LSU AgCenter Research Enables Better Flood Protection for Homes

The American Society of Civil Engineers (ASCE) recently released its new standard for flood-resistant design and construction, ASCE/SEI 24-24, which provides new minimum requirements that can be adopted for all structures subject to building codes and floodplain management regulations. The new elevation standard was directly supported by LSU research and should help reduce flood risk and make flood insurance more affordable.

“Without the research by the LSU AgCenter, the advancements made to the elevation requirements would not have been possible,” said Manny Perotin, co-chair of the Association of State Floodplain Managers’ Nonstructural Floodproofing Committee, who helped update the standard. “Dr. Carol Friedland’s research shows there are better ways to protect communities from flooding than adding one foot of additional freeboard.”

The research team, led by Friedland, an engineer, professor, and director of LSU AgCenter’s LaHouse, showed how previous standards were failing to protect some homeowners. They mapped the impact of moving from a standard based on a fixed freeboard amount to being based on real risk in every census tract in the U.S. In response to these findings, they developed a free online tool to help builders, planners, managers, and engineers calculate the elevation required under the new standards.

“Many on the committee said it would be too hard to do these complex calculations,” said Adam Reeder, principal at the engineering and construction firm CDMSmith, who helped lead the elevation working group for the new ASCE 24 elevation standards. “But the LSU AgCenter’s years of research in this area and the development of the tool makes calculations and implementation simple. This allowed the new elevation standard to get passed.”

Flooding, the biggest risk to homes in Louisiana, continues to threaten investments and opportunities to build generational wealth.  On top of flood losses, residents see insurance premiums increase without resources to help them make informed decisions and potentially lower costs. In response to this problem, Friedland is working on developing a whole suite of tools together with more than 130 partners as part of a statewide Disaster Resilience Initiative.

Until now, we’ve been building homes in Louisiana to an elevation standard that allows four out of 10 homes to flood at least once in 50 years.

– Illustration by Elsa Hahne

When presenting to policy makers and various organizations, Friedland often starts by asking what percentage of buildings they want to flood in their community in the next 50 years.

“Of course, we all want this number to be zero,” Friedland said. “But we have been building and designing so 40% will flood. People have a hard time believing this, but it’s the reality of how past standards did not adequately address flood risk.”

Designing to the 100-year elevation means a building has a 0.99 chance of not flooding in any given year. But when you run that probability over a period of 50 years (0.99 x 0.99 x 0.99… 50 times, or 0.99 ^ 50), the number you end up with is a 60.5% chance of not flooding in 50 years. This means a 39.5% chance of flooding at least once.

As the AgCenter’s research led to guidelines, then to this new standard, Friedland has also been providing testimony to the International Code Council to turn the stronger standard into code.

“It’s incredibly exciting to have reached this point and see research translated into real change. Communities will finally be better protected.”

Carol Friedland, Professor and Director, LSU AgCenter’s LaHouse

More than two-thirds of the cost of natural hazards in Louisiana comes from flooding, according to LSU AgCenter research in partnership with the Governor’s Office of Homeland Security and Emergency Preparedness for the State Hazard Mitigation Plan. That cost was recently estimated to rise to $3.6 billion by 2050.

“Historically, we have lived with almost a 40% chance of flooding over 50 years, which in most people’s opinion is too high—and the number could be even higher,” Reeder said. “Most building owners don’t understand the risk they are living with, and it only becomes apparent after a flood. The work done by the LSU AgCenter is critical in improving resilience in communities that can’t afford to be devastated by flooding.”

“This may be the most significant upgrade in the nation’s flood loss reduction standards since the creation of the National Flood Insurance Program minimums in 1973, and it could not come at a better time as annual flood losses in the country now average more than $45 billion per year,” said Chad Berginnis, executive director of the Association of State Floodplain Managers.

In addition to LaHouse’s work to prevent flooding, Friedland’s team is also working to increase energy efficiency in homes to help residents save money on utility bills. Their HEROES program, an acronym for home energy resilience outreach, education, and support, is funded by the U.S. Department of Agriculture has already reached 140,000 people in Louisiana.

Read more:

ASCE 24-24 Delivers Major Update to Flood Resistant Design Standards (Association of State Floodplain Managers)

Calculating the Real Cost of Wind and Flood Risk in Louisiana (LSU Working for Louisiana, 2024)

Making Homes More Resilient and Affordable (LSU Working for Louisiana, 2023)

LSU Helps Homeowners Tackle the True Cost of Flooding (LSU Working for Louisiana, 2021)