When most people hear "infrastructure," they picture roads, buildings, and other human-made structures. But experts at the University of Georgia’s Institute for Resilient Infrastructure Systems (IRIS) also use the term to describe natural features that offer direct and indirect benefits to communities and ecosystems, from forests to river flood plains to marshes.
As IRIS director, Brian Bledsoe works with students and faculty from across the university, and with private sector and nonprofit partners, to combine science and nature to keep communities in Georgia and beyond safe from hazards such as flooding, extreme heat, wildfire, and drought. Bledsoe and his team focus on the interface of engineering, ecology, and resilience with an emphasis on integrating natural infrastructure—including streams, healthy flood plains, and living shorelines—into conventional designs to protect people, communities, and livelihoods.
This interview with Bledsoe has been edited for length and clarity.
Resilient infrastructure is strong yet flexible and quick to bounce back when bad things happen. It’s a system because it’s made of physical parts—both built and natural elements—as well as of people and social institutions. Our work at IRIS often focuses on adapting water, transportation, and energy systems to a range of potential future conditions. In the past, these systems were designed with a very specific projection of the future in mind. A resilient system, on the other hand, is not designed to perform well for just one future scenario; instead, it can function across a range of future scenarios. The most resilient infrastructure systems are those in which the natural infrastructure and conventional infrastructure work together.
Examples of a resilient system could range from a living shoreline that uses natural materials such as oyster shells to stabilize the shoreline and reduce erosion, to designing and placing levees to be farther from rivers and allow space for a natural flood plain to form, which can reduce flood risk in populated areas up and down stream. In both cases, the natural infrastructure has an inherent capacity to self-adjust to future conditions while providing benefits beyond flood and erosion protection, such as water quality and habitat.
IRIS conducts cutting-edge research, raises awareness of natural infrastructure solutions, and develops new workforce training and education programs for future engineers and resilience professionals.
We aim to work across the full life cycle of a resilient infrastructure project from early scoping and planning through design implementation, and operations and maintenance. This could entail determining which segments of a stream are the most compromised and are contributing to flooding challenges downstream; designing a stream restoration project that addresses risk; advising as the project is implemented; and creating a management plan to ensure that a stream restoration and its benefits last.
A defining attribute of IRIS is our interdisciplinary approach to finding engineering and resilience solutions that are technically sound and innovative while also delivering benefits to communities and ecosystems over the long term. So we try to build partnerships in all stages of a project.
Our core team at IRIS is fairly small, but faculty, staff, and students from over a dozen disciplines across the UGA campus are involved in our work, including engineers, ecologists, social scientists, and economists. A good example of this interdisciplinary teamwork is our research on better accounting for changes in flood flows, land use, and channel conditions in flood hazard maps. This work engages engineers, meteorologists, geologists, sociologists, and anthropologists to improve communication of flood risks to the public and to better understand how flood exposure differs across communities and demographic groups. We often see that low-income and under-resourced communities have substantially higher exposure to flooding. With an understanding of these patterns, we can identify mixes of natural and conventional infrastructure measures to address inequities in flood exposure.
Indeed. IRIS has a wide range of partners spanning nonprofits, governments, and the private sector. Some recent partners who come to mind include the U.S. Navy, the Georgia Department of Transportation, insurance companies, and several private engineering firms. We also worked with Ducks Unlimited, the nonprofit organization that conserves wetlands and waterfowl habitat, to develop a graduate fellowship in natural infrastructure. IRIS also partnered with the U.S. Army Corps of Engineers to found the Network for Engineering With Nature in 2019, bringing together researchers, practitioners, and educators to address major infrastructure challenges while aligning ecological, social, and engineering processes to create multiple benefits. Finally, we work with municipalities such as Tybee Island to help create and implement resilience plans.
Simply put, nature-based solutions restore and engineer nature for the benefit of people and the environment. There are generally four attributes of nature-based solutions: they perform infrastructure services such as purifying water or cooling a town during high temperatures; they’re multipurpose, so that a flood protection measure also provides ecological and social co-benefits by creating, for example, wildlife habitat and recreation opportunities; they consist at least partially of natural or living materials; and they can respond to changing conditions and recover after a disturbance.
"Nature-based solutions" is a broad umbrella term, but it also includes things such as restored marshes, reefs, and islands that act as speed bumps and shock absorbers against storms; forests managed and optimized to collect, filter, and release rainfall back into groundwater, streams, and rivers, which leads to reduced water treatment costs; and flood plains that act as pressure release valves to reduce downstream flooding by spreading water over a larger area while reducing the speed of floodwaters.
Natural infrastructure offers some combination of habitat or biodiversity benefit, recreational opportunities, and sometimes water quality improvements—all at the same time. And public health research shows that for every dollar invested in creating urban river parkways, society gets back many dollars’ worth of benefits in terms of reduced cardiovascular disease, reduced diabetes, and better mental health outcomes as a result of people out exercising or just being out in nature. The air is cleaner, and temperatures are more pleasant. You see people rafting and fishing, and an urban area’s biodiversity can be enjoyed by everyone from bird-watchers to kids looking for salamanders with their elementary school science class.
And natural infrastructure has an inherent capacity to adapt to changing conditions—and to, in many cases, self-repair, such as flooded wetlands that in the months and years after a disaster can capture sediment and absorb nutrients, and where ultimately plant life grows back. How many concrete walls have you ever seen rebuild themselves after a storm using solar energy? But natural infrastructure can do that.
I’m from Georgia originally, but I lived out in Colorado for many years. I moved to Fort Collins in July 1997, the exact week of the Spring Creek flood. In the aftermath of that flood, the city of Fort Collins made major changes to its flood management programs and policies. One of the central elements of the approach was to develop an extensive interconnected network of parks, natural areas, flood plains, and trails along the city’s streams and river corridors. As a result of this network of natural infrastructure, when another big flood came along in 2013, Fort Collins had virtually no damage.
One of our areas of research is trying to improve methods for flood hazard mapping, particularly across areas where different demographic groups live. For example, here in Georgia, we found that African American and Hispanic families below the federal poverty level in the city of Athens are two to three times more likely to be exposed to flood risks than other people in the city. One result of this effort has been to build partnerships with the local government, including the Oconee Rivers Greenway Commission, a committee of residents that advises the Athens-Clarke County mayor and commission on issues related to the Oconee rivers and their tributaries in an effort to share information and identify opportunities to deploy natural infrastructure to reduce flood exposure for African American, Hispanic, and other communities of color. We’re also working with city officials in Charlotte, North Carolina, to prioritize locations for urban stream restoration that maximize the full range of benefits, especially increased access to green space, for people in that city.
Natural infrastructure is not an "either/or" situation: it’s a "yes and" situation, where we need to bring together conventional and natural infrastructure to provide more benefits to communities. I see more and more communities across Georgia embracing natural stormwater infrastructure such as rain gardens and bioswales—which are vegetated channels that collect and move stormwater from paved surfaces while also filtering and allowing it to soak to the ground. Communities are incorporating natural areas into their flood management plans; they’re also doing urban stream restoration. There are strong efforts underway to protect and sustain the state’s coastal marshes and ecosystems in the face of sea level rise and give them some space to migrate inland from rising waters.
Agricultural producers are also taking climate resilience seriously; they recognize that their practices should be mindful of water use and drought impacts, and that they can help important species such as pollinators adapt to more extremes in water availability and weather patterns.
I’ve learned that developing resilient systems is a never-ending journey. You can’t ever really take your eye off the ball, because the environment we operate in is ever-changing.