Estimation of soil erosion rate in Shahroud-Mayami watershed using SLEMSA model and GIS technique

The productivity of natural resources requires the accurate recognition of predominant mechanisms on environmental processes. Soil, as one of the most important natural resources, will always need a comprehensive planning and management for efficiency and conservation against the erosion. Soil erosion, as an environmental hazard, causes the loss of a large volume of fertile soil in the world annually. Therefore, purposes of this study are to estimate the amount of soil erosion per t. h-1 yr-1 in Shahroud-Mayami watershed using SLEMSA model, and finally provide the erosion map of study area through integrating the data by GIS technique. For this, first, the parameters of the mentioned model and the numerical values of erosion rates were estimated based on existing relationships. Then, their digital layers were prepared in the environment of ArcGIS software, and the erosion map of Shahroud-Mayami watershed was plotted by integration of these layers. The results show that study area includes three erosional belts with minimum rate of less than 2.371 to a maximum of 353.425 t. h-1 yr-1 that are located in the north and northwest, south, and center of study area. Spatial position of erosional belts indicates the importance of topography parameters such as slope, aspect, sediments instability in side’s slope and rainfall erosivity in soil degradation. Versus, the minimum erosional class, with eroded soil of less than 2.371 t. h-1 yr-1, involve the 48.42% of total area that illustrate the expansion of erosion minimum rate per its maximum rate in study region. This erosion values require the comprehensive and applied planning and management in long-term according to natural potential of the area.