HYBRID APPROACHES TO COASTAL PROTECTION AS A SUSTAINABLE ALTERNATIVE TO BUILT SOLUTIONS

Catalyzed by disasters such as the Indian Ocean Tsunami in 2004 and Hurricane Katrina in 2005, interest in techniques to protect coastlines from inundation has risen rapidly. It is well known that marshes, oyster reefs, mangroves, and other coastal ecosystems provide natural protection from storm surge. Whether natural or engineered, these are referred to as green solutions, and they use the innate wave attenuating properties of dynamic ecosystems. However, communities increasingly rely on built solutions (also referred to as grey or hard infrastructure), including levees, sea walls, and rip-rap revetments; but these structures can be detrimental, in many cases effectively removing natural protective systems. A third option––which receives less attention but has much potential––is the hybrid approach, which integrates both grey and green approaches, aiming to maximize coastal protection while reducing ecosystem damage.

Research on Superstorm Sandy’s effects on coastal communities in New Jersey shows that salt marshes alone are insufficient in preventing damage, highlighting the necessity for a synergistic approach that includes built infrastructure. Initiatives aimed at natural and hybrid approaches like “Rebuild By Design” and “Designing With Water” in New York and Boston respectively are gaining traction, but one of the barriers is a lack of data on the long term benefits. Other challenges associated with hybrid systems include development timescales and policy barriers, so that built solutions often seem more tractable.

Successful adoption therefore requires substantial community buy-in. Education and awareness building— teaching the public that these ecosystems have inherent value above and beyond their protective functions—are therefore important. Coastal resiliency projects might gain more traction if marketed with a focus on ecosystem services rather than simply storm surge protection. Some of these might include increased tourism, species diversity, fishery stability, and extended life cycles for built infrastructure. We contend that hybrid strategies, incorporating natural and grey infrastructure, should be a strong focus of future studies.