Engineering With Nature

Islands

EWN® employs nature-based solutions, including the creation and restoration of islands with multiple habitats, to reduce coastal storm and flood risks while providing environmental and socio-economic benefits.

EWN Islands

Sustainable Islands

The EWN® Program supports nature-based solutions that reduce coastal storm and flood risks while providing environmental and socio-economic benefits. Combining the beneficial use of dredged sediments with the restoration or creation of islands increases habitat, recreation, keeps sediment in the system and reduces coastal storm and flood impacts. Our team of scientists and engineers along with our partners collaboratively pursue novel ways of approaching creation and restoration of islands that produce the desired engineering outcomes while also achieving substantially greater environmental and social benefits.

EWN Islands

Island Resilience Uncertainties

Islands often consist of multiple habitats such as beaches, dunes and marsh which is essentially equivalent to a ‘multiple lines of defense’ strategy where combined, these habitats have a greater capacity to reduce waves and erosion than a single habitat type alone. Regardless of their size and habitat composition, islands have the potential to increase coastal resilience by reducing waves and erosion to nearby shorelines, while providing habitat and recreation opportunities.

However, many islands are being lost at an alarming rate along the Gulf of Mexico and Atlantic coast. The degradation and loss of islands is due to the combined processes of wave action, climate change, subsidence, and inadequate sediment input. Restoration or creation of islands using dredged sediments keeps the sediment in the system, helping them to keep up with sea level rise.

Despite the coastal resilience benefits of islands, perceived uncertainties related to their ability to sufficiently reduce coastal storm and flood impacts, is considered a barrier to the implementation of Island beneficial use projects. Among these uncertainties are questions about the long-term performance of islands relative to conventional engineered solutions and their ability to adapt to changing conditions such as sea level rise as they grow and mature over time. In addition, ecological uncertainties related to the replacement of subtidal habitat with higher elevation habitat, known as ‘habitat trade-offs’ are also cited as a barrier to implementation.

Given the potential advantages of islands, EWN seeks to address these uncertainties with science-based investigations of island performance, impacts, and benefits through collaborative multi-disciplinary efforts. Through a series of case studies led by USACE Districts and others, we highlight the role of islands in providing the resilience, environmental and socio-economic benefits to the communities and the ecosystems they reside in.

Island Erosion and Restoration

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Image Gallery

EWN Islands

Island Projects

Figure 1. Photo of Mordecai Island in 2019. Background Mordecai is an undeveloped back barrier island that runs parallel to the Barnegat Bay ......
During the 1990s, placement of shoal material dredged from Horseshoe Bend of the lower Atchafalaya River occurred at wetland development sites loca......
Peanut Island, located in the Lake Worth Lagoon (LWL) within Palm Beach County, Florida, was originally created in 1918 using the material excavate......
Coastal islands and marshes of the Chesapeake Bay are disappearing along with the critical ecosystem services and shoreline protection benefits the......
Dating to the late 1860’s, Baptiste Collette Bayou was a small canal that extended between the Mississippi River and the historic Breton Island Sou......
The Snook Islands project site is located adjacent to the Lake Worth Golf Course (LWGC) in the Lake Worth Lagoon (LWL) in central Palm Beach County......
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EWN Islands

Publications

The Engineering With Nature® (EWN) Program supports nature-based solutions that reduce coastal-storm and flood risks while providing environmental ......
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