By Rachel Brown Hackney
The environmental scientist from Miami known worldwide as “Dr. Beach” told about 110 people at the Dec. 1 Siesta Key Association (SKA) meeting that South Lido Key residents “definitely need sand … but you can’t sacrifice what you’ve got for another area.”
Dr. Stephen Leatherman, a professor and director of the Laboratory for Coastal Research at Florida International University — known for his Top 10 U.S. beaches lists — was addressing the proposal for the dredging of 1.2 million cubic yards of sand from Big Sarasota Pass to renourish about 1.6 miles of South Lido.
“I think you ought to have an Environmental Impact Statement [EIS] done,” Leatherman said, earning a round of applause. “I think we need to really study this very carefully and leave no stone unturned. If it takes more time [to undertake the EIS], so be it.”
Leatherman’s comments came just two days after the Sarasota County Commission received a letter from the U.S. Army Corps of Engineers (USACE), turning down the board’s Aug. 23 request to pursue an EIS on the Lido project. In July, the SKA formally asked the County Commission to seek the EIS.
“I think we have to do no harm,” Leatherman said in an allusion to the Hippocratic Oath that physicians take. “We can’t rob Peter to pay Paul,” he added of removing sand from Big Pass to renourish Lido. He did acknowledge the Lido shoreline erosion, nonetheless.
“Once the [USACE] gets rolling on a project,” Leatherman pointed out, “it could go on for 50 years.”
Although the permit the City of Sarasota and the USACE have applied for from the Florida Department of Environmental Protection (FDEP) would be for 15 years, Brandon Burch, manager of the Lido project for the USACE, reiterated in Sarasota what his predecessor, Milan Mora, told community residents in September 2013: The Lido Renourishment Project has been planned for a 50-year period. Burch was one of the speakers who welcomed the public to an FDEP open house on the project on Nov. 30.
“As these Corps projects go,” Leatherman continued at the SKA meeting, “you can’t change them around, really. … They are set in stone.”
He added, “I’d be very worried about dredging large, deeper channels, unless you want to go the whole way, like New Jersey, and put jetties in and play that game. … Once you go down that path, you’re going to have a whole different system here.”
The most recent material the USACE submitted to FDEP, in late August — in response to questions from state staff — says the two primary borrow areas targeted for the initial renourishment project are B and C. B “is a southern extension of the existing [Big Pass] channel offshore of Siesta Key,” while C is “within the ephemeral channel” of the pass.
“I guess you could take a little bit of sand and see what happens,” Leatherman said — perhaps just a few hundred thousand cubic yards from the pass’ ebb shoal.
“Then if nothing bad happens over a period of years,” he continued, the USACE could take a little bit more for Lido.
When former SKA Director Bob Waechter asked Leatherman whether he considered 1.2 million cubic yards of sand a small amount of sand, Leatherman replied that he did not.
Leatherman did stress more than once that he was not appearing at the SKA meeting because he had been hired as a consultant on the Lido project. “I’m not actually working on this for anyone.”
‘Models aren’t perfect’
SKA First Vice President Bob Stein asked Leatherman to explain what an EIS is, for those in the audience who might not be familiar with such a study.
With an EIS, Beach replied, “you have to consider all the situations, not just the [dredging of the] sand itself.” The research would include a focus on ecological factors, such as fauna, flora and fishes, he added. “It’s a complete analysis done in an area.”
In response to an audience member’s question about whether he would feel comfortable seeing the Lido project go forward if an EIS showed that it would have no negative impacts, Leatherman said, “Every place is a little bit different. … Models aren’t perfect.”
Even if the EIS indicated no problems would be expected, he continued, he still would consider the first dredging of sand as an experiment. “Coastal engineering … sometimes is more art than a science,” he added. Beaches seem simple, he noted, but they are not.
Leatherman told the audience that when he was a professor years ago at the University of Maryland, he offered a class on beaches and wave energy. About 250 students signed up for it the first year, he continued. “It was full of football players,” who thought a course about beaches would have to be easy, Leatherman said. “After the first midterm, they were all gone.”
The science of currents and wave action, he noted, is “not like the physics of gravitation.” With wave energy, he stressed, all one can do is deal with approximations. “We don’t know exactly how that all works.” Referring to the math involved in the modeling, he added, “These equations aren’t perfect, and so we make assumptions.”
In emphasizing that point, Leatherman related an anecdote about his having been hired as a consultant to the Town of Kiawah Island, S.C., about 10 years ago. Kiawah Island lies south of Folly Beach County Park, which is one of the few state parks in the Charleston area, he told the audience. “The beach [at the park] was getting very narrow,” more than a decade ago, he said, so the USACE and the State of South Carolina decided that to renourish it, they should dredge a very deep channel in an area built up by sand that had eroded from the park. After all, he continued, they figured that would be the best quality of sand for the renourishment.
A few years after the dredging, a big shoal that was known as Bird Key — a well-known bird-nesting area between Folly Beach and Kiawah Island — just disappeared. Additionally, he said, at the north end of Kiawah Island, where the world-famous Ocean Course golf course is located, “they were losing the 18th green. This is serious business.”
He worked with the people on Kiawah Island to use available sand to reconnect the 18th green to the rest of the island. “This is a case where there was modeling done [by the USACE],” he pointed out.
Leatherman asked the audience members to think about what happens when someone digs holes in a beach in a tidal zone. “[The holes] fill in … There is an equilibrium to things.”
He further explained that in renourishing a beach where the goal is to make it wide and flat — as proposed on Lido — “about 90% of the sand is underwater, just like an iceberg.”
- Tags: Dr. Beach