping intensity. This was achieved under much greater water stress and with considerably worse infrastructure condition. Water efficiency was determined to be high on half of the schemes that were using short-furrow irrigation; equivalent, in a basin perspective, to drip irrigation. Two of the three top performing schemes (>150% intensity) were old gravity schemes. Farmers on approximately 75% of Limpopo smallholder schemes are currently engaging in land exchange transactions in a highly insecure and un-formalised institutional setup. Land exchange prevalence longer than two years was moderately associated with cropping intensity and strongly associated with commercialisation. This result has three important implications. First, it suggests that more land is utilised on the schemes when there is vibrant land-leasing activity. Secondly, schemes with a higher prevalence of long-term leasing seem to have a strong tendency to be more commercialised. Thirdly, the duration of the lease is significant, as neither single-season, nor annual leases yielded any positive associations, while those exchanges that were two years or longer, were associated with increased performance. These findings highlight the potential for longer-term land-exchange interventions to address the widespread low land utilisation on smallholder schemes, and to catalyse more commercially-oriented farming. An irrigation scheme typology was derived from the cluster analysis and was aligned to a contemporary irrigation farming typology. The key descriptors included technology type, purpose of farming and scheme management type. By matching scheme type to the farmer typology (or typologies), strategic decisions regarding technology choices for infrastructure, land, and water institutional interventions can be better informed. All schemes demand attention to the multiple factors required to achieve performance, not least water-tenure security, irrigation management organisational development, and infrastructure modernisation. Complexity was demonstrated by the finding that multiple factors contribute to success, and that there are many dimensions that change independently and have a cascading effect through the system in ways that are difficult to predict. Agricultural systems support to achieve productivity and profitability are essential for success. The research findings lead to the recommendation that, in addition, strategic planners must also consider the implications of the dominant factors of water-technology choices so that these are manageable, and the dynamics of farm-size change based on land exchange processes, in order to harness new opportunities to maximise irrigation scheme performance in future.
- Full Text:
- Date Issued: 2019
The suspended sediment yield and provenance of the Inxu River Catchment, Eastern Cape
- Authors: Nyamela, Namso
- Date: 2019
- Subjects: Suspended sediments -- South Africa -- Inxu River , Sedimentation and deposition -- South Africa -- Inxu River , Watershed management -- South Africa -- Inxu River , Erosion -- South Africa -- Inxu River , Soil erosion -- South Africa -- Inxu River
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/72150 , vital:30010
- Description: The excessive deposition and accumulation of suspended sediment leads to the degradation of water resources such as dams and rivers. For the purpose of preserving and protecting these resources, suspended sediment needs to be managed, and its management should be catchment-wide and catchment-specific. This is certainly the case for the eroded Inxu River Catchment, which has been identified as a major contributor of sediment to the planned Lalini Dam on the Tsitsa River (a tributary of the Mzimvubu River). Knowledge of suspended sediment flux and catchment sources will aid the design of relevant strategies to manage suspended sediment production. Suspended sediment flux was determined from sediment samples that were collected using citizen-based monitoring techniques at calendar- and event-based sampling frequency, along with discharges estimated using stage-discharge relationships. Sediment source areas were identified by determining the suspended sediment contribution from major sub-catchments and observing similarities in the characteristics of the sub-catchments that produced the most sediment. The Inxu River Catchment produced 5.5 t/ha/yr between 01 May 2016 and 30 April 2017. When compared to modelled sediment yield (7 t/ha/yr) from Le Roux et al. (2015), modelled output was not far off from the measured results and both measured and modelled results identified similar sediment source areas. Q-SSC relationships observed at the Inxu River Outlet indicated that sediment was eroded from local areas and sub-catchment sediment contribution confirmed that most of the sediment was from the lower Inxu River Catchment. Within this area, the Ncolosi and Qwakele River Sub-catchments were major sediment source areas and were subject to widespread gully erosion. Gully erosion was prominent on gentle slopes, foot slopes and valley-bottoms that have concave slope curvature and lie on the Tarkastad Formation. This Formation is associated with some of the most dispersive soils in the area. Moreover, the catchment is vulnerable to erosion due to cultivation and subsequent land abandonment, continuous grazing and dense rural populations. Other studies in the Mzimvubu catchment identified similar catchment characteristics that contribute to excessive erosion. This study has successfully measured sediment yield and identified areas that should be targeted and prioritised for rehabilitation within the Inxu River Catchment. The findings could be applied to a wider catchment scale. The study has successfully demonstrated the use of citizen-based monitoring and desktop techniques and has also identified some pitfalls of this approach.
- Full Text:
- Date Issued: 2019
- Authors: Nyamela, Namso
- Date: 2019
- Subjects: Suspended sediments -- South Africa -- Inxu River , Sedimentation and deposition -- South Africa -- Inxu River , Watershed management -- South Africa -- Inxu River , Erosion -- South Africa -- Inxu River , Soil erosion -- South Africa -- Inxu River
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/72150 , vital:30010
- Description: The excessive deposition and accumulation of suspended sediment leads to the degradation of water resources such as dams and rivers. For the purpose of preserving and protecting these resources, suspended sediment needs to be managed, and its management should be catchment-wide and catchment-specific. This is certainly the case for the eroded Inxu River Catchment, which has been identified as a major contributor of sediment to the planned Lalini Dam on the Tsitsa River (a tributary of the Mzimvubu River). Knowledge of suspended sediment flux and catchment sources will aid the design of relevant strategies to manage suspended sediment production. Suspended sediment flux was determined from sediment samples that were collected using citizen-based monitoring techniques at calendar- and event-based sampling frequency, along with discharges estimated using stage-discharge relationships. Sediment source areas were identified by determining the suspended sediment contribution from major sub-catchments and observing similarities in the characteristics of the sub-catchments that produced the most sediment. The Inxu River Catchment produced 5.5 t/ha/yr between 01 May 2016 and 30 April 2017. When compared to modelled sediment yield (7 t/ha/yr) from Le Roux et al. (2015), modelled output was not far off from the measured results and both measured and modelled results identified similar sediment source areas. Q-SSC relationships observed at the Inxu River Outlet indicated that sediment was eroded from local areas and sub-catchment sediment contribution confirmed that most of the sediment was from the lower Inxu River Catchment. Within this area, the Ncolosi and Qwakele River Sub-catchments were major sediment source areas and were subject to widespread gully erosion. Gully erosion was prominent on gentle slopes, foot slopes and valley-bottoms that have concave slope curvature and lie on the Tarkastad Formation. This Formation is associated with some of the most dispersive soils in the area. Moreover, the catchment is vulnerable to erosion due to cultivation and subsequent land abandonment, continuous grazing and dense rural populations. Other studies in the Mzimvubu catchment identified similar catchment characteristics that contribute to excessive erosion. This study has successfully measured sediment yield and identified areas that should be targeted and prioritised for rehabilitation within the Inxu River Catchment. The findings could be applied to a wider catchment scale. The study has successfully demonstrated the use of citizen-based monitoring and desktop techniques and has also identified some pitfalls of this approach.
- Full Text:
- Date Issued: 2019
A baseline survey of channel geomorphology with particular reference to the effects of sediment characteristics on ecosystem health in the Tsitsa River, Eastern Cape, South Africa
- Huchzermeyer, Nicholaus Heinrich
- Authors: Huchzermeyer, Nicholaus Heinrich
- Date: 2018
- Subjects: Fluvial geomorphology -- South Africa -- Eastern Cape , Stream health -- South Africa -- Eastern Cape , River sediments -- South Africa -- Eastern Cape , Watershed management -- South Africa -- Eastern Cape , Dams -- Environmental aspects -- South Africa -- Eastern Cape , Tsitsa River (South Africa) , Ntabelanga Dam (South Africa)
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/58056 , vital:27040
- Description: Fluvial systems are dynamic systems in which variables in a catchment and river channel affect the morphology of river reaches. South African rivers are increasingly being exposed to stresses from a combination of factors, one of the most prevalent being the impacts of damming rivers which result in varying downstream sediment fluxes and flow regimes. The sediment load combined with flow characteristics for respective river channels provides the physical habitat for aquatic ecosystems. The damming of the Tsitsa River, through the construction of the Ntabelanga Dam, will change the overall downstream geomorphology. This creates an opportunity for research in the preconstruction window. The current condition of the Tsitsa River was monitored by completing a baseline survey of the channel geomorphology with specific reference to the influence of sediment on river habitats and ecosystem health. Five sites were established in variable reaches of the Tsitsa River, with Site 1 located above the proposed Ntabelanga Dam inundation and Sites 2-5 below the proposed dam wall. Each site included a range of features that can be monitored for their response to the dam. Physical variables, water quality and biota were monitored seasonally to note changes in habitat quality. A baseline survey of the present geomorphology and associated instream habitats of the selected reaches was set up by conducting cross-sectional surveys of channel topography, water slope surveys, discharge measurements and visual and quantitative assessments of substrate. Level loggers were installed at each site to collect continuous data on variations in depth and temperature. Monitoring surveys, in terms of fine sediment accumulation, were conducted to characterise dynamic habitat arrangements and macroinvertebrate community composition. A taxa related physical habitat score for the Tsitsa River was created. The relationship between water quality, physical and ecological characteristics of the Tsitsa River will aid further research in the area as well as create a better understanding of the influence of sediment on river habitats and ecosystem health. Monitoring sites can be used to monitor the impact of catchment-wide rehabilitation on river health prior to the dam being built. After dam construction, the top site above the dam inundation can still be used as a point to monitor the impact of catchment rehabilitation on ecosystem health in terms of fine sediment accumulation.
