Estimating of gully erosion based on REGEM model equations and modification of it’s for Ardebil province

Document Type : Original Article

Author

Department of soil science and engineering, faculty of agriculture and natural resources, University of Mohaghegh Ardabili

Abstract

Small gully due to high density per unit area is one of the most important causes of soil and water losses in watersheds that have gully erosion. In this research, with the selection of 81 small gullies in three watersheds from Ordadagh, Mulla Ahmad and Sarcham in Ardebil province, the size of gullies was determined with a one-year interval and the change in length, average width, depth and volume of them were recorded. Also, gullies size was estimated using the REGEM model with a one-year interval and the correlation between observed and estimated values was investigated. In order to modify and optimize the model for the studied areas, the model was corrected using regression models and again evaluated for estimating the gullies size and its variations over one year. To correct the model, the regressive shear stress parameters and soil erosion parameters of the REGEM model were used to estimate the dimensions of the gully including length, average width and moderate depth. The results show that the REGEM model only in Sarcham area had the useful efficiency in estimating gully erosion and its estimation correlation coefficient with measured gullies volume changes was 0.66. While estimating the size of the gullies with the modified model, in all three regions, showed a significant correlation with the measured values. The correlation between the measured and estimated values by modified model for gullies volume change was determined to be 0.76, 0.67, and 0.78, for Ordadagh, Mulla Ahmad and Sarcham respectively. Therefore, in order to apply the model in other regions, it is necessary to correct the model according the conditions of the region.

Keywords


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