If Orlando Flooded After Ian, Are Other Cities Safe?


WINTER SPRINGS, Fla. – Lisa Roney was awake in the overnight hours watching the power of Tropical Storm Ian when the water started coming in the back door. Her husband grabbed a shop vac while Roney, 62, guided rivers of water out the front door with a mop. Two soaked rugs and some soggy drywall later, Roney said they prevented the worst.

“We were desperate,” the retired professor said. “We knew we did not have flood insurance, so we just worked our asses off to save our house.”

Roney admits her backyard gets “swampy” in summer storms, but her house isn’t in a floodplain. She says the water that filled her house didn’t come from the rain; it came from a nearby retention pond that overflowed.

Ian’s record rainfall was rated as a 1,000-year rain event by National Oceanic and Atmospheric Administration standards, easily overwhelming Central Florida’s stormwater infrastructure and causing widespread flooding.

With climate change predicted to bring more such rain events in the future, with both greater frequency and intensity, scientists and engineers are calling for local governments to review their standards and start planning for the wetter world to come.

1,000-year storm

Hurricane Ian was downgraded to a tropical storm while still 40 miles south of Orlando in the early morning hours of Sept. 29. Yet it went on to drop a historic rainfall on Central Florida.

Orlando saw between 12 and 13 inches of rain, with some areas seeing as much as 16 inches, according to the National Weather Service in Melbourne. Winter Springs, where Roney lives, received 14.97 inches, the weather service reported.

Jeff Carney, director of the Florida Institute for Built Environment Resilience at UF, says that 1,000-year designation isn’t as impressive as it sounds. “I’ve lived through about three 1,000-year events in my life,” he said. “I’m not that old.”

The designation of storms by year doesn’t mean that these kinds of events only happen once in that many years. It is the likelihood of any storm reaching that strength and effect in any given year. Essentially, there was a 1-in-1,000 chance of Hurricane Ian causing the flooding it did.

Carney says these numbers can be useful for understanding the rarity and severity of storms, but that they don’t reflect an easy, mathematical definition.

“That number is clearly a rough estimate,” he said. “Just the science alone is probably very old.”

Yet these numbers guide the standards for stormwater infrastructure and other preventative measures for flooding.

In Orlando, the storm sewers are built to handle a 10-year storm for six hours, said city spokeswoman Ashley Papagni. “All development within the city is required to meet the St. Johns River Water Management District stormwater management design criteria,” she said in an email.

In Seminole County, retention ponds such as the one Roney says overflowed into her home have to meet a 25-year, 24-hour design standard, according to the county’s comprehensive plan.

Increasing strength

The problem is the storms are getting stronger.

“Nowadays, a normal storm can probably reach a 25-year, 6-hour standard,” said Ni-Bin Chang, director of the Stormwater Management Academy at the University of Central Florida.

In July and August alone, the U.S. had six 1,000-year flooding events by NOAA standards in Kentucky, Illinois, Mississippi, St. Louis, Dallas and Death Valley, Calif.

While the effects of climate change on Florida’s overall rainfall remain uncertain, NOAA predicts warmer weather might create more intense storms and expects hurricane rainfall to increase in coming years.

Scientists at the Lawrence Berkeley National Laboratory in California and Stony Brook University in New York found that climate change likely increased Hurricane Ian’s rainfall by 10%.

Tropical Storm Nicole, which struck on Nov. 10, was much less wet than Ian, but it still caused flooding conditions around already-swollen rivers, dropping 5 to 7 inches of rain throughout Central Florida, according to the National Weather Service.

Chang said local governments need to undergo what he calls a “holistic assessment” of policies, current infrastructure, environmental conditions and available technologies to identify and minimize hot spots for flooding.

“We will need to have some kind of policy change … to reinforce the drainage capacity,” Chang said.

Papagni and Orange County deputy director of public works Brett Blackadar said the city and the county were both undergoing extensive reviews of stormwater policies and infrastructure in the wake of Ian.

