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Boston Society of Architects

Safe Feature

Natural defenses

Working with the elements can help mitigate risk

Natural Defenses-1

The Way Fire burns on August 19, 2014, in the Sierra National Forest near Kernville, California.

Photo: Stuart Palley

The term “natural disaster” is an oxymoron. There really are no disasters in nature. All disasters are man-made: the result of individual actions—or inaction—and a host of societal, economic, and political factors.

In 2014, I organized an exhibition for the National Building Museum that posed fundamental questions about where, and how, we build. Designing for Disaster opened in the aftermath of Superstorm Sandy and the 2012 Rio Earth Summit. At every level, from family preparedness to federal policy, I discovered that what many of us had considered safe in the past was no longer proving safe enough. Everywhere I turned, acceptable levels of risk were being recalculated, recalibrated, and redefined.

No matter the nuances or complexities of a particular risk equation, they all had at least one variable that could be manipulated to decrease either the severity or likelihood of the risk—identified vulnerabilities, such as the number of people or type of strategic assets in harm’s way—or increase the capacity and effectiveness of the systems and infrastructure designed to perform during the event. The upshot: Mitigation measures can decrease vulnerabilities or increase performance, or do both.

But mitigation is challenging: More demanding than simply rebuilding, it requires rethinking. And after a disaster, it can be a hard sell, especially if it runs counter to a community’s desire to quickly return to normal. That’s why “designing for disaster” can be such a powerful turn of phrase. It focuses on understanding and working with the forces of nature—not standing in opposition to them.

When it comes to designing for the impacts of earthquakes, for example, structural engineers have made great strides combining new technologies with lessons learned over the past 25 years—including those from two greater-than-6.6-magnitude earthquakes, one in Los Angeles and the other in the San Francisco Bay area. Whether today’s design solutions feature base isolators, buckling restrained braces, moment frames, fluid viscous dampers, expansion joints, or shear walls, a structure’s seismic performance is often just as much about accommodating and dissipating anticipated forces as it is about resisting them. After all, the earth and the ground beneath us are in continuous motion—it’s just that most of the time we don’t feel it.

Designing for wildfires may be even more illustrative of how we need to embrace and design with an understanding of natural systems. After decades of government focus on prevention and fire suppression, which inadvertently fueled more severe fires, the watchword in wildfire mitigation today is adaptation, or “fire-adapted” communities. This means encouraging residents who live in the wildlandurban interface (akin to a floodplain, or an active fault line) to focus on creating fire-safe environments in the area around their homes. By minimizing fuel sources in the home ignition zone—both on and immediately around a home—communities can increase their defensible space, improving a home’s capacity to survive direct flames or radiant heat.

River Bluff Ranch, a development in Spokane County, Washington, was designed with local fire officials from the ground up to withstand a major wildfire. To open up panoramic views for residents and simultaneously reduce fire fuel sources, the area around each home site was thinned out, creating expansive lawns and defensible space. The roads were engineered as fire breaks, and that network accommodates concurrent evacuation and fire access. Utilities are underground, and a series of water storage tanks are readily accessible. Perhaps most important, key principles—such as prohibiting wood shake roofing and otherwise limiting the material in the home ignition zone—are written into the homeowners’ covenants and provide a framework for maintaining a culture of fire safety. In 2016, residents were evacuated because of a nearby fire, but no homes in the community were lost.

Today, no issue is more prevalent or pressing than designing for water: floods, storm surges, sea-level rise, and even tsunamis. Since we all live in a watershed, there is almost always a risk of flooding. Shorelines and coastal regions are particularly vulnerable, since they are where a watershed meets a larger mass of water. The scale and scope of the threat continues to increase as new problem areas—often traced to development patterns that alter natural water retention and runoff—join traditionally vulnerable river cities and coastal communities. Current thinking in water-hazard mitigation includes restoring disrupted natural systems. Whether it’s retreating altogether, “making room for the river,” elevating structures, or creating living shorelines, these tactics adapt to the ebb and flow of the waters. By redefining the water’s edge as a fluid boundary that connects the environment, infrastructure, and public amenities, architects and landscape architects are beginning to revolutionize the way we live with nature.

Davenport, Iowa, is the largest river city in the country without major structural flood protection. Instead, it has opted to “live with” and embrace the Mississippi River. First adopted in 2004 and updated in 2014, RiverVision has redefined the city’s edge by strengthening its natural defenses, such as wetlands, and creating an adaptive, multiuse riverfront. Centennial Park, for example, includes elements engineered to slow and absorb water, as a well as a skate park designed to contain floodwaters when necessary. One key to the city’s efforts: It now owns 9 miles of riverfront. Davenport’s flood protection also includes building-level mitigation. At Modern Woodmen Park, where the minor-league baseball team Quad Cities River Bandits play, an elevated outfield berm and portable flood panels help ensure the field stays high and dry. The city can also deploy a scaffold walkway to bring fans into the ballpark if the surrounding area is flooded.

Remarkably, even the US Army Corps of Engineers, without abandoning conventional flood controls, is investigating nature-based infrastructure as well as strategic retreat. Federal flood mitigation efforts include the National Flood Insurance Program, which subsidizes coverage in communities that have implemented baseline floodplain management. And more comprehensive flood-reduction measures are incentivized through premium discounts. The message is clear: We can design for disaster.

The Federal Emergency Management Agency (FEMA) recommends preparedness, not mitigation

Perversely, I think design professionals sometimes treat mitigation strategies as if they were insider information, only to be used professionally and on the behalf of a client. I’m not so sure we fully capitalize on this knowledge for ourselves, much less for the greater good. Politics aside, even compiling the following grossly abbreviated list of US disasters and tragedies from the past two decades gave me pause: September 11, Hurricane Katrina, Superstorm Sandy, the Boston Marathon bombing, Sandy Hook, the Las Vegas shooting. I’m beginning to think we all need to regain our equilibrium and sense of safety by taking some small, individual steps that can actually decrease our own vulnerabilities—whatever they may be. Only then can we hope to regain a modicum of stability and control on a larger scale.

How, or where, do you start? The Federal Emergency Management Agency (FEMA) recommends preparedness, not mitigation: taking small, relatively low-cost, and responsible steps, such as discussing emergency plans with your family and friends, creating an emergency preparedness kit, or evacuating when requested. Why start there? Because these simple actions can save your life and potentially others within your community. Making a small investment in your safety provides a sense of control that can be liberating and empowering. As it turns out, we are more likely to employ and invest in a mitigation strategy, such as purchasing insurance coverage or making modifications to our home, if we previously prepared for a disaster.

We need to remember that mitigation is the only preemptive phase of emergency management. It is designed to break the cycle of disaster, rather than repeat it. Preparedness, response, and recovery are essentially reactive. Mitigation not only helps save lives, protect property, and reduce losses but also can help individuals, communities, and regions recover more quickly after a disaster. It translates into safer, more resilient communities.