- Full Text:
- Date Issued: 2018
- Authors: Huchzermeyer, Nicholaus Heinrich
- Date: 2018
- Subjects: Fluvial geomorphology -- South Africa -- Eastern Cape , Stream health -- South Africa -- Eastern Cape , River sediments -- South Africa -- Eastern Cape , Watershed management -- South Africa -- Eastern Cape , Dams -- Environmental aspects -- South Africa -- Eastern Cape , Tsitsa River (South Africa) , Ntabelanga Dam (South Africa)
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/58056 , vital:27040
- Description: Fluvial systems are dynamic systems in which variables in a catchment and river channel affect the morphology of river reaches. South African rivers are increasingly being exposed to stresses from a combination of factors, one of the most prevalent being the impacts of damming rivers which result in varying downstream sediment fluxes and flow regimes. The sediment load combined with flow characteristics for respective river channels provides the physical habitat for aquatic ecosystems. The damming of the Tsitsa River, through the construction of the Ntabelanga Dam, will change the overall downstream geomorphology. This creates an opportunity for research in the preconstruction window. The current condition of the Tsitsa River was monitored by completing a baseline survey of the channel geomorphology with specific reference to the influence of sediment on river habitats and ecosystem health. Five sites were established in variable reaches of the Tsitsa River, with Site 1 located above the proposed Ntabelanga Dam inundation and Sites 2-5 below the proposed dam wall. Each site included a range of features that can be monitored for their response to the dam. Physical variables, water quality and biota were monitored seasonally to note changes in habitat quality. A baseline survey of the present geomorphology and associated instream habitats of the selected reaches was set up by conducting cross-sectional surveys of channel topography, water slope surveys, discharge measurements and visual and quantitative assessments of substrate. Level loggers were installed at each site to collect continuous data on variations in depth and temperature. Monitoring surveys, in terms of fine sediment accumulation, were conducted to characterise dynamic habitat arrangements and macroinvertebrate community composition. A taxa related physical habitat score for the Tsitsa River was created. The relationship between water quality, physical and ecological characteristics of the Tsitsa River will aid further research in the area as well as create a better understanding of the influence of sediment on river habitats and ecosystem health. Monitoring sites can be used to monitor the impact of catchment-wide rehabilitation on river health prior to the dam being built. After dam construction, the top site above the dam inundation can still be used as a point to monitor the impact of catchment rehabilitation on ecosystem health in terms of fine sediment accumulation.
- Full Text:
- Date Issued: 2018
Aquatic habitat shift assessment in a groundwater-fed semi-arid stream: an investigation into the response of Karoo hydroecology to system variability
- Authors: Ellis, Natalie
- Date: 2018
- Subjects: Aquatic habitats -- South Africa -- Karoo , Arid regions -- South Africa -- Karoo , Biotic communities -- South Africa -- Karoo , Stream ecology -- South Africa -- Karoo
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/61882 , vital:28072
- Description: From introduction: The subject of biological response to changes in aquatic habitat is one which has been well explored in many regions of the world. Examples include work in south east Spain by Mellado Diaz et al. (2008) and Oliva-Paterna et al. (2003), in western United States of America by Hauer and Lorang (2004), and in West Germany by Meyer et al. (2003). Similarly, a number of studies have been conducted in semi-arid regions, exploring elements such as erosion, climate, lithology and landscape formations (e.g. Boardman et al., 2013; Le Maitre et al., 2007; Meyer et al., 2003). However, apart from the study by Uys (1997), and Uys and O’Keeffe (1997), there is a noticeable lack of literature on aquatic habitat shifts in semi-arid stream systems, despite these systems being recognised for their high natural variability. This study provides a base-level approach to conducting habitat shift assessments in a semi-arid stream system and monitoring the hydroecological responses to system variability.
- Full Text:
- Date Issued: 2018
- Authors: Ellis, Natalie
- Date: 2018
- Subjects: Aquatic habitats -- South Africa -- Karoo , Arid regions -- South Africa -- Karoo , Biotic communities -- South Africa -- Karoo , Stream ecology -- South Africa -- Karoo
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/61882 , vital:28072
- Description: From introduction: The subject of biological response to changes in aquatic habitat is one which has been well explored in many regions of the world. Examples include work in south east Spain by Mellado Diaz et al. (2008) and Oliva-Paterna et al. (2003), in western United States of America by Hauer and Lorang (2004), and in West Germany by Meyer et al. (2003). Similarly, a number of studies have been conducted in semi-arid regions, exploring elements such as erosion, climate, lithology and landscape formations (e.g. Boardman et al., 2013; Le Maitre et al., 2007; Meyer et al., 2003). However, apart from the study by Uys (1997), and Uys and O’Keeffe (1997), there is a noticeable lack of literature on aquatic habitat shifts in semi-arid stream systems, despite these systems being recognised for their high natural variability. This study provides a base-level approach to conducting habitat shift assessments in a semi-arid stream system and monitoring the hydroecological responses to system variability.
- Full Text:
- Date Issued: 2018
Developing a citizen technician based approach to suspended sediment monitoring in the Tsitsa River catchment, Eastern Cape, South Africa
- Authors: Bannatyne, Laura Joan
- Date: 2018
- Subjects: Sediments (Geology) -- Management , Sediments (Geology) -- South Africa -- Eastern Cape , Watersheds -- South Africa -- Eastern Cape , Suspended sediments -- South Africa -- Eastern Cape , Suspended sediments -- Monitoring -- Citizen participation , Tsitsa River
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/62593 , vital:28211
- Description: Suspended sediment (SS) in channels is spatiotemporally heterogeneous and, over the long term, is known to be moved predominantly by flood flows with return periods of ~1 - 1.5 years. Flood flows in the Tsitsa catchment (Eastern Cape Province, South Africa) are unpredictable, and display a wide range of discharges. Direct, flood-focused SS sampling at sub-catchment scale was required to provide a SS baseline against which to monitor the impact on SS of catchment rehabilitation interventions, to determine the relative contributions of sub-catchments to SS loads and yields at the site of the proposed Ntabelanga Dam wall, and to verify modelled SS baselines, loads and yields. Approaches to SS sampling relying on researcher presence and/or installed equipment to adequately monitor SS through flood flows were precluded by cost, and the physical and socioeconomic conditions in the project area. A citizen technician (CT)-based flood-focused approach to direct SS sampling was developed and implemented. It was assessed in terms of its efficiency and effectiveness, the proficiency of the laboratory analysis methods, and the accuracy of the resulting SS data. A basic laboratory protocol for SSC analysis was developed, but is not the focus of this thesis. Using basic sampling equipment and smartphone-based reporting protocols, local residents at eleven points on the Tsitsa River and its major tributaries were employed as CTs. They were paid to take water samples during daylight hours at sub-daily timestep, with the emphasis on sampling through flood flows. The method was innovative in that it opted for manual sampling against a global trend towards instrumentation. Whilst the management of CTs formed a significant project component, the CTs benefitted directly through remuneration and work experience opportunities. The sampling method was evaluated at four sites from December 2015 - May 2016. The CTs were found to have efficiently and effectively sampled SS through a range of water levels, particularly in the main Tsitsa channel. An acceptable level of proficiency and accuracy was achieved, and many flood events were successfully defined by multiple data points. The method was chiefly limited by the inability of CTs to sample overnight rises and peaks occurring as a result of afternoon thunderstorms, particularly in small tributaries. The laboratory process was responsible for some losses in proficiency and accuracy. Improved laboratory quality control was therefore recommended. The CT-based approach can be adapted to other spatial and temporal scales in other areas, and to other environmental monitoring applications.
- Full Text:
- Date Issued: 2018
- Authors: Bannatyne, Laura Joan
- Date: 2018
- Subjects: Sediments (Geology) -- Management , Sediments (Geology) -- South Africa -- Eastern Cape , Watersheds -- South Africa -- Eastern Cape , Suspended sediments -- South Africa -- Eastern Cape , Suspended sediments -- Monitoring -- Citizen participation , Tsitsa River
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/62593 , vital:28211
- Description: Suspended sediment (SS) in channels is spatiotemporally heterogeneous and, over the long term, is known to be moved predominantly by flood flows with return periods of ~1 - 1.5 years. Flood flows in the Tsitsa catchment (Eastern Cape Province, South Africa) are unpredictable, and display a wide range of discharges. Direct, flood-focused SS sampling at sub-catchment scale was required to provide a SS baseline against which to monitor the impact on SS of catchment rehabilitation interventions, to determine the relative contributions of sub-catchments to SS loads and yields at the site of the proposed Ntabelanga Dam wall, and to verify modelled SS baselines, loads and yields. Approaches to SS sampling relying on researcher presence and/or installed equipment to adequately monitor SS through flood flows were precluded by cost, and the physical and socioeconomic conditions in the project area. A citizen technician (CT)-based flood-focused approach to direct SS sampling was developed and implemented. It was assessed in terms of its efficiency and effectiveness, the proficiency of the laboratory analysis methods, and the accuracy of the resulting SS data. A basic laboratory protocol for SSC analysis was developed, but is not the focus of this thesis. Using basic sampling equipment and smartphone-based reporting protocols, local residents at eleven points on the Tsitsa River and its major tributaries were employed as CTs. They were paid to take water samples during daylight hours at sub-daily timestep, with the emphasis on sampling through flood flows. The method was innovative in that it opted for manual sampling against a global trend towards instrumentation. Whilst the management of CTs formed a significant project component, the CTs benefitted directly through remuneration and work experience opportunities. The sampling method was evaluated at four sites from December 2015 - May 2016. The CTs were found to have efficiently and effectively sampled SS through a range of water levels, particularly in the main Tsitsa channel. An acceptable level of proficiency and accuracy was achieved, and many flood events were successfully defined by multiple data points. The method was chiefly limited by the inability of CTs to sample overnight rises and peaks occurring as a result of afternoon thunderstorms, particularly in small tributaries. The laboratory process was responsible for some losses in proficiency and accuracy. Improved laboratory quality control was therefore recommended. The CT-based approach can be adapted to other spatial and temporal scales in other areas, and to other environmental monitoring applications.
