Facing a future of flooding, Hillsborough County officials ponder how to keep communities above water

Researchers have spent two years identifying Hillsborough’s weaknesses in the face of sea-level rise. Now it’s up to county officials to do something about it.
When Hurricane Michael made landfall  in October 2018, the eye of the storm was 300 miles away from downtown Tampa. Yet Bayshore Boulevard along the city's waterfront was still flooded by a swollen and violent Hillsborough Bay.
When Hurricane Michael made landfall in October 2018, the eye of the storm was 300 miles away from downtown Tampa. Yet Bayshore Boulevard along the city's waterfront was still flooded by a swollen and violent Hillsborough Bay. [ JAMES BORCHUCK | Tampa Bay Times ]
Published Oct. 30, 2019

TAMPA — To county officials, the headlines are the stuff of nightmares.

The waters in Tampa Bay could rise above today’s sea level by as much as 8.5 feet by 2100, one report says.

Just constructing the necessary sea walls will cost Hillsborough County an estimated $2.7 billion by 2040, another study found.

But it’s the safety of the people living here that keeps University of South Florida researchers up at night. That’s true even for those living far from the county’s coast line — the people asked to “shelter in place” in communities like Gibsonton and East Tampa that are well outside evacuation zones.

Most homes in those communities were built before Hurricane Andrew ushered in a wave of changes to state building codes. And their largely low-income population can’t afford to fortify those houses and may struggle to purchase enough supplies to ride out a storm.

Related: RELATED: Will the Tampa Bay area be under water in 100 years? Rising seas tell a frightening story

Working with county experts and the College of Public Health, researchers at USF’s Florida Center for Community Design and Research have spent two years gaming out climate scenarios while creating the county’s first-ever comprehensive “Community Vulnerability Study” — a definitive list of preparedness plans and potential flood risks within the Tampa Bay area.

“We wanted to take a systems approach and think about this holistically because these vulnerabilities don’t happen in isolation,” said Brian Cook, an assistant research professor at USF’s School of Architecture and Community Design.

Last week, county commissioners got a look at the first part of their work, a 470-page handbook available on the Hillsborough Planning Commission’s website. It is intended to serve as the scientific bedrock for further studies on how Hillsborough can best tackle this issue.

Related: RELATED: Climate change is here. Will Tampa Bay finally get ready?

The heart of the project compiles a decade’s worth of research studies on flooding in the Tampa Bay area, identifies more than 100 potential “vulnerabilities” existing within Hillsborough County today and curates and compares other plans from surrounding local governments, state and federal agencies and other nations.

The risks were grouped into categories then plotted on maps that the researchers could overlay in countless combinations. Once risks were identified, they were marked on maps showing projected flood zones for the year 2045 — the same maps used by agencies such as the Metropolitan Planning Organization when it plans future projects.

Researchers say the maps back up numerous studies in recent years that have placed the Tampa Bay region among the most vulnerable in the world to climate change. And the risks, they say, could be even greater than anticipated.

Take, for instance, hotel placement. After plotting Hillsborough’s 482 hotels on the projected flood zone maps up to the year 2045, the team found that only 188 — or about 39 percent — were located in areas that would remain unaffected by storm-related flooding.

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That means the county should not only prepare to fortify, fix or completely rebuild many of those structures in the future, but will also have to consider how best to evacuate 30,000 to 50,000 guests. Many could be tourists who don’t know where to find a safe location to ride out a storm.

“There is a big proportion of our hotel stock built along the coast because we’re capitalizing on our geography, but these are some of the other things we’ll have to think about,” Cook said.

Related: RELATED: Florida could face $76 billion in climate change costs by 2040, report says

Another example: Hillsborough County is home to 17 of Florida’s 92 “superfund sites" contaminated by hazardous waste. Most are clustered together in parts of east county that are quickly sprouting large housing developments, the researchers found.

If a Category 3 storm were to blow through the unincorporated region, 8 of those sites would be inundated with toxic water. The area of most concern is the Raleigh Street Dump, a heavily contaminated site located off U.S. 41 that could be easily flooded by even a Category 1 hurricane, causing battery waste, fiberglass chemicals and other free-flowing contaminants to spill into the water supplies for nearby neighborhoods.

While the study is still not complete, the team has already identified other tasks for the county to address, including the number of families reliant on public transportation who are living in hurricane evacuation zones, the volume of water-absorbing wetlands being paved over in flood-prone south Tampa, and the growing gap between the county’s population and its drainage and road capacity.

“We have gathered as much information as possible, looked at what other communities around the state, the country, and the world are doing, and now we feel that we really do have one of the most robust studies that’s ever been done in the state of Florida,” said the design and research center’s Director, Taryn Sabia.

This story was produced in partnership with the Florida Climate Reporting Network, a multi-newsroom initiative founded by the Miami Herald, the South Florida Sun Sentinel, The Palm Beach Post, the Orlando Sentinel, WLRN Public Media and the Tampa Bay Times.