Buffering of suspended sediment transport in lowland river during low water stages: quantification in river Seine using environmental radionuclides
Year: 2000
Type: article
Abstract: This study was undertaken to test the application of environmental radioactive tracers for estimating sediment mass and sediment residence time in rivers. A continuous sampling of the Seine river suspended matter (SM) using sediment traps was made during two months, between Paris and the estuary, along a 120 km long river section. The hydrological regime corresponded to the low water stage, where the SM transport is reduced. The measured tracers in the SM include short - lived natural (7 Be, 234 Thxs) and artificial (131I) radionuclides, as well as the longer-lived natural 210 Pbxs and its descendant the 210 Po. 137Cs was used to check grain-size effects. A simple steady state model allowed us to estimate the total sediment mass, i.e. the SM, plus the resuspendable matter (RM), and the sediment residence time. Despite their different half-lives (8 to 53 days) and their different geochemical properties, consistent results were obtained with 131 I, 7 Be and 234 Thxs. The best estimate of the sediment mass present in the river is (24-41)·103 tons; it is essentially composed of the RM which is 10-17 times more abundant than the SM. In these hydrological conditions, the sediment residence time is quite long (1.6-2.8 months).
Authors: Ph. Bonté, J.M. Mouchel, A.J. Thomas, M.F. Le Cloarec, Jean-Pascal Dumoulin, S. Sogon, L. Tessier
Language: English
Subfield: Soil Science
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W1531666981