Flood risk in Orange County isn’t going away, according to a new, countywide flood vulnerability assessment. The study by Drummond Carpenter reveals the assets most vulnerable to flooding impacts in Orange County are categorized under either critical infrastructure, like sewer lift stations and stormwater ponds, or transportation and evacuation routes.
At Tuesday’s commission meeting, county staff presented key findings from the assessment funded in part by Resilient Florida, a state program that provides grants for local communities tackling challenges from flooding and sea level rise.
About 57% of critical infrastructure in Orange County will be at risk of flooding impacts by the year 2070, according to the vulnerability assessment. In addition to stormwater ponds, sewer lift stations and other wastewater treatment facilities, some of the other assets within that “critical infrastructure” category are marinas and boat ramps, electric vehicle charging stations and communication towers.
Stormwater ponds make up about 40% of the county’s critical infrastructure, according to data shared Tuesday by county staff and consultants. And by the year 2070, nearly 84% of those stormwater ponds are expected to be vulnerable to flooding in what’s known as a 500-year storm event.
Max Wallace, a senior engineer at Drummond Carpenter who worked on the assessment, told commissioners Tuesday the study was about weighing different levels of flooding risk throughout the county — not about identifying infrastructure that might be failing.
“I really need to emphasize that this isn't indicating that any of these [assets] are designed improperly,” Wallace said. “It's just that we're looking at these extreme [storm] events that are exceeding that intended level of service.”
The study uses 100-year and 500-year storm events to model how assets will likely perform under different flooding scenarios, as is required by the state grant funding. Those are standard terms used for weighing statistical probability; they’re not meant to represent the actual number of years expected between floods, according to the U.S. Geological Survey.
Lee Mullon, a principal engineer with Drummond Carpenter, said 2022’s Hurricane Ian showed how difficult it can be to precisely predict the likelihood and extent of a flooding event in any given year.
“These types of events can happen any given day, any given year … You can't put a time stamp on when to expect this,” Mullon said. “We saw it in 2022. We can see it again in 2025.”
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While the share of assets vulnerable to flooding is relatively similar across the county’s districts, in a 500-year storm event scenario, District 3 has the largest share of critical infrastructure expected to be vulnerable by the year 2070.
Commissioner Mayra Uribe represents District 3 and said it’s one of the oldest areas in Central Florida, built long before stormwater pond requirements.
“We’ve got neighborhoods where manmade ponds and so forth are just not able to sustain all the other development that's gone around it,” Uribe said. “What could have been an innocent pond for 50 homes — now, 200 homes are dependent [on] that same pond.”
A high percentage of parks and conservation areas in Orange County are expected to become more vulnerable to flooding. Wallace said that could actually be a good thing.
“This is actually really kind of meeting our expectations, because — especially the conservation areas, many of these are intended to act as these floodplain service providers, by storing these floodwaters and providing that relief,” Wallace said.
Additionally, parks aren’t generally intended to be used by people during extreme storm events, Wallace said.
District 1 Commissioner Nicole Wilson urged her colleagues to remember why setting land aside for conservation — and keeping it there — is so important, including for floodwater management.
“The data continues to show that investment in those conservation lands is worthy in more ways than one,” Wilson said. “We know we love recreating there. We know we love the benefit of having these beautiful places. But we also understand that …. we're potentially investing in something that can save a nearby community.”
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Some good news from the study: no potential flooding impacts were identified for affordable public housing, emergency operation centers or health care facilities.
“What we consider low vulnerability — these would include, actually, all of the facilities essential to government functioning,” Wallace said. “These are things like your fire stations, police stations, government buildings.”
Moving forward, Chief Sustainability and Resilience Officer Carrie Black said the plan is to share the study’s findings with the county’s Sustainability Advisory Board and community groups, as well as owners of the regionally significant assets identified as vulnerable to flooding.
From there, the county will use data from the assessment to evaluate and prioritize future Resilient Florida projects, as well as to help guide discussions on improving stormwater infrastructure in the county.
Public works staff are working on the second phase of a study evaluating stormwater utility rates in the county, Stormwater Resiliency Project Manager Julie Bortles said Tuesday. The goal is to present commissioners with a list of prioritized capital improvement projects by early next year.
