چكيده لاتين
Soil erosion is one of the most important environmental issues and problems that we face today. Increasing exploitation and lack of proper human management of the natural environment have a great impact on intensifying the process of soil degradation and erosion. Today, soil erosion is one of the major problems of watersheds, agricultural areas, and natural resources, which causes land degradation and reduces soil fertility. Therefore, studying, identifying, and zoning areas susceptible to soil erosion has become very necessary. The purpose of this study is to assess the risk of soil erosion using 15 morphometric indices, including branching ratio, drainage density, drainage texture, infiltration coefficient, watercourse frequency, average slope, flow power index, elongation ratio, form coefficient, roughness number, topographic moisture, shape factor, circularity ratio, density coefficient, and roughness ratio. All these indicators were obtained from the SRTM Digital Elevation Model (DEM) with a spatial accuracy of 30 meters to zone the potential risk of soil erosion in the Karkheh watershed using WSA and averaging methods. In the first step, the necessary pre-processing, which includes removing hydrological errors, was performed on the digital elevation model using ArcGIS 10.8 software. Then, all the mentioned indicators were prepared for the sub-basins of the study area to zone the potential for soil erosion. The results of this study showed that in the WSA method, the central areas of the watershed are at greater risk of soil erosion, while in the results of the averaging method map, except for the central areas of the Moro watershed, its northeastern areas are also in the high erosion risk class. Finally, in order to examine the accuracy and validity of the methods used in this study, a comparison was made with the results of studies conducted by other researchers in the Karkheh watershed. Accordingly, the WSA method is more accurate in showing the rate of soil erosion in the central areas of the Karkheh basin than the averaging method. It is suggested that in order to prevent the risk of erosion in areas with high risk of erosion, construction and construction of stone and earth dams on the natural streambeds in the highlands to control and store runoff, and construction of retaining walls on the banks of the Karkheh River to prevent bank collapse and the spread of soil erosion.