- Full Text:
- Date Issued: 2018
Geomorphological connectivity and sensitivity examined in a recently degraded gravel-bed stream: implications for river-floodplain rehabilitation
- Authors: Powell, Rebecca
- Date: 2017
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/53722 , vital:26313
- Description: The study of river complexity and sensitivity to future human land-use activities and climate change is a fast growing field within the discipline of fluvial geomorphology. Associated with this is a need to improve river rehabilitation and catchment management approach, design and effectiveness. This study aimed to investigate drivers of the recent geomorphological sensitivity of the Baviaanskloof River-floodplain, an upland system in South Africa, by integrating the concepts of geomorphological connectivity and Panarchy. The understanding generated was used to evaluate the approach of the State agency, Working for Wetlands (WfWet), to river-floodplain rehabilitation in the catchment.The concepts of geomorphological connectivity and Panarchy provide useful frameworks for understanding interactions between geomorphological processes and structure across scales of space and time. Geomorphological connectivity explains the degree to which water and sediment is linked in a river landscape, determined by the distribution of erosional and depositional landforms (Brierley et al. 2006; Fryirs et al. 2007a; Fryirs et al. 2007b). Panarchy attempts to explain lagged response to disturbances, non-linear interactions, and sudden shifts in system state, and has been applied largely to ecological systems. Panarchy theory, when combined with the concept of geomorphological connectivity, provides a guiding framework for understanding river complexity in greater depth. The first results chapter of this study investigated river long-term and recent geomorphological history, towards understanding the nature and timing of river geomorphological cycling between erosion and deposition. Optically Stimulated Luminescence dating of alluvial fan and floodplain sedimentary units was conducted, for analysis of river-floodplain long-term history (100s to 1 000s of years). Interviews with 11 local landowners, combined with analysis of historic aerial imagery and river-floodplain topographic surveys, provided a means of describing recent (last few decades) geomorphological dynamics. The results indicated that the Baviaanskloof is naturally a cut- and-fill landscape over scales of several hundred to thousands of years, characterized by the alternation between phases of high fluvial energy and alluvial fan expansion, and low energy conditions associated with floodplain accretion. Recent and widespread river-floodplain degradation was compressed into a short period of approximately 30 years, suggesting that one or more drivers have pushed the system beyond a threshold, resulting in increased water and sediment connectivity. The second results chapter investigated the role of human land-use activities and flooding frequency and magnitude, as drivers of recent river-floodplain degradation. Human impacts were investigated by describing land-use activities for the preceding 80 years, and relating these activities to changes in river-floodplain form and behavior. Temporal trends in flood events of different frequency and magnitude were investigated by analyzing rainfall data, integrated with landowner reports of flood-inducing rainfall magnitudes. The findings indicated that human land-use activities have been an important driver of recent river- floodplain degradation, through the enhancement of water and sediment connectivity across spatial scales of the catchment. Episodic and high magnitude floods synergized with human driven increased connectivity, precipitating stream power and geomorphological threshold breaches, resulting in a shift in river behaviour. The third results chapter investigated the influence of tributary-junction streams and fans on the geomorphological form, behavior and sensitivity of the Baviaanskloof River. Local- scale topographic impacts of tributary fans and streams were described using topographic surveys and geomorphological mapping techniques. Tributary streams form a major control on the behaviour of the river, by influencing the degree of coarse sediment connectivity with the main channel. Although tributary fans buffer the river from disturbances occurring in the wider catchment, they initiate topographic variations along the floodplain, influencing local-scale patterns of deposition and erosion along the river. The main river responds to water and sediment inputs from tributary junction streams by locally adjusting longitudinal slope, maintaining an overall constant slope of 0.0066 m/m. The response of the Baviaanskloof River to tributary junction fans and streams is however variable, and is fashioned by complex interactions between geomorphological and anthropogenic factors. The final two chapters of the thesis evaluate the findings of the study within the context of river-floodplain rehabilitation approaches in South Africa, and within the theoretical, philosophical and methodological context of the research. The first of these two chapters evaluates the approach of the WfWet programme to river-floodplain rehabilitation in the Baviaanskloof. The chapter indicates that the present practice of WfWet is to reinstate a pre-degradation state, which is not suited to the Baviaanskloof River-floodplain, since the river-floodplain has passed a geomorphological threshold, resulting in a new set of interacting processes and landforms. The author presents a conceptual model illustrating the existence of geomorphological adaptive cycles interacting across spatial and temporal scales, thereby attempting to explain a river Panarchy specific to the Baviaanskloof. From this conceptual model, a hierarchical rehabilitation framework, targeting geomorphological processes and structure situated at different spatial and temporal scales of the landscape is suggested. The final chapter discusses the implications of integrating the concepts of geomorphological connectivity and river Panarchy theory in studies of river complexity and sensitivity to geomorphological change. The author suggests that there is scope for further investigation of the application of the two concepts within the discipline of fluvial geomorphology, particularly with regard to developing quantitative approaches to measuring and describing connectivity and Panarchy.
- Full Text:
- Date Issued: 2017
- Authors: Powell, Rebecca
- Date: 2017
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/53722 , vital:26313
- Description: The study of river complexity and sensitivity to future human land-use activities and climate change is a fast growing field within the discipline of fluvial geomorphology. Associated with this is a need to improve river rehabilitation and catchment management approach, design and effectiveness. This study aimed to investigate drivers of the recent geomorphological sensitivity of the Baviaanskloof River-floodplain, an upland system in South Africa, by integrating the concepts of geomorphological connectivity and Panarchy. The understanding generated was used to evaluate the approach of the State agency, Working for Wetlands (WfWet), to river-floodplain rehabilitation in the catchment.The concepts of geomorphological connectivity and Panarchy provide useful frameworks for understanding interactions between geomorphological processes and structure across scales of space and time. Geomorphological connectivity explains the degree to which water and sediment is linked in a river landscape, determined by the distribution of erosional and depositional landforms (Brierley et al. 2006; Fryirs et al. 2007a; Fryirs et al. 2007b). Panarchy attempts to explain lagged response to disturbances, non-linear interactions, and sudden shifts in system state, and has been applied largely to ecological systems. Panarchy theory, when combined with the concept of geomorphological connectivity, provides a guiding framework for understanding river complexity in greater depth. The first results chapter of this study investigated river long-term and recent geomorphological history, towards understanding the nature and timing of river geomorphological cycling between erosion and deposition. Optically Stimulated Luminescence dating of alluvial fan and floodplain sedimentary units was conducted, for analysis of river-floodplain long-term history (100s to 1 000s of years). Interviews with 11 local landowners, combined with analysis of historic aerial imagery and river-floodplain topographic surveys, provided a means of describing recent (last few decades) geomorphological dynamics. The results indicated that the Baviaanskloof is naturally a cut- and-fill landscape over scales of several hundred to thousands of years, characterized by the alternation between phases of high fluvial energy and alluvial fan expansion, and low energy conditions associated with floodplain accretion. Recent and widespread river-floodplain degradation was compressed into a short period of approximately 30 years, suggesting that one or more drivers have pushed the system beyond a threshold, resulting in increased water and sediment connectivity. The second results chapter investigated the role of human land-use activities and flooding frequency and magnitude, as drivers of recent river-floodplain degradation. Human impacts were investigated by describing land-use activities for the preceding 80 years, and relating these activities to changes in river-floodplain form and behavior. Temporal trends in flood events of different frequency and magnitude were investigated by analyzing rainfall data, integrated with landowner reports of flood-inducing rainfall magnitudes. The findings indicated that human land-use activities have been an important driver of recent river- floodplain degradation, through the enhancement of water and sediment connectivity across spatial scales of the catchment. Episodic and high magnitude floods synergized with human driven increased connectivity, precipitating stream power and geomorphological threshold breaches, resulting in a shift in river behaviour. The third results chapter investigated the influence of tributary-junction streams and fans on the geomorphological form, behavior and sensitivity of the Baviaanskloof River. Local- scale topographic impacts of tributary fans and streams were described using topographic surveys and geomorphological mapping techniques. Tributary streams form a major control on the behaviour of the river, by influencing the degree of coarse sediment connectivity with the main channel. Although tributary fans buffer the river from disturbances occurring in the wider catchment, they initiate topographic variations along the floodplain, influencing local-scale patterns of deposition and erosion along the river. The main river responds to water and sediment inputs from tributary junction streams by locally adjusting longitudinal slope, maintaining an overall constant slope of 0.0066 m/m. The response of the Baviaanskloof River to tributary junction fans and streams is however variable, and is fashioned by complex interactions between geomorphological and anthropogenic factors. The final two chapters of the thesis evaluate the findings of the study within the context of river-floodplain rehabilitation approaches in South Africa, and within the theoretical, philosophical and methodological context of the research. The first of these two chapters evaluates the approach of the WfWet programme to river-floodplain rehabilitation in the Baviaanskloof. The chapter indicates that the present practice of WfWet is to reinstate a pre-degradation state, which is not suited to the Baviaanskloof River-floodplain, since the river-floodplain has passed a geomorphological threshold, resulting in a new set of interacting processes and landforms. The author presents a conceptual model illustrating the existence of geomorphological adaptive cycles interacting across spatial and temporal scales, thereby attempting to explain a river Panarchy specific to the Baviaanskloof. From this conceptual model, a hierarchical rehabilitation framework, targeting geomorphological processes and structure situated at different spatial and temporal scales of the landscape is suggested. The final chapter discusses the implications of integrating the concepts of geomorphological connectivity and river Panarchy theory in studies of river complexity and sensitivity to geomorphological change. The author suggests that there is scope for further investigation of the application of the two concepts within the discipline of fluvial geomorphology, particularly with regard to developing quantitative approaches to measuring and describing connectivity and Panarchy.
- Full Text:
- Date Issued: 2017
Towards a holistic view of land and water management in the Gamtoos River catchment: applying a political geoecology approach
- Authors: Robb, Breanne Nicola
- Date: 2017
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/7914 , vital:21323
- Description: The Eastern Cape of South Africa is characterised by water scarcity, constraint on usage, and inter-basin transfers. Water from the Gamtoos River catchment supplies water users both within the catchment and outside the catchment boundaries. This requires careful management of water and land to prevent overexploitation. However, management is complex as it is divided among various stakeholders with differing interests. Political geoecology is an approach that has the potential to provide holistic insight into the catchment’s water context. It was proposed to account for spatial patterns underlying interrelationships between resource distribution, human productive activity, and power relations by integrating the fields of political ecology and geoecology. This research was undertaken to further develop political geoecology as an approach for examining human-environment relations in geography through a case study of land and water management in the Gamtoos River catchment and its subcatchments. Distribution of resources and human influences were elucidated through generation of maps. To facilitate spatial analysis, the study area was delineated into catchment zones. Additionally, stakeholders were identified and classified at local, regional, national, and international levels. Power relations between stakeholders were investigated through qualitative content analysis of transcribed semi-structured interviews and survey questionnaires that were administered to 34 research participants (selected through purposive and snowball sampling) directly involved in resource management in the catchment. Findings were spatially interpreted for each of the zones. The source zone was characterised by natural vegetation, steep, rugged topography, limited access ability, and power relations around restoration and conservation interests, which arose most significantly in the Baviaanskloof. The natural recapture zone was characterised by irrigated cultivation in areas of less harsh terrain in the upstream (Baviaanskloof and Kouga) sub-catchments. In the marginal Baviaanskloof, localised power relations over water distribution primarily arose. In the thriving commercial farming context of the Kouga, power relations included a local upstream-downstream legal conflict, competing levels of governance, issues with establishing water users’ associations (WUAs), and lack of adequate implementation of processes by government. Regional power relations are most prominent in the thriving commercial farming context of the overlapping regulated recapture and final use zones in the downstream Gamtoos sub-catchment. The reliance on upstream sub-catchments and tensions with the city of Port Elizabeth over water use are mediated through decisions made at the national level. Non-location specific power relations included indirect influence through energy, markets, and standards organisations, barriers in government preventing successful process implementation, and equity issues (particularly limiting the success of emerging farmers). These results illustrated that resource distribution, human productive activity, and power relations combine to produce unique characteristics in each of the zones in the Gamtoos catchment. The application of political geoecology in this case study situated the approach as useful for examining human- environment relations in geography.
