Bilan d'érosion d'un cours d'eau Alpin: l'Isère à Grenoble (France)

Berlin

2008

S. 85-103

4 Abb., 6 Tab., 42 Lit. Ang.

Artikel aus einer ZeitschriftUnselbständiges Werk

200146101

Erosion data of a major alpine river: the Isère River at Grenoble (France): - The Isère River is one of the major suppliers of suspended matter to the Rhône River. In addition, the large area covered by the Isère River Basin makes it a particularly valuable source of information about current sedimentary dynamics in the Northern Alps. Instruments for studying the flow of total dissolved matter (TDM) and suspended matter (SM) have been set up step by step since 1994. The results presented here are the first to be based on the systematic measurement of a major Alpine watercourse. Decade-long data of this type are scarce for the Alpine area. The present measurements have enabled a sedimentary assessment of the Isère Basin to be made; total erosion was estimated at 3.73 Mt yr−1 and the mean specific erosion rate at 652 t km−2 yr−1. Mean fluvial erosion at 2.0 Mt yr−1 is slightly greater than that caused by chemical processes, whose mean value is estimated at 1.73 Mt yr−1. Rates of erosion vary widely from year to year, however, especially regarding suspended matter. The annual amount of SM thus greatly exceeds TDM in years when the flow is very high. The amount of dissolved matter exported nevertheless remains considerable and is a reliable indicator of the importance of dissolution processes within the basin.