GRAY LEADS TO GREEN IN THE BLUE: BUILDING INFRASTRUCTURE TO ENHANCE COASTAL HABITAT

Abstract

Structures that are used to build and protect coastal habitats and properties are often referred to as gray infrastructure, distinct from the green infrastructure provided by nature. This green infrastructure includes natural habitats such as mangroves, coral reefs, shellfish reefs, saltmarshes, and seagrasses - all of which have been demonstrated to maintain shorelines, balance hydrology, buffer land from storms, improve water quality, and provide recreational and aesthetical values. Concerns arise when built infrastructure damages such beneficial habitats, as can happen if designs are inadequate or poorly planned. The result is that much of the current narrative around gray/green infrastructure has created a false and dangerous dichotomy: green infrastructure is labelled a ‘nature-based solution’, while gray infrastructure is portrayed or perceived by certain stakeholders as the opposite (sometimes implying that engineered solutions are not long-term solutions at all, but rather short-term solutions that can pose long-term problems). Coastal structures can stabilize shorelines, prevent erosion, and create space for colonization by mangroves, seagrasses, corals, and other foundational marine species. The structures themselves can contribute to improving water quality, creating the enabling conditions for ecosystem recovery.