ABSTRACT

Balle, G.R.A.; Ahouansou, D.M.M.; Sintondji, L.C.O., and Agbossou, E.K., 2021. Analyses of short- and long-term shoreline trends of the southwest Benin coast. Journal of Coastal Research, 37(2), 316–325. Coconut Creek (Florida), ISSN 0749-0208.

Coastal zones are the economic heart of coastal countries and are therefore densely populated. In recent times, coastal zones are found to be globally eroding at variable spatiotemporal scales, leading to loss of business activities, ecosystems, economic lands, and infrastructures. Similar to elsewhere in the world, in West Africa and particularly the Benin Republic, the problem of the eroding shoreline is on the increase. Currently, the Grand-Popo section (the western part of the Benin coast) is experiencing serious shoreline change, which is causing the destruction of physical infrastructure and ecosystems. This study aims to determine the shoreline change trends in the study area over approximately a 10-year period from 1988 to 2018. To attend this objective, the SPOT and Sentinel-2 remotely sensed data of 10-m resolution were used, and the shoreline feature was extracted using the high-water line as an indicator. The shoreline feature dynamics were analysed using the Digital Shoreline Analysis System extension in ArcGIS, where the shoreline change statistics were computed and analysed. The results indicate that from 1988 to 2001, a high net shoreline accretion occurred, representing 80.39% of the entire study area at an average rate of 3.46 m/y. From 2001 to 2012, the Grand-Popo shoreline was affected by erosion representing approximately 85.17% of the study area at an average erosion rate of –4.54 m/y. Net shoreline accretion corresponding to 76.08% of the entire study coast at an average rate of 7.98 m/y also occurred between 2001 and 2012. Considering the entire study period (1988 to 2018), 68.51% of the shoreline accreted at an average rate of 0.79 m/y whereas 31.49% of the entire coast eroded at an average rate of –0.75 m/y. Major erosion was observed near the mouth of the Bouche du Roy estuary.

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