- December 4, 2024
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Longboat Key’s beaches might look a little different to snowbirds returning for the season. Hurricane Helene is largely to blame.
“Beaches stand as your first line of defense, and they did their job. But it came at a cost,” Town Manager Howard Tipton said at the town commission’s Nov. 12 workshop.
Interim Director of Public Works Charlie Mopps was joined by Dr. Al Browder, senior coastal engineer of The Foth Companies, to present the annual beach update on Nov. 12.
Estimates from Browder’s team showed that Longboat Key’s beaches have lost about 60% of the sand that’s been placed on the island since 2021. A good portion of that was lost this summer.
“The triple threat basically took a lot of our sand away,” Mopps said.
All three storms — Debby, Helene and Milton — brought big waves, but it’s the storm surge that causes the most damage.
“The question, really, and the differences in impacts, has a lot more to do with how high was the surge level at the time those big waves came rolling up on the beach,” Browder said. “And that’s where the real distinction between events comes in. … Hurricane Helene is the primary story here in all of this damage to the beach.”
The storm surge in Helene reached over 6.5 feet, according to estimates by Browder and others.
After Milton delivered one last punch on the island this hurricane season, Browder’s team took another look at Longboat Key’s beaches.
They estimated that about 643,000 cubic yards of sand eroded from the beach and the dunes.
About 12 cubic yards of sand per foot of beach was moved among the three storms.
“That doesn’t necessarily mean lost, but it got moved from the place where we wanted it. You want it on the beach, you want it on the dunes, you want the wide recreational space,” Browder said.
When considering the amount of sand offshore and still in the island’s “system,” the amount lost is more like 407,300 cubic yards.
That’s what will be considered a loss in the town’s claim to the Federal Emergency Management Agency. The agency won’t view the offshore sand as “lost,” Browder said.
Looking at the beach, it has visible differences from before the summer. Less vegetation, flatter.
“All the vegetation has been severely stripped back, but there’s still a substantial volume of the dune still in place,” Browder said. “So it took quite a beating, but it definitely prevented a lot of damage.”
The fact the dunes look different is a testament to their effectiveness.
“If that dune feature wasn’t there prior to Helene and this insane year that we’ve had, there’d be a good chance that we’d still be rebuilding GMD,” Mopps said about the importance of the dunes.
Before the storms, Browder said the island’s beaches were performing as expected. The current groin structures on the north end were stabilizing the shoreline and building the beach.
There still exists some “hot spot” problem areas, though, even before the hurricanes.
“The mid-key shoreline experienced a lot of erosion consistent with the historical trends that we normally see,” Mopps said
The Gulfside Road beach is the main problem.
This naturally erosive beach’s problems are exacerbated by manmade seawalls on that road and, at a previous commission meeting, Mopps and Browder told commissioners a short-term and long-term solution was likely necessary to fix the problem.
Now, the town is in the middle of an interim beach nourishment project to place 80,000 cubic yards of sand on the Gulfside Road beach, dredged from Longboat Pass.
The bid price was around $2.5 million for the sand placement, with an all-in estimate of $2.7 million when considering mobilization and other factors.
Mopps said, if the town can get this completed quickly, there’s a good chance of full reimbursement from a Florida Department of Environmental Protection program.
Either way, Mopps said the town will likely get some money from the FDEP for this project.
Going forward, Browder believes a groin field at Gulfside Road is the right solution and a necessary one.
“You can’t afford to continue to throw sand out there over and over and over again forever,” Browder said.
This will include eight groins, seven of which are T-head groins, named for the shape of the structures. The structures will get smaller as they go south, a gradual transition that's necessary to prevent a steep drop-off.
All of them will be largely made of gravel-filled, geotextile material with rocks to create the end of the T. The rocks are easy to manipulate and can be moved to adjust down the road, if necessary, Browder said.
It’s a delicate arrangement, according to Browder. The structures need to lock down the sand but can’t be arranged in a way that could cause more problems down the beach.
District 4 Commissioner Debra Williams expressed concern about potential down-drift effects, but Browder assured her that modeling allows the engineers to prevent such effects.
Plus, Browder said Department of Environmental Protection permits are extensive and would assess these possibilities.
Commissioners didn’t raise much opposition to the idea of a long-term solution at Gulfside Road, and Browder said the team is preparing to go into the permitting process for this project.
This will be a long process, though.
“Big structures placed on the open coast is a big permitting deal, so they're going to take their time evaluating this,” Browder said.
In the meantime, Mopps and town staff will have to work with FEMA to try to get reimbursed for the lost sand from this summer’s hurricanes.
After the town knows if it will get monetary compensation, staff can create more concrete plans.
“It sounds like the next thing we need to do is figure out whether or not we’re going to get 407,000 cubic yards paid for, or largely paid for,” Schneier said. “Once we know that, we can come back to decide on some options, how to deploy that sand…and if we want to do more.”
