The Delaware Estuary Living Shoreline Initiative (DELSI) is a pilot project designed to stabilize eroding shorelines of tidal marshes. PDE with Rutgers University has developed the DELSI Tactic of living shorelines which uniquily uses a combination of native wetland plants, natural structures, and intertidal shellfish to trap sediment and absorb waves. The DELSI Tactic provides an economical approach to communities in the Delaware Estuary that are struggling to combat the erosion of tidal marshes.
Tidal marshes act as the estuary's kidneys by filtering water. They also provide spawning sites, foraging areas, and nesting grounds to fish, birds, and animals. And when waters rise, marshes act like sponges, retaining floodwaters and buffering against powerful storm surges.
-Identify the best existing living shorelines tactics applicable to coastal erosion in the Delaware Estuary
-Develop the new DELSI Tactic of living shorelines using native plants and shellfish in our unique design
-Provide educational materials and workshops to agencies, land owners, and communities
How can mussels stabilize and restore shorelines?
Inside the marshes of the mid-Atlantic region, ribbed mussels (Geukensia demissa) are kingpins, collectively outweighing all other animals combined. Like many bivalve shellfish, these are referred to as "ecosystem engineers" because they have the ability to build their own habitats and transform the landscape for other species. DELSI is attempting to take advantage of this unique "mussel power." Ribbed mussels bind to the roots of vegetation and can form clusters as dense as hundreds per square meter. In exchange for this shelter, mussels fertilize marsh plants and trap sediment for their use.
Where is DELSI being implemented?
Study sites are being targeted between the Maurice River and Cohansey River watersheds of southern New Jersey. Installations have only been completed to date at the Maurice River. The Partnership for the Delaware Estuary (PDE) hopes to expand the DELSI in time using the lessons being learned through pilot studies.
How is DELSI being implemented?
Treatments consisting of coconut-fiber logs and mats were first deployed in 2008 in areas experiencing various levels and types of erosion. Tests reveal that mussels attach to the fibers of these products similar to the way they attach to marsh plants. In addition, bagged oyster and clam shells and coated wooden stakes are also being tested as potential treatments. PDE monitors the performance of each tactic to determine which attracts the greatest amount of ribbed mussels and other animals, and which has the most benefits for marsh plants. Elevation is also being monitored to determine if marshes are sinking, eroding, stabilizing, or rising vertically. Expansion to additional study sites in the tidal Delaware Estuary is also expected if additional funding is found.
If you would like more information about this project, please contact the Restoration Coordinator or call (800) 445-4935.