The resilience of U.S. coastal communities to storms, flooding, erosion and other threats can be strengthened when they are protected by natural infrastructure such as marshes, reefs and beaches, or with hybrid approaches, such as a “living shoreline” — a combination of natural habitat and built infrastructure, according to a new NOAA study.
The study, published in Environmental Science and Policy, assesses reports and peer-reviewed studies on the strengths and weaknesses of using built infrastructure, such as seawalls or dikes, natural infrastructure, or approaches which combine both. The study focuses on how these approaches help coastal communities reduce their risk of flooding and erosion, as well as additional benefits, and the tradeoffs when decision makers choose one type over another.
This new study points out that there is still a need for built approaches in some locations. However, natural or hybrid approaches can be used in many cases.
Some natural ecosystems can maintain themselves, recovering after storm events and reducing the cost of upkeep. Natural habitats such as coral reefs, marshes and dunes can act as buffers for waves, storms and floods. Natural ecosystems also can, in many cases, keep pace with sea level rise, while built infrastructure does not adapt to changing conditions.
Hybrid approaches, such as combining some habitat restoration with openable flood gates or removable flood walls, provide benefits while also providing more storm and erosion protection than natural approaches alone. The study highlights hybrid approaches in the New York City metro area and in Seoul, South Korea, to deal with their monsoon flooding events.
Threats like coastal erosion, storms and flooding can reshape the shoreline and threaten coastal property. With approximately 350,000 houses, business, bridges and other structures located within 500 feet of the nation’s shoreline, erosion is a problem many U.S. coastal communities are addressing.