Integrated watershed modeling for simulation of spatiotemporal redistribution of post-fallout radionuclides: Application in radiocesium fate and transport processes derived from the Fukushima accidents. (October 2015)

• Record Type: Journal Article
• Authors: Mori, Koji; Tada, Kazuhiro; Tawara, Yasuhiro; Ohno, Koichi; Asami, Mari; Kosaka, Koji; Tosaka, Hiroyuki
• Is Part Of: Environmental modelling & software. Volume 72(2015:Oct.)
• Page Start: 126
• Page End: 146
• Publication Date: 2015-10
• Subjects: Watershed modeling -- Sediment transport -- Fallout radionuclides -- Fukushima Dai-ichi -- GETFLOWS; IAEA International Atomic Energy Agency -- JAEA Japan Atomic Energy Agency -- LULC Land use and land cover -- MEXT Ministry of Education, Culture, Sports, Science and Technology, Japan -- NPP Nuclear power plant -- SDI Soil detachability index -- U.S. DOI U.S. Department of Interior Bureau of Reclamation; Environmental monitoring -- Computer programs -- Periodicals; Ecology -- Computer simulation -- Periodicals; Digital computer simulation -- Periodicals; Computer software -- Periodicals; Environmental Monitoring -- Periodicals; Computer Simulation -- Periodicals; Environnement -- Surveillance -- Logiciels -- Périodiques; Écologie -- Simulation, Méthodes de -- Périodiques; Simulation par ordinateur -- Périodiques; Logiciels -- Périodiques; Computer software; Digital computer simulation; Ecology -- Computer simulation; Environmental monitoring -- Computer programs; Periodicals; Electronic journals; 363.70015118
• DOI: 10.1016/j.envsoft.2015.06.012
• Languages: English
• ISSNs: 1364-8152

Abstract

Abstract: Simulation of the watershed-scale fate and transport of radionuclides is required in order to predict the consequences of contamination redistribution. Integrated watershed modeling is a suitable technique for this task, but it requires fully coupled investigation of radionuclide behavior in surface water, suspended sediment and subsurface aquifers. We developed a novel simulator for computing the spatiotemporal redistribution of fallout radionuclides in watersheds. The simulator was applied to an actual reservoir basin contaminated by fallout radionuclides from the Fukushima Dai-Ichi Nuclear Power Plant accident in 2011. As a result, the simulated 137 Cs concentration in bottom sediment showed a reasonably close match with the measurement data. The distribution coefficient of 137 Cs consistent with the latest measurement data was identified as being at least 400, 000 L/kg, and it was estimated that more than 90% of the total 137 Cs distributed in the fallout remains in the catchment area. Highlights: We propose a new simulator to assess environmental impact of fallout radionuclide. Simulation treats surface and subsurface fully coupled hydrological processes. Spatiotemporal variation of the deposited 137 Cs can be successfully reproduced. Deposited 137 Cs is predominantly transported with the suspended sediment. Results indicate that most of the deposited 137 Cs remains within the catchment.