Cartographie de la vulnérabilité côtière au long de quelques plages de Mostaganem

Abstract

The coastline of Mostaganem Province is particularly vulnerable to coastal erosion and marine flooding. Climate change and the continuous rise in sea level are expected to intensify these hazards, threatening both natural ecosystems and human activities located along the coast. In this context, the present study aims to assess the physical coastal vulnerability of the coastal sector extending from the Macta estuary to the Cheliff estuary using the Coastal Vulnerability Index (CVI) developed by Thieler and Hammar-Klose. The assessment is based on the integration of seven physical variables: geology, geomorphology, coastal slope, shoreline change, tidal range, significant wave height, and sea-level rise. Geographic Information Systems (GIS) were used to process the data and produce thematic maps as well as the coastal vulnerability map. The results reveal a significant spatial variability in vulnerability along the 33 km of coastline investigated. Sandy beaches, unconsolidated sediments, and gently sloping coastal areas exhibit the highest levels of vulnerability, particularly in Stidia, Ouréah, Salamandre, Sidi Majdoub, and Sonaghter. In contrast, rocky coasts and cliffed areas display lower vulnerability due to their greater resistance to marine erosion. Spatial analysis indicates that high and very high vulnerability sectors account for 24.20 km, representing 73.33% of the studied coastline. Moderate vulnerability covers approximately 3.70 km (11.21%), while low vulnerability represents 5.10 km (15.45%). Comparison with the study conducted by Bengoufa et al. (2021) highlights a higher proportion of highly vulnerable sectors, reflecting a more detailed assessment achieved through the integration of a larger number of physical environmental variables. This study confirms the value of Geographic Information Systems as an effective decision-support tool for coastal risk assessment and integrated coastal zone management. It also emphasizes the need to implement adaptation measures such as sand fences, artificial beach nourishment, artificial reefs, and, where necessary, hard coastal protection structures to enhance the resilience of the coastline against future environmental changes.