Author(s): Niklas Henning; Ingo Schnauder; Stefan Haun; Silke Wieprecht

Linked Author(s): Silke Wieprecht, Stefan Haun, Ingo Schnauder, Niklas Henning

Keywords: Morphologically active river corridor braiding rivers flume experiments spatio-temporal analyses morphodynamics

Abstract: River braiding relies on active morphodynamic processes and is therefore severely threatened by the effects of river regulations. When maintaining or restoring active braiding, lateral confinement and sediment supply are usually the main control parameters, while the sediment characteristics, discharge, and valley slope are given. In flume experiments at the University of Stuttgart (IWS), sediment supply was varied stepwise to assess its effect on morphology, while keeping all other variables, including discharge, constant. In the first step, the adaptation times required to reach a global morphological equilibrium after changes in the supply rate were determined based on continuous measurements of sediment transport rates and periodic scans of the wetted and dry surface elevation. In a second step, the morphologically active river corridor (MAC) was calculated from DEMs of difference (DoDs) and analyzed statistically. The median of the MAC decreased almost linearly with decreasing sediment supply rates. In contrast, the variation or amplitude in MAC was relatively constant for the tested higher sediment supply rates, but decreased significantly in the lowest tested supply rate. The findings indicate that MAC may be a robust parameter to validate and differentiate the spatio-temporal extent of morphological activity in dynamic river systems.

DOI:

Year: 2025