Document Type : Research Paper
Authors
1 PhD, Tarbiat Modares University, Tehran, Iran
2 Assistant Professor, Kharazmi University, Tehran, Iran
3 Professor, Esfahan University, Iran
4 MSc department of civil engineering, urmia branch,islamic azad university, urmia
Abstract
Nowadays, desertification as a great problem affects most of the countries in the world, especially developing countries. Desertification phenomenon that occurs in arid, semi-arid and dry semi-wet regions, will reduce the land potential. In this study MEDALUS model was applied for quantitative assessment of desertification risk with emphasis on five criterion in Shahroud-Bastam Basin, because of easy style and data accessibility and also compatible with the effective indices on land degradation. For this purpose, first, the study area was divided into five homogeneous units. Then, five criteria including soil quality, climate, vegetation, management, erosion and 13 indicators were used for quantitative evaluation of desertification in homogeneous units. Index layers for each criterion were prepared using GIS. These indices were ranked in accordance with Modified MEDALUS model. The geometric mean was then calculated and map was produced for each criterion. Land degradation map of each homogeneous unit was prepared using the geometric mean criteria. Finally, from their combination, desertification susceptibility map produced. According to the results, climatic and erosion criteria with an average weight of 1.607 and 1.467, had the most effectiveness on desertification and vegetation with average weight of 1.377 had the least effectiveness. As a results, from the total of study area, with area of 7737.71 km2, 40% (3096.311 km) is located in the C3 class or extreme critical erosion, that requiring more attention to implement desertification control programs. Result of this research is a managing tool available for decision-making regarding the selection of priority areas in the fight against desertification.
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