Evaluation of empirical erosion and sedimentation models in the semi-humid and alpine regions: case of Mazdaran watershed, North of Iran

Abstract Soil erosion is a global problem that increasingly contributes to soil degradation. Although erosion analysis requires the availability of erosion and sedimentation data, the lack of sediment monitoring stations and the resulting limitations in collecting sediment measurements have necessitated the use of experimental models in many areas. The aim of the present study was to compare FSM and MPSIAC models for estimating erosion in the Mazdaran Basin (Firoozkuh, Iran). For this purpose, the required maps were prepared for both models and the erosion rate was estimated using the two models to compare their efficiency using the corresponding relative error (RE), root mean square error (RMSE) and coefficient of determination (R2) values. The results showed that, considering erodibility based on the FSM model, the studied catchment consisted of regions with a high and very high erosion rate, while the MPSIAC model identified regions with low, medium and high erosion rates. With an R2 value of 0.73, an RE value of 0.88% and an RMSE value of 3.23, the MPSIAC model provided more accurate estimates of the erosion rate in the studied area. Using the MPSIAC model, soil erosion was estimated at 18142.45 tons per year (i.e. 6.22 tons/ha per year), which is three times higher than the naturally occurring soil erosion rate. The high erosion rate in this area underlines the importance of erosion control measures in the region.