Influence of inclination and permeability of solitary woody riparian plants on local hydraulic and sedimentary processes
| Autor: | Julian J. Zemke, Stéphane Rodrigues, Jürgen Herget, Thomas Euler |
|---|---|
| Rok vydání: | 2013 |
| Předmět: |
Hydrology
geography geography.geographical_feature_category Biogeomorphology 010504 meteorology & atmospheric sciences Sediment Fluvial 010502 geochemistry & geophysics 01 natural sciences Flume Permeability (earth sciences) Ridge Sedimentary rock Geomorphology Geology 0105 earth and related environmental sciences Water Science and Technology Riparian zone |
| Zdroj: | Hydrological Processes. 28:1358-1371 |
| ISSN: | 0885-6087 |
| DOI: | 10.1002/hyp.9655 |
| Popis: | The role of solitary woody riparian plants with respect to local erosion and deposition of sediments is investigated. A focus is laid on the characteristics ‘inclination’ and ‘permeability’ of the plant's projected frontal area. Therefore, two experimental studies using cylindrical obstacles were carried out in a laboratory flume, one aiming at inclination, the other at permeability. The first series revealed that the total amount of mobilized sediment around the cylinder on average decreased by 8–10% per 5° increasing inclination in streamwise direction. Locations of maximum scour depth simultaneously shifted downstream. A horseshoe vortex system, causing the frontal and lateral scouring, ceased to exist below inclinations of 25–30°. The second series revealed that with increasing permeability, frontal scour incision is delayed, and the eroded sediment volume is significantly reduced. With permeable obstacles, two system states were observed: first, frontal scouring with leeside deposition at higher flow velocities and, second, moderate leeside scouring at lower flow velocities. For up-scaling and comparison, a field study focussing on fluvial obstacle marks at poplars and willows in secondary channels of the River Loire was additionally conducted. A modified analytical model enabled us to quantify the amount of deposited sediments leeside of the plants. Leeside sediment ridges are significantly stabilized and have a higher preservation potential when covered by pioneer vegetation. Under such conditions, they may indeed induce the development of stable islands. Eventually, ‘sediment ridge width’ turned out to be a suitable indicator for leeside deposited sediment volume, irrespective of spatial scale. Copyright © 2012 John Wiley & Sons, Ltd. |
| Databáze: | OpenAIRE |
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