Shoreline Change Assessment of the Moroccan Atlantic Coastline Using DSAS Techniques

Abstract

Gharnate, A.; Taouali, O., and Mhammdi, N., 2024. Shoreline change assessment of the Moroccan Atlantic coastline using DSAS techniques. Journal of Coastal Research, 40(2), 418–435. Charlotte (North Carolina), ISSN 0749-0208. Coastal zones are critical from a physical, social, and economic point of view; however, most of the world's coastal zones are highly vulnerable to coastal erosion because of high population density, tourist attractions, and developed economies. To support mitigation strategies, a coastal erosion vulnerability assessment is essential to generate accurate information on this significant phenomenon. This study presents an integrated approach to coastal erosion vulnerability using a geospatial assessment of coastal dynamics in the Moroccan Atlantic coastal region between Rabat and Casablanca. To contribute to current and future knowledge of the study area's coastline dynamics, a cartographical and statistical approach was used to calculate historical rates of coastline change using aerial photos and satellite images from 1969 to 2022. To accomplish this, the images have been followed by the digitalization of the coastlines, as contained in the images created by using software ArcGIS10.8. These digitalized shorelines were subsequently incorporated into the digital shoreline analysis system, which provided multidate maps with graphical end point–rate (EPR) values. The results for Oued Cherrat estuary and the adjacent sandy beach indicate a general phase of erosion, with the average overall EPR value having reached –2.00 m/y, with the notable exception of a small part of the sandy beach, where progradation manifested itself in the form of an EPR value of +0.10 m/y. The Oued Nfifikh estuary is showing more erosion than the Oued Cherrat estuary. The retreat has affected the greater part of the area, reaching a maximum EPR speed of –5.00 m/y, with the possible exception of a smaller portion that has seen the shoreline progress at an average speed equal to +0.75 m/y. The resulting data may be used by the appropriate authorities to help effectively protect coastlines from erosion and to mitigate its impact on the environment and coastal properties.