Environmental Sensitivity Index maps in a high maritime transit area: The Moroccan coast of the Gibraltar Strait study case

The Strait of Gibraltar separates Europe and Africa and constitutes an important maritime transit area with an associated high risk of oil spill accidents. In this paper, a geomorphologic and environmental study has been carried out to obtain Environmental Sensitivity (ESI) Maps to beach oiling events along the protected coastline of Jbel Moussa (north Mediterranean coast of Morocco), which belongs to the Intercontinental Biosphere Reserve of the Mediterranean (IBRM) and is declared as RAMSAR site. ESI maps are of great interest to generate information about coastline sensitivity and provide a concise summary of coastal resources that are at risk as well as allow choosing sound cleanup strategies. Results show that beaches investigated have a high diversity in geomorphology and dynamic behaviours and show sediments with different level of permeability. These factors are of great interest to determine the hydrocarbons residence time in beach sediments. This coastline also showed a great diversity of flora, with an important forested area, a lagoon and fauna, which includes mammals, birds, reptiles and amphibians. Further, the area constitutes a natural refuge for migratory birds and hosts a small colony of Barbary Macaque. Anthropogenic uses are very limited because it is a rural area characterized by agricultural and traditional fishing activities. The crossing of the information obtained allowed determining different degrees of coastal sensitivity and accessibility, sound methods and techniques of intervention and cleanup, which ranged from natural recovery to flushing/washing. Last, taking into account the road network connections, four hydrocarbons stocking areas were determined.