Issaouane Erg confined to basins. Sand in the Issaouane Erg, below the level of the sand dunes, has accumulated to a depth of 20 to 30 meters. It has barchan dunes as well as star dunes of 300 to 430 meters high. The presence of both barchan dunes (which form due to unidirectional winds) and star dunes (which form when winds from various directions deposit sand) "suggests that wind regimes have changed over time". NASA's "Earth Observatory" notes all three types of erg dunes are present in the photos of the Issaouane Erg taken from the International Space Station: stationary mega dunes,
Erg Ferradj Erg Ferradj Erg Ferradj () is a town and commune in Abadla District, Béchar Province, in western Algeria. According to the 2008 census its population is 4,406, down from 4,670 in 1998, and an annual population growth rate of -0.6%, the second lowest in the province. The commune covers an area of . Erg Ferradj lies at an elevation of to the west of an extensive palm plantation covering 3000 hectares lying along the western side of the Oued Guir. The rocky hills of the hamada are found on both sides of the river, but are more dramatic on the