Quantification of the sediment budget of a river basin, based on reconstruction of the post-fallout redistribution of Chernobyl particle-bound $^{137}$Cs

Vladimir Belyaev (1) , Eugenia Shamshurina (1) , Maxim Markelov (1) , Valentin Golosov (1, 2) , Nadezda Ivanova (1) , Valeriy Bondarev (1) , Tatiana Paramonova (1) , O. Evrard (3, 4) , Catherine Ottle (3, 5) , Irène Lefèvre (3, 4) , Philippe Bonté (3, 4)

1 MSU - Lomonosov Moscow State University
2 KFU - Kazan Federal University
3 LSCE - Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette]
4 GEDI - Géochimie Des Impacts
5 MOSAIC - Modélisation des Surfaces et Interfaces Continentales

Quantitative assessment of the sediment budget of a fluvial system is a key approach to understanding its geomorphic behaviour and an essential tool for investigating the redistribution of particle-bound contaminants along the sediment cascade. Here, we present a study involving the application of several independent approaches for quantifying the post-fallout (1986-2009) redistribution of Chernobyl particle-bound $^{137}$Cs and the basin-scale sediment budget for the River Plava basin situated in the northern part of the Srednerusskaya Upland (Central European Russia). The techniques employed include $^{137}$Cs-based sediment tracing, two soil erosion models and the analysis of soil profile morphology. The results show that most of the sediment originating from human-accelerated soil erosion on cultivated slopes is redeposited on the uncultivated lower parts of the slopes or in the bottoms of infilled gullies, hollows and 1-3rd order valleys. The River Plava valley itself represents a system dominated by efficient transport, with very limited floodplain sediment storage. The $^{137}$Cs-contaminated sediment export from the River Plava basin outlet exerts a significant impact on the River Upa. Its floodplain sediment contamination by $^{137}$Cs downstream of the River Plava mouth increases by almost an order of magnitude.

Keywords: sediment budget; $^{137}$Cs; sediment sources and sinks; fluvial system; human-accelerated soil erosion; Central European Russia

Domains: Environmental Sciences; Global Changes; Continental interfaces, environment; Geomorphology; Hydrology; Soil study

Vladimir Belyaev, Eugenia Shamshurina, Maxim Markelov, Valentin Golosov, Nadezda Ivanova, et al.. Quantification of the sediment budget of a river basin, based on reconstruction of the post-fallout redistribution of Chernobyl particle-bound $^{137}$Cs. Erosion and Sediment Yields in the Changing Environment (Proceedings of a symposium held at the Institute of Mountain Hazards and Environment, CAS-Chengdu, China, 11–15 October 2012), IAHS Publ. 356, 2012. ⟨cea-02615665⟩