Investigation of Soil loss changes with emphasis on runoff erosion in the Kol river catchment

Soil erosion has been considered as the primary cause of soil degradation because soil erosion leads to the loss of topsoil and soil organic matter, which are essential for the growing of plants. Quantification of soil loss is a significant issue for soil and water conservation practitioners and policy makers. At the watershed level, the two most important hydrological phenomena that can occur from rainfall procedures are surface runoff and soil erosion.There are many models to study the soil erosion. One of the most widely used model for estimating this phenomenon is the Revised Universal Soil Loss Equation (RUSLE). Six factors are included in the RUSLE model: Rainfall erosivity, soil erodibility, slope length and steepness, vegetation cover and management and supporting practices. In this study, multi-sources data are used to generate the necessary parameters of the RUSLE model. Since Surface runoff and soil erosion are the two significant hydrologic reactions, the Soil Conservation Service Curve Number (SCS-CN) model is used to estimate runoff. This study has shown that a strong relationship between the surface runoff estimation and the maximum erosion potential in the study area. The advantage offered by this model is its simplicity and the diversity of the parameters used reflecting the function of runoff under the hydrological system.