The updated Federal Flood Risk Management standard, published in the July 11 Federal Register, requires all infrastructure in flood-prone communities to be designed and built to protect against future flood risks caused by climate change, as well as current ones. 

According to agency officials, one of three approaches must be used for projects receiving FEMA funding:  designing and building projects at locations and elevations using the “best available” climate science, which includes considering nature-based solutions; adding an additional two feet to the base flood elevation for projects deemed "non-critical," and three feet for critical structures; or building to the 500-year flood level in locations where the 500-year floodplain is mapped. 

Previously, non-critical projects only had to be built to be protective to withstand a 100-year flood. 

This change alone nearly doubles the number of residents who will be affected by FEMA requirements—from about 15 million to between 30 million and 40 million, says Dan Cox, an Oregon University coastal and ocean engineering professor and chair of the American Society of Civil Engineers’ 7-22 chapter on flood loads. 

FEMA says the rule allows the agency to consider the best-available science in rebuilding communities after disaster strikes. It applies to FEMA-funded actions involving new construction, substantial improvements or repairs from substantial damage, as well as hazard mitigation assistance projects involving structural elevation, dry flood-proofing and mitigation reconstruction. 

Cox notes that the FEMA standard and the ASCE updated 7-22 chapters on hazard resilience are moving in the same direction, although communities must choose to adopt the latter and incorporate it into their building codes. Under the FEMA rule, communities that receive FEMA funding are required to comply. 

Edgar Westerhof, North America solution leader for climate adaptation at Arcadis, says the rule is a step in the right direction for an increasingly dire need. The firm is one of many consultants working on a major resilience program for the New York City Dept. of Design and Construction that will, among other things, elevate by several feet long stretches of the waterfront in lower Manhattan to reduce flood risk. 

But he says more regional coordination is needed to evaluate flood risks holistically. Additionally, the standard does not fully address the compounding risks of extreme weather flooding made worse by other problems, such as daily high-tide events in some coastal areas, Westerhof says. “Understanding the more frequent occurrences of compound risk is where we need to stretch and do more research, and that’s not well explained in this rule.” 

Michael Mittelholzer, assistant staff vice president of environmental policy for the National Association of Home Builders told ENR that his group believes the standard will only create more complexity and confusion for local municipalities that must now look to determine which specific FEMA grant programs apply when planning new projects. 

In addition, although single-family homes are not likely to fall under the FEMA standard’s requirements, infrastructure deemed as “critical” – such as wastewater and drinking water plants, and power and transportation infrastructure in new planned communities would. This could leave home construction in these communities on hold until compliance requirements for critical projects are met, he says. 

The homebuilders' group submitted comments expressing reservations about the proposed rule in December, noting it would increase costs for builders.  

FEMA acknowledges that incorporating design resilience features into projects could “marginally” raisecosts but contends this small increase falls far short of the savings associated with avoided costs from flood damage. 

The FEMA rule goes into effect September 9.