- Full Text:
- Date Issued: 2017
- Authors: Robb, Breanne Nicola
- Date: 2017
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/7914 , vital:21323
- Description: The Eastern Cape of South Africa is characterised by water scarcity, constraint on usage, and inter-basin transfers. Water from the Gamtoos River catchment supplies water users both within the catchment and outside the catchment boundaries. This requires careful management of water and land to prevent overexploitation. However, management is complex as it is divided among various stakeholders with differing interests. Political geoecology is an approach that has the potential to provide holistic insight into the catchment’s water context. It was proposed to account for spatial patterns underlying interrelationships between resource distribution, human productive activity, and power relations by integrating the fields of political ecology and geoecology. This research was undertaken to further develop political geoecology as an approach for examining human-environment relations in geography through a case study of land and water management in the Gamtoos River catchment and its subcatchments. Distribution of resources and human influences were elucidated through generation of maps. To facilitate spatial analysis, the study area was delineated into catchment zones. Additionally, stakeholders were identified and classified at local, regional, national, and international levels. Power relations between stakeholders were investigated through qualitative content analysis of transcribed semi-structured interviews and survey questionnaires that were administered to 34 research participants (selected through purposive and snowball sampling) directly involved in resource management in the catchment. Findings were spatially interpreted for each of the zones. The source zone was characterised by natural vegetation, steep, rugged topography, limited access ability, and power relations around restoration and conservation interests, which arose most significantly in the Baviaanskloof. The natural recapture zone was characterised by irrigated cultivation in areas of less harsh terrain in the upstream (Baviaanskloof and Kouga) sub-catchments. In the marginal Baviaanskloof, localised power relations over water distribution primarily arose. In the thriving commercial farming context of the Kouga, power relations included a local upstream-downstream legal conflict, competing levels of governance, issues with establishing water users’ associations (WUAs), and lack of adequate implementation of processes by government. Regional power relations are most prominent in the thriving commercial farming context of the overlapping regulated recapture and final use zones in the downstream Gamtoos sub-catchment. The reliance on upstream sub-catchments and tensions with the city of Port Elizabeth over water use are mediated through decisions made at the national level. Non-location specific power relations included indirect influence through energy, markets, and standards organisations, barriers in government preventing successful process implementation, and equity issues (particularly limiting the success of emerging farmers). These results illustrated that resource distribution, human productive activity, and power relations combine to produce unique characteristics in each of the zones in the Gamtoos catchment. The application of political geoecology in this case study situated the approach as useful for examining human- environment relations in geography.
- Full Text:
- Date Issued: 2017
An erosion and sediment delivery model for semi-arid catchments
- Authors: Bryson, Louise Kay
- Date: 2016
- Subjects: Sedimentation and deposition , Erosion , Watershed management -- South Africa , Water-supply -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:6056 , http://hdl.handle.net/10962/d1020331
- Description: Sedimentation has become a significant environmental threat in South Africa as it intensifies water management problems in the water-scarce semi-arid regions of the country. As South Africa already allocates 98% of available water, the loss of storage capacity in reservoirs and degraded water quality has meant that a reliable water supply is compromised. The overall aim of this thesis was to develop a catchment scale model that represents the sediment dynamics of semi-arid regions of South Africa as a simple and practically applicable tool for water resource managers. Development of a conceptual framework for the model relied on an understanding of both the sediment dynamics of South African catchments and applicable modelling techniques. Scale was an issue in both cases as most of our understanding of the physical processes of runoff generation and sediment transport has been derived from plot scale studies. By identifying defining properties of semi-arid catchments it was possible to consider how temporal and spatial properties at higher levels emerged from properties at lower levels. These properties were effectively represented by using the Pitman rainfall-runoff model disaggregated to a daily timescale, the Modified Universal Soil Loss Equation (MUSLE) model incorporating probability function theory and through the representation of sediment storages across a semi-distributed catchment. The model was tested on two small and one large study catchment in the Karoo, South Africa, with limited observed data. Limitations to the model were found to be the large parameter data set and the dominance of structural constraints with an increase in catchment size. The next steps in model development will require a reduction of the parameter data set and an inclusion of an in-stream component for sub-catchments at a larger spatial scale. The model is applicable in areas such as South Africa where water resource managers need a simple model at the catchment scale in order to make decisions. This type of model provides a simple representation of the stochastic nature of erosion and sediment delivery over large spatial and temporal scales.
- Full Text:
- Date Issued: 2016
- Authors: Bryson, Louise Kay
- Date: 2016
- Subjects: Sedimentation and deposition , Erosion , Watershed management -- South Africa , Water-supply -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:6056 , http://hdl.handle.net/10962/d1020331
- Description: Sedimentation has become a significant environmental threat in South Africa as it intensifies water management problems in the water-scarce semi-arid regions of the country. As South Africa already allocates 98% of available water, the loss of storage capacity in reservoirs and degraded water quality has meant that a reliable water supply is compromised. The overall aim of this thesis was to develop a catchment scale model that represents the sediment dynamics of semi-arid regions of South Africa as a simple and practically applicable tool for water resource managers. Development of a conceptual framework for the model relied on an understanding of both the sediment dynamics of South African catchments and applicable modelling techniques. Scale was an issue in both cases as most of our understanding of the physical processes of runoff generation and sediment transport has been derived from plot scale studies. By identifying defining properties of semi-arid catchments it was possible to consider how temporal and spatial properties at higher levels emerged from properties at lower levels. These properties were effectively represented by using the Pitman rainfall-runoff model disaggregated to a daily timescale, the Modified Universal Soil Loss Equation (MUSLE) model incorporating probability function theory and through the representation of sediment storages across a semi-distributed catchment. The model was tested on two small and one large study catchment in the Karoo, South Africa, with limited observed data. Limitations to the model were found to be the large parameter data set and the dominance of structural constraints with an increase in catchment size. The next steps in model development will require a reduction of the parameter data set and an inclusion of an in-stream component for sub-catchments at a larger spatial scale. The model is applicable in areas such as South Africa where water resource managers need a simple model at the catchment scale in order to make decisions. This type of model provides a simple representation of the stochastic nature of erosion and sediment delivery over large spatial and temporal scales.
- Full Text:
- Date Issued: 2016
Links between valley confinement, landforms and vegetation distribution in a semi-arid valley floor environment, Baviaanskloof, South Africa
- Authors: Smith-Adao, Lindie B
- Date: 2016
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/953 , vital:20006
- Description: Although a large body of international literature has advanced our understanding of river systems, a considerable amount of gaps exit in the knowledge of dryland systems. River systems reflect complex interactions between biophysical processes and patterns. Understanding how processes generate observed patterns and, in turn, how patterns influence processes is crucial to understanding river structure and function. It requires an interdisciplinary approach in both research and resulting applications. The aim of this thesis was to examine the relationship between valley confinement, fluvial style, valley floor morphology and vegetation in the semi-arid environment of the Baviaanskloof river catchment, South Africa. This interdisciplinary investigation used a mixed method approach that involved desktop analyses and field surveys to understand dynamics at multiple scales, from the whole catchment to local (site, reach and quadrat or sample plot) scales. The desktop analyses included historical rainfall patterns and climate extremes, aerial photograph time-series and remote sensing greenness indices, and the field surveys focussed on cross-valley landform profiles, groundwater depth levels, sediment size distribution and soil chemistry, and vegetation distribution patterns. Based on the integrative assessment of these techniques a framework was developed of the links between valley confinement, surface-groundwater interaction, hydrogeomorphic processes and landforms, vegetation and human activities. Study findings highlighted the fact that very strong links exist between these factors. In this semi-arid area water availability (groundwater and streamflow conditions) was the primary control on valley floor vegetation composition and patterning. One group of species was associated with the wetted channel reaches at confined and semi-confined valley settings, while the other was associated with dry bed channel reaches at unconfined valley settings. The analyses also indicated that the environmental variables which best explained the variation in vegetation at the differing geomorphic landforms were related to landform position (elevation and distance), sediment size (fine and coarse sand) and available phosphorus (i.e. human impacts). The different plants, in turn, also affected landforms through their influence on sediment erosion, transport and deposition. Specially, they build, maintained or modified geomorphic landforms at confined, semi-confined and unconfined valley settings across the valley floor. Valley confinement was a primary control influencing hydrogeomorphic processes and their associated landforms. Alluvial fans and terraces acted as critical additional controls at especially the unconfined valley setting. Implications for restoration efforts in the catchment included strategies that took cognisance of: active revegetation on floodplain surfaces related to former agricultural fields; channel switching associated with the highly dynamic and unpredictable nature of geomorphic features; unstable multi-thread braided channels in the unconfined valley setting; and the selection of representative monitoring sites.
- Full Text:
- Date Issued: 2016
- Authors: Smith-Adao, Lindie B
- Date: 2016
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/953 , vital:20006
- Description: Although a large body of international literature has advanced our understanding of river systems, a considerable amount of gaps exit in the knowledge of dryland systems. River systems reflect complex interactions between biophysical processes and patterns. Understanding how processes generate observed patterns and, in turn, how patterns influence processes is crucial to understanding river structure and function. It requires an interdisciplinary approach in both research and resulting applications. The aim of this thesis was to examine the relationship between valley confinement, fluvial style, valley floor morphology and vegetation in the semi-arid environment of the Baviaanskloof river catchment, South Africa. This interdisciplinary investigation used a mixed method approach that involved desktop analyses and field surveys to understand dynamics at multiple scales, from the whole catchment to local (site, reach and quadrat or sample plot) scales. The desktop analyses included historical rainfall patterns and climate extremes, aerial photograph time-series and remote sensing greenness indices, and the field surveys focussed on cross-valley landform profiles, groundwater depth levels, sediment size distribution and soil chemistry, and vegetation distribution patterns. Based on the integrative assessment of these techniques a framework was developed of the links between valley confinement, surface-groundwater interaction, hydrogeomorphic processes and landforms, vegetation and human activities. Study findings highlighted the fact that very strong links exist between these factors. In this semi-arid area water availability (groundwater and streamflow conditions) was the primary control on valley floor vegetation composition and patterning. One group of species was associated with the wetted channel reaches at confined and semi-confined valley settings, while the other was associated with dry bed channel reaches at unconfined valley settings. The analyses also indicated that the environmental variables which best explained the variation in vegetation at the differing geomorphic landforms were related to landform position (elevation and distance), sediment size (fine and coarse sand) and available phosphorus (i.e. human impacts). The different plants, in turn, also affected landforms through their influence on sediment erosion, transport and deposition. Specially, they build, maintained or modified geomorphic landforms at confined, semi-confined and unconfined valley settings across the valley floor. Valley confinement was a primary control influencing hydrogeomorphic processes and their associated landforms. Alluvial fans and terraces acted as critical additional controls at especially the unconfined valley setting. Implications for restoration efforts in the catchment included strategies that took cognisance of: active revegetation on floodplain surfaces related to former agricultural fields; channel switching associated with the highly dynamic and unpredictable nature of geomorphic features; unstable multi-thread braided channels in the unconfined valley setting; and the selection of representative monitoring sites.
