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Atlantic Beach, Fla., to Adopt Sea Level Rise Vulnerability Plans

The Florida city was recognized regionally for its sea level rise vulnerability assessment, which showed that the community will continue flooding at an even higher rate. Plans are being developed to mitigate for these findings.

Measurement gauge marker for rising water levels.
Atlantic Beach is a city in Duval County, Fla., one of the Jacksonville Beach communities with around 12,655 residents, who have experienced increasing “nuisance flooding” during the last decade.

City officials began to take notice, and with the creation of the Statewide Office of Resiliency and the increased attention to sea level rise under Gov. Ron DeSantis, the city applied for and received a grant of $40,000 to conduct a vulnerability assessment to analyze future flood risk from projected sea level rise.

With the assessment finished, and the residents onboard, the city now turns its attention on developing a policy and plans for future development and for some current infrastructure.
The assessment was so well done it received a regional award from the Northeast Florida Regional Council (NEFRC). The NEFRC is an independent agency that analyzes local growth management, economic development, emergency preparedness, resiliency and community development.

It was the forward-thinking modeling and the adherence to the FEMA methodology and the likelihood of 100-year floods out 25, 50 and 100 years in the future that impressed the NEFRC reviewers. The assessment produced a series of flood maps, using this methodology but also calculating future sea level rise, which FEMA doesn’t do.

“This allows residents and businesses to see future vulnerabilities in ways they are used to seeing, bringing the need for resiliency home, Sean Lahav, resiliency coordinator for NEFRC, said in an email. “Because of forward-thinking modeling considerations made by local government staff and outside engineering consultants, Atlantic Beach was able to conduct a robust and meaningful vulnerability assessment that will be of tremendous value to future planning discussions.”

City engineer Steve Swann explained that there had been concern about sea level rise in neighboring cities, which prompted Atlantic Beach’s concern. “We had a couple of areas where we’ve experienced an increase in nuisance flooding where 40 years ago, we didn’t have a flooding problem,” Swann said.

He said the nuisance flooding was such that it closed roads but didn’t flood houses.

After creation of the Office of Resiliency, the city got the grant. It wasn’t a lot of money but enough for what was needed, Swann said. The city had just finished its stormwater master plan and had modeled its drainageways, and from there, doing a coastal hazard assessment to figure out where future storm surge will be with sea level rise wasn’t that hard, said Swann.

The city hired two consultants: Jones Edmunds & Associates as the stormwater experts, and Applied Technology & Management (ATM) to do coastal modeling. Each firm did its analysis and then the data from both studies was combined to develop assessment for 100-year floods in 25, 50 and 100 years.

“We decided to use the same [FEMA] methodology for 25, 50 and 100 years in the future using our sea level rise predictions, then basically building new flood insurance rate maps for the new sea level conditions that we might see,” Swann said. “So, we ended up with a new set of flood insurance rate maps.”

The data indicates that sea level rise will be 1.1 feet in 25 years; 2.7 years in 50 years; and 6.75 feet in 100 years, although the 100-year prediction is a “shot in the dark.”

The city had public meetings to explain what the data were showing and got good reception. The city was able to show from data from tide gauges that for the past 60 to 70 years, sea level rise has occurred at about an inch a decade, and the curve had been steady. But the curve is beginning to show a sharp, upward trend, falling in line with sea level rise predictions by the National Oceanic and Atmospheric Administration, and the U.S Army Corps of Engineers.

The city looked at the 25-year and 50-year predictions now when considering major infrastructure projects and will also look at current infrastructure like wastewater treatment plants to determine how those facilities can adapt to future flooding.

“We don’t talk about climate change or why it’s happening because it doesn’t really matter,” Swann said. “What matters is we have very good empirical data from our tide gauges that say, yes, the sea level is increasing. So we can mitigate a lot of the naysayers and say, ‘Look guys, when you were a kid, these roads didn’t used to flood and now they’re flooding. Something is happening.”

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