Geodynamics Research International Bulletin (GRIB), Vol. (II)– No. 02, SN:05, Spring Issue All rights reserved for GRIB XXXIV Geodynamics Research International Bulletin (GRIB), Vol. (II)– No. 02, SN:05, Spring Issue All rights reserved for GRIB An Estimation of Sediment by Using Erosion Potential Method and Geographic Information Systems in Chamgardalan Watershed: A Case Study of Ilam Province, Iran Saleh Yousefi 1 , NasrollahMoradi Kivarz 2 , Bahar Ramezani 3 , Niloofar Rasoolzadeh 4 , Nastaran Naderi 5 , Somayeh Mirzaee *6 1 Department of Watershed Management, Faculty of Natural Resources, Tarbiat Modares University, Tehran, Iran. 2 Faculty of Water Engineering, Maraghe Azad University, Maraghe, Iran. 3 Department of Watershed Management, Faculty of Natural Resources, Azad University, Noor, Iran. 4 Department of Watershed Management, Faculty of Natural Resources, Azad University, Noor, Iran. 5 Department of Environmental Engineering, Faculty of Natural Resources, AlamehMohadesehNooriUniversity, Noor, Iran. 6 Department of Watershed Management, Faculty of Natural Resources, LorestanUniversity, Iran. *Corresponding Author (s.mirzaee90@yahoo.com) Article History: Received: Mar 04, 2014 Reviewed: Mar 11, 2014 Revised: May 08, 2014 Accepted: May 11, 2014 Published: Jun 15, 2014 ABS TRACT Soil erosion can be considered one of the most important obstacles in the way of sustainable development of agriculture and natural resources.The aim of thepresentstudy isto estimate qualitatively and quantitatively the erosion and sediment yield of watershed by using EPM (Erosion Potential Method) and field data in GIS software, in Chamgardalan watershed, west of Iran.A grid-based distributed model EPM compatible with ArcGIS9.3 Geographic Information Systems (GIS), was applied to 583.7 km2 Upper Ilam Dam River in Ilam province. Model parameters were derived from a digital elevation model (DEM), land use and soil type map of the basin. These parameters and the observed daily meteorological data (1998-2010) were used (1) to test the performance of the EPM model to estimate total sediment yield, (2) to identify different erosion components. The observed total sediment was22.60 t/h/year, whereas the model estimated the amount of total sediment as 19.97 t/h/year.The predicted amount of total sediment was near the observed amount inthe stations at basin outlet.Wecan develop Erosion Potential M ethod (EPM)for other homogeneous units which don’t have hydrological stations, because thecost of erosion modeling and watershed management are less than building and settinghydrological stations. Keywords: EPM, Geographic Information System, Erosion Rate, Land Use, Sediment Yield. 1. INTRODUCTION In studying soil erosion risk, it is important to formulate effective soil conservation plans. Erosion causes serious consequences for economy as well as the environmental productivity. The important influences of soil erosion are manifest in areas which don’t have erosion but suffer from its consequences by sediment deposition in watercourses and reservoirs, water quality and flow rate decreasing (Mansouri Daneshvar and Bagherzadeh, 2012). All these results have a negative impact on water of river regimes. There are many erosion classifications available in the literature review. Since water erosion is the most significant problem in western Iran, this paper places an emphasis on the estimation of potential and actual risk of soil erosion caused by water. Traditionally, the most common method used in western and central Balkan areas is quantitative analysis of erosion processes proposed by Gavrilovic (1970, a and b). Moreover, numerous cartographic methods are available today to estimate the risk of the soil erosion by water (Husnjak et al., 2000).Various methodologies and procedures are proposed to estimate soil erosion and it is important to consider all the influencing factors (such as scale, characteristics of the area, etc.) to choose the appropriate one. Surface erosion and mass movements in the catchment body, produce the soil loss which is due to its moving to another area as a sediment. Development strategies led to changes in land use which exposed sensitive geological formations, consisting largely of shale and marl, to soil erosion. Moreover, poor vegetation cover in the Zagros Mountains was one of the main factors which caused millions of tons of soil to be transported by Vol. (2), No. 02, SN:05, Spring Issue- 2014 4 th Article- P. XXXIV to XLI Available online at: www.geo-dynamica.com GRIB Geodynamics Research International Bulletin ISSN 2345 - 4997