Design Optimization and Field Performance Evaluation of the Wave Suppression and Sediment Collection (WSSC) System: Computational Fluid Dynamics (CFD) Modeling, Surface Elevation Table (SET) Survey, and Marker Clay Stud

Coastal erosion is an issue of concern for Louisiana, in the United States, and for all other coastal communities in the world. Among many coastal protection and restoration technologies, shoreline protection structures focus on wave reductions to prevent waves from hitting the coastal landforms directly. A novel technology called the Wave Suppression and Sediment Collection (WSSC) system focuses on solving the limitations of conventional shoreline protection structures regarding mobility, constructability, and sustainability. The primary goals of this study are to optimize the WSSC units for wave reduction and sediment transport and to verify the performance of this technology in an actual field environment. Computational Fluid Dynamics (CFD) simulations were carried out to optimize the designs of the units in terms of pipe diameters and face slope. Results have indicated that increasing pipe diameters decreases wave reduction and increases sediment transport ability of the units. Further, it was found that increasing the face slope decreases the wave reduction ability; however, no effect was found on the sediment transport efficiency. Parametric optimization suggested that a porosity (open-to-total area ratio) of 30% should yield satisfactory wave reduction and balanced sediment transport by the units. For better output from the units, the designs should be modified according to site-specific requirements. Field site investigations involved Surface Elevation Table (SET) surveying and marker clay experiments. SET surveys showed significant sediment accumulation over eleven months behind the units. Also, no significant change was observed at the control site over three months, which proves the effectiveness of the technology in stopping erosion and facilitating land building. Marker clay experiments validated the SET measurements and proved that there was a significant amount of sediment deposition over the white Feldspar clay layer over six months. This strengthens the conclusion that the WSSC units can be used successfully in a Louisiana marsh environment to battle coastal erosion and land loss.