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Investigating and modelling sediment transportation by means of natural radionuclides as tracers in East London Harbour, South Africa
Thesis (MMil)--Stellenbosch University, 2025.
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| Format: | Thesis |
| Language: | en_ZA |
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Stellenbosch : Stellenbosch University
2025
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| _version_ | 1867614119165689856 |
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| access_status_str | Open Access |
| author | Botlholo, Rehab Kgomotso |
| author2 | Bezuidenhout, J. |
| author_browse | Bezuidenhout, J. Botlholo, Rehab Kgomotso |
| author_facet | Bezuidenhout, J. Botlholo, Rehab Kgomotso |
| author_sort | Botlholo, Rehab Kgomotso |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (MMil)--Stellenbosch University, 2025. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/134526 |
| institution | Stellenbosch University (South Africa) |
| language | en_ZA |
| last_indexed | 2026-06-10T12:46:58.390Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2025 |
| publishDateRange | 2025 |
| publishDateSort | 2025 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/134526 Investigating and modelling sediment transportation by means of natural radionuclides as tracers in East London Harbour, South Africa Botlholo, Rehab Kgomotso Bezuidenhout, J. Le Roux, R. R. Stellenbosch University. Faculty of Military Science. School for Science and Technology. Sediment transport -- Harbors -- South Africa -- East London Radioactive tracers in hydrogeology Marine sediments -- South Africa -- Eastern Cape Radioisotopes — Environmental aspects — South Africa — Eastern Cape UCTD Thesis (MMil)--Stellenbosch University, 2025. Botlholo, R. K. 2025. Investigating and modelling sediment transportation by means of natural radionuclides as tracers in East London Harbour, South Africa. Unpublished masters thesis. Stellenbosch: Stellenbosch University [online]. Available: https://scholar.sun.ac.za/items/ef61d937-c1dc-4b20-b699-6d1232c58772 ENGLISH ABSTRACT: Sediment consists of particle deposits found in the bottom layers of various water bodies, including oceans, lakes, and rivers. Sediment is a naturally occurring component of fluvial systems contributing to riverine landscapes and aquatic ecosystems. However, excessive sediment emerging from erosion can be harmful and degrade riverine and coastal environments in that it can accumulate in river channels and produce silt that obstructs the channel capacity, leading to navigation issues. This challenge is seen particularly in East London Harbour due to its location at the mouth of the Buffalo River, and it is of interest as it is the only commercial harbour in South Africa with river inflow. This study investigates the sediment transport by using naturally occurring radionuclides, potassium (⁴⁰K), thorium (²³²Th), and uranium (²³⁸U), in East London Harbour, using in situ measurements. This study deployed the Delta Underwater Gamma Detector System (DUGS) on the seafloor of the harbour. Full-Spectrum Analysis (FSA) was implemented to extract the activity concentrations of the radionuclides. Geostatistical tools and Exploratory Data Analysis (EDA), including the semi-variograms and ternary diagrams, were used to identify factors that influence sediment transport. The Kriging model in ArcGIS Pro confirmed reliable and usable predictions of activity concentrations. As a result, the distribution maps of the radionuclides were generated to display areas of low and high sedimentation. The findings of this study show lower concentrations of ⁴⁰K, ²³²Th, and ²³⁸U in the shipping channel due to the dredging operations that are conducted periodically. Meanwhile, higher concentrations occur slightly upstream, close to the main breakwater. These have been transported by the river and are concentrated in the area where sediment is trapped. The harbour is dominated by the presence of mud and heavy minerals reflected by ⁴⁰K and ²³²Th signatures on the ternary diagram. However, most sediments do not contain ²³⁸U and thus it may not be a suitable tracer of sedimentation in this harbour. The research confirms that the use of naturally occurring radionuclides to trace sediment is effective, as is the successful deployment of the DUGS on the seafloor of the harbour, providing useful baseline information for the harbour’s sustainable management. AFRIKAANSE OPSOMMING: Geen opsomming beskikbaar nie. Masters 2025-12-12T08:37:29Z 2025-12-12T08:37:29Z 2025-12 Thesis https://scholar.sun.ac.za/handle/10019.1/134526 en_ZA Stellenbosch University 88 pages : illustrations application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Sediment transport -- Harbors -- South Africa -- East London Radioactive tracers in hydrogeology Marine sediments -- South Africa -- Eastern Cape Radioisotopes — Environmental aspects — South Africa — Eastern Cape UCTD Botlholo, Rehab Kgomotso Investigating and modelling sediment transportation by means of natural radionuclides as tracers in East London Harbour, South Africa |
| title | Investigating and modelling sediment transportation by means of natural radionuclides as tracers in East London Harbour, South Africa |
| title_full | Investigating and modelling sediment transportation by means of natural radionuclides as tracers in East London Harbour, South Africa |
| title_fullStr | Investigating and modelling sediment transportation by means of natural radionuclides as tracers in East London Harbour, South Africa |
| title_full_unstemmed | Investigating and modelling sediment transportation by means of natural radionuclides as tracers in East London Harbour, South Africa |
| title_short | Investigating and modelling sediment transportation by means of natural radionuclides as tracers in East London Harbour, South Africa |
| title_sort | investigating and modelling sediment transportation by means of natural radionuclides as tracers in east london harbour south africa |
| topic | Sediment transport -- Harbors -- South Africa -- East London Radioactive tracers in hydrogeology Marine sediments -- South Africa -- Eastern Cape Radioisotopes — Environmental aspects — South Africa — Eastern Cape UCTD |
| url | https://scholar.sun.ac.za/handle/10019.1/134526 |
| work_keys_str_mv | AT botlholorehabkgomotso investigatingandmodellingsedimenttransportationbymeansofnaturalradionuclidesastracersineastlondonharboursouthafrica |