Assessment of radiocaesium washoff transport from a pilot catchment in the first period after nuclear contamination

¹ VUJE Tmava a.s., Okruzna 5, 91864 Tmava, Slovakia
² Utrecht Centre for Environment and Landscape Dynamics-UCEL, Faculty of Geographical Sciences, Utrecht University, P.O. Box 80115, 3508 TC Utrecht, The Netherlands
³ GeoModel Ltd., Milana Marecka 3, 84107 Bratislava, Slovakia

Abstract

As part of the EC-funded project SPARTACUS a GIS-embedded radionuclide redistribution model was developed based on the existing LISEM soil erosion model. It simulates lateral radiocaesium transport and exchange in the active topsoil layer and runoff water in catchment during a rainstorm event. The model was applied for the assessment of the relative extent of radiocaesium transport from the Mochovce catchment following an accidental nuclear contamination using selected rainfall intensity scenarios. In this case, a 15 mm rainfall event during 30 minutes with a maximum rainfall intensity of 75 mm/h during 8 minutes was selected to assess the effect of ploughing on ¹³⁷Cs transport. The model results demonstrate that particulate transport contributes considerably to the ¹³⁷Cs transport within and from the Mochovce catchment. The ¹³⁷Cs transport from unploughed soils appears to be a factor of 35 larger than the transport from ploughed soils. The implications of the model results for selecting appropriate mitigating measures to reduce ¹³⁷Cs following a nuclear accident are discussed.