Abstract
Marsh terracing is a coastal restoration technique that can dissipate wind driven waves, reduce fetch, and potentially reduce erosion from adjacent marsh platform in the northern Gulf of Mexico. This technique consists of constructing segmented berms of bare soil from sediment excavated within shallow coastal ponds. Over 980 linear km of marsh terraces have been built in Texas and Louisiana in the last 30 years; however very little research has focused on optimization of terrace design and implementation. The objective of this study was to understand wave regimes in marsh terrace fields under a range of wind conditions to identify an optimal terrace design for reducing wave energy. The Simulating WAves Nearshore (SWAN) model was used in this study to compute wind waves at two terrace fields in coastal Louisiana. Simulations were based on real terrace field conditions with and without terraces. Model validation was performed under stationary conditions (constant wind parameters) using wind data from NOAA stations and wave parameters collected by wave instruments during 5 months at each study field. Results from this study will help us to understand wave dynamics in marsh terrace environments with different terrace designs and without terraces. At the end of this project we expect to identify the most effective terrace design for reducing wave energy, which is related to marsh erosion, leading to an optimal implementation of this restoration technique in the northern Gulf of Mexico.
