Assessing coastal vulnerability to erosion and storm surges: The case of Richards Bay, South Africa

Abstract

Sandy beaches are dynamic in nature and subject to natural and anthropogenic processes that influence their evolution. One of the key drivers of coastal evolution is coastal erosion. Sandy beaches are more susceptible to erosion because their fine sand is easily erodible. As approximately 80% of South Africa’s coastline consists of sandy beaches, including environmentally sensitive dune systems, an impetus is to improve our knowledge and understanding of processes in the coastal zone to aid in coastal zone management and planning for future hazards. This research integrated geographical information systems, remote sensing and modelling techniques to determine the interrelationships between the spatial and temporal dynamics of shoreline change along the Richards Bay coastline in South Africa. Shoreline positions were quantified over 45 years between 1977 and 2022 using the United States Geological Survey’s Digital Shoreline Analysis System. The historical data were then used to estimate shoreline positions 10 years and 20 years into the future using the extrapolated linear regression method. The study revealed persistent erosion north of the harbour, with accretion occurring south of the harbour. Furthermore, the storm surge analysis revealed that a 10 m surge inundated 82% of the study area.
Contribution: This serves as an important source of information for flood risk analysis and disaster management within and around the Port of Richards Bay, South Africa.