Bennco Engineering provided marine engineering and environmental consulting services for an emergency dune and boardwalk repair. A section of the boardwalk had collapsed due to inadequate embedment of the foundation piles resulting from storm erosion. The scope encompassed conducting structural assessments, designing and repairing dunes and boardwalks, and preparing and submitting FDEP Coastal Construction Control Line (CCCL) permit application packages.

A team of engineers performed an investigation of the existing boardwalk and dune along the shoreline. The scope included a visual assessment of the structural components to identify the cause of boardwalk collapse and deterioration including splits, rot, displacement, and corrosion.

The dune design was based on maximizing the volume of sand seaward of the project property landward of the Seasonal High Tide Line. The boardwalk was designed with helical piles due to limited access and potential vibration during pile installation due to the proximity of the adjacent historic structures. An erosion analysis was conducted to determine the minimum pile embedment so the boardwalk would be stable after storm events. Bennco Engineering performed construction administration services including monitoring of the helical pile installation to verify the boardwalk was built in accordance with the construction documents.

Bennco Engineering also prepared and processed an FDEP Coastal Construction Control Line (CCCL) permit application for the dune restoration project and boardwalk repair, including authorization for construction during sea turtle nesting season.

As required by the FDEP, we conducted mapping of existing dune vegetation, developed a proposed planting plan for vegetation, and prepared design parameters for the planting. The planting plans included the location of existing native dune vegetation to be preserved, buried, or replanted, proposed dune vegetation plantings for stabilization and mitigation, and areas of invasive exotic plants for removal and maintenance protocols.