Erg Chebbi Erg Chebbi Erg Chebbi () is one of Morocco's several ergs – large seas of dunes formed by wind-blown sand. There are several other ergs such as Erg Chigaga near M'hamid. Technically all these ergs are within an area of semi-arid Pre-Saharan Steppes and not part of the Sahara desert which lies some distance to the south. In places, the dunes of Erg Chebbi rise up to 150 meters from the surrounding hamada (rocky desert) and altogether it spans an area of 28 kilometers from north to south and up to 5–7 kilometers from east to west lining the Algerian
Grand Erg Oriental of the Sahara is probably As-Sahra al-Libiyah, which straddles the inland border of Libya and Egypt. Erg is a Tamachek Berber word, and also a geographic term of art. The Grand Erg Oriental used to be associated with the Wadi Igharghar, a mostly dry and buried river with a sizable network of tributaries which, should it possess any water, would flow north into the erg from the Ahaggar mountains of the central Sahara. Yet such dry, anciently-made river beds, lying seemingly useless beneath the desert sands, can preserve the infrequent rain water, by carrying it off underground and so rescue