Experimental study of wave-driven sediment suspension in flexible vegetation canopies with rippled beds
Year: 2026
Type: article
Abstract: Laboratory experiments have been used to investigate the impact of flexible vegetation on sediment suspension over rippled sandy beds. Flexible vegetation mimics were examined across a range of wave conditions and stem densities, with rigid vegetation cases included for comparison. Measurements of velocity and suspended sediment concentration were used to compare near-bed hydrodynamics, bedform response, and sediment resuspension within the vegetation canopies. The results show that stem flexibility does not modify the dominant mechanisms governing near-bed sediment suspension when ripples are present. Flexible vegetation did not significantly modify ripple crest height or wavelength relative to bare sediment beds (p > 0.05), whereas rigid vegetation disrupted ripple geometry in the majority of cases tested (p < 0.05). Flexible canopies produced modest, statistically non-significant reductions in near-bed velocity of 0–5% relative to bare-bed conditions, confined to the lower 25% of the stem height, compared to reductions of 14–23% under rigid canopies (p < 0.001), which was observed over the entire stem length. Near-bed TKE within flexible canopies was statistically indistinguishable from bare-bed values across all conditions tested (p > 0.74), consistent with suppression of stem-generated vortex shedding due to stem reconfiguration and the preservation of ripple-induced turbulence as the dominant near-bed TKE source. Near-bed suspended sediment concentration collapsed onto a single power-law relationship with near-bed velocity across all vegetation types, densities, and wave conditions (R² = 0.97), with good agreement obtained using bare-bed ripple formulations applied with measured near-bed velocities. The results indicate that, for wave propagation over vegetated rippled beds, sediment resuspension is governed primarily by bedform-scale processes rather than by vegetation-induced TKE. The findings contrast with flat-bed and dense-canopy studies and highlight the importance of explicitly accounting for bedforms when modelling sediment transport in vegetated coastal environments.
Source: Applied Ocean Research
Authors: K. Ions, X. Wang, N. Mori, D.E. Reeve, H. Karunarathna
Language: English
Subfield: Ecology
Field: Environmental Science
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $2,950
OpenAlex ID: W7164878486