Quantitative Assessment of Soil-water Erosion with the EPM Model (Case Study: Badranloo Watershed basin)

Soil erosion is one of environmental problems in northern Khorasan province and Badranloo basin. Surveys show that about 461574 tons of soil are eroded from the loess fertile lands of the Badranloo basin annually which has led to a decrease in soil fertility and accumulation of sediment. The sediment resulting from erosion reduces the useful life of dams and water structures in the low stream of basin. The aim of this study was quantitative evaluation of water erosion in the Badranloo basin and the Experimental erosion Potential Method (EPM) has been used in this regard. In this study, within evaluating the water erosion, the specific sediment value for sub-basins and the whole of Badranloo watershed is calculated by ILWIS 3.3 software and specific sediment yield map (GSp) was prepared. ANOVA method was used in SPSS software for analyzing the geological and escalation erosion, along with for statistical analysis of the role of topographic factors in the severity of soil erosion. The results indicate the alarming state of ecological instability in the basin area. So, the annual average water erosion of soil in the basin is about 23.73 ton / ha. Among sub-basins, the sub-basin No. 4 located in the center of the basin with an annual concentration of about 63.89 ton / ha has the highest soil erosion. Groove and mass erosion are common water erosions at the basin level. In addition to lithology conditions and land -use change, among topographic factors, slope and direction of gradient have the greatest effect on the severity of the soil erosion of the basin due to the high correlation.