ST. PETE BEACH — Waterfront homeowners in the Don Cesar neighborhood and other flood-prone areas will soon be able to raise their seawalls to 5 feet above sea level using one of three city-supplied designs — and a single permit instead of four.
The designs, which double as aquatic habitat, are meant to curb the street flooding that hits the area during king tides and small storms.
Public Works Director Camden Mills said the city is a co-applicant with Ecosphere Restoration Institutes and the Tampa Bay Estuary Program in the search for natural ways to ease that flooding.
“We are producing template designs” that residents can use to “adapt their shorelines and install these living shorelines,” Mills said. They “can use these types of designs as references, which should help save on some of those upfront costs in hiring an engineer or designer.”
Tom Ries, president of Ecosphere Restoration Institutes, told commissioners a seawall wipes out habitat for aquatic life.
“All the action is happening in vegetation areas. That’s where the juvenile fish are, that’s where everything is,” he said. “When we take that out and put in a seawall, all we have left is upland and deep water. We lost all that habitat value.”
The fix doesn’t always mean tearing out the existing wall, he said.
“We’ve done these projects where a seawall will remain in place. We just put rocks and plants in front of it, so they are living seawalls now,” Ries said. “That rock ... is actually protecting the seawall. The waves aren’t hitting the seawall and causing resuspension.”
Resuspension occurs when waves or boat wakes strike a seawall and reflect back into the water, stirring up bottom sediment and clouding the water. Suspended particles such as sand, mud, algae and organic matter scatter and block sunlight, harming aquatic ecosystems.
Ries laid out the problem in a piece he wrote for the Invading Sea, an outlet covering climate change and environmental issues affecting Florida. Decades of filling bays and waterways to create waterfront lots left the state’s shorelines heavily hardened, he wrote, and replacing those walls with “nature-based design solutions, such as living shorelines” restores ecosystem function and, if done well, never needs replacing.
“The restored life and associated ecosystem services can naturally migrate upslope in response to sea-level rise,” he wrote.
Even so, he cautioned, any seawall left in place should be assessed and, where possible, raised to 5 feet NAVD — an elevation he said should protect adjacent infrastructure through at least 2050 under current sea-level projections.
Most seawalls in the area sit at 3.8 to 4 feet, Ries said. “If we don’t get them up to 5, just king tides will come into the streets.” On tight lots, he added, an integrated panel can be bolted onto an existing wall to create spaces “for critters to live.”
The upgrades won’t hold back a storm like Hurricane Helene, he cautioned, but “it will help for everyday high tides and small storms.”
Ecosphere Restoration, the city and the estuary program used a $39,000 grant and about $50,000 in engineering work to produce and permit the three designs, Ries said.
“What’s so unique about this is the designs we have will literally be given to all the residents that have waterfront property,” he said. “We designed these specifically so you need one permit instead of four. It’s very progressive that the city is doing this.”
The city will hand out the permitting guide along with a list of contractors who have agreed to use the permitted designs, so homeowners don’t have to file extra paperwork. Ries said he counted 70 waterfront houses with the same depth and conditions, “so these plans are easy to transfer.”
Commissioner Lisa Robinson praised the work. “I’m looking at the big picture. It’s great if it’s something we can share with other communities that are in the same situation,” she said. “We definitely do have some old seawalls and some tide issues, to say the least.”
Mayor Scott Tate asked how the approach would work on properties that have no seawall, just sloping mangroves. Ries said one surveyed house had mangroves growing over an original wall. There, he said, the design calls for a “seat wall” that sticks 16 inches out of the ground and ties into the seawalls on either side at an elevation of 5 feet.
The permitting design guide will be available from the city.