Shoreline dynamics of South Africa using satellite imagery
| dc.contributor.advisor | Theron, Andre Karl | en_ZA |
| dc.contributor.author | Theron, Danie | en_ZA |
| dc.contributor.other | Stellenbosch University. Faculty of Engineering. Dept. of Civil Engineering. | en_ZA |
| dc.date.accessioned | 2025-03-14T13:30:46Z | en_ZA |
| dc.date.available | 2025-03-14T13:30:46Z | en_ZA |
| dc.date.issued | 2024-12 | en_ZA |
| dc.description | Thesis (MEng)--Stellenbosch University, 2024. | en_ZA |
| dc.description.abstract | ENGLISH ABSTRACT: Most South African beaches lack sufficient monitoring, which impedes a holistic understanding of shoreline dynamics amid increasing environmental and anthropogenic pressures. This study addressed this critical knowledge gap by utilising a satellite-derived shoreline algorithm (CoastSat) to rectify years of inadequate monitoring and to contribute to a thorough understanding of South African shoreline dynamics. Enhancements were made to the open-source CoastSat algorithm to enable a semi-automated, nationwide application. As a result, a pioneering database was created, spanning from 1984 to 2023 and covering nearly all sandy areas of the South African coastline. This extensive and coherent database represents the first of its kind for South Africa. The accuracy of the satellite-derived shoreline data (SDS) was assessed by comparing it with Lidar-surveyed data from 27km of beach area across six different beaches in the eThekwini Municipality. The results showed a very strong correlation (R = 0.95) between the SDS and the surveyed data, although an overall landward bias of 11.2m was observed. By incorporating wave runup in the analysis the accuracy was significantly improved, reducing bias by up to 79%. These findings were consistent with previous CoastSat studies from abroad. In addition to developing this extensive shoreline dynamics database, four local case studies and four regional assessments were carried out. These efforts served two primary objectives: to further the understanding of South African coastal dynamics both locally and regionally, and to demonstrate the utility of the database. For example, (i) A study of the Tugela River Mouth revealed shoreline erosion of several hundred metres from 2005 to 2023, which is important information for ongoing and planned catchment projects, such as large dams, that impact fluvial sand yield to the coast. (ii) The consistent extreme accretion south of the Richards Bay port entrance sharply contrasted with the extreme erosion to the north. This highlighted the impacts of various coastal engineering interventions, providing valuable insights into their effectiveness and guiding future coastal management strategies based on the lessons learned. (iii) Studies of the seasonal shoreline responses at St Helena Bay and Cape Town bays (Table Bay and False Bay) showed how the magnitude of these responses was related to the degree of wave exposure. (iv) Regional investigations found interesting distinctions in shoreline evolution: for instance, the west coast typically experienced shoreline retreat during winter, the south coast had less extreme winter erosion, and the east coast, particularly from Port St Johns northward, saw the greatest erosion shifting from winter to spring. This information is invaluable for informing local, regional, and provincial vulnerability assessments and guiding resource allocation more effectively. This study successfully established the first comprehensive database of shoreline dynamics for the entire South African sandy coastline. The data and insights provided could serve as a valuable resource for coastal managers, policymakers, engineers, researchers, and other stakeholders, facilitating the development of informed, effective, and sustainable coastal management strategies that address both current and future challenges. Future research can build on these data and insights by exploring new, unresearched avenues or enhancing methods and technologies to mitigate the identified errors and limitations. | en_ZA |