- Full Text:
- Date Issued: 2016
Sediment connectivity in the upper Thina Catchment, Eastern Cape, South Africa
- Van der Waal, Benjamin Cornelis Wentsel
- Authors: Van der Waal, Benjamin Cornelis Wentsel
- Date: 2015
- Subjects: Soil erosion -- South Africa -- Eastern Cape , Sedimentation and deposition -- South Africa -- Eastern Cape , Watersheds -- South Africa -- Eastern Cape , Arroyos -- South Africa -- Eastern Cape , Sediment transport -- South Africa -- Eastern Cape , Soil conservation -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4892 , http://hdl.handle.net/10962/d1019754
- Description: [Portion of abstract]: Sediment dynamics are influenced by transformed landscape connectivity in catchments worldwide. The upper Thina catchment, an important high rainfall resource in the northern Eastern Cape, South Africa, is an example of where ongoing subsistence farming on communal land has led to overgrazing and trampling that has initiated large erosive features (e.g. gullies) and river incision. The formation of gullies led to increased hillslope-channel connectivity and the resultant river incision decreased the channel-valley fill connectivity. These two changes in connectivity led to increased sediment export from the catchment that has various down-stream ecological and socio-economic impacts. This study investigates how the change in hillslope-channel and channel-valley fill connectivity has altered the sediment dynamics in the Vuvu catchment, a headwater tributary of the Thina River. A combination of methods were used to assess the changes in hillslope-channel and channel-valley fill connectivity. High resolution aerial images were used to map source features, such as fields, gullies, sheet erosion, landslides, roads and livestock tracks. Topographic and geological characteristics of the source features were extracted using a Geographic Information System. Furthermore, hillslope-channel pathways, such as the natural drainage network, continuous gullies, discontinuous gullies, roads and livestock tracks were mapped and analysed in terms of topographic and geological characteristics. Historic aerial images were assessed to calculate the date the larger gullies began forming. Recent aerial photos and cross sectional surveys of the valley fill were combined to map the various sediment sinks. Particle size and organic content were analysed for flood bench cores and terrace samples. The chronology of the flood benches was determined using unsupported Pb-210 and Cs-137 dating, and determined for the terraces using Optically Stimulated Luminescence dating. Quantitative and qualitative sediment tracing approaches, using mineral magnetic properties, were used to trace the origin of suspended sediment (collected during flood events), sediment stored in the flood benches and sediment stored in the terraces. Hydrological monitoring was used to assess the potential to store sediment on flood benches along the valley fill through flood bench inundation frequency. Hydrological and hydraulic modelling extended the measured inundation frequencies to a 73 year period and other cross sections along the valley fill. Furthermore, a future scenario of an increased vegetation cover and reduced hillslope-channel connectivity was assessed in terms of channel-valley fill inundation frequency.
- Full Text:
- Date Issued: 2015
- Authors: Van der Waal, Benjamin Cornelis Wentsel
- Date: 2015
- Subjects: Soil erosion -- South Africa -- Eastern Cape , Sedimentation and deposition -- South Africa -- Eastern Cape , Watersheds -- South Africa -- Eastern Cape , Arroyos -- South Africa -- Eastern Cape , Sediment transport -- South Africa -- Eastern Cape , Soil conservation -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4892 , http://hdl.handle.net/10962/d1019754
- Description: [Portion of abstract]: Sediment dynamics are influenced by transformed landscape connectivity in catchments worldwide. The upper Thina catchment, an important high rainfall resource in the northern Eastern Cape, South Africa, is an example of where ongoing subsistence farming on communal land has led to overgrazing and trampling that has initiated large erosive features (e.g. gullies) and river incision. The formation of gullies led to increased hillslope-channel connectivity and the resultant river incision decreased the channel-valley fill connectivity. These two changes in connectivity led to increased sediment export from the catchment that has various down-stream ecological and socio-economic impacts. This study investigates how the change in hillslope-channel and channel-valley fill connectivity has altered the sediment dynamics in the Vuvu catchment, a headwater tributary of the Thina River. A combination of methods were used to assess the changes in hillslope-channel and channel-valley fill connectivity. High resolution aerial images were used to map source features, such as fields, gullies, sheet erosion, landslides, roads and livestock tracks. Topographic and geological characteristics of the source features were extracted using a Geographic Information System. Furthermore, hillslope-channel pathways, such as the natural drainage network, continuous gullies, discontinuous gullies, roads and livestock tracks were mapped and analysed in terms of topographic and geological characteristics. Historic aerial images were assessed to calculate the date the larger gullies began forming. Recent aerial photos and cross sectional surveys of the valley fill were combined to map the various sediment sinks. Particle size and organic content were analysed for flood bench cores and terrace samples. The chronology of the flood benches was determined using unsupported Pb-210 and Cs-137 dating, and determined for the terraces using Optically Stimulated Luminescence dating. Quantitative and qualitative sediment tracing approaches, using mineral magnetic properties, were used to trace the origin of suspended sediment (collected during flood events), sediment stored in the flood benches and sediment stored in the terraces. Hydrological monitoring was used to assess the potential to store sediment on flood benches along the valley fill through flood bench inundation frequency. Hydrological and hydraulic modelling extended the measured inundation frequencies to a 73 year period and other cross sections along the valley fill. Furthermore, a future scenario of an increased vegetation cover and reduced hillslope-channel connectivity was assessed in terms of channel-valley fill inundation frequency.
- Full Text:
- Date Issued: 2015
Sediment linkages in a small catchment in the Mount Fletcher southern Drakensberg region, South Africa
- Authors: Mzobe, Pearl Nonjabulo
- Date: 2014
- Subjects: Soil erosion -- South Africa -- Mount Fletcher , Soil conservation -- South Africa -- Mount Fletcher , Soil degradation -- South Africa -- Mount Fletcher , Food security -- South Africa , Wetland management -- South Africa -- Mount Fletcher , Watersheds -- South Africa -- Mount Fletcher
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:4879 , http://hdl.handle.net/10962/d1013224
- Description: Soil erosion is a persistent problem that requires continued control efforts as agricultural land loses productivity and communities dependent on the land become increasingly vulnerable to decreased food security. The negative effects of soil erosion in Khamopele River catchment, in the Mount Fletcher southern Drakensberg region of South Africa, are manifest in extensive gullying and wetland loss. Soil erosion has resulted in siltation in a recently constructed dam and the alteration of aquatic habitats. This research was undertaken to identify the sources of eroded sediment in the small upper catchments of the Mzimvubu River catchment to inform broader catchment management strategies. The scale of erosion was quantified using field surveys of gully extent and form. Environmental magnetic tracing techniques were used to determine the sources of eroded sediment in Khamopele River and upper Tina River catchments. The radionuclide ¹³⁷Cs was used to determine soil loss over a 55 year period in Khamopele River catchment. The Landscape Connectivity framework was used to describe the sediment source, pathway and sink interactions at sample area level. Results indicated that historical and contemporary land management practices such as uncontrolled grazing, grassland burning and furrows promoted soil erosion in the catchment. Soil erosion was most pronounced in the Taung sample area where there was extensive gullying, tunnelling and subsurface erosion. Environmental magnetic tracing results indicated that there were clear differences in source areas. Despite its prevalence in the area, gully erosion was not shown to be a major source of sediment to downstream sinks. Topsoil and hillslope derived sediment were shown to be mobile in the catchment, suggesting that sheet erosion processes were dominant in the catchment. Radionuclide tracing studies showed that at least 20 cm of soil had been eroded from the Khamopele River catchment surface since 1956. This research has shown that it is possible to distinguish source areas of erosion in the catchment by matching catchment mineral magnetic signatures to those in sink areas. This means that rehabilitation projects can use resources efficiently as the areas needing the most attention can be identified.
- Full Text:
- Date Issued: 2014
- Authors: Mzobe, Pearl Nonjabulo
- Date: 2014
- Subjects: Soil erosion -- South Africa -- Mount Fletcher , Soil conservation -- South Africa -- Mount Fletcher , Soil degradation -- South Africa -- Mount Fletcher , Food security -- South Africa , Wetland management -- South Africa -- Mount Fletcher , Watersheds -- South Africa -- Mount Fletcher
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:4879 , http://hdl.handle.net/10962/d1013224
- Description: Soil erosion is a persistent problem that requires continued control efforts as agricultural land loses productivity and communities dependent on the land become increasingly vulnerable to decreased food security. The negative effects of soil erosion in Khamopele River catchment, in the Mount Fletcher southern Drakensberg region of South Africa, are manifest in extensive gullying and wetland loss. Soil erosion has resulted in siltation in a recently constructed dam and the alteration of aquatic habitats. This research was undertaken to identify the sources of eroded sediment in the small upper catchments of the Mzimvubu River catchment to inform broader catchment management strategies. The scale of erosion was quantified using field surveys of gully extent and form. Environmental magnetic tracing techniques were used to determine the sources of eroded sediment in Khamopele River and upper Tina River catchments. The radionuclide ¹³⁷Cs was used to determine soil loss over a 55 year period in Khamopele River catchment. The Landscape Connectivity framework was used to describe the sediment source, pathway and sink interactions at sample area level. Results indicated that historical and contemporary land management practices such as uncontrolled grazing, grassland burning and furrows promoted soil erosion in the catchment. Soil erosion was most pronounced in the Taung sample area where there was extensive gullying, tunnelling and subsurface erosion. Environmental magnetic tracing results indicated that there were clear differences in source areas. Despite its prevalence in the area, gully erosion was not shown to be a major source of sediment to downstream sinks. Topsoil and hillslope derived sediment were shown to be mobile in the catchment, suggesting that sheet erosion processes were dominant in the catchment. Radionuclide tracing studies showed that at least 20 cm of soil had been eroded from the Khamopele River catchment surface since 1956. This research has shown that it is possible to distinguish source areas of erosion in the catchment by matching catchment mineral magnetic signatures to those in sink areas. This means that rehabilitation projects can use resources efficiently as the areas needing the most attention can be identified.
- Full Text:
- Date Issued: 2014
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.
- Full Text:
- Date Issued: 2012
- 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.
- Full Text:
- Date Issued: 2012
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.
- Full Text:
- Date Issued: 2012
- 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.
