Grand Erg Oriental follow the wind's direction. There are other types of dunes, as well as "complex" dunes. Saharan winds are also known to clear an area of sand altogether, leaving bare rock (hamada) or gravel (reg). The "Grand Erg Oriental" is accessible overland by an Algerian road, which goes south from Constantine. It passes through the Aurès mountains, then salt lakes by the city of Biskra. Next the road skirts the western edge of the erg. After about 500 km. in all, it reaches the ancient oasis of Ourgla [Wargla]. Since late antiquity Wargla was a stop for the Saharan trade, being
Erg Ferradj elementary schools, with 39 classrooms including 27 in use. There are a total of 1,096 school students. 2.8% of the population has a tertiary education, and another 14.9% has competed secondary education. The overall literacy rate is 71.3%, and is 77.2% among males and 65.3% among females. Erg Ferradj has 2 polyclinics and 2 room care facilities; residents must travel to Abadla or Méchraâ Houari Boumédienne for further medical treatment. Erg Ferradj has 3 operational mosques, with another 1 under construction. The commune is composed of three localities: Erg Ferradj Erg Ferradj () is a town and commune in Abadla