Applicability of K for modelling dissolved 137Cs concentrations in Fukushima river water: Case study of the upstream Ota River

Watershed‐Geochemical Model to Simulate Dissolved and Particulate 137Cs Discharge From a Forested Catchment

“…For the results from Sakuma, Tsuji, et al (2018) without the coupled forest compartment model, 91% of the results are within a factor of two of the measurements. The corresponding result with the forest compartment model is 93%, that is, slightly higher in this study than the Sakuma, Tsuji, et al (2018) study. Furthermore, the Pearson correlation coefficient (r) is much better in this study (r = 0.62) than in the previous study (r = −0.33).…”

“…However, the Pearson correlation coefficient is positive for Case 3 with the forest compartment model; therefore, this model can better reproduce the dynamics of field observations. Furthermore, the root mean square error (RMSE) in Case 3 is slightly lower than Sakuma, Tsuji, et al (2018) (RMSE = 0.214 in Case 3, and 0.216 in Case 0).…”

“…We simulated water and suspended sediment discharge using the same initial and boundary conditions and input data as Sakuma, Tsuji, et al (2018). Therefore, simulation cases 0-3 all gave identical results for water and suspended sediment discharge (Figures S1-S3, and cf.…”

“…Tsuji et al ( 2016) and Sakuma, Tsuji, et al (2018) reported water discharge rates (m 3 s −1 ), suspended sediment fluxes (kg s −1 ), and particulate and dissolved 137 Cs concentrations (Bq L −1 ) during 2014-2015, including typhoon periods, at the catchment's outlet (Figure 1). We used these observed values as comparators for the simulation results of this study.…”

“…The distribution coefficients for the 0.001-and 0.01-mm sizes were set at 200-360 m 3 kg −1 . These were based on the partitioning between dissolved 137 Cs and bound 137 Cs in suspended solids measured from river water samples collected at the catchment outflow during 2014-2015 (361 ± 242 m 3 kg −1 , n = 33 under baseflow conditions, and 197 ± 77 m 3 kg −1 , n = 24 during three typhoons on 6 October 2014, 14 October 2014, and 16 July 2015) by Tsuji et al (2016) and Sakuma, Tsuji, et al (2018). The distribution coefficients for the 0.1-and 0.3-mm sizes were set to 50 m 3 kg −1 based on the study by Sakuma, Tsuji, et al (2018).…”