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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

A review of the fluvial geomorphology monitoring of the receiving streams of the Mooi-Mgeni [River] Transfer Scheme Phase 1.

Hunter, Alistair Malcolm Scott. January 2009 (has links)
The Mgeni River is the major water resource for the eThekwini Metropolitan and Msunduzi Municipalities. At the end of 2002, the Mooi-Mgeni Transfer Scheme Phase 1, which transfers water from the Mooi River into the Mgeni catchment to augment the water supply to this region, was completed. The interbasin transfer of water resulted in the loss of habitat, erosion of the stream channel and transformation of the riparian zone in the receiving streams. Stream regulation resulting in an altered flow regime is considered the greatest threat to a riverine environment. An Environmental Management Plan (EMP), incorporating fluvial geomorphological monitoring procedures, was implemented to monitor the impact of the transfer on the receiving streams, the Mpofana and Lions Rivers, and to determine the rate and magnitude of erosion. A comparison of the geomorphological monitoring procedure of the EMP with best practice geomorphological monitoring derived from a review of the national and international stream geomorphological literature was conducted in this study. In addition, the implementation of the EMP geomorphological monitoring procedures was described and onsite observations of physical impacts on the receiving streams were completed. The geomorphological monitoring of the EMP included the use of erosion pins, survey of stream cross-sections and fixed-point photography. Photographs and data were collected from February 2003 to June 2006. The comparison of these monitoring methods against stream assessment best practices revealed the strengths and weaknesses of the geomorphological monitoring implemented in the receiving streams. Several key weaknesses were revealed. Firstly, an inadequate number of stream cross sections was included in the monitoring procedures. Secondly, although the erosion pins indicated some general trends in the erosion of the stream channel, they did not give a true impression of the rate and magnitude of change in slope and channel width of the stream, and the location of the erosion pins sites did not take into account the actual direction of flow during transfer as erosion pin sites were selected during low flow conditions. In addition, it was difficult to determine whether the erosion pins had been lost due to erosion or to turbulence. The results were difficult to assess and did not show whether the erosion was localised at the pins or the section of bank or stream profile. Thirdly, analysis of platform changes in the stream channel (e.g. through a comparison of aerial photograph sets) was lacking and no attempt was made to integrate the results from the different methods. Overall, the study concluded that the geomorphological monitoring of the EMP was limited, and it did not highlight the rate and magnitude of erosion in the receiving streams. Based on the findings of this study, recommendations are provided for geomorphological monitoring of the receiving streams of the Mooi Mgeni Transfer Scheme. / Thesis (M.Env.Dev.)-University of KwaZulu-Natal, Pietermaritzburg, 2009.
2

The geomorphology of wetlands in the upper Mooi River catchment, KwaZulu-Natal.

Longmore, Jennifer Lyn. January 2001 (has links)
Wetlands are now recognized as being an integral component of the physical landscape. Geomorphology has recently been recognised by wetland scientists as being of fundamental importance in wetland genesis, maintenance and evolution, thereby providing the context for informed, effective wetland management and conservation. At present there exists a paucity of geomorphological wetland research in South Africa. A hydro-geomorphic approach was adopted to attain an understanding of wetland genesis, distribution and functioning of a range of different palustrine wetland systems in the upper Mooi-River Catchment of KwaZulu-Natal. The physical, chemical and landscape-morphological characteristics of wetland soils were investigated to interpret the processes operating within those wetland systems. Both field and laboratory work suggest that wetland creation and maintenance in the upper Mooi River catchment may be attributed primarily to climatic factors, landscape position, landform and geological characteristics. These factors were found to cumulatively control the hydrological characteristics of wetlands, which impart an important influence on internal wetland conditions. While soil properties do not appear to be a primary factor in the establishment of these wetlands, they are nevertheless found to be important in the regulation of the hydrological dynamics of wetland systems. The close interdependence between wetlands and the surrounding landscape and the hydrological cycle is evident in the wetland systems investigated. Geomorphic processes within wetlands such as overbank flooding, overland flow, sedimentation, piping, leaching, soil swelling, shrinkage and cracking and channel incision and dynamics were found to be important variables in determining the nature and internal characteristics of wetland systems. In several of the systems investigated, all of the above mentioned processes were operative, while in other systems, a number of these processes were either insignificant or absent. Canonical Variate Analysis indicated that while commonalities exist between the palustrine wetland systems investigated in this study, significant differences were found between different groups. This supports the argument that a subclassification of the palustrine system into five different palustrine wetland types is warranted. While the scope of the present research did not allow for an extensive investigation of suitable methods of rehabilitation, the study suggests that an understanding of geomorphic process and wetland dynamics will be beneficial to wetland management and conservation as a whole. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 2001.

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