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.