As the Tampa Bay region slowly but surely rebuilds infrastructure ranging from beaches to the baseball stadium, one bright spot stands out. Living shorelines, even in locations with the highest wave energy, generally came through all three 2024 hurricanes with minimal damage.
“We were surprised at how well the living shorelines we’ve assessed so far – including those that were most likely to be impacted by storm surges and high winds – weathered these storms,” said Tom Ries, president of the non-profit Ecosphere Restoration Institute. “It’s a testament to the value of these nature-based shoreline stabilization solutions when they can withstand the worst hurricanes this region has seen in decades.”
Serra Herndon, director of habitat restoration at Tampa Bay Watch (TBW), concurs. “Our living shorelines performed as we hoped and expected,” she said. “The triumphs are Lassing Park in St. Petersburg and MacDill Air Force Base where areas in which living shorelines had been completed withstood noticeable damage while other adjacent areas that were not protected experienced significant impacts.”
A living shoreline is a protected, stabilized coastal edge made of natural materials such as plants, sand or rock. Living shorelines are an important part of the Tampa Bay Estuary Program’s habitat restoration plan because they provide habitat and filter pollutants while offering protection against erosion. One size does not fit all, but there are numerous soft design options that are better than vertical walls, which have extremely limited ecosystem service elements. Learn more here: https://baysoundings.com/living-shorelines-provide-habitat-protect-inland-areas/
The north end of Lassing Park looks as though it hadn’t been hit with high winds and six to eight feet of storm surge, and coastal marsh grasses are thriving in spite of the inundation. The southern section, where living shorelines hadn’t been installed, is highly eroded.
The impact was also clear at MacDill, where funding and permitting required gaps in the living shorelines. “The oyster reef balls and salt marsh are still intact and as green and vibrant as ever, even though they had beaches and docks washed out in other locations,” adds Eric Plage, TBW’s environmental scientist. “You can see some damage in the marshes where storm debris is covering them, but otherwise, they look great.”
MacDill officials are working on obtaining emergency funding to fill the gaps in the living shoreline, Herndon said.
Audubon’s living shorelines, including more than a mile of concrete breakwaters protecting critical bird nesting habitat in Tampa Bay, also fared well, said Audrey DeRose-Wilson, director of bird conservation. “The concrete wave attenuation units protecting the Alafia Bank Critical Wildlife Area did not shift as the storms moved through. Some mangrove trees were lost, which resulted in a loss of wading bird nesting habitat, and we are still waiting for additional reports on erosion at other locations in the Coastal Islands Sanctuaries.”
Ries, who has designed or installed more than 50 living shorelines over the past 30 years, has evaluated some of the shorelines where he expected to see the most damage.
Hurricane Debbie originally damaged Bayfront Park in Sarasota in 2012, when wind and water pushed boats ashore and lifted the sidewalk. Working with a small budget, Ecosphere partnered with the Sarasota Bay Estuary Program to put in native plants and signage explaining their importance behind a small line of rocks. Fast forward five years, and Hurricane Irma came through in 2017 with minimal damage, although the winds from that storm didn’t directly hit the park.
Hurricane Helene pushed three feet of water ashore and killed nearly all of the plants but left the shoreline and sidewalk mostly intact, Ries said. “We knew this was a temporary educational spot, and that we’ll need more than just plants to hold back that kind of energy. Going forward, we’ll want to work with a coastal engineer and put in something offshore to break up some of that energy and an earthen berm at a five-foot elevation using the North American Vertical Datum of 1988 to protect the sidewalk.”
The City of Bradenton was planning to replace a failing seawall at Manatee Mineral Springs Park when Ries met with officials in 2022 and persuaded them that they didn’t really need a new seawall. Working with coastal engineers at Environmental Science Associates, rock was installed where the seawall had been, with oyster bags and domes serving as breakwaters.
“It’s been in the ground for less than a year, but nothing moved – oysters have colonized all the hard surfaces already,” Ries said. “The park faces north, so it didn’t get the full brunt of either storm but it’s good to see that these structures are working in this location.”
Every shoreline has its own challenges and a failing seawall with a nearby sidewalk at Frenchman’s Creek on Eckerd College raised multiple issues. “We wanted to take the seawall out and move out into the water, but there were oysters and seagrasses right up against the seawall,” he said. “Instead we lowered the seawall, elevated the sidewalk, and planted the slope with native plants.”
That was 45 days before Hurricane Helene struck and shoreline erosion was an issue. “We had a lot of sand wash over and kill the plants, but structurally, it’s still fine. I don’t think it would have eroded at all had the plants been in the ground longer.”
Ongoing erosion at Apollo Beach Park in south Hillsborough County both created problems and allowed planners more leeway in designing solutions because there were no seagrasses or oyster beds in a high-energy location with an eight-foot escarpment, Ries said. The park’s first shoreline stabilization attempt used Envirolok geobags planted with marsh grasses. “They washed away in the first storm and it wasn’t even a hurricane.”
Working with coastal engineers hired by Hillsborough County, Ries directed the installation of a series of offshore breakwaters with marsh grasses planted behind them. “The breakwaters held, there was minimal erosion and the rocks are all in place.”
Ries helped design another living shoreline at Safety Harbor’s Waterfront Park when its aging seawall needed replacement. “This is a high-energy location, and we couldn’t just use plants,” he said. Instead, the seawall was cut to the mud line and used as a base for oyster bags coupled with rock and estuarine plants behind them.
“If you visit now, the first thing you’ll see is that the rocks are still in place with nothing eroded, although the plants need to be replaced. The second thing you’ll see is the pier is gone – this was a six- to eight-foot tidal surge. The shoreline is going to need some work with new rocks and plants, but it held.”
Managers are hopeful that the success of living shorelines through severe storms will encourage more people to consider using them instead of seawalls, or at least modifying seawalls to create hybrid living shorelines, Herndon said.
“I think all of us who have been building living shorelines feel some vindication,” she adds. “There are some important lessons learned, but we’re looking at three decades worth of living shorelines showing that they do stop erosion while still providing habitats.”
Originally published Dec. 10, 2024