Evaluation of Erosion Status of Romeshgan Basin by BLM Model and Multi Criteria Decision Making Method

Soil is the bedrock of life and economic and social activities, biological and biological diversity. Lack of statistics and information on soil erosion and sediment production in many catchments of the country necessitate the application of appropriate methods and models for estimating the severity of soil erosion and sedimentation. In this study, using the BLM Erosion Estimation Model and ElectRE-1 Multi-Criteria Decision Making Method, the erosion rate in the Romeshgan basin has been investigated and the erosion intensity and zoning map has been prepared. Results of applying ELECTRE-1 model show that topographic factor (slope) with weight of 0.5578 is more effective than other factors in basin erodibility and plays the main role. Also based on this model, sub-basin 1 in the north of the basin had the highest vulnerability to erosion and then sub-basin 2, 4 and 3, respectively. Using the BLM model, it was found that the low erosion class in the Romshgan catchment covers the most extent and then there are high, very high, moderate and minor erosional classes. In general, the area has moderate erodibility. The overlap of the layers indicated that the maximum erosion intensity was in the slopes and mountain units, which included new and old alluvial deposits and cone deposits, marl, lime, siltstone, sandstone, conglomerate and gypsum. Also, rainfed agriculture units have the highest intensity and forest and pasture units have the least amount of erosion. In terms of slope factor, lands with slope of 8 to 30 percent have the highest degree of erosion.