Shoreline change, sea level rise and the impacts along the coastline of Walvis Bay, Namibia

Abstract

Coastal erosion is a global threat impacting communities worldwide. Traditional “action-reaction” management approaches using grey infrastructure are often employed, but there's a growing interest in nature-based solutions (NBS) for a more sustainable approach. This study examines coastal dynamics and the impact of climate change-induced sea level rise on Walvis Bay. Walvis Bay, with a low elevation, is highly vulnerable to erosion due to its geographic location and lack of natural protection. The study analyses shoreline changes between 1992 and 2023 using remote sensing and GIS techniques. Landsat images were used with the Digital Shoreline Analysis System (DSAS) using Linear Regression Rate (LRR), End Point Rate (EPR) and Net Shore Movement (NSM) to assess erosion and accretion. Furthermore, information on community knowledge and current adaptation strategies was obtained through questionnaires and interviews. Walvis Bay faces a substantial threat from coastal erosion due to sea level rise. The average erosional rate is −2.8 m/year for EPR and LRR. This indicates significant erosion in some sections of the sandspit, where land is being lost at a rapid pace. While the average accretional rate is about 3 m/year for EPR and LRR, where portions of the sandspit is gaining land at a rate higher than that of erosion. The study highlights the importance of employing a combination of scientific knowledge and community knowledge for effective coastal management. The findings suggest a need for proactive measures, potentially including NBS, to adapt to future shoreline changes and protect vulnerable coastal communities.