Water Erosion Susceptibility Mapping Using Geomorphological Factors in Omarabad Watershed of Urmia

Spatial distribution of erosion phenomena and susceptibility analysis of different parts of watersheds to their types, plays an important role in environmental planning, so that the preparation of susceptibility maps to types of erosion and identification of factors affecting it, can Reducing the risk of various erosive phenomena will lead to providing the necessary management measures for the relevant areas. In this research, a bivariate statistical method was investigated for analyzing the susceptibility of Surface, Rill, Channel and Riverbank erosion phenomena using eight factors of rock resistance, land use and land cover, slope percentage, slope aspect, plan curvature, slope length, stream power index and soil hydrologic group in Omarabad watershed of Urmia. The results showed that regarding the effect of various factors predisposing to the occurrence of Surface, Rill, Channel and Streambank erosion, acceptable results with a clear trend in surface and rill erosion were not obtained, However, in the case of channel and streambank erosion, each of the factors, according to the relevant classes, has a positive or negative effect on the occurrence of this type of erosion and the effect of one factor cannot be considered as complete, positive or negative. factors such as lithology, slope length, slope percentage, slope aspect and SPI have the most positive effect on the occurrence of Channel and Streambank erosion. On the other hand, according to the calibration of the susceptibility map to Channel and Streambank erosion, only 20% of the area with Channel and Streambank erosion related to calibration were in the range of areas with very high to severe sensitivity in the susceptibility map. This indicates the inefficiency of the susceptibility map produced using the above eight predisposing factors and emphasizes the research on other more important and effective factors in creating the desired erosion phenomena in the study area.