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Spatio-temporal analysis of coastal sediment erosion in Cape Town through remote sensing and geoinformation science
Coastal erosion can be described as the landward or seaward propagation of coastlines. Coastal processes occur over various space and time scales, limiting in-situ approaches of monitoring change. As such it is imperative to take advantage of multisensory, multi-scale and multi-temporal modern spati...
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| Format: | Thesis |
| Language: | English |
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School of Architecture, Planning and Geomatics
2023
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| _version_ | 1867613263363047424 |
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| access_status_str | Open Access |
| author | Fanikiso, Lynn |
| author2 | Smith, Julian |
| author_browse | Fanikiso, Lynn Smith, Julian |
| author_facet | Smith, Julian Fanikiso, Lynn |
| author_sort | Fanikiso, Lynn |
| collection | Thesis |
| description | Coastal erosion can be described as the landward or seaward propagation of coastlines. Coastal processes occur over various space and time scales, limiting in-situ approaches of monitoring change. As such it is imperative to take advantage of multisensory, multi-scale and multi-temporal modern spatial technologies for multi-dimensional coastline change monitoring. The research presented here intends to showcase the synergy amongst remote sensing techniques by showcasing the use of coastal indicators towards shoreline assessment over the Kommetjie and Milnerton areas along the Cape Town coastline. There has been little progress in coastal studies in the Western Cape that encompass the diverse and dynamic aspects of coastal environments and in particular, sediment movement. Cape Town, in particular; is socioeconomically diverse and spatially segregated, with heavy dependence on its 240km of coastline. It faces sea level rise intensified by real-estate development close to the high-water mark and on reclaimed land. Spectral indices and classification techniques are explored to accommodate the complex bio-optical properties of coastal zones. This allows for the segmentation of land and ocean components to extract shorelines from multispectral Landsat imagery for a long term (1991-2021) shoreline assessment. The DSAS tool used these extracted shorelines to quantify shoreline change and was able to determine an overall averaged erosional rate of 2.56m/yr. for Kommetjie and 2.35m/yr. for Milnerton. Beach elevation modelling was also included to evaluate short term (2016-2021) sediment volumetric changes by applying Differential Interferometry to Sentinel-1 SLC data and the Waterline method through a combination of Sentinel -1 GRD and tide gauge data. The accuracy, validation and correction of these elevation models was conducted at the pixel level by comparison to an in-field RTK GPS survey used to capture the current state of the beaches. The results depict a sediment deficit in Kommetjie whilst accretion is prevalent along the Milnerton coastline. Shoreline propagation and coastal erosion quantification leads to a better understanding of geomorphology, hydrodynamic and land use influences on coastlines. This further informs climate adaptation strategies, urban planning and can support further development of interactive coastal information systems. |
| format | Thesis |
| id | oai:open.uct.ac.za:11427/37948 |
| institution | University of Cape Town (South Africa) |
| language | eng |
| last_indexed | 2026-06-10T12:33:21.255Z |
| license_str | Not specified — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UCTD — University of Cape Town Open Access Repository |
| publishDate | 2023 |
| publishDateRange | 2023 |
| publishDateSort | 2023 |
| publisher | School of Architecture, Planning and Geomatics |
| publisherStr | School of Architecture, Planning and Geomatics |
| record_format | dspace |
| source_str | UCTD — University of Cape Town Open Access Repository |
| spelling | oai:open.uct.ac.za:11427/37948 Spatio-temporal analysis of coastal sediment erosion in Cape Town through remote sensing and geoinformation science Fanikiso, Lynn Smith, Julian Shoko, Moreblessings Coastal Erosion DSAS Shoreline change Interferometry Waterline method Coastal erosion can be described as the landward or seaward propagation of coastlines. Coastal processes occur over various space and time scales, limiting in-situ approaches of monitoring change. As such it is imperative to take advantage of multisensory, multi-scale and multi-temporal modern spatial technologies for multi-dimensional coastline change monitoring. The research presented here intends to showcase the synergy amongst remote sensing techniques by showcasing the use of coastal indicators towards shoreline assessment over the Kommetjie and Milnerton areas along the Cape Town coastline. There has been little progress in coastal studies in the Western Cape that encompass the diverse and dynamic aspects of coastal environments and in particular, sediment movement. Cape Town, in particular; is socioeconomically diverse and spatially segregated, with heavy dependence on its 240km of coastline. It faces sea level rise intensified by real-estate development close to the high-water mark and on reclaimed land. Spectral indices and classification techniques are explored to accommodate the complex bio-optical properties of coastal zones. This allows for the segmentation of land and ocean components to extract shorelines from multispectral Landsat imagery for a long term (1991-2021) shoreline assessment. The DSAS tool used these extracted shorelines to quantify shoreline change and was able to determine an overall averaged erosional rate of 2.56m/yr. for Kommetjie and 2.35m/yr. for Milnerton. Beach elevation modelling was also included to evaluate short term (2016-2021) sediment volumetric changes by applying Differential Interferometry to Sentinel-1 SLC data and the Waterline method through a combination of Sentinel -1 GRD and tide gauge data. The accuracy, validation and correction of these elevation models was conducted at the pixel level by comparison to an in-field RTK GPS survey used to capture the current state of the beaches. The results depict a sediment deficit in Kommetjie whilst accretion is prevalent along the Milnerton coastline. Shoreline propagation and coastal erosion quantification leads to a better understanding of geomorphology, hydrodynamic and land use influences on coastlines. This further informs climate adaptation strategies, urban planning and can support further development of interactive coastal information systems. 2023-06-10T20:20:28Z 2023-06-10T20:20:28Z 2023 2023-06-10T19:13:52Z Master Thesis Masters MSc http://hdl.handle.net/11427/37948 eng application/pdf School of Architecture, Planning and Geomatics Faculty of Engineering and the Built Environment |
| spellingShingle | Coastal Erosion DSAS Shoreline change Interferometry Waterline method Fanikiso, Lynn Spatio-temporal analysis of coastal sediment erosion in Cape Town through remote sensing and geoinformation science |
| thesis_degree_str | Master's |
| title | Spatio-temporal analysis of coastal sediment erosion in Cape Town through remote sensing and geoinformation science |
| title_full | Spatio-temporal analysis of coastal sediment erosion in Cape Town through remote sensing and geoinformation science |
| title_fullStr | Spatio-temporal analysis of coastal sediment erosion in Cape Town through remote sensing and geoinformation science |
| title_full_unstemmed | Spatio-temporal analysis of coastal sediment erosion in Cape Town through remote sensing and geoinformation science |
| title_short | Spatio-temporal analysis of coastal sediment erosion in Cape Town through remote sensing and geoinformation science |
| title_sort | spatio temporal analysis of coastal sediment erosion in cape town through remote sensing and geoinformation science |
| topic | Coastal Erosion DSAS Shoreline change Interferometry Waterline method |
| url | http://hdl.handle.net/11427/37948 |
| work_keys_str_mv | AT fanikisolynn spatiotemporalanalysisofcoastalsedimenterosionincapetownthroughremotesensingandgeoinformationscience |