Functionality Evaluation of the Wave Suppressor and Sediment Collection (WSSC) System: Wave Reduction, Sediment Collection, Mathematical Model, and Preliminary Field Evaluation

Erosion along shorelines in open water bodies and waterways is a major cause in conversion of wetlands and uplands to an open water environment. Conventional shoreline protective structures are expensive to construct in these environments, and they may impede environmental exchanges that are essential for connectivity and functionality. The Wave Suppression and Sediment Collection (WSSC) System (Wave Robber(TM)) could become an alternative Device in shoreline protection. The primary goals of this study are to evaluate its performance in both wave reductions and sediment collection in the lab, and to optimize the design and to compare the efficiency of the Device in different conditions. This study showed that the WSSC can collect and retain sediment while reducing about 84 to 90% wave height. A new mass balance model was developed to evaluate its performance in sediment collection. A variable &agr;, ranging from 0 to 1, represents the sediment collection efficiency of the Devices, was introduced into this model. The sediment data fitted the model reasonably well, yielding the correlation coefficients of about 0.87. Modeling results show that the sediment collection efficiency of WSSC for silt-clay soil was about 14%. The model used could become useful for not only evaluating this Device, but even using it to evaluate existing Devices. The sensitivity study showed that the wave height and the initial concentration were the most important factors effecting sediment collection. Water depth also plays an important role in that it reduces the sediment collection as the water depth increases. The preliminary field study showed some elevation changes behind the WSSC due to sediment accumulation.