Multidecadal satellite-derived sandy shoreline change along the Mediterranean coast of Morocco
Abstract
Morocco's sandy Mediterranean coastline plays a crucial role in supporting local economies and ecotourism. Due to ongoing residential and tourist development and the increasing threat of climate change, monitoring shoreline change is essential for effective coastal management. This study investigates the spatiotemporal variability of shoreline change in this region from 1984 to 2023 using the CoastSat toolbox to analyze optical satellite imagery from Google Earth Engine. The methodology involved identifying 105 km of sandy coastline, generating 3833 transects, extracting time series of waterline positions corrected for tidal levels, and analyzing shoreline displacement trends using the Digital Shoreline Analysis System (DSAS). Our findings reveal an overall weak erosive shoreline trend, averaging -0.05 m/yr based on the Linear Regression Rate (LRR) method, yet falling within the shoreline trend uncertainty estimated at ± 0.35 m/yr. Large spatial and temporal variability in shoreline change was observed. The Tétouan coast, for instance, experienced consistent and widespread erosion, ranging from -0.7 to -2.9 m/yr. Similarly intense erosion was also recorded locally in the central part of the Saïdia coast (up to -2.78 m/yr). This variability can be attributed to a combination of natural and anthropogenic drivers: (1) Inlet dynamics causing adjacent sectors to undergo major shoreline changes with alternating erosion or accretion phases; (2) Human interventions such as dam construction upstream reducing sediment supply, which appears to be a major contributor to large-scale erosion along the Tétouan coast; (3) Coastal engineering structures like groynes and port extensions alter sediment transport, often causing accretion on the updrift side and erosion on the downdrift side. The study highlights the importance of long-term, high-frequency shoreline monitoring for assessing coastal change accurately and guiding management strategies in vulnerable areas. It also underscores the usefulness of optical satellite imagery in documenting long-term coastal evolution in datascarce regions
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BibTeX
@article{souiri2026multidecadal,
title = {{Multidecadal satellite-derived sandy shoreline change along the Mediterranean coast of Morocco}},
author = {Smail Souiri and Mounir Hakkou and Abdelhaq Aangri and Ayoub Belattmania and Bruno Castelle},
journal = {Regional Studies in Marine Science},
year = {2026},
month = oct,
doi = {10.1016/j.rsma.2025.104667},
url = {https://hal.science/hal-05844008v1},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Multidecadal satellite-derived sandy shoreline change along the Mediterranean coast of Morocco
AU - Smail Souiri
AU - Mounir Hakkou
AU - Abdelhaq Aangri
AU - Ayoub Belattmania
AU - Bruno Castelle
PY - 2026
DA - 2026/10/30
JO - Regional Studies in Marine Science
DO - 10.1016/j.rsma.2025.104667
UR - https://hal.science/hal-05844008v1
AB - Morocco's sandy Mediterranean coastline plays a crucial role in supporting local economies and ecotourism. Due to ongoing residential and tourist development and the increasing threat of climate change, monitoring shoreline change is essential for effective coastal management. This study investigates the spatiotemporal variability of shoreline change in this region from 1984 to 2023 using the CoastSat toolbox to analyze optical satellite imagery from Google Earth Engine. The methodology involved identifying 105 km of sandy coastline, generating 3833 transects, extracting time series of waterline positions corrected for tidal levels, and analyzing shoreline displacement trends using the Digital Shoreline Analysis System (DSAS). Our findings reveal an overall weak erosive shoreline trend, averaging -0.05 m/yr based on the Linear Regression Rate (LRR) method, yet falling within the shoreline trend uncertainty estimated at ± 0.35 m/yr. Large spatial and temporal variability in shoreline change was observed. The Tétouan coast, for instance, experienced consistent and widespread erosion, ranging from -0.7 to -2.9 m/yr. Similarly intense erosion was also recorded locally in the central part of the Saïdia coast (up to -2.78 m/yr). This variability can be attributed to a combination of natural and anthropogenic drivers: (1) Inlet dynamics causing adjacent sectors to undergo major shoreline changes with alternating erosion or accretion phases; (2) Human interventions such as dam construction upstream reducing sediment supply, which appears to be a major contributor to large-scale erosion along the Tétouan coast; (3) Coastal engineering structures like groynes and port extensions alter sediment transport, often causing accretion on the updrift side and erosion on the downdrift side. The study highlights the importance of long-term, high-frequency shoreline monitoring for assessing coastal change accurately and guiding management strategies in vulnerable areas. It also underscores the usefulness of optical satellite imagery in documenting long-term coastal evolution in datascarce regions
SN - 2352-4855
ER -