| Résumé | Understanding growth patterns, survival, and seasonal variations in plant characteristics is essential for newly established vegetated slopes to ensure their long-term effectiveness in dissipating wave energy, particularly in cold climate regions with extended winters and short summers. This study investigates the growth patterns, seasonal and interannual variations in plant morphological properties, and their corresponding effect on wave energy attenuation under controlled conditions, to evaluate the wave dissipation characteristics of newly established vegetated slope over multiple seasons, based on experimental data from large-scale physical modeling experiments. These experiments capture the one-year growth cycle of a newly constructed marsh with live saltmarsh vegetation native to eastern Canada and the USA.
The findings reveal that even a newly established marsh with young, relatively sparse plants can contribute to wave energy dissipation. A clear seasonal variation in plant morphological properties was observed, resulting in a significant increase in vegetation-induced wave dissipation after one year of growth. Different species exhibited different responses against wave forces leading to different wave dissipation characteristics depending on their plant traits. However, under conditions of considerable depth-induced wave breaking, the effectiveness of vegetation in dissipating wave energy was considerably reduced. Overall, our data with young saltmarsh plants showed a maximum of about 60% contribution by vegetation to total wave energy dissipation under minimal depth-induced breaking conditions, and a maximum of about 25% contribution to total wave energy dissipation under significant depth-induced breaking conditions, indicating a considerable reduction in percentage contribution to total wave energy dissipation by vegetation with wave breaking. |
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