A Coastal Susceptibility Index Assessment of KwaZulu-Natal, East Coast of South Africa

The KwaZulu-Natal coastline on the east coast of South Africa is one of the most densely populated coastlines in Africa and has been subjected to human developments over the last 18 years. In recent years, extreme coastal events, due to a rapidly changing climate have caused much damage along the coast and are predicted to increase in intensity and frequency with the rise in eustatic sea-level. Therefore, assessing the coastal susceptibility in KwaZulu-Natal (KZN) attempts to identify the most sensitive locations along the coast to anticipated sea-level rise and related coastal hazards. This study discusses the application of the Coastal Susceptibility Index, which incorporates and ranks six physical variables, namely: geomorphology, coastal slope, historical shoreline change rate, significant wave height, mean tide range, and relative sea-level rise, to calculate the CSI. This information was displayed based on quartiles, indicating sections of the coastline with a very high, high, moderate or low susceptibility. The majority (34.33%) of the studied KZN is ranked as high susceptibility. More than half the coast (56.72%) is characterized as highly and very highly sensitive, primarily due to the susceptible geological landforms, low lying topography, high erosion rates and a highly significant wave height. The study provides a framework for decision-makers to prioritize coastal zones that require enhanced natural resilience and adopt appropriate management strategies within the study area.

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