Assessment and analysis of non-point source nitrogen and phosphorus loads(Case Study: Ilam Reservoir watershed)

An estimate of nutrient pollution load from the watershed of the reservoir is one of the important issues in the management of eutrophication. Additionally، with considering such attributes of the watershed as slope، the kind of soil، land use and Meteorological variables، the SWAT which is one the efficient model in water and soil modeling is used to evaluation of pollution load entering the Reservoir of Ilam dam because of diverse contamination resources such as chemical fertilizer and Livestock and poultry operations. The results of this study indicate that the SWAT model to simulate the nutrients in the watershed have a satisfactory performance. Based on obtained result، the highest pollution load of nitrogen (136. 2 ton per year) and phosphor (19. 8 ton per year) are occurred in Gol Gol Sub basin.