Quantitative Evaluation of Coastal Forests on Natural Disaster Mitigation - Considering the Complexity of Vegetation Structures

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K14838
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 22040:Hydroengineering-related
• Research Institution: Kyoto University
• Principal Investigator: Chang Che-Wei 京都大学, 防災研究所, 特定助教 (20866826)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: 海岸林 / 波浪減衰 / 沿岸災害 / 気候変動適応策 / マングローブ / Eco-DRR / 水理模型実験

Outline of Final Research Achievements

The study discovered correlations between morphological parameters of mangroves in field surveys, based on which a new parameterization was proposed. Using 3D-printed scale models that replicated the exact root structure of mangroves, we studied wave-mangrove interactions and established the empirical formulas for force coefficients that represent mangrove resistance. By inspecting fluid velocity and turbulence surrounding mangroves, we identified the blockage effects and the enhanced turbulent kinetic energy induced by mangrove roots, which highlighted the importance of mangrove roots to hydrodynamics. With the empirical formulas of force coefficients from laboratory experiments, we parameterized mangrove-induced resistance in a Boussinesq-type model to simulate water waves through mangroves. The model results showed that accounting for both drag ad inertia effects improves the model simulation of experimental measurements without relying on calibration.

Free Research Field

海岸工学

Academic Significance and Societal Importance of the Research Achievements

現地調査での測定は豊富なデータベースを構成し、他の研究者が数値シミュレーションでマングローブをパラメータ化するのに利用できる。実験室実験により、波とマングローブの相互作用や波浪減衰に対するマングローブの効果について、根の構造を含めた詳細な情報が明らかになったことは、環境保全や沿岸保護にとって非常に重要な発見となる。開発したマングローブ効果を組み込んだ数値モデルは、将来のリスク評価に利用することができる。