- Full Text:
- Date Issued: 2012
The influence of Acacia Mearnsii invasion on soil properties in the Kouga Mountains, Eastern Cape, South Africa
- Van der Waal, Benjamin Wentsel
- Authors: Van der Waal, Benjamin Wentsel
- Date: 2010
- Subjects: Acacia mearnsii -- South Africa , Wattles (Plants) -- South Africa , Soil erosion -- South Africa -- Eastern Cape , Conservation of natural resources -- South Africa , Biological invasions -- South Africa -- Eastern Cape , Alien plants -- South Africa -- Eastern Cape , Invasive plants -- South Africa -- Eastern Cape , Biogeography -- South Africa -- Eastern Cape , Soil management -- South Africa -- Eastern Cape , Soil moisture -- South Africa -- Eastern Cape , Soils -- Sodium content -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4839 , http://hdl.handle.net/10962/d1005515 , Acacia mearnsii -- South Africa , Wattles (Plants) -- South Africa , Soil erosion -- South Africa -- Eastern Cape , Conservation of natural resources -- South Africa , Biological invasions -- South Africa -- Eastern Cape , Alien plants -- South Africa -- Eastern Cape , Invasive plants -- South Africa -- Eastern Cape , Biogeography -- South Africa -- Eastern Cape , Soil management -- South Africa -- Eastern Cape , Soil moisture -- South Africa -- Eastern Cape , Soils -- Sodium content -- South Africa -- Eastern Cape
- Description: The invasion of Acacia mearnsii in the Kouga catchment, Eastern Cape, South Africa, has various negative impacts on the ecosystem. These impacts include: reduced species richness, increased water use, increased nutrients and increased N cycling rates. The native shrubby fynbos vegetation has adapted to the acidic nutrient poor soils and Mediterranean climate of the Kouga Mountains. Fynbos, however, is currently being out competed by the much taller Acacia mearnsii trees, due to their competitive nature and ability to fix nitrogen, thereby enriching the soil. The invaded sections of the valley bottoms and lower hill slopes are characterised by an almost complete monoculture of Acacia mearnsii, with very few fynbos species still present. The Department of Water and Environmental Affairs sponsored Working for Water programme started clearing Acacia mearnsii in 1996 in the Kouga Mountains. Cleared sites have remained bare for long periods, indicating that soil properties are not favourable for indigenous propagule re-establishment. The aim of this research was to assess how A. mearnsii invasion and clearing affect fynbos recovery through its impact on soils. This was done by characterising vegetation and soil properties on fynbos, infested and cleared slopes. Vegetation cover for various growth forms was determined and a species list was compiled for each plot. The slope angle, surface hardness, litter cover, bare ground cover and soil depth were measured in the field, whereas water repellency, particle size and the chemical composition were measured in the laboratory. Furthermore, the plant establishment capacity of soils from fynbos, infested and cleared slopes was calculated. This was done by germinating fynbos seeds and growing fynbos plants in soils from the various slopes. The effect that invasion and clearing has on soil erosion was quantified using erosion plots on fynbos, infested and cleared slopes. The invasion and clearing of Acacia mearnsii led to an increase in soil nutrients, especially nitrogen, phosphorus, potassium, carbon and manganese. Furthermore, soils became more acidic, with increased water repellency and reduced surface hardness. The vegetation changed to a tree-dominated structure, replacing the native species. Native plant germination was relatively unaffected by invasion and clearing, with an increase in germination just after clearing. Plant growth of a native grass, Themeda triandra, and herb, Helichrysum umbraculigerum, has increased on soils from cleared slopes. This study showed that soil movement increased on slopes which are invaded and cleared of Acacia mearnsii, with erosion rates doubling on invaded slopes
- Full Text:
- Date Issued: 2010
- Authors: Van der Waal, Benjamin Wentsel
- Date: 2010
- Subjects: Acacia mearnsii -- South Africa , Wattles (Plants) -- South Africa , Soil erosion -- South Africa -- Eastern Cape , Conservation of natural resources -- South Africa , Biological invasions -- South Africa -- Eastern Cape , Alien plants -- South Africa -- Eastern Cape , Invasive plants -- South Africa -- Eastern Cape , Biogeography -- South Africa -- Eastern Cape , Soil management -- South Africa -- Eastern Cape , Soil moisture -- South Africa -- Eastern Cape , Soils -- Sodium content -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4839 , http://hdl.handle.net/10962/d1005515 , Acacia mearnsii -- South Africa , Wattles (Plants) -- South Africa , Soil erosion -- South Africa -- Eastern Cape , Conservation of natural resources -- South Africa , Biological invasions -- South Africa -- Eastern Cape , Alien plants -- South Africa -- Eastern Cape , Invasive plants -- South Africa -- Eastern Cape , Biogeography -- South Africa -- Eastern Cape , Soil management -- South Africa -- Eastern Cape , Soil moisture -- South Africa -- Eastern Cape , Soils -- Sodium content -- South Africa -- Eastern Cape
- Description: The invasion of Acacia mearnsii in the Kouga catchment, Eastern Cape, South Africa, has various negative impacts on the ecosystem. These impacts include: reduced species richness, increased water use, increased nutrients and increased N cycling rates. The native shrubby fynbos vegetation has adapted to the acidic nutrient poor soils and Mediterranean climate of the Kouga Mountains. Fynbos, however, is currently being out competed by the much taller Acacia mearnsii trees, due to their competitive nature and ability to fix nitrogen, thereby enriching the soil. The invaded sections of the valley bottoms and lower hill slopes are characterised by an almost complete monoculture of Acacia mearnsii, with very few fynbos species still present. The Department of Water and Environmental Affairs sponsored Working for Water programme started clearing Acacia mearnsii in 1996 in the Kouga Mountains. Cleared sites have remained bare for long periods, indicating that soil properties are not favourable for indigenous propagule re-establishment. The aim of this research was to assess how A. mearnsii invasion and clearing affect fynbos recovery through its impact on soils. This was done by characterising vegetation and soil properties on fynbos, infested and cleared slopes. Vegetation cover for various growth forms was determined and a species list was compiled for each plot. The slope angle, surface hardness, litter cover, bare ground cover and soil depth were measured in the field, whereas water repellency, particle size and the chemical composition were measured in the laboratory. Furthermore, the plant establishment capacity of soils from fynbos, infested and cleared slopes was calculated. This was done by germinating fynbos seeds and growing fynbos plants in soils from the various slopes. The effect that invasion and clearing has on soil erosion was quantified using erosion plots on fynbos, infested and cleared slopes. The invasion and clearing of Acacia mearnsii led to an increase in soil nutrients, especially nitrogen, phosphorus, potassium, carbon and manganese. Furthermore, soils became more acidic, with increased water repellency and reduced surface hardness. The vegetation changed to a tree-dominated structure, replacing the native species. Native plant germination was relatively unaffected by invasion and clearing, with an increase in germination just after clearing. Plant growth of a native grass, Themeda triandra, and herb, Helichrysum umbraculigerum, has increased on soils from cleared slopes. This study showed that soil movement increased on slopes which are invaded and cleared of Acacia mearnsii, with erosion rates doubling on invaded slopes
- Full Text:
- Date Issued: 2010
A fluvial geomorphological study of river rehabilitation in the Kouga region, Eastern Cape
- Authors: Pietersen, Adrian
- Date: 2009
- Subjects: Fluvial geomorphology -- South Africa -- Eastern Cape , Alien plants -- South Africa -- Eastern Cape , Kouga Riparian Rehabilitation Project , Stream conservation -- South Africa -- Eastern Cape , Wattles (Plants) -- South Africa -- Eastern Cape , Riparian restoration -- South Africa -- Eastern Cape , Acacia mearnsii -- South Africa -- Eastern Cape , Kouga Region (South Africa) , Kouga River (South Africa)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4887 , http://hdl.handle.net/10962/d1015228
- Description: The Kouga Riparian Rehabilitation Project (KRRP) is seen as a pilot rehabilitation project in the Kouga region that is heavily invaded with Acacia mearnsii along the riparian zones of many mountain streams. Clearing of these black wattles and re-planting of indigenous vegetation are imperative to rehabilitation efforts. In this context, two invaded catchments were identified - the Baviaans and the Heuningnes. The aim of this research is to characterise the effects that the woody alien invasive Acacia mearnsii has had on the river channel morphology of the Baviaans and Heuningnes Rivers. A desktop and initial field analysis of the relevant study area catchments was completed. This was followed by a comparison of the channel morphology of the various study channel reaches using fixed channel transects. Ecological resource quality objectives (RQOs) for river rehabilitation from a fluvial geomorphological viewpoint were then established. A long-term monitoring protocol to assess whether or not these RQOs will be achieved was recommended. Follow-up channel transects were measured post wattle clearance in the Baviaans and short-term (<2yrs) changes in channel form were described. Differences in terms of the effect of Acacia mearnsii on channel form were then interpreted by direct comparison and through statistical analysis. Results indicate a number of significant differences between those channels impacted by black wattle infestation and those channels seen as unimpacted and natural. Short-term changes (<2yrs) that occurred within the study period post Baviaans wattle clearance were shown to be minimal for channel form as well as for bed material. The lack of any clear relationship or explanation between channel form and other channel controls suggests vegetation as the primary control. Vegetation, specifically the invasive alien vegetation, is the key controlling variable acting on channel form in the two study catchments.
- Full Text:
- Date Issued: 2009
- Authors: Pietersen, Adrian
- Date: 2009
- Subjects: Fluvial geomorphology -- South Africa -- Eastern Cape , Alien plants -- South Africa -- Eastern Cape , Kouga Riparian Rehabilitation Project , Stream conservation -- South Africa -- Eastern Cape , Wattles (Plants) -- South Africa -- Eastern Cape , Riparian restoration -- South Africa -- Eastern Cape , Acacia mearnsii -- South Africa -- Eastern Cape , Kouga Region (South Africa) , Kouga River (South Africa)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4887 , http://hdl.handle.net/10962/d1015228
- Description: The Kouga Riparian Rehabilitation Project (KRRP) is seen as a pilot rehabilitation project in the Kouga region that is heavily invaded with Acacia mearnsii along the riparian zones of many mountain streams. Clearing of these black wattles and re-planting of indigenous vegetation are imperative to rehabilitation efforts. In this context, two invaded catchments were identified - the Baviaans and the Heuningnes. The aim of this research is to characterise the effects that the woody alien invasive Acacia mearnsii has had on the river channel morphology of the Baviaans and Heuningnes Rivers. A desktop and initial field analysis of the relevant study area catchments was completed. This was followed by a comparison of the channel morphology of the various study channel reaches using fixed channel transects. Ecological resource quality objectives (RQOs) for river rehabilitation from a fluvial geomorphological viewpoint were then established. A long-term monitoring protocol to assess whether or not these RQOs will be achieved was recommended. Follow-up channel transects were measured post wattle clearance in the Baviaans and short-term (<2yrs) changes in channel form were described. Differences in terms of the effect of Acacia mearnsii on channel form were then interpreted by direct comparison and through statistical analysis. Results indicate a number of significant differences between those channels impacted by black wattle infestation and those channels seen as unimpacted and natural. Short-term changes (<2yrs) that occurred within the study period post Baviaans wattle clearance were shown to be minimal for channel form as well as for bed material. The lack of any clear relationship or explanation between channel form and other channel controls suggests vegetation as the primary control. Vegetation, specifically the invasive alien vegetation, is the key controlling variable acting on channel form in the two study catchments.
