Contribution of diachronic study in the spatio-temporal evolution of the Agadir bay (Morocco) [Apport de l'étude diachronique dans l'évolution spatio-temporelle de la baie d'Agadir (Maroc)]

The study of the evolution of the coastline is based on the determination of the dynamic equilibrium of the system,which must integrate components at different temporal and spacial scales. in order to provide additional knowledge on this issue,we treat the case of the coastal of agadir. this coastline suffers from a lot of human intervention and its dunes suffer from severe erosion. the southern beach of agadir is experiencing a very clear loss of beach sand; the coastline recedes; threatening developments and tourist attraction on the site. the study of the evolution of the coastline of the bay of agadir has allowed us the quantification of the linear erosion over a period of 49 years. it shows that the build up or loss of beach sand varied during this period. the area located near the northern breakwater built in 1968 (sector 2),tapers with an average rate of 2.75 ± 0.94 m/an. the southern sector across from hoteliers complex,records an erosion rates of about 3.07 ± 0.94 m/an,and the northern of sector 5 represented by the mouth of the oued souss,shows an average erosion rate of 6.024 ± 0.833 m/an.