International Symposium on
Drylands Ecology and Human Security

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Importance of the Satellite Imagery for the Characterization of Original Mechanisms of Desertification Processes in Southwestern Morocco (Tan-Tan, Tarfaya and Laayoune): Socio-economic Impacts and Impediment to Development

Aicha Benmohammadi1, J. Brahim, M. Ahizoun & Z. Saltani

1Directrice UFR « Morphogenèse dunaire en domaine littoral et continental »,
Equipe Géosciences de l’Environnement, Laboratoire Biotechnologie Environnement et Qualité,
Faculté des Sciences de Kénitra, Morocco



This principal objective of this talk is to review the desertification processes presently active in the coastal zone between Tan-Tan and Laayoun, southern Morocco. During the last decades, landward sand displacement has become very important and a major threat in region of the Moroccan Atlantic Sahara. The immediate negative effects of sand movement are strongly felt on roads, harbors, industrial and agricultural infrastructures as well as on the development of the urban and rural centers. The situation has presented a real challenge to the socio-economic development policy that the Moroccan government has been trying to implement in these regions.

Our investigation of desertification processes is based on a multidisciplinary approach that combines field work and the analysis of airborne or satellite imagery documents. Because of its desert climate, our area of study is characterized by a very precarious balance between water, sand, wind and recently human beings. This makes it highly prone to rapid desertification related environment changes and thus a privileged site for the study of these changes which might be of natural, anthropogenic or combined origin.

The most conspicuous changes presently observed in the area of study are the advancement or retreat of the dune migration front and of the natural vegetation cover, the reduction of the extent of the Khnifiss lagoon and the disorganization of the hydrographic network. It should be noted that the dunes have been omnipresent on this sector since the beginning of the Quaternary. Older dunes have modeled the landscape which is currently used as a receptacle for the current ones. The resulting morphogenesis has thus been tenaciously maintained several thousand years in spite of the recorded climatic variations which have led only to minor fluctuations in the extent, the size and the orientation of the dune fields.

To explain such constancy through time and to understand the factors that influence this dune development in view of eventually controlling it; requires the understanding of the principal vectors of propagation of the sandy material, namely the ocean, the relief and the wind. The particular combination of these three vectors in the Atlantic coastal segment investigated is such as the phenomenon of sand movement is carried here to its paroxysms.