- Full Text:
- Date Issued: 2009
A situational analysis on the public participation processes in integrated water resources management in the Kat River Valley, Eastern Cape, South Africa
- Authors: Naidoo, Merle
- Date: 2009
- Subjects: South Africa. Dept. of Water Affairs and Forestry , Water-supply -- South Africa -- Kat River Valley , Water quality management -- South Africa -- Kat River Valley , Water-supply -- Government policy -- South Africa -- Kat River Valley , Water resources development -- South Africa -- Kat River Valley , Integrated water development -- South Africa -- Kat River Valley , Rural development -- South Africa -- Kat River Valley
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4854 , http://hdl.handle.net/10962/d1005530 , South Africa. Dept. of Water Affairs and Forestry , Water-supply -- South Africa -- Kat River Valley , Water quality management -- South Africa -- Kat River Valley , Water-supply -- Government policy -- South Africa -- Kat River Valley , Water resources development -- South Africa -- Kat River Valley , Integrated water development -- South Africa -- Kat River Valley , Rural development -- South Africa -- Kat River Valley
- Description: Public participation in water management processes is one of the internationally recognised and adopted principles of Integrated Water Resource Management. The South African Department of Water Affairs and Forestry aims to facilitate the decentralisation of water management powers to the local community level via the establishment of regional and local water management institutions, namely Catchment Management Agencies, Water User Associations and Catchment Forums. The National Water Act (No. 36 of 1998) acknowledges that the discriminatory laws and practices of the past have prevented equal access to water and the use of water resources. The contribution of water management institutions to social and economic development, in particular poverty eradication and food security, is mentioned in the water act. The participation of poor rural communities living in the Kat valley, an area where an elite minority reap the benefits of water use for agriculture, is the focus of this research. Their participation, perceptions and experiences are documented and explored to determine how the promulgation of post-apartheid water policy and legislation has affected their access to water. The results of this research are based on data collected from several methods including surveys, workshops and observation. Analysis of these data revealed the complicated and stagnant nature of participation from Kat valley rural communities in local water management initiatives and organisations. Existing water management organisations were not successful in stimulating poor people’s participation as they were unable to address their primary concerns, namely a secure source of potable water, employment and access to water for agricultural purposes. This thesis asserts that the Department of Water Affairs and Forestry, as the custodian of South Africa’s water resources, has not taken on a supportive, accountable role in assisting marginalised communities with improving their access to water for domestic purposes and securing access to water rights for productive use. This, in turn, has led to dissatisfaction among these communities and a wariness of participatory activities that focus mainly on raising environmental awareness. The establishment of effective accountability relationships among all stakeholders, pro-poor water management structures and initiatives, as well as integrated and co-operative management of natural resources, are needed to revitalise the present participation of poor communities living in rural areas.
- Full Text:
- Date Issued: 2009
- Authors: Naidoo, Merle
- Date: 2009
- Subjects: South Africa. Dept. of Water Affairs and Forestry , Water-supply -- South Africa -- Kat River Valley , Water quality management -- South Africa -- Kat River Valley , Water-supply -- Government policy -- South Africa -- Kat River Valley , Water resources development -- South Africa -- Kat River Valley , Integrated water development -- South Africa -- Kat River Valley , Rural development -- South Africa -- Kat River Valley
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4854 , http://hdl.handle.net/10962/d1005530 , South Africa. Dept. of Water Affairs and Forestry , Water-supply -- South Africa -- Kat River Valley , Water quality management -- South Africa -- Kat River Valley , Water-supply -- Government policy -- South Africa -- Kat River Valley , Water resources development -- South Africa -- Kat River Valley , Integrated water development -- South Africa -- Kat River Valley , Rural development -- South Africa -- Kat River Valley
- Description: Public participation in water management processes is one of the internationally recognised and adopted principles of Integrated Water Resource Management. The South African Department of Water Affairs and Forestry aims to facilitate the decentralisation of water management powers to the local community level via the establishment of regional and local water management institutions, namely Catchment Management Agencies, Water User Associations and Catchment Forums. The National Water Act (No. 36 of 1998) acknowledges that the discriminatory laws and practices of the past have prevented equal access to water and the use of water resources. The contribution of water management institutions to social and economic development, in particular poverty eradication and food security, is mentioned in the water act. The participation of poor rural communities living in the Kat valley, an area where an elite minority reap the benefits of water use for agriculture, is the focus of this research. Their participation, perceptions and experiences are documented and explored to determine how the promulgation of post-apartheid water policy and legislation has affected their access to water. The results of this research are based on data collected from several methods including surveys, workshops and observation. Analysis of these data revealed the complicated and stagnant nature of participation from Kat valley rural communities in local water management initiatives and organisations. Existing water management organisations were not successful in stimulating poor people’s participation as they were unable to address their primary concerns, namely a secure source of potable water, employment and access to water for agricultural purposes. This thesis asserts that the Department of Water Affairs and Forestry, as the custodian of South Africa’s water resources, has not taken on a supportive, accountable role in assisting marginalised communities with improving their access to water for domestic purposes and securing access to water rights for productive use. This, in turn, has led to dissatisfaction among these communities and a wariness of participatory activities that focus mainly on raising environmental awareness. The establishment of effective accountability relationships among all stakeholders, pro-poor water management structures and initiatives, as well as integrated and co-operative management of natural resources, are needed to revitalise the present participation of poor communities living in rural areas.
- Full Text:
- Date Issued: 2009
Human-river relationships in the Kat River catchment and the implications for integrated water resource management (IWRM) : an exploraratory study
- Authors: Birkholz, Sharon Alice
- Date: 2009
- Subjects: Aquatic ecology -- South Africa -- Kat River , Rivers -- South Africa -- Kat River -- Sociological aspects , Rivers -- South Africa -- Kat River , Water supply -- South Africa -- Kat River -- Management , Human ecology -- South Africa -- Kat River , Stream ecology -- South Africa -- Kat River
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: vital:4838 , http://hdl.handle.net/10962/d1005514
- Description: Through out this study ‘relational scenarios’ were seen as the possible outcomes of the expression of human-river relationships in a catchment. Working within Inglis’s (2008, pg. 10) comment that ‘the Human World Relationship is expressed through a person’s views and behaviour towards the natural world, which can be either constructive or destructive’, two relational scenarios were selected to represent these two predicted outcomes of human-environment (or in the case of this thesis human-river) relationships: IWRM, seen as constructive and mutually beneficial to both the social and ecological system, and the Tragedy of the Commons, seen as destructive and parasitic in nature. In respect to this assertion, a conceptual framework or model was developed and used to guide the inductive process of this research. Through a social survey (administered via semi-structured interviews) of stakeholders (water-users) in the Kat River Catchment, Eastern Cape, South Africa, social attitudes towards the Kat River were explored. These attitudes were considered as variables that relate to the expression of ‘Human World Relationships’ namely ‘values and behaviour’ (Inglis, 2008, pg. 10). The findings of this thesis confirm that attitudes are influential components of human-river relationships in the Kat River Catchment. It was observed from the findings that the attitudes individuals have towards the Kat River have the potential to influence the ways people interact with the River and its associated resources, and are in turn influenced by the condition of the River and connections people have or make with the River within their daily lives. Such relationships in turn affect the management of the River and its water resources and influence how individuals approach water-related issues and undertake the associated activities. Given this understanding it was then proposed that attitudes could provide information that enables the prediction of likely ‘relational scenarios’ (IWRM or the Tragedy of the Commons) in a catchment. The findings appear to support this proposal, and three main attitude groups (utilitarian, associative and dissociative) were identified and used to further the discussion into how this knowledge could be used in predicting possible relational scenarios based on human-river relationships. Further exploration of the identified attitude groups suggested that these variables are significantly influenced by environmental ethics and place attachment (present in the community) and a series of guiding frameworks were developed to facilitate the exploration of the attitude groups relative to these concepts. The frameworks were generated from the hypothesis that knowledge of attitude groups in a catchment, in connection with the relative degrees to which moral values and worldviews are expressed, could provide insight into the readiness of a catchment system for the implementation of IWRM and/or the facilitative steps needed to shift the influence of unfavourable attitude groups (i.e. dissociative attitudes). Such steps would most likely involve extensive educational, awareness and capacity building programs. Finally, given the above theoretical frameworks, inductively developed from the findings of the social survey and related literature, the conceptual model was reevaluated and extended to include the thesis findings and hypotheses. It is suggested that in a catchment where there is a balance between the expression of utilitarian and associative attitude groups, then there is a high probability of finding present evidence of mutually beneficial human-river relationships already in play, as well as ‘fertile soil’ for the promotion of IWRM and philosophies and skills that generate such relationships. Alternatively in an area with a strong expression of dissociative attitudes, it is more likely to find evidence of destructive, more parasitic-like relationships being expressed, and a lack of commitment and interest in being involved in changing the status quo. It is likely that where both associative and dissociative attitudes are present there will be an overlap of elements of both scenarios – a situation that is probable in most catchments – depending on the strength of expression of either attitude group the balance will shift (be shifting) between the two relational scenarios.
