Assessment the Desertification Trend Using The IMDPA Modele With Emphasis on Three Criteria Climate, Water and Geomorphology and Geology (Case Study: Dehloran Plain In Ilam Province)

Since the desertification is increases, providing the appropriate management strategies will decreased the desertification intensity and its expansions. For this, understanding of desertification process as well as its driving forces seems to be necessary to study in a research project. The main purpose of this study is to assess the desertification by using, IMDPA model in three periods those of 2000-2004, 2005-2009, 2010-2014 on Dehloran plain, Ilam province having 543.52 Km2areas. For this purpose, three affective criteria of climate, water and geomorphology-geology have been used for assessment of desertification. Each criterion was also evaluated by using a number of indices. The results of the desertification process in the first period of 2000-2004 showed that the criteria of climate geomorphology and geology and water, respectively, with weighted average 1.38, 1.30 and 1.19 were the most affective criteria in this period. Differently, in the second period of 2005-2009 the criteria of water, climate and geomorphology and geology, respectively, with weighted average 1.80, 1.50 and 1.30, had the most impact on increasing desertification. In the third period of 2010-2014 the criteria of climate geomorphology and geology and water, respectively, with weighted average 1.88, 1.30 and 1.20, were the most effective criteria in the intensity of desertification. Salinity index was recognized as the most affective indices in desertification process in all periods of time. This index hadthe greatest impact in the second period due to the indiscriminate use of farmers from exploitation wells which resulted in both decreasing groundwater levels and increasing salinity index. Overall, in study area the salinity index had an increasing trend which could be because of low rainfall, decreasing groundwater levels, and the special geology conditions.