Assessement and Predicting of Soil Erosion Risk at Semi-arid Mountain: Intergeration of the USLE Model and GIS Technique for Soil Conservation Planning Case Study: Sareskandarchy Catchement, Eastern Slope

Soil erosion is a major environmental proplem in the world which causes economic losses and threatens the sustainable development. Many factors are responsible for erosion acceleration in catchement scale. Soil erosion by water is the result of interplay between catchement environmental factors such as soil, topography, drainage density and land use pattern and other factors. The soil erosion problem is more serious with hilly catchements which are subject to heavy rainfall, in semi arid mountains. In the study area-as a semi-arid region–which is situated on eastern slope of Sahand mountain (NW of Iran) soil erosion with water is very intensive. This area is as a major farmland and grazing land. Gullies and rills are the traces of water erosion. These phenomens are seen in many parts of study area. In order to investigatien on responsible factors to soil erosion and assessement of the risk to erosion, we used USLE model. By using this model, we studied the role of topography, land use, and soil type on soil erosion. The results suggested that slope and slope length play a major role on determining the erosion pattern. The depth of gullies is increased at parts where the length of slopes is increased. In these parts there is increased linear erosion through the increased rates of silt.