- Full Text:
- Date Issued: 2009
- Authors: Birkholz, Sharon Alice
- Date: 2009
- Subjects: Aquatic ecology -- South Africa -- Kat River , Rivers -- South Africa -- Kat River -- Sociological aspects , Rivers -- South Africa -- Kat River , Water supply -- South Africa -- Kat River -- Management , Human ecology -- South Africa -- Kat River , Stream ecology -- South Africa -- Kat River
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: vital:4838 , http://hdl.handle.net/10962/d1005514
- Description: Through out this study ‘relational scenarios’ were seen as the possible outcomes of the expression of human-river relationships in a catchment. Working within Inglis’s (2008, pg. 10) comment that ‘the Human World Relationship is expressed through a person’s views and behaviour towards the natural world, which can be either constructive or destructive’, two relational scenarios were selected to represent these two predicted outcomes of human-environment (or in the case of this thesis human-river) relationships: IWRM, seen as constructive and mutually beneficial to both the social and ecological system, and the Tragedy of the Commons, seen as destructive and parasitic in nature. In respect to this assertion, a conceptual framework or model was developed and used to guide the inductive process of this research. Through a social survey (administered via semi-structured interviews) of stakeholders (water-users) in the Kat River Catchment, Eastern Cape, South Africa, social attitudes towards the Kat River were explored. These attitudes were considered as variables that relate to the expression of ‘Human World Relationships’ namely ‘values and behaviour’ (Inglis, 2008, pg. 10). The findings of this thesis confirm that attitudes are influential components of human-river relationships in the Kat River Catchment. It was observed from the findings that the attitudes individuals have towards the Kat River have the potential to influence the ways people interact with the River and its associated resources, and are in turn influenced by the condition of the River and connections people have or make with the River within their daily lives. Such relationships in turn affect the management of the River and its water resources and influence how individuals approach water-related issues and undertake the associated activities. Given this understanding it was then proposed that attitudes could provide information that enables the prediction of likely ‘relational scenarios’ (IWRM or the Tragedy of the Commons) in a catchment. The findings appear to support this proposal, and three main attitude groups (utilitarian, associative and dissociative) were identified and used to further the discussion into how this knowledge could be used in predicting possible relational scenarios based on human-river relationships. Further exploration of the identified attitude groups suggested that these variables are significantly influenced by environmental ethics and place attachment (present in the community) and a series of guiding frameworks were developed to facilitate the exploration of the attitude groups relative to these concepts. The frameworks were generated from the hypothesis that knowledge of attitude groups in a catchment, in connection with the relative degrees to which moral values and worldviews are expressed, could provide insight into the readiness of a catchment system for the implementation of IWRM and/or the facilitative steps needed to shift the influence of unfavourable attitude groups (i.e. dissociative attitudes). Such steps would most likely involve extensive educational, awareness and capacity building programs. Finally, given the above theoretical frameworks, inductively developed from the findings of the social survey and related literature, the conceptual model was reevaluated and extended to include the thesis findings and hypotheses. It is suggested that in a catchment where there is a balance between the expression of utilitarian and associative attitude groups, then there is a high probability of finding present evidence of mutually beneficial human-river relationships already in play, as well as ‘fertile soil’ for the promotion of IWRM and philosophies and skills that generate such relationships. Alternatively in an area with a strong expression of dissociative attitudes, it is more likely to find evidence of destructive, more parasitic-like relationships being expressed, and a lack of commitment and interest in being involved in changing the status quo. It is likely that where both associative and dissociative attitudes are present there will be an overlap of elements of both scenarios – a situation that is probable in most catchments – depending on the strength of expression of either attitude group the balance will shift (be shifting) between the two relational scenarios.
- Full Text:
- Date Issued: 2009
An assessment of the companion modelling approach in a context of negotiating water allocation strategies : the case of the Kat River Valley, Eastern Cape, South Africa
- Authors: Gumede, Felicity Hlengiwe
- Date: 2008
- Subjects: Water supply -- South Africa -- Kat River Valley -- Management , Water resources development -- South Africa -- Kat River Valley , Integrated water development -- South Africa -- Kat River Valley
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4820 , http://hdl.handle.net/10962/d1005494 , Water supply -- South Africa -- Kat River Valley -- Management , Water resources development -- South Africa -- Kat River Valley , Integrated water development -- South Africa -- Kat River Valley
- Description: This Masters research took place in the Kat River Valley in the Eastern Cape, South Africa. The Kat River Valley is a semi-rural catchment that covers an area of approximately 1700km² and is characterized by a complicated history of dispossession and resettlement. Farming is the main activity that is practiced in the area. This includes the farming of citrus at a commercial scale, rangeland stock farming and small-scale vegetable farming. The economy of the catchment is enhanced mostly by commercial citrus farming, which consumes by far the largest amount of water in the river through irrigation. Water allocation is a burning issue among water users in the catchment and needs to be negotiated taking into consideration social, economic and environment impacts. The aim of this study is to describe, discuss and evaluate the Companion Modelling (ComMod) approach, which used a simulation model and a role-playing game related to the model in order to facilitate and develop negotiating skills as well as build capacity in decision-making amongst local stakeholders for water resource management in the Kat River Valley. The ComMod approach, developed by a group of Companion Modellers, is a community-based science approach that emerged in the 1990s. The ComMod approach is used in order to facilitate collective learning, negotiation and institutional innovation in dealing with resource management complexities faced by rural communities. Through ComMod, the model (KatAWARE) and its related role-playing game was developed by having the contact with local stakeholders. The information to feed the model and the role-playing game came from informal interviews, surveys, geographic information systems (GIS), workshops and focus groups. The use of workshops in the implementation of ComMod was a success. Results show that (1) new knowledge was acquired, which allowed stakeholders to have a broad understanding of a catchment system. (2) Awareness was created about complex systems and enabled stakeholders to see an individual action into to the broader system. (3) Strong interrelationships were fostered amongst different water users, which allowed stakeholders to share their view points. The ComMod process was however associated with a number of limitations, many of which resulted from the constraints that were imposed by the socio-economic background of the study area. Nevertheless, the outcome of the study shows that the ComMod process was useful in helping the Kat River Water Users Association (KRWUA) stakeholders develop negotiating skills regarding water allocation strategies for the development of the Catchment Management Plan.
- Full Text:
- Date Issued: 2008
- Authors: Gumede, Felicity Hlengiwe
- Date: 2008
- Subjects: Water supply -- South Africa -- Kat River Valley -- Management , Water resources development -- South Africa -- Kat River Valley , Integrated water development -- South Africa -- Kat River Valley
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4820 , http://hdl.handle.net/10962/d1005494 , Water supply -- South Africa -- Kat River Valley -- Management , Water resources development -- South Africa -- Kat River Valley , Integrated water development -- South Africa -- Kat River Valley
- Description: This Masters research took place in the Kat River Valley in the Eastern Cape, South Africa. The Kat River Valley is a semi-rural catchment that covers an area of approximately 1700km² and is characterized by a complicated history of dispossession and resettlement. Farming is the main activity that is practiced in the area. This includes the farming of citrus at a commercial scale, rangeland stock farming and small-scale vegetable farming. The economy of the catchment is enhanced mostly by commercial citrus farming, which consumes by far the largest amount of water in the river through irrigation. Water allocation is a burning issue among water users in the catchment and needs to be negotiated taking into consideration social, economic and environment impacts. The aim of this study is to describe, discuss and evaluate the Companion Modelling (ComMod) approach, which used a simulation model and a role-playing game related to the model in order to facilitate and develop negotiating skills as well as build capacity in decision-making amongst local stakeholders for water resource management in the Kat River Valley. The ComMod approach, developed by a group of Companion Modellers, is a community-based science approach that emerged in the 1990s. The ComMod approach is used in order to facilitate collective learning, negotiation and institutional innovation in dealing with resource management complexities faced by rural communities. Through ComMod, the model (KatAWARE) and its related role-playing game was developed by having the contact with local stakeholders. The information to feed the model and the role-playing game came from informal interviews, surveys, geographic information systems (GIS), workshops and focus groups. The use of workshops in the implementation of ComMod was a success. Results show that (1) new knowledge was acquired, which allowed stakeholders to have a broad understanding of a catchment system. (2) Awareness was created about complex systems and enabled stakeholders to see an individual action into to the broader system. (3) Strong interrelationships were fostered amongst different water users, which allowed stakeholders to share their view points. The ComMod process was however associated with a number of limitations, many of which resulted from the constraints that were imposed by the socio-economic background of the study area. Nevertheless, the outcome of the study shows that the ComMod process was useful in helping the Kat River Water Users Association (KRWUA) stakeholders develop negotiating skills regarding water allocation strategies for the development of the Catchment Management Plan.
- Full Text:
- Date Issued: 2008
Severe convective storm risk in the Eastern Cape Province of South Africa
- Authors: Pyle, Desmond Mark
- Date: 2007
- Subjects: Storms -- South Africa -- Eastern Cape Natural disasters -- South Africa -- Eastern Cape Disasters -- South Africa -- Eastern Cape Disaster relief -- South Africa -- Eastern Cape -- Management Meteorology -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4853 , http://hdl.handle.net/10962/d1005529
- Description: This study investigates the temporal, spatial and impact characteristics of severe convective storm hazard and risk in the Eastern Cape Province of South Africa. Using historical data on severe convective storms dating from 1897, patterns of the hazard threat and risk to various geographic populations were investigated. A conceptual framework that emphasises the combined role hazard and vulnerability play in defining risk was used for the study. A methodology for ranking the severity of the storms in the historical dataset, based on recorded damage/impact, was specifically developed for the study. It is intended that this methodology will have a potentially wider application and may be adapted to a range of hazard impact and risk studies in South Africa and internationally. The study was undertaken within the context of the South African Disaster Management Act of 2002. Findings of the study show that severe convective storms can occur throughout the province, but there are clearly demarcated areas of higher frequency and concentration. The impact of storms is particularly severe on impoverished and vulnerable rural populations in the eastern parts of the province, where there is an urgent need for building capacity in disaster risk management. A major outcome of the study is the production of a severe convective storm hazard/risk map of the Eastern Cape, which it is hoped will be of benefit to a number of stakeholders in the province, particularly disaster management, but also the South African Weather Service, agricultural organisations, development/planning authorities, educational authorities and risk insurers. It is hoped that this map and the study in general will assist in guiding the operational responses of the various authorities, especially in terms of those interventions aimed at disaster risk reduction in the Eastern Cape.
- Full Text:
- Date Issued: 2007
- Authors: Pyle, Desmond Mark
- Date: 2007
- Subjects: Storms -- South Africa -- Eastern Cape Natural disasters -- South Africa -- Eastern Cape Disasters -- South Africa -- Eastern Cape Disaster relief -- South Africa -- Eastern Cape -- Management Meteorology -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4853 , http://hdl.handle.net/10962/d1005529
- Description: This study investigates the temporal, spatial and impact characteristics of severe convective storm hazard and risk in the Eastern Cape Province of South Africa. Using historical data on severe convective storms dating from 1897, patterns of the hazard threat and risk to various geographic populations were investigated. A conceptual framework that emphasises the combined role hazard and vulnerability play in defining risk was used for the study. A methodology for ranking the severity of the storms in the historical dataset, based on recorded damage/impact, was specifically developed for the study. It is intended that this methodology will have a potentially wider application and may be adapted to a range of hazard impact and risk studies in South Africa and internationally. The study was undertaken within the context of the South African Disaster Management Act of 2002. Findings of the study show that severe convective storms can occur throughout the province, but there are clearly demarcated areas of higher frequency and concentration. The impact of storms is particularly severe on impoverished and vulnerable rural populations in the eastern parts of the province, where there is an urgent need for building capacity in disaster risk management. A major outcome of the study is the production of a severe convective storm hazard/risk map of the Eastern Cape, which it is hoped will be of benefit to a number of stakeholders in the province, particularly disaster management, but also the South African Weather Service, agricultural organisations, development/planning authorities, educational authorities and risk insurers. It is hoped that this map and the study in general will assist in guiding the operational responses of the various authorities, especially in terms of those interventions aimed at disaster risk reduction in the Eastern Cape.
- Full Text:
- Date Issued: 2007