The sedimentology and palaeoenvironmental significance of vlei sediments on the Winterberg range, South Africa
- Authors: Dewey, Felicity Joy
- Date: 1989
- Subjects: Geology, Stratigraphic -- Holocene Sedimentology Sediments (Geology) -- South Africa -- Eastern Cape -- Winterberg range Geology, Stratigraphic -- Pleistocene Paleoecology -- South Africa -- Eastern Cape -- Winterberg range
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4797 , http://hdl.handle.net/10962/d1001897
- Description: Palaeoenvironmental reconstruction of the late Pleistocene and Holocene geological periods for central and southern Africa has been hampered by the erratic distribution of suitable sites, incomplete and inaccurately dated sequences and the limited nature of published data. One geomorphological feature which has supplied valuable evidence for fluctuations in past environmental conditions, is the vlei or dambo. The type-site of these waterlogged features is in south central Africa, but similar features have been described on other continents. The clastic and organic sediments contained within these features are affected by, and therefore reflect to some degree, the environment under which they were formed. The characteristics of the sediments supply information as to their transport and mechanisms of deposition. From these processes, the environmental conditions at the time of vlei formation can be inferred. The environmental history of the Eastern Cape region has been considerably neglected, and is far less well understood than other countries such as Malawi, Zambia and Zimbabwe. A study site in the Winterberg Range (Eastern Cape) was selected which permitted the comparison of two vleis, the objective being to establish an accurate late Pleistocene sediment chronology for the entire plateau area. Radiocarbon dates from organic layers indicate that these sediments span the last 12 000 years BP, suggesting that organic accumulation at this site began at roughly the same time as at sites further afield. The vlei sediments are analysed in terms of their morphology, particle slze distribution, and other physical and chemical characteristics. These data facilitate the construction of detailed stratigraphic diagrams and a chronological summary of sediment accumulation, from which the period and governing processes of vlei development under changing environments may be described. It is found that the Winterberg vleis contain sediments which respond to changes in the prevailing environment. This makes these sediments useful indices from which to trace such changes during the late Pleistocene and Holocene times. These features are found to be similar in many respects to those described elsewhere in Southern Africa. The study attempts to provide greater understanding of contemporary vlei processes and emphasises the necessity of their preservation, as finite and valuable resources, by future generations
- Full Text:
- Date Issued: 1989
- Authors: Dewey, Felicity Joy
- Date: 1989
- Subjects: Geology, Stratigraphic -- Holocene Sedimentology Sediments (Geology) -- South Africa -- Eastern Cape -- Winterberg range Geology, Stratigraphic -- Pleistocene Paleoecology -- South Africa -- Eastern Cape -- Winterberg range
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4797 , http://hdl.handle.net/10962/d1001897
- Description: Palaeoenvironmental reconstruction of the late Pleistocene and Holocene geological periods for central and southern Africa has been hampered by the erratic distribution of suitable sites, incomplete and inaccurately dated sequences and the limited nature of published data. One geomorphological feature which has supplied valuable evidence for fluctuations in past environmental conditions, is the vlei or dambo. The type-site of these waterlogged features is in south central Africa, but similar features have been described on other continents. The clastic and organic sediments contained within these features are affected by, and therefore reflect to some degree, the environment under which they were formed. The characteristics of the sediments supply information as to their transport and mechanisms of deposition. From these processes, the environmental conditions at the time of vlei formation can be inferred. The environmental history of the Eastern Cape region has been considerably neglected, and is far less well understood than other countries such as Malawi, Zambia and Zimbabwe. A study site in the Winterberg Range (Eastern Cape) was selected which permitted the comparison of two vleis, the objective being to establish an accurate late Pleistocene sediment chronology for the entire plateau area. Radiocarbon dates from organic layers indicate that these sediments span the last 12 000 years BP, suggesting that organic accumulation at this site began at roughly the same time as at sites further afield. The vlei sediments are analysed in terms of their morphology, particle slze distribution, and other physical and chemical characteristics. These data facilitate the construction of detailed stratigraphic diagrams and a chronological summary of sediment accumulation, from which the period and governing processes of vlei development under changing environments may be described. It is found that the Winterberg vleis contain sediments which respond to changes in the prevailing environment. This makes these sediments useful indices from which to trace such changes during the late Pleistocene and Holocene times. These features are found to be similar in many respects to those described elsewhere in Southern Africa. The study attempts to provide greater understanding of contemporary vlei processes and emphasises the necessity of their preservation, as finite and valuable resources, by future generations
- Full Text:
- Date Issued: 1989
Assessment of factors influencing the quality of surface and ground water in the Hout Bay river catchment
- Authors: Pearce, Meryl Winsome
- Date: 1989
- Subjects: Water -- South Africa -- Hout Bay Hydrology Water -- Pollution -- South Africa -- Hout Bay Water quality -- South Africa -- Hout Bay Aquatic ecology Water quality Hout Bay river (South Africa) Groundwater -- South Africa -- Hout Bay
