Hindcasting of Radioactive Contamination of the Kiev Reservoir Using Models of Various Detalisation

Data of 137Cs measurements in the Kiev Reservoir after the Chernobyl accident were used for comparison of simulation results of two multi-chamber models of radionuclide migration in reservoirs. One of the models uses two-chamber approach to describe exchange processes between the water column and bottom sediments and the other uses three-chamber approach. It is revealed that the adequate results for short time periods (8–10 days) typical for the estimates during the “acute” period after an accident were provided by a three-chamber model only. On medium timescales (6 months), both models showed adequate results, although the accuracy of the three-chamber model was also better. However, the two-chamber model is also a reasonable choice, because input data required for the three-chamber model can be unavailable or not reliable enough. The impact of the spatial inhomogeneity of the values of some migration parameters on simulation accuracy was also analyzed.