Cape May Point State Park
Marine mattresses protect historic beach for 23 years to create thriving dune system
- Engineer: Geosyn International
- Owner/Developer: City of Cape May, State of NJ DNR
Cape May Point State Park is one of the most notoriously erosive sections of the U.S. Atlantic coastline. Stabilization of the dune and shoreline were required to save historical buildings and critical marsh habitat.
Triton Marine Mattresses were installed over a layer of old construction debris in the tidal zone with no need for an extended apron or embedded toe. Over time, the mattress toe became covered with sand and much of the sand subgrade layer washed into the voids of the concrete debris used as the core, resulting in an irregular and steeper surface supporting the mattress units. The flexibility of the mattress units allowed them to stay in contact with the subgrade, preventing any further scour of the dune system.
In late 1997, a severe storm event exposed the installation to direct wave attacks of 8 ft or more, with the mattresses protecting the dune as intended. In 2004 and 2006, the USACE re-nourished the beach area covering the dunes and mattresses with sand and then new plantings were installed. The site was re-visited in August of 2019, 23 years after the installation and the Triton Marine Mattresses were continuing to perform, creating a thriving beach dune system and protection from future events like Superstorm Sandy.