Aeolian Sand Transport Potential and Its Environmental Impact in Dakhla Oasis, Egypt

Abstract

Sand dune encroachment is one of the most environmental issues in Africa. It is a natural cause of desertification in the Western Desert, Egypt. The arid lands in Africa are strongly influenced by desertification. Sand dune movements threaten irrigated lands and water canals, residential areas, and water wells Dakhla Oasis. Sand dunes in Dakhla Oasis are crescentic and linear dunes. Several villages in Dakhla suffer from dune encroachment. The rate of Dakhla dune movement was measured using two sets of aerial photographs, 1961 and 1982 and Landsat images 2019. The rate of sand dune movement is between 0.5 and 14.0 m/yr with an average of 5.8 m/year for the crescentic dunes. That of liner or longitudinal dune (Seif) movement is 7.5 m/year. Sand dune movements are determined by dune size and local wind direction and velocity. Small dunes generally move faster than the larger ones. The rates of crescentic dune growth in terms of width and length average between 25 and 37 cm/year. The present chapter applied Sand drift potential (DP) formula using Fryberger model on the average effective wind speed sets at Dakhla and Farafra oases. The period from March to May showed the highest resultant drift potential. Controlling sand dune movements is very difficult and more expensive.