Exploitation of beach sand and coastal dunes. Impact on the equilibrium of coastline between Boumerdes and Zemmouri El-Bahri (East Algiers), Algeria

Résumé

Overexploitation of the sand of the coastal dunes and beaches, causes an imbalance in the fragile coastal area and exposes it to the aggressive action of the sea. The case of beach Zemmouri and Boumerdes El-Bahri is edifying. The beach is bordered by a set of two juxtaposed coastal dunes. One directly along the beach which is commonly called active dune, the other named ancient dune is in second position towards the continent. Two main phenomena, first the erosive action of the sea and also the overuse of sandpits are the major causes of coastal degradation. We are witnessing a disappearance of the active dune and partial destruction of the ancient dune. In some places, depressions are created which facilitate the intrusion of marine waters. In order to study this phenomenon, we have conducted beach profiles with a frequency of a survey every two months for a year.