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Modeling the Attenuation of Surge, Current, and Wave by Vegetation in Coastal Waters

Abstract

There are many ongoing efforts to quantify the effectiveness of vegetation in coastal protection, however, the vegetation-related attenuation processes have not been well understood yet, and the results from experiment, field, and model studies are highly variable. In this study, a 3D vegetation-resolving model CH3D-SSMS was applied to simulate the interaction of realistic coastal wetlands with surges, waves, and currents during hurricanes.

First, a comprehensive study of storm tides, waves, and currents along New Jersey, New York, and Connecticut coasts during Sandy was conducted using the CH3D-SSMS modeling system. The model was thoroughly validated using an extensive set of data obtained from various sources. Nonlinear surge-tide-wave interaction was found around New York City, where two tidal systems (with 3.5 hours phase lag) join.

Then, the role of wetlands in protecting the coastal communities was examined in an estuarine wetland (Piermont Marsh) with the Village of Piermont to the North during Sandy. The attenuation effect of native Typha, a candidate for restoration, was quantified and compared with that of the invasive Phragmites. Additionally, numerical experiments with regards to various future storm and sea level rise (SLR) scenarios 15 were conducted. The results show that the marsh can provide significant flood protection capacity under southeasterly (150 deg) wind. Based on the marsh configurations predicted for 2100, it appears that under medium SLR, Piermont Marsh will be able to survive and effectively buffer the village from waves and flood debris.

Last, the 3D vegetation-resolving model was used to examine the role of mangroves and salt marshes along the shore of Biscayne Bay in buffering surge, wave, and inundation in Southeast Florida during Hurricane Andrew. The simulated water levels, and magnitude and extent of maximum inundation agreed well with the observed data, whereas the removal of vegetation from the model led to massive flooding with increased total inundation volume and total inundation area in the highly populated low lying area behind Biscayne Bay. Additional simulations show that the surge-wave inundation buffering capacity of the mangrove forest depends on the vertical structure of the wetted leaf area index and frontal leaf area index.

About this Resource

This dissertation was written by Ruizhi Zou as part of his PhD program at the University of Florida. Ruizhi was supervised by Peter Sheng and some of his research was conducted in collaboration with Hudson River Reserve as part of a Science Collaborative project.

Citation

Zou, Ruizhi. 2018. Modeling the Attenuation of Surge, Current, and Wave by Vegetation in Coastal Waters. Dissertation submitted to the University of Flordia. Available at: https://ufdc.ufl.edu/UFE0052091