Observational Study on Wave Attenuation Effect of Salt Marsh during Typhoon-a Case Study of Mangzhou Wetland in Zhu-jiang River Estuary
Coastal salt marshes can reduce the impact of storm surges and typhoon waves,thereby enhancing the ability of the coast to resist natural disasters such as typhoons and reducing economic losses.Therefore,they play an important role in protecting the coast and preventing and mitigating disasters.In this study,the wave attenuation function of Mangzhou wetland in Zhujiang River Estuary was analyzed by using the field measured wave data during the typhoon'Parrot'activity in June 2020,so as to quantitatively study the wave attenuation effect of salt marsh vegetation.The results showed that during the period of typhoon'Parrot',the maximum increase of storm surge in Mangzhou wetland was 0.43 m,and the floodplain time was longer than 6 h.The wave height attenuation rates of the measured waves passing through the salt marsh vegetation zones with widths of 100 m and 230 m was 90.5％and 97.2％,respectively,and the vegetation disaster re-duction ability is excellent.According to the estimation results of the empirical formula of wave height atten-uation rate,the wave height attenuation rates of waves passing through vegetation widths of 100 m and 200 m was 94.0％and 97.0％respectively,which are basically consistent with the measured results.Due to the short influence time and weak intensity of typhoon'Parrot',the water level measured in the field was below 1 m,while the average plant height of salt marsh vegetation was about 2 m,and the crown of vegetation was not submerged.Therefore,the vegetation could be regarded as a permeable embankment,and the friction damping of its stems and leaves led to the attenuation of wave energy.In addition,the effective wave height measured in the field was below 0.10 m,and there was no large amount of vegetation lodging or even stem fracture.Therefore,the salt marsh vegetation had fully played its role in wave attenuation.In summary,al-though the area of Mangzhou salt marsh is only 3.39 km2,its wave attenuation effect is still very significant.
万方数据
维普
