Green infrastructure for the reduction of coastal disasters: a review of the protective role of coastal forests against tsunami, storm surge, and wind waves

Abstract

ABSTRACT Green infrastructure, utilizing coastal ecosystems, provides a nature-based solution to counteract coastal hazards and rising sea level. Coastal forests, a major type of green infrastructure, are recognized as natural barriers against ocean waves. They can attenuate waves, mitigate erosion, and stabilize shorelines. With growing interests in coastal forests and their function of adapting to future risks, many researchers studied vegetation effects in coastal protection. Yet our limited expertise in quantifying vegetation-induced resistance limits the practical applications. This paper aims to review and categorize the studies related to wave attenuation and mitigation of sediment erosion by coastal forests and identify the potential directions in future works. We first reviewed field observations of extreme tsunami and weather events which showed the effectiveness of coastal forests in reducing wave energy. Next, we covered the studies on wave–vegetation interaction, including mathematical/numerical models and laboratory tests. We categorized the developed models based on different governing equations and introduced how vegetation effects were incorporated. We also discussed the experiments and vegetation models used in laboratory tests. Besides, we highlighted recent studies on the mitigation of coastal erosion. Finally, we recommend the potential directions to quantify the effects of coastal forests on wave attenuation and sedimentation.