Nearly a decade after dredging Port Miami left a swath of dead coral yet to be repaired, a new federal assessment confirms damage was far more widespread than originally reported.
The National Oceanic and Atmospheric Administration report found dredging and rock chopping that pulverized the ocean bottom created a blizzard of silt that buried at least 278 acres around the reef, and likely far more. The report upholds previous findings and will be used to permit future dredