Engineering with Nature to Reduce Wave Energy in Wetlands

Abstract

A body of literature quantifying wave attenuation through vegetation has developed within the last few decades and serves as the foundation for growing interest in wetlands for engineering with nature applications. Wave dissipation is shown to be highly variable, influenced by hydrodynamics, plant structure, and the interaction between the two. The current method of predicting wave dissipation often makes use of an empirical drag coefficient, which is given as a function of nondimensional flow parameter. These empirical equations are shown to have limitations, particularly in the transition from the submerged to emergent regime, and are highly variable in nature and in magnitude. Vegetation is shown to preferentially dissipate energy at frequencies higher than the spectral peak for single-and double-peaked wave spectra. Idealized simulations of Jamaica Bay with STeady-state spectral WAVE (STWAVE) demonstrate the potential for vegetation to provide shoreline protection by reducing wave height under severe wind and water level conditions.