“We are currently in the process of reviewing the areas that received the most significant flooding,” Blackadar said, noting some drainage projects have already been identified.

“As an example, we are starting construction in early 2023 to help address the historical flooding in the Orlo Vista/Westside Manor [neighborhood].”

Yet that example highlights one of the largest challenges to making necessary changes: cost.

After Orlo Vista flooded in 2017 following Hurricane Irma, FEMA and the state gave the county $10 million for a high-priority drainage improvement plan. However, when bidding opened in August, the lowest was $21.5 million. The county is awaiting a response from FEMA about additional funding.

Seminole County representatives did not return a request for comment.

Low-impact development

A rebuild of existing infrastructure is likely out of the question, Chang said. “We probably cannot take up all the old drainage systems and reinstall them,” he said. “That would be too expensive.” Instead, Chang advocates for an approach using low-impact development or LID.

LID technology involves mimicking natural processes of absorbing stormwater, such as rain gardens, roof gardens and lining trenches with more water-intensive native plants. These types of solutions will have to be built to work “in concert with the old drainage systems,” Chang said. “[Municipalities] will have to have a kind of holistic study of hypothetical models … from which we can figure out where LID technology can be implemented.”

Carney says policies could include greater requirements on new construction to raise buildings above flooding, but he also says one of the most effective tools is preserving green spaces. “The Dutch call it making room for the river,” he said, referencing a flood protection plan in the Netherlands.

When developments drains marshes and pave over previously wooded areas, “You’ve eliminated that system’s ability to absorb water,” Carney said.

Preserving green spaces or even turning land into water-absorbing green space, such as the Orlando Wetlands Park in east Orange County, allows water to collect away from housing.

“Natural systems have more space and flexibility,” said Carney, the UF scientist.

Mapping the flood

New development also partially explains why flooding happens in areas that weren’t designated as flood zones, Carney said.

“Once you’ve got 50 neighborhoods all in a row, that means the downstream people are going to have floods they never predicted,” Carney said. “If you’re putting people in those systems, you’re likely putting people in harm’s way.”

FEMA’s floodplain maps include any area with a 1% chance of flooding, or, put another way, areas that would flood in a 100-year flood event. But they are based on historical precedent, not predictions, according to the agency.

Homes and structures designated to be in floodplains are required to carry additional flood insurance. Last year, FEMA released Risk Rating 2.0 that rates flood risks to properties individually and prices policies accordingly, rather than charging the same rate for any home in a floodplain.

Only about 3% of homes in metro Orlando carry mandated flood insurance, according to information from the agency. According to Orange County’s Blackadar, 33% of the homes in the county that experienced flooding were in not designated floodplains.

Charlie Piper, a UCF professor whose home on University Acres Drive flooded without insurance, said her neighborhood became a drainage point for water around the city that “had nowhere to go.”

Even commercial buildings were caught off guard. Jeff Howard said his storage unit at a CubeSmart on S.R. 436 flooded. The company required customers to carry insurance for other types of disasters but not floods.

CubeSmart did not return a request for comment.

Theresa Rogers of Orlando’s Kingswood neighborhood, who did not carry flood insurance, had her house flood when a large tree fell over and blocked the storm drains on her street. “That can happen anywhere,” she said.

FEMA has paid more than $719 million in individual assistance already from Hurricane Ian, according to its website. Overall damage to the state has been estimated to as much as $75 billion.

In its email to the Sentinel, the agency urged people who are not in designated flood zones to consider getting flood insurance.

Roney, the Winter Springs homeowner who fought off the rising water, says she is considering flood insurance for the future. But she fears that if nothing changes, the damage could be more considerable.

“What if next time that whole pond lets loose?” she said.

Ian’s flooding fury – Total rainfall in inches

  • Downtown Orlando – 12.49
  • Orlando Int’l Airport – 13.2
  • Winter Park – 12.93
  • Winter Springs – 14.97
  • Sanford Airport – 16.1
  • Kissimmee – 14.49
  • Daytona Beach -16.57

SOURCE: National Weather Service in Melbourne

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