Suspended sediment dynamics in a large drainage basin: the River Rhine

✍ Scribed by Nathalie E. M. Asselman

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 293 KB
• Volume: 13
• Category: Article
• ISSN: 0885-6087
• DOI: 10.1002/(sici)1099-1085(199907)13:10<1437::aid-hyp821>3.0.co;2-j

✦ Synopsis

The behaviour of suspended sediment in rivers is often a function of energy conditions, i.e. sediment is stored at low ¯ow and transported under high discharge conditions. The timing of maximum sediment transport can, however, also be related to mixing and routing of water and sediment from dierent sources. In this study suspended sediment transport was studied in the River Rhine between Kaub and the German±Dutch border. As concentrations decrease over a runo season and as the relationship between water discharge and suspended sediment concentrations during most ¯oods is characterized by clockwise hysteresis, it is concluded that sediment depletion occurs during a hydrological year and during individual ¯oods. However, analyses of the sediment contribution from the River Mosel indicate that clockwise hysteresis may result from sediment depletion as well as from early sediment supply from a tributary. Thus, although the suspended sediment behaviour in the downstream part of the River Rhine is partly a transport phenomenon related to energy conditions, mixing and routing of water from dierent sources also plays an important role.

Suspended sediment transport during ¯oods was modelled using a `supply-based' model. Addition of a sediment supply term to the sediment rating curve leads to a model that produces better estimates of instantaneous suspended sediment concentrations during high discharge events. A major constriction of the model is that it cannot be used to predict suspended sediment concentrations as long as the amount of sediment in storage and the timing of sediment supply are unknown.