Investigation of the Relationship between Geomorphic Characteristics and Sediment Production in Nirchai Basin

Aims & Backgrounds: Today, soil erosion and sediment production are considered a danger to humans and their lives, so in areas where soil erosion is not controlled, soils gradually erode and lose their fertility. The aim of this study is to model the relationship between the amount of suspended sediment load and the geomorphic features of the Nirchai River Basin. Methodology: In this study, GIS was used to extract geomorphic features and its relationship with sedimentation. Stepwise multivariate regression analysis was used to determine the relationship between geomorphic characteristics and sedimentation of each sub-basin. The results of investigating the relationship between geomorphic characteristics and sediment in sub-basins showed that the amount of sediment produced had a positive correlation with the volume of flow and the form factor of the basin and was significant at the level of 5 percent. Also, in order to identify the factors affecting the amount of sediment in the basin among the existing variables, the principal component analysis method was used. Findings: The results show that among 25 variables affecting sediment production, four factors of area, basin coefficient, environment and discharge were 37/78, 25/47, 18/5 and 11/22 percent of variance of all variables of research. Conclusion: Therefore, it is concluded that in total, all the effective factors of the four final extracted factors were able to explain 92.9 percent of the variance of all research variables.