Estimating of erosion and sediment yield of Gorganrud basin using erosin potential method

Abstract

Soil erosion can be considered as one of the most important obstacles in the way of sustainable development of agriculture and natural resources. The aim of this study is to estimate erosion and sediment yield of basin using Erosion Potential Method, in Gorganrud basin, north of Iran. The main factors in the EPM (slope average percent, erosion, rock and soil resistance, and land-use) were evaluated using a GIS software. Then, each of the parameters has been classified in different categories based on the importance. Finally, the prepared layers integrated and overlaid in EPM model, and soil erosion map are calculated. The spatial distribution of erosion intensify classes showed that 7.4% of the total basin area had tolerate erosion, 25.9% slight erosion, 27.96% moderate erosion, 10.46% strong erosion, 9.91% very strong erosion, and 18.34% destructive erosion. The highest amount of erosion occurred in the northwest to northeast regions with lithological units including loess, and alluvial deposits and agricultural use despite the fact that slope factors in these areas were less than 10%. In the central, western, and eastern parts of the basin, in spite of 15%-55% of slope, the areas depicted a slight to moderate potential of erosion. This is supposed to be due to the dense forest coverage in the region that decreases the energy of rain droplets. Results showed that about 66.7% of the study area is classified in moderate to destructive erosion intensify (Wsp >15 t ha-1 year-1). For avoiding soil erosion in this basin, soil conservation operation should be performed.