A comparison of the performance of selected conceptual models of the rainfall-runoff process in semi-arid catchments near Grahamstown
- Authors: Roberts, Peter J T
- Date: 1979
- Subjects: Runoff , Rainfall , South Africa , Grahamstown
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4798 , http://hdl.handle.net/10962/d1001898
- Description: A comparison of the performance of selected conceptual models of the rainfall-runoff process forms the central theme of this study and the comparison was conducted with three major objectives in mind. The first objective was to develop a conceptual model that could be used by practising hydrologists for the refinement and extension of historical streamflow records. The major requirements of the model were that it should be simple in structure and easy to operate and yet be flexible in terms of complexity of structure and input requirements as well as producing output at a level of accuracy that is competitive with that of the more complex models presently available. A comparison of the performance of the required model with that of other models formed an integral part of the development process. The second objective of the comparative study was to contribute to current knowledge of the criteria used in the selection of a suitable model for a particular application. There are, at present, no reliable guidelines to assist the hydrologist in selecting a suitable model from the wide range of models available and a comparative study would indicate the merits of various forms of model structure. The third objective is associated with the problems that arise when no streamflow data are available for model calibration. One approach is to calibrate the model in a nearby gauged catchment that the hydrologist regards as being 'hydrologically similar' and transferring the model parameter values to the ungauged catchment. Little is known about the feasibility of this parameter transfer process or about the choice of a model for such an application. The third objective was to test the feasibility of the parameter transfer process and to make use of the comparison of model performance to determine the model characteristics that are most suitable for the purpose
- Full Text:
- Date Issued: 1979
- Authors: Roberts, Peter J T
- Date: 1979
- Subjects: Runoff , Rainfall , South Africa , Grahamstown
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4798 , http://hdl.handle.net/10962/d1001898
- Description: A comparison of the performance of selected conceptual models of the rainfall-runoff process forms the central theme of this study and the comparison was conducted with three major objectives in mind. The first objective was to develop a conceptual model that could be used by practising hydrologists for the refinement and extension of historical streamflow records. The major requirements of the model were that it should be simple in structure and easy to operate and yet be flexible in terms of complexity of structure and input requirements as well as producing output at a level of accuracy that is competitive with that of the more complex models presently available. A comparison of the performance of the required model with that of other models formed an integral part of the development process. The second objective of the comparative study was to contribute to current knowledge of the criteria used in the selection of a suitable model for a particular application. There are, at present, no reliable guidelines to assist the hydrologist in selecting a suitable model from the wide range of models available and a comparative study would indicate the merits of various forms of model structure. The third objective is associated with the problems that arise when no streamflow data are available for model calibration. One approach is to calibrate the model in a nearby gauged catchment that the hydrologist regards as being 'hydrologically similar' and transferring the model parameter values to the ungauged catchment. Little is known about the feasibility of this parameter transfer process or about the choice of a model for such an application. The third objective was to test the feasibility of the parameter transfer process and to make use of the comparison of model performance to determine the model characteristics that are most suitable for the purpose
- Full Text:
- Date Issued: 1979
An examination of the spatial variation of surficial sediment characteristics in the Howison's Poort Reservoir
- Authors: Weaver, Alex van Breda
- Date: 1979
- Subjects: Howison's Poort Reservoir , South Africa , Sedimentation and deposition
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:4790 , http://hdl.handle.net/10962/d1001890
- Description: From Introduction: Lakes, estuaries and man-made water impoundments can be considered as intervening basins which provide for the temporary storage both of sediment and of water. Because of the potential energy of soil in elevated positions and because of the kinetic energy of water flowing under the influence of gravity, eroded material is eventually transported to the lowest possible level, i.e. the ocean deeps, or some intervening basin. This denudation process may be compared with Newton’s second law of thermodynamics which states that each system tends to move in the direction of lowest energy. Sedimentation in intervening basins may be seen as part of the natural process of landscape evolution. The rates at which sedimentation occurs may be strongly influenced by the activities of man.
- Full Text:
- Date Issued: 1979
- Authors: Weaver, Alex van Breda
- Date: 1979
- Subjects: Howison's Poort Reservoir , South Africa , Sedimentation and deposition
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:4790 , http://hdl.handle.net/10962/d1001890
- Description: From Introduction: Lakes, estuaries and man-made water impoundments can be considered as intervening basins which provide for the temporary storage both of sediment and of water. Because of the potential energy of soil in elevated positions and because of the kinetic energy of water flowing under the influence of gravity, eroded material is eventually transported to the lowest possible level, i.e. the ocean deeps, or some intervening basin. This denudation process may be compared with Newton’s second law of thermodynamics which states that each system tends to move in the direction of lowest energy. Sedimentation in intervening basins may be seen as part of the natural process of landscape evolution. The rates at which sedimentation occurs may be strongly influenced by the activities of man.
- Full Text:
- Date Issued: 1979
- «
- ‹
- 1
- ›
- »