Author(s): Honghai Li

Linked Author(s): Honghai Li

Keywords: Numerical modeling; Waves; Hydrodynamics; Structure design; Wetland restoration;

Abstract: This study was performed in support of the design analysis for the lateral expansion of Poplar Island, a restored wetland, Maryland. The expansion includes a tall island and an embayment. A series of dike islands at the opening of the embayment would render consideration of minimizing sedimentation and reducing wave energy inside the embayment. Four designs of dike islands were made as a way to protect potential habitat and to reduce wave action within the embayment. Corresponding to the designs, historical storms, representing a range of recurring events at 5-, 25-, 50-, and 100-year return periods, were selected based on an earlier study (Melby et al., 2005). Numerical models were applied to evaluate different dike island designs by calculating waves, current, and water level changes. Results indicate that the expanded Poplar Island system is dominated by the combined effects of wind-induced circulation and wind-generated waves, and the astronomical tide plays a comparatively weak role. With and without dike islands, the changes in water level show only a slightly different pattern in the open water and the embayment. The addition of islands can reduce current speed mostly in the vicinity of the structures and affects local flow patterns by forming a secondary circulation in the embayment. Wave energy is greatly reduced in the embayment due to the inclusion of islands.

DOI: https://doi.org/10.3850/38WC092019-1345

Year: 2019