Erosion and sedimentation in the Daryan watershed, north west of Iran

Soil erosion that initiation and advancement of it can tend to the great changes on landscape, degrades the lands and deteriorates the environment. recognition of the most important factors contributing in erosion that can lead to identify alternative solution for its prevention and control, Daryan watershed locating in Semnan province-Iran, where vast part of it is covered by gravel depositions were selected as study area. In this study, for estimation of erosion and sediment were used MPSIAC method. Results of the erosion were shown that initiation and advancement of erosion are function of mean annual precipitation, weather temperature, land slope class and aspect, Geological formation, source of land, soil typeand its physical and chemical characteristics, vegetation type,land use and mean annual runoff depth of given area. Accordingly, it was fund out that land slope, and soil characteristics including soil depth, Na and TDS of soil are highly correlate to the rate of erosion initiation as well as its progress. thus based on the gained results, the best strategic solution for prevention and control of erosion in the studied area and the areas with similar environmental conditions can be prevention of surface runoff concentration and land rehabilitation together with vegetal cover management in this area. Most of the deposition unit A11, which is a rate of 110428 tonnes per year and the lowest related to the unit C6 is 9066 tonnes per year. Most of the soil erosion in the hydrological A11 due to a large area of ablation rate of 346848 tonnes per year and a minimum level of hydrological units, C6 to 22089 tons per year.