Abstract
Soil in the Kuchibuto River catchment was contaminated by Cs-137 which was released by the Fukushima Daiichi Nuclear Power Plant (FDNPP) in 2011. The contaminated soil particles will transport and redistribute during flood storms. In this study, we simulated soil erosion and transport by a multi-class soil erosion and transport model. Flood storms in 2011 were used for calibrating the model. Simulated suspended solid flux both in the calibration and validation period show a good agreement with the observed data at the monitoring sites. Our simulation results also show, from Mar. 11, 2011, when the FDNPP exploded, to Jan. 1, 2014, an estimated 6211 t of clay (<3μm), 36210 t of silt (3-63μm) and 8880 t of sand (>63μm) were eroded and transport to the Abukuma River. In the study period, soil erosion mainly occurred in the middle portion of the catchment.
