Concrete Coastlines: A Double-Edged Sword for Coastal Protection
Understanding Concrete Shorelines
Concrete shorelines, also known as “hardened shorelines,” are human-made structures designed to protect coastal areas from erosion and storm damage. These structures, typically made of concrete or other hard materials, form a physical barrier between the ocean and the land, preventing waves from reaching and eroding the shoreline.
Prevalence and Impact of Concrete Shorelines
In the United States, approximately 14% of the coastline is covered in concrete. This number is expected to rise significantly in the coming decades, particularly in densely populated coastal areas such as Boston, San Francisco, and Florida.
While concrete shorelines provide protection from erosion, they can also have negative consequences for the environment. Concrete walls can reflect waves back into the ocean, increasing their destructive energy and exacerbating erosion in adjacent areas. They can also destroy tidal marshes, vital habitats for marine life and natural buffers against storms.
Living Shorelines: A More Sustainable Approach
Marine researchers and coastal managers are increasingly advocating for “living shorelines” as a more sustainable alternative to concrete structures. Living shorelines use natural materials and structures, such as marsh sills, to protect shorelines while preserving and enhancing natural habitats.
Marsh sills are low-profile structures made of natural materials like oyster shells or native vegetation. They are designed to mimic natural shoreline features and provide a gradual transition between the ocean and the land. Living shorelines can help reduce erosion, filter pollutants, and provide habitat for a variety of marine species.
Evidence for the Effectiveness of Living Shorelines
Studies have shown that living shorelines can be as effective as concrete structures in protecting shorelines from erosion. In North Carolina, for example, a study found that 76% of bulkheads (concrete seawalls) surveyed were damaged, while no damage was observed on shorelines protected by marsh sills.
Living shorelines have also been shown to be more resilient to hurricanes and other extreme weather events. During Hurricane Sandy, for example, concrete seawalls in New Jersey suffered significant damage, while living shorelines in the same area remained intact.
Adoption and Implementation of Living Shorelines
Living shorelines are gaining popularity as a more sustainable and effective approach to coastal protection. Several states, including New Jersey and North Carolina, have adopted policies and programs to encourage the use of living shorelines.
Coastal property owners and municipalities are also increasingly turning to living shorelines as a way to protect their shorelines while preserving the natural environment. Living shorelines can be designed to meet specific needs and conditions, making them a versatile solution for a variety of coastal areas.
Conclusion
While concrete shorelines have traditionally been used to protect coastal areas, their negative environmental impacts are becoming increasingly evident. Living shorelines offer a more sustainable and effective alternative, providing protection from erosion while preserving and enhancing natural habitats. As coastal communities face the challenges of rising sea levels and climate change, living shorelines are likely to play an increasingly important role in protecting our coastlines.