Sediment supply control on morphodynamic processes in gravel?bed river widenings
نویسندگان
چکیده
Reach-scale widening of channelized rivers can locally reactivate morphodynamic processes and increase habitat heterogeneity. Following process-based restoration principles, construction efforts are often limited to bank protection removal local erosion initiation. Despite significant advances in our understanding fluvial processes, the influence sediment supply on morphodynamics is still inadequately understood. Using mobile-bed laboratory experiments, we studied morphological development river widenings subalpine gravel-bed response different levels. The initial setup included a channel with longitudinal slope around 1% floodplain one side, which was 25 widths long three wide. After removing fixed bank, available for shifting. Seven experimental series sequences steady bed-forming discharge unsteady larger floods were conducted. Sediment supplied at rates 20%, 60%, 80%, 100% channel's transport capacity. experiments combined two-dimensional hydrodynamic numerical simulations closely track both resulting flow conditions. found be critical driver activity widenings, close capacity promoting active widening, relocation, lateral channel-floodplain connectivity. In contrast, low maintained stable, single-thread disconnected from its floodplain. Further, results indicate that an or structural measures triggering deflection previously sediment-starved reaches after transition period several years decades. Our highlight fundamental importance reach-scale restoration.
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ژورنال
عنوان ژورنال: Earth Surface Processes and Landforms
سال: 2022
ISSN: ['1096-9837', '0197-9337']
DOI: https://doi.org/10.1002/esp.5460