Green and Gray: Understanding the Shades of Resilient Infrastructure

Coastal communities around the country are looking for cost-effective ways to increase their resilience (to sea level rise, coastal erosion and flooding, changes to coastal habitats, etc.), Green infrastructure is proving to be a viable management option for saving money and preserving habitat. Gray infrastructure, however, is still the focus of many resilience programs. More recently, researchers are starting to explore combined gray and green, or “hybrid” infrastructure management options. To better understand what this all means I have compiled a list of key resources in this area of interest.

Green infrastructure refers to the use of plants and water to perform ecosystems services.  This white paper explains how green infrastructure can benefit water, land, and air resource systems while offering co-benefits to the community, like flood protection and native species habitat. While more work needs to be done to quantify the cost and value of green infrastructure options, early findings show that they offer low cost options to communities looking to improve their resilience. The Environmental Protection Agency (EPA) has put together a great set of resources for those looking to learn more. Here you can find tools for designing, financing, and maintaining different types of green infrastructure.

Gray infrastructure refers to the use of concrete and steel to support community operations. This community resilience guide describes the value of the “built environment” and offers a six step approach to gray infrastructure planning and management for long-term community resilience. It can be very costly to build, maintain, and/or relocate gray infrastructure (like culverts, sea walls, and roads), so communities are looking for creative ways to improve their resilience and manage the important built environment.

Hybrid infrastructure combines green and gray management options in an effort to optimize community resilience to a range of environmental and community hazards. This paper describes how green infrastructure and combinations of green-gray infrastructure are highly effective for improving coastal community resilience, but they explain that more work needs to be done to quantify and assess the usage and value of combined green-gray options.

In the end, coastal communities are looking to find creative and cost-saving ways to improve their resilience to the array of coastal hazards they face.  Therefore, interest in green infrastructure and combined green-gray, or “hybrid” options is on the rise. The resources linked here provide a foundation for understanding the direction of this area of interest.