Journal cover Journal topic
Hydrology and Earth System Sciences An interactive open-access journal of the European Geosciences Union
Hydrol. Earth Syst. Sci., 20, 2467-2482, 2016
https://doi.org/10.5194/hess-20-2467-2016
© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
23 Jun 2016
Rainfall erosivity in catchments contaminated with fallout from the Fukushima Daiichi nuclear power plant accident
J. Patrick Laceby1, Caroline Chartin2, Olivier Evrard1, Yuichi Onda3, Laurent Garcia-Sanchez4, and Olivier Cerdan5 1Laboratoire des Sciences du Climat et de l'Environnement (LSCE), Unité Mixte de Recherche 8212 (CEA-CNRS-UVSQ/IPSL), Université Paris-Saclay, Gif-sur-Yvette, France
2Georges Lemaître Centre for Earth and Climate Research, Earth and Life Institute, Université catholique de Louvain, Louvain, Belgium
3Graduate School of Life and Environmental Sciences, Center for Research in Isotopes and Environmental Dynamics (CRIED), University of Tsukuba, Tsukuba, Japan
4Laboratoire de Biogéochimie, Biodisponibilité et Transferts de Radionucléides, IRSN/PRP-ENV/SERIS/L2BT, Cadarache, France
5Bureau de Recherches Géologiques et Minières, Orléans, France
Abstract. The Fukushima Daiichi nuclear power plant (FDNPP) accident in March 2011 resulted in the fallout of significant quantities of radiocesium over the Fukushima region. After reaching the soil surface, radiocesium is quickly bound to fine soil particles. Thereafter, rainfall and snowmelt run-off events transfer particle-bound radiocesium downstream. Characterizing the precipitation regime of the fallout-impacted region is thus important for understanding post-deposition radiocesium dynamics. Accordingly, 10 min (1995–2015) and daily precipitation data (1977–2015) from 42 meteorological stations within a 100 km radius of the FDNPP were analyzed. Monthly rainfall erosivity maps were developed to depict the spatial heterogeneity of rainfall erosivity for catchments entirely contained within this radius. The mean average precipitation in the region surrounding the FDNPP is 1420 mm yr−1 (SD 235) with a mean rainfall erosivity of 3696 MJ mm ha−1 h−1 yr−1 (SD 1327). Tropical cyclones contribute 22 % of the precipitation (422 mm yr−1) and 40 % of the rainfall erosivity (1462 MJ mm ha−1 h−1 yr−1 (SD 637)). The majority of precipitation (60 %) and rainfall erosivity (82 %) occurs between June and October. At a regional scale, rainfall erosivity increases from the north to the south during July and August, the most erosive months. For the remainder of the year, this gradient occurs mostly from northwest to southeast. Relief features strongly influence the spatial distribution of rainfall erosivity at a smaller scale, with the coastal plains and coastal mountain range having greater rainfall erosivity than the inland Abukuma River valley. Understanding these patterns, particularly their spatial and temporal (both inter- and intraannual) variation, is important for contextualizing soil and particle-bound radiocesium transfers in the Fukushima region. Moreover, understanding the impact of tropical cyclones will be important for managing sediment and sediment-bound contaminant transfers in regions impacted by these events.

Citation: Laceby, J. P., Chartin, C., Evrard, O., Onda, Y., Garcia-Sanchez, L., and Cerdan, O.: Rainfall erosivity in catchments contaminated with fallout from the Fukushima Daiichi nuclear power plant accident, Hydrol. Earth Syst. Sci., 20, 2467-2482, https://doi.org/10.5194/hess-20-2467-2016, 2016.
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Short summary
Characterizing rainfall erosivity in the Fukushima fallout-impacted region is important for predicting radiocesium behavior. The majority of rainfall (60 %) and rainfall erosivity (86 %) occurs between June and October. Tropical cyclones contribute 22 % of the precipitation though 44 % of the rainfall erosivity. Understanding the rainfall regime and the influence of tropical cyclones is important managing radiocesium transfers in contaminated catchments in the Fukushima prefecture.
Characterizing rainfall erosivity in the Fukushima fallout-impacted region is important for...
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