Field Verification of Erosion Models Based on Studies of Five Small Catchments on the Central Russian Upland

There is a shortage of work on the verification of erosion models in Russia, despite the obvious significance of this research. The soil matter eroded within the arable land, removed beyond its borders, and redeposited on the grassed part of arable catchments was quantitatively determined for five small catchments with an arable land area of 88–98% located in different parts of Central Russian Upland based on the results of field assessments of sediment loss and accumulation obtained using the soil truncation and radiocesium methods. The obtained results were used to verify the calculations of soil loss and accumulation for the same catchments, evaluated on the basis of rainstorm and snowmelt erosion soil losses calculated using the WaTEM/SEDEM models and a modified version of the State Hydrological Institute (SHI) model, respectively. A good agreement was found between the modeled and measured average long-term soil erosion rates. Deviations from the average estimates of this indicator in the studied catchments ranged from 3 to 22%, which is comparable to the accuracy of the estimates based on the field methods. The modeled proportion of sediment redeposition on arable land is close to average field estimate for all studied catchments but differs significantly for some individual catchments. Estimates of sediment redeposition on uncultivated slopes and in the bottoms of small dry valleys based on WaTEM/SEDEM should be considered as semiquantitative. The spatial location of areas with sediment accumulation within arable land is modeled using WaTEM/SEDEM with some errors and on the grassed sides and in the bottoms of dry valleys, schematically.