Efficiency assessment of G2 and IntErO models for annual soil erosion and sediment yield prediction in Kasilian representative watershed, Mazandaran province

Document Type : Research

Authors

1 Department of Watershed Management, Faculty of Natural Resources, Tarbiat Modares University

2 Department of Watershed Management Engineering, Faculty of Natural Resources, Tarbiat Modares University, Noor, Mazandaran, Iran

3 Department of Watershed Management, Faculty of Natural Resources, Razi University

10.22092/wmrj.2023.362025.1539

Abstract

Introduction and purpose: Soil erosion and sediment yield have become a threat to food security, and many researches have been conducted in order to manage and prevent it in many countries. Considering the need to know the rate of erosion and sediment yield, the current research was conducted using empirical models with the aim of estimating the rate of erosion and sediment yield of the Kasilian representative watershed and evaluating and comparing empirical models with observational data.
Materials and methods: The G2 and IntErO models were used to estimate soil erosion and sediment yield in the Kasilian representative watershed in Mazandaran province. Then, by using the observational data and the sediment gauge curve of the Valikben hydrometric station in the watershed outlet, the annual specific sediment yield was also calculated and the results of the models were evaluated.
Results and discussion: The results of the G2 and IntErO models showed the rate of soil erosion in this watershed to be 1.30 and 2.35 t ha-1 yr-1, respectively. Also, annual specific sediment yield with the G2 and IntErO models and observational data was obtained as 0.44, 0.84 and 0.16 t ha-1 yr-1, respectively. The results of G2 model showed that in this watershed, the vegetation retention factor has a greater effect on erosion than the rainfall erosivity factor, and most of the watershed is in a very low erosion class due to the type of vegetation cover. The IntErO model identified the watershed as elongated and steep and showed the maximum outflow in the return period of 20 years to be 141.3 m3 s-1 and the dominant erosion type is the surface erosion.
Conclusion: The investigated experimental models had similar results. Although, taking into account the changes in land use in the Kasilian representative watershed, the estimated values of annual erosion and sediment yield are acceptable and reasonable, the differences with the observational data was very high and apparently indicated the low efficiency of the models. However, it is necessary to mention that the inappropriateness of the sampling intervals of runoff and sediment in this watershed has been a very important reason for the low intensity of annual sediment yield based on observational data. In other words, the daily measurement intervals for this small watershed have caused the real data of sediment concentration to be collected at the same time as flood hours or peak discharges that have the most sediment transport. To solve this problem, it is suggested to do sampling in small watersheds at shorter time intervals (several times a day or even hourly) so that high concentrations of sediments are collected at the same time as high flows and are included in the calculation of sediment yield.

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Watershed Management Research Journal

Articles in Press, Accepted Manuscript
Available Online from 21 September 2023

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History

  • Receive Date: 10 May 2023
  • Revise Date: 12 June 2023
  • Accept Date: 21 September 2023

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