The Relation between wind characters and rivers dynamic in placing of sands massive in Khuzestan Plain (Case study: Northern Erg of Ahwaz)

One of the evidences of erosion process in the arid regions is wind erosion. Relative flatness, poverty of the vegetation, the dominant winds and alluvial weak formation are the most important intensive factors of the wind erosion. These conditions are in the central regions and the coastal plain in the south of Iran and the enormous sands massive where have been formed, scatter are the result of the condition in the region. Certainly, wind sands always are counted as an environmental hazard, because of their transportation and accumulation that have formed sandy massive. These phenomena are counted as a threat for humanity activities that have formed around them. Domination of dry condition during of warm spell and gust of severe winds with warm and dry nature in Khuzestan plain move wind sands in the region. However, accumulation and special morphology of these forms is seen erg massive in certain spot. However, it has not universality in all coastal plain. The main question of the research is the source of sands and the reasons of special settles and placing of the sandy massive in Khuzestan plain. The method of the research is on the basis of analysis of zonal wind characteristics by using of WRplot software and study of relation of direction gust of dominant wind and settles of sandy massive in the region. Topographic and geological maps, daily wind data and samples of sand in field works are principal data and tools of the research. Sand samples become analysis in gradient software and they have been fit with wine roses. result of the research indicate that the direction of the southern zagros folds have canalized and have lead Northwest Dominant winds besides alluvial fans, terraces and the beds of the important rivers are the main source of sands in surface of the plain. Also, drainage and the main rivers in surface of the plain affect morphology, distribution and relocation of the ergs massive.