Research Articles (School for Geospatial Studies and Information Systems)

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Browsing Research Articles (School for Geospatial Studies and Information Systems) by Subject "Hydrodynamics"

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    Analysing the changes in the bathymetry of Saldanha Bay between the years 1977 and 2021
    (CONSAS Conference, 2022-12) Du Toit, Louis; Henrico, Ivan; Bezuidenhout, Jacques; Mtshawu, Babalwa
    The construction of the Saldanha Port has been the reason for the major changes in the bathymetry and sediment dynamics observed in Saldanha Bay in the last decades. In this paper, newly acquired soundings from the National Hydrographer were used to analyse the changes between 1977 and 2021 - over a 44-year period - in the bathymetry of Saldanha Bay. The Ordinary Kriging (OK) interpolation method, available through the Geostatistical Wizard in ArcGIS Pro, was used for creating surface models to conduct comparisons with the bathymetry of Saldanha Bay. The results indicate a general increase in depth since 1977 of between 0.395 and 3.203 m, and an average increase in depth within the Big Bay of 1.799 m. Between 1977 and 2021, a total volume loss of 49 364 560.0 m3 in sediment was calculated - an indication of how the sedimentation process in Saldanha Bay has changed subsequent to the construction of the harbour.
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    Determining the change in the bathymetry of Saldanha Bay due to the harbour construction in the seventies
    (2020-09) Henrico, Ivan; Bezuidenhout, Jacques
    ENGLISH ABSTRACT: Bathymetry is the science to study and measure the depths of the ocean floor. The differences in water depth, underwater slope and ocean floor structure were investigated using a geographic information system (GIS). This article investigates changes to the hydrodynamic sedimentation processes in Saldanha Bay as a result of the harbour constructions that took place in the early 1970s. The construction of the harbour included the massive dredging operations and resultant relocation of 30 million m3 of soil. Bathymetric data from Saldanha Bay before (1957) and after (1977) the construction of the harbour in the early seventies were analysed and compared in ArcGIS. It was found that the overall depth of the inner part of Saldanha Bay increased with about 1.4 m and that the bottom and slopes were smoothed. The physical structure that was constructed for the harbour had a serious impact on the hydrodynamic sedimentation processes. It was found that these interventions altered the depth profile of the Bay and the article finally draws conclusions on coastal and beach formation, based on the change in the hydrodynamic sedimentation processes of Saldanha Bay.