Wave energy is reflected by hardened shorelines, leading to further shoreline destabilization.

When waves hit the beach at an angle, sand is transported alongshore by wave energy. Waves also transport sand along the shore in a zig-zag patterns as they rush onto and off of the beach. This natural movement of sand is disrupted by hardened shorelines, furthering erosion.

Hardened shorelines can contribute to chemical weathering.

They can leach toxins, into the surrounding water and further impacting the ecosystem, such as:

• Copper 
• Chromium
• Arsenic

Hardened shoreline barriers prevent the natural migration of salt marshes inland in response to coastal inundation, leading to their loss instead of allowing for their adaptation.

Loss of marsh habitat negatively impacts wildlife and plant populations, making Long Island more vulnerable to coastal flooding, erosion, and storm damage.

Allow for natural sediment movement patterns which will change a shoreline’s shape naturally within interference from a hard structure. 

Allows for natural sediment movement patterns which will change a shoreline’s shape naturally without interference from a hard structure. 

Creation of habitat and nursery grounds for wildlife and native marsh plants, which in turn supports fisheries, recreation, and tourism. 

Maintains or restores the connection between the coast and upland habitat that would otherwise be divided by a hard structure.

This allows for natural landward migration of coastal habitats as they adapt to rising seas, and also allows for the movement of wildlife that are dependent on access to coastal habitat for spawning or other aspects of their lifecycle. 

Natural or restored wetlands improve water quality by filtering excess nutrients and other pollutants from runoff as it passes over and through the marsh on its way to the estuary.

Natural or restored wetlands can help reduce flooding through absorption, which is very important for low-elevation communities on eastern Long Island.

Salt marsh ecosystems are blue carbon systems, they sequester and store significant amounts of carbon from the atmosphere and surrounding water.

According to NOAA, one square mile of salt marsh stores the carbon equivalent of 76,000 gallons of gas annually, helping to combat climate change. 

Often less expensive to install and maintain than hardened shoreline stabilization methods such as bulkheads. 

Provide an attractive, natural appearance, and allows for greater public access and viewing. 

Project Goals and Partners

Faced with an increasing demand for shoreline protection among property owners, the Town of Southold wanted to provide its residence with an example of an environmentally-conscious alternative to shoreline hardening. 

For this reason, The Peconic Estuary Partnership  has been hard at work to create a living shoreline demonstration at The Suffolk County Marine Environmental Learning Center (SCMELC) in Southold, New York in collaboration with:

• The Town of Southold
• Suffolk County
• Cornell Cooperative Extension (CCE)

With funding form: 

• USEPA
• The Suffolk County Water Quality Protection and Restoration Program
• The Town of Southold

Ribbed Mussels

This living shoreline, installed along the banks of a creek at the SCMELC facility, incorporates several layers of shoreline stabilization as well as ribbed mussel (Geukensia demissa).

 A combination of cultured ribbed mussel and adult, transplanted ribbed mussel were used in the shoreline project. Transplanted ribbed mussel were collected from the existing population in this waterbody. Smooth cordgrass (Spartina alterniflora) seeds (from nearby marshes) were collected, propagated and raised in the CCE habitat restoration greenhouse prior to being planted.

Spartina Grass and Further Stabilization

This demonstration project also incorporates other natural structures to further stabilize the shoreline and provide a surface to which plant roots and mussels can attach.

For example, bagged shell, rocks, coir logs, and wooden terracing are all included in the living shoreline project in order to test and demonstrate benefits, effectiveness, and appearances of each material in combination with the living features of the shoreline, Spartina grass and ribbed mussels.

Benefits of Ribbed Mussels in Living Shoreline Systems

Increased filtration of nutrients, pollutants, and bacteria

Ribbed mussels are one of the few shellfish capable of foraging on small-size bacteria and efficiently removing a wider range of particles; thereby, improving water quality. 

Enhanced growth of marsh plants

Research has shown that the presence of ribbed mussel increases the growth and survival of smooth cordgrass by providing nutrients to the plant via deposition of feces.

Increased primary production 

Help fuel primary production and the spreading of marsh plants by adding important nutrients to surrounding sediment, effectively “fertilizing” plant life. 

Increased habitat complexity 

Considered an “ecosystem engineer” species because they have the ability to build new and more complex habitats, providing more places for other coastal species to use for shelter from sunlight, heat, air, and predators.

Heightened carbon sequestration

Improved salt marsh resilience

Ribbed mussels form clusters that bind tightly to treat plant roots and other surfaces, building, and strengthening the marsh to better resist erosion and storm damage. 

Improved adaptation to rising sea level

As mussel densities increase, they help to trap and collect particles suspended in the water column, causing the marsh to increase in elevation. This allows the marsh to adapt its vertical growth to rising sea levels and better resist erosion. 

Low risk of illegal removal 

This species is not considered edible; therefore, they are unlikely to be poached or illegally removed from the marsh. This allows ribbed mussels to be placed in areas closed to shellfish harvest, whereas other species such as clams or oysters are not allowed to be placed.