A Statistical View to the Water Erosion in Iran

Soil erosion and its consequences are major obstacles for development of the country. On the other hand, natural factors underlying erosion in Iran have caused Iran to have a high potential for water erosion. Knowing the erosion conditions are very important for erosion control, but significant differences can be observed in the presented information. Then, in this article it has been tried to present an illustrated image of the water erosion conditions in Iran. Reviews show that professionals have declared specific erosion rate of 16 to 25 t/h/y. In landscape of the country watersheds plan, the mean of specific erosion, total erosion of the country and total sediment of the country have been estimated using EPM model equal to 6.94 t/h/y, 975 and 129 million tons respectively. While, using the rating curves studies, total sediment yield has been estimated equal to 250 million tons per year. The results of erosion and sediment studies in 38 catchments in Qazvin province, indicate the rate of 16.6 t/h/y for the mean of specific erosion. The average sediment production of country is less than 15 t/h/y, based on the sediment measurement in reservoirs of small dams. Therefore, accurate estimation of the sediment yield with proper methods is necessary, since the estimated methods and the achieved values are very different. However, it can be said that the average erosion rate of the country lies between 7 and maximum 16 t/h/y. According to the area of Iran, soil erosion of the country would be 1.15 to 2.64 billion tons annually that is considered a high rate of water erosion.