| dc.description.abstract | AFRIKAANSE OPSOMMING: Die meeste Suid-Afrikaanse strande het onvoldoende monitering, wat 'n holistiese begrip van kuslyn-dinamika te midde van toenemende omgewings- en menslike drukke belemmer. Hierdie studie het hierdie kritieke kennisgaping aangespreek deur 'n satelliet-afgeleide kuslyn algoritme, CoastSat, te gebruik om jare se onvoldoende monitering aan te spreek en by te dra tot 'n deeglike begrip van Suid-Afrikaanse kuslyn-dinamika. Verbeterings is aangebring aan die oopbron CoastSat algoritme om 'n semi-outomatiese, nasionale toepassing moontlik te maak. Gevolglik is 'n baanbreker databasis geskep wat strek vanaf 1984 tot 2023 en byna alle sandareas van die Suid-Afrikaanse kuslyn dek. Hierdie uitgebreide en samehangende databasis verteenwoordig die eerste van sy soort vir Suid-Afrika. Die akkuraatheid van die satelliet-afgeleide kuslyn data (SDS) is beoordeel deur dit te vergelyk met Lidar topografiese data van 27km strandgebied oor ses verskillende strande in die eThekwini Munisipaliteit. Die resultate het 'n baie sterk korrelasie (R = 0.95) tussen die SDS en die gemete Lidar data getoon, alhoewel 'n algehele landwaartse verskuiwing (“bias”) van 11.2m waargeneem is. Deur golfoploop in die ontleding in te sluit, is die akkuraatheid aansienlik verbeter, wat die verskuiwing met tot 79% verminder het. Hierdie bevindings is in ooreenstemming met vorige studies van regoor die we reld wat ook CoastSat gebruik het. Benewens die ontwikkeling van hierdie uitgebreide kuslyn-dinamika databasis, is vier plaaslike gevallestudies en vier streeksassesserings uitgevoer. Hierdie studies het twee prime re doelwitte gedien: om die begrip van Suid-Afrikaanse kusdinamika beide plaaslik en op streeks basis, te bevorder en om die nut van die databasis te demonstreer. Byvoorbeeld, (i) 'n Studie van die Tugela Riviermond het kuslynerosie van verskeie honderde meter van 2005 tot 2023 getoon, wat belangrike inligting is vir deurlopende en beplande opvangsgebiedprojekte, soos groot damme, wat die toevoer van riviersand na die kus beï nvloed. (ii) Die volgehoue groot kusopbou suid van die Richardsbaai hawe-ingang het skerp gekontrasteer met die erge erosie na die noorde. Dit het die impakte van verskeie kusingenieurs-intervensies uitgelig, wat waardevolle insigte in hul doeltreffendheid verskaf en kusbestuurstrategiee advies bied. (iii) Studies van die seisoenale kuslyn-veranderinge by St Helena Baai en Kaapstad se baaie (Vals- en Tafelbaai) het getoon hoe die omvang van hierdie veranderinge verband hou met golf blootstelling. (iv) Streeksondersoeke het interessante verskille in kuslynevolusie gevind: byvoorbeeld, die weskus het tipies kuslyn-erosie gedurende die winter ervaar, die suidkus het minder ekstreme winter erosie ondervind, en op die ooskus, veral vanaf Port St Johns noordwaarts, het die grootste erosie verskuif vanaf winter na lente. Hierdie bevindings is van groot waarde vir plaaslike, streeks en provinsiale kwesbaarheids-studies asook meer effektiewe toewysing van hulpbronne. Hierdie studie het suksesvol die eerste omvattende databasis van kuslyn-dinamika vir die hele Suid-Afrikaanse sandkuslyn gevestig. Die data en insigte wat verskaf word, kan dien as 'n waardevolle hulpbron vir kusbestuurders, beleidsmakers, ingenieurs, navorsers, en ander belanghebbendes, wat die ontwikkeling van ingeligte, effektiewe en volhoubare kusbestuurstrategiee fasiliteer sodat huidige en toekomstige uitdagings aangespreek word. Toekomstige navorsing kan voortbou op hierdie data en insigte deur nuwe, onnagevorste rigtings te verken of metodes en tegnologiee te verbeter om die geï dentifiseerde foute en beperkings te verminder. | af_ZA |
| dc.description.version | Masters | en_ZA |
| dc.format.extent | xvi, 153, xx pages : illustrations | en_ZA |
| dc.identifier.uri | https://scholar.sun.ac.za/handle/10019.1/131764 | en_ZA |
| dc.language.iso | en | en_ZA |
| dc.publisher | Stellenbosch University | en_ZA |
| dc.subject.lcsh | Shorelines -- Monitoring -- South Africa | en_ZA |
| dc.subject.lcsh | Coasts -- South Africa | en_ZA |
| dc.subject.lcsh | Remote-sensing images | en_ZA |
| dc.subject.lcsh | Coastal ecology | en_ZA |
| dc.subject.lcsh | UCTD | en_ZA |
| dc.title | Shoreline dynamics of South Africa using satellite imagery | en_ZA |
| dc.type | Thesis | en_ZA |