Particle size characteristics of suspended and bed sediments in the rhône river

Autor: Sergio Santiago, Claude Corvi, Jean Tarradellas, Gérard Larbaigt, Richard Lynn Thomas, Linda McCarthy, Jean-Luc Loizeau, Jean-Pierre Vernet, Daniel Rossel
Rok vydání: 1992
Předmět:
Zdroj: Hydrological Processes, Vol. 6 (1992) pp. 227-240
ISSN: 1099-1085
0885-6087
DOI: 10.1002/hyp.3360060210
Popis: Ten large volume water samples were taken from the Rhone River (Switzerland- France) in November 1989 for recovery of total suspended sediment by continuous flow centrifugation. The samples were freeze-dried and analysed for particle size, organic carbon, total nitrogen, and carbonate. For comparative purposes, four bed sediments collected in July 1989 are also described. The Rhone can be subdivided into three sections on the basis of the origins of the water. The first section is the Upper Rhone River draining into Lake Geneva. Waters are derived from glaciers, with low temperature and conductivity and high turbidity. Suspended sediment is coarse, has a bimodal distribution, and is low in both organic matter and carbonate. The second reach is from Lake Geneva to the confluence with the Saone at Lyon and has warmer water with higher conductivity and very low turbidity. Suspended sediment is higher in organic matter, with high carbonate originating from the lake. The final section is from Lyon to Aries, with warmer water and higher conductivity and turbidity due to modification by the Saone. Sediment is rich in organic matter, which may account for an observed decline in oxygen in the river waters downstream from Lyon. Carbonate in these sediments also decreases due to increased turbidity from the Saone. Suspended sediments other than from the Upper Rhone show a remarkable consistency in grain size, predominantly in the fine silts (mode 9-11 Jim). This consistency indicates a high degree of suitability for geochemical analysis. Bed sediments were bimodal throughout, with a dominant coarse population in two out of the four samples. Grain size statistical parameters could be easily explained by application of the theory of mixing of two major populations in the sand size (bed traction load) and the fine silt/clay size (suspended sediment load).
Databáze: OpenAIRE
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