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4800 , http://hdl.handle.net/10962/d1001900
- Description: An investigation into the quality of surface water and ground water was conducted during 1988 in the 38,8 km² Hout Bay River catchment near Cape Town. The main objective of the study was to determine those areas and activities which constitute a pollution source and to ascertain the relative proportion which each contributes to the pollution problem and health risk of the surf zone of the beach at Hout Ba . The objective was achieved by monitoring the chemical and microbiological attributes of the Hout Bay River, its tributaries and stormdrains in wet and dry conditions on a routine basis and during storm events. Hout Bay is a rapidly developing residential area in which sewage disposal occurs by means of septic tank soakaway systems. Ground water quality was monitored to investigate the contribution to contamination by septic tank effluent. Results showed that stormdrain effluent in dry and wet conditions and surface runoff during rainfall were the main vectors of pollution. Although the pollution concentration was high during dry conditions the greatest pollution discharge to the surf zone of Hout Bay occurred during storm events. In view of the proposed residential development it is imperative that pollution control measures be undertaken so as to secure the future recreational and aesthetic value of Hout Bay
- Full Text:
- Date Issued: 1989
- Authors: Pearce, Meryl Winsome
- Date: 1989
- Subjects: Water -- South Africa -- Hout Bay Hydrology Water -- Pollution -- South Africa -- Hout Bay Water quality -- South Africa -- Hout Bay Aquatic ecology Water quality Hout Bay river (South Africa) Groundwater -- South Africa -- Hout Bay
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4800 , http://hdl.handle.net/10962/d1001900
- Description: An investigation into the quality of surface water and ground water was conducted during 1988 in the 38,8 km² Hout Bay River catchment near Cape Town. The main objective of the study was to determine those areas and activities which constitute a pollution source and to ascertain the relative proportion which each contributes to the pollution problem and health risk of the surf zone of the beach at Hout Ba . The objective was achieved by monitoring the chemical and microbiological attributes of the Hout Bay River, its tributaries and stormdrains in wet and dry conditions on a routine basis and during storm events. Hout Bay is a rapidly developing residential area in which sewage disposal occurs by means of septic tank soakaway systems. Ground water quality was monitored to investigate the contribution to contamination by septic tank effluent. Results showed that stormdrain effluent in dry and wet conditions and surface runoff during rainfall were the main vectors of pollution. Although the pollution concentration was high during dry conditions the greatest pollution discharge to the surf zone of Hout Bay occurred during storm events. In view of the proposed residential development it is imperative that pollution control measures be undertaken so as to secure the future recreational and aesthetic value of Hout Bay
- Full Text:
- Date Issued: 1989
A hydrogeological investigation of the Grootegeluk mine
- Authors: Johnstone, Andrew Clifford
- Date: 1989
- Subjects: Hydrogeology -- South Africa Coal mines and mining -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4795 , http://hdl.handle.net/10962/d1001895
- Description: The study concerns an assessment of the hydrogeological impact of an open cast coal mine in the North Western Transvaal Province of South Africa. The hydrogeological impact of the mine is assessed in terms of groundwater quality and levels. A monitoring system was installed to enable the present and future impact of mining operations on the hydrogeological regime to be assessed. Grootegeluk Mine is situated in the Waterberg Coal Field of South Africa and began production in 1980. The mine extracts fifteen million tons of mine material annually from a single open pit. Forty percent of the mined material is saleable product and the remaining sixty percent is stacked on discard dumps. The Daarby fault forms the northern boundary of the open pit and serves to bring the younger Letaba and Clarens Formations into contact with the older Beaufort and Ecca Groups. The mine discards are deposited north of the fault on a different hydrogeological environment from which they are mined. Dewatering of the mine open pit has resulted in a steady decline in water levels in the Ecca Group, south of the Daarby fault. In contrast, water levels north of the Daarby fault in the Letaba and Clarens Formations have risen. The short term hydrochemical impact of the mine discard dumps and slimes dams have resulted in a rise in the calcium, sulphate, chloride, fluoride and nitrate concentrations of the ambient groundwater . The longer term hydrochemical impact from the waste dumps, acid mine drainage, is not evident at present in the groundwater below the waste dumps. However, it is expected to manifest itself during the next ten years. A monitoring system was installed at the mine to allow groundwater levels and quality to be monitored. By measuring groundwater quality and levels the impact of the mine on the regional hydrogeology can be monitored and assessed presently, and during the next forty years of production. Monitoring will also enable the timeous implementation of remedial measures at an early stage and eliminate the need for large late stage "clean up" operations. Future monitoring of both water levels and quality will be crucial in evaluating the mine's impact on the regional groundwater regimes over the next forty years of production. The remedial measures recommended for leachate presently emanating from the waste dumps and slimes dams north of the Daarby fault, are a number of collector wells drilled into the basalts and sandstone north of the Daarby fault. The proposed positions of the wells (boreholes) are as close as possible to the dumps and slimes dams with expansion taken into consideration. The boreholes should be designed to lower the water level in the vicinity of the dumps in order to create a nett groundwater gradient towards the dumps and as a result, halt the spread of leachate away from the dumps. Grootegeluk plans to backfill the open pit with plant discards on completion of the mining of zone 2. The backfilled material will consist of the currently produced plant waste and will be covered with overburden and topsoil. It is expected that the backfilling will have a major impact on groundwater quantity if no remedial measures are implemented. The two remedial measures discussed are chemical treatment of the discard material before backfilling or the continual abstraction of water from the pit resulting in a nett groundwater inflow into the pit. No material from the present waste dumps and slimes dams will be transported into the open pit as backfill material
