REEFENSE X-REEFS: HYBRID BIOLOGICAL AND ENGINEERED REEF STRUCTURES FOR NATURE-BASED COASTAL DEFENSE

Coastal flooding and erosion from extreme weather events affect thousands of vulnerable coastal communities globally. The effects of coastal hazards are predicted to worsen during this century from population growth and climate change-driven sea level rise. As such, nature-based solutions are gaining increasing momentum as a promising strategy to the mitigate risk and cost of coastal flooding and associated hazards. In tropical coral-lined coasts, among the areas globally most susceptible and vulnerable to climate change and sea-level rise, there is increasing interest in the use of coral reef restoration as a form of nature-based coastal protection 1–3. However, there are limited reef- engineered examples to date that have been specifically designed for coastal protection 4. One of the key challenges is that it involves the interaction of complex processes at multiple spatial scales 5. Here, we present the design and development of hybrid engineered and biological coral reef-mimicking structures that are designed to be fast-growing and resilient, while still providing immediate protection from waves. The Reef Engineering to Enhance Future Structures (X-REEFS) is one of the selected projects in the Reefense Program by the Defense Advanced Research Projects Agency (DARPA). The X-REEFS Project aims to develop a hybrid biological and engineered reef system to mitigate coastal flooding and erosion.