- Full Text:
- Date Issued: 1989
- Authors: Johnstone, Andrew Clifford
- Date: 1989
- Subjects: Hydrogeology -- South Africa Coal mines and mining -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4795 , http://hdl.handle.net/10962/d1001895
- Description: The study concerns an assessment of the hydrogeological impact of an open cast coal mine in the North Western Transvaal Province of South Africa. The hydrogeological impact of the mine is assessed in terms of groundwater quality and levels. A monitoring system was installed to enable the present and future impact of mining operations on the hydrogeological regime to be assessed. Grootegeluk Mine is situated in the Waterberg Coal Field of South Africa and began production in 1980. The mine extracts fifteen million tons of mine material annually from a single open pit. Forty percent of the mined material is saleable product and the remaining sixty percent is stacked on discard dumps. The Daarby fault forms the northern boundary of the open pit and serves to bring the younger Letaba and Clarens Formations into contact with the older Beaufort and Ecca Groups. The mine discards are deposited north of the fault on a different hydrogeological environment from which they are mined. Dewatering of the mine open pit has resulted in a steady decline in water levels in the Ecca Group, south of the Daarby fault. In contrast, water levels north of the Daarby fault in the Letaba and Clarens Formations have risen. The short term hydrochemical impact of the mine discard dumps and slimes dams have resulted in a rise in the calcium, sulphate, chloride, fluoride and nitrate concentrations of the ambient groundwater . The longer term hydrochemical impact from the waste dumps, acid mine drainage, is not evident at present in the groundwater below the waste dumps. However, it is expected to manifest itself during the next ten years. A monitoring system was installed at the mine to allow groundwater levels and quality to be monitored. By measuring groundwater quality and levels the impact of the mine on the regional hydrogeology can be monitored and assessed presently, and during the next forty years of production. Monitoring will also enable the timeous implementation of remedial measures at an early stage and eliminate the need for large late stage "clean up" operations. Future monitoring of both water levels and quality will be crucial in evaluating the mine's impact on the regional groundwater regimes over the next forty years of production. The remedial measures recommended for leachate presently emanating from the waste dumps and slimes dams north of the Daarby fault, are a number of collector wells drilled into the basalts and sandstone north of the Daarby fault. The proposed positions of the wells (boreholes) are as close as possible to the dumps and slimes dams with expansion taken into consideration. The boreholes should be designed to lower the water level in the vicinity of the dumps in order to create a nett groundwater gradient towards the dumps and as a result, halt the spread of leachate away from the dumps. Grootegeluk plans to backfill the open pit with plant discards on completion of the mining of zone 2. The backfilled material will consist of the currently produced plant waste and will be covered with overburden and topsoil. It is expected that the backfilling will have a major impact on groundwater quantity if no remedial measures are implemented. The two remedial measures discussed are chemical treatment of the discard material before backfilling or the continual abstraction of water from the pit resulting in a nett groundwater inflow into the pit. No material from the present waste dumps and slimes dams will be transported into the open pit as backfill material
- Full Text:
- Date Issued: 1989
The exploration and evaluation of groundwater units in the Van Rynevelds Pass Dam Basin, north of Graaff-Reinet, Cape Province
- Authors: Woodford, A C
- Date: 1989 , 2013-08-30
- Subjects: Aquifers -- South Africa -- Graaff-Reinet , Hydrogeology -- South Africa , Groundwater -- South Africa -- Graaff-Reinet
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4880 , http://hdl.handle.net/10962/d1013275
- Description: This thesis deals with a groundwater investigation conducted in the Van Rynevelds Pass Dam basin, north of Graaff-Reinet, in the Cape Province. The objective of the study was to assess the groundwater potential of the basin in terms of its development and exploitation as a municipal supply. In order to achieve this objective, fieldwork was carried out involving a hydrocensus, geological/geophysical mapping, drilling, aquifer testing and hydrochemical sampling. The fieldwork was conducted during the period January 1983 to February 1984. The investigation revealed that the most significant ground water occurrence in the study area is an alluvial/weathered bedrock aquifer (Graaff-Reinet aquifer ) . The volume of ground water stored in the Graaff-Reinet aquifer is in the order of 27 x 10⁶ m³, while its exploitation potential is conservatively estimated at 9 300 m³/day. However, the quality of this water is poor and should be blended with dam water or better quality groundwater. Two minor fractured aquifer units were also identified.
- Full Text:
- Date Issued: 1989
- Authors: Woodford, A C
- Date: 1989 , 2013-08-30
- Subjects: Aquifers -- South Africa -- Graaff-Reinet , Hydrogeology -- South Africa , Groundwater -- South Africa -- Graaff-Reinet
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4880 , http://hdl.handle.net/10962/d1013275
- Description: This thesis deals with a groundwater investigation conducted in the Van Rynevelds Pass Dam basin, north of Graaff-Reinet, in the Cape Province. The objective of the study was to assess the groundwater potential of the basin in terms of its development and exploitation as a municipal supply. In order to achieve this objective, fieldwork was carried out involving a hydrocensus, geological/geophysical mapping, drilling, aquifer testing and hydrochemical sampling. The fieldwork was conducted during the period January 1983 to February 1984. The investigation revealed that the most significant ground water occurrence in the study area is an alluvial/weathered bedrock aquifer (Graaff-Reinet aquifer ) . The volume of ground water stored in the Graaff-Reinet aquifer is in the order of 27 x 10⁶ m³, while its exploitation potential is conservatively estimated at 9 300 m³/day. However, the quality of this water is poor and should be blended with dam water or better quality groundwater. Two minor fractured aquifer units were also identified.
- Full Text:
- Date Issued: 1989
An erosion hazard assessment technique for Ciskei
- Authors: Weaver, Alex van Breda
- Date: 1989
- Subjects: Soil erosion -- South Africa -- Ciskei
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4792 , http://hdl.handle.net/10962/d1001892
- Description: The study examines the relationship between the spatial variation in soil erosion and various natural and anthropogenic attributes of the region between the coastal plateau and the Winterberg escarpment of Ciskei. A raster-based geographical information system is derived for four separate study catchments and data on soil erosion and various soil erosion hazard indices are read into a computerised data matrix. The independent variables (soil erosion hazard indices) used in the study are selected on the basis of a review of the literature and on the availability of data in the Ciskei region. Multivariate analyses of the relationship between soil erosion and the various independent variables reveals that the primary variables affecting the spatial variation in soil erosion are land use, dominant soil type, geology, veld type and mean annual precipitation. All of these variables are readily quantifiable at the regional scale for large areas of Ciskei. An erosion hazard assessment model for use in central Ciskei is developed based on the results of the statistical analyses. The model is tested in separate study areas and is shown to provide an efficient method of identifying areas of differing susceptibility to soil erosion. The derived model is simple to operate and has input requirements which are easily met. It can be applied without the aid of computers, or where large areas are to be mapped it is well suited to computerisation
- Full Text:
- Date Issued: 1989
- Authors: Weaver, Alex van Breda
- Date: 1989
- Subjects: Soil erosion -- South Africa -- Ciskei
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4792 , http://hdl.handle.net/10962/d1001892
- Description: The study examines the relationship between the spatial variation in soil erosion and various natural and anthropogenic attributes of the region between the coastal plateau and the Winterberg escarpment of Ciskei. A raster-based geographical information system is derived for four separate study catchments and data on soil erosion and various soil erosion hazard indices are read into a computerised data matrix. The independent variables (soil erosion hazard indices) used in the study are selected on the basis of a review of the literature and on the availability of data in the Ciskei region. Multivariate analyses of the relationship between soil erosion and the various independent variables reveals that the primary variables affecting the spatial variation in soil erosion are land use, dominant soil type, geology, veld type and mean annual precipitation. All of these variables are readily quantifiable at the regional scale for large areas of Ciskei. An erosion hazard assessment model for use in central Ciskei is developed based on the results of the statistical analyses. The model is tested in separate study areas and is shown to provide an efficient method of identifying areas of differing susceptibility to soil erosion. The derived model is simple to operate and has input requirements which are easily met. It can be applied without the aid of computers, or where large areas are to be mapped it is well suited to computerisation
- Full Text:
- Date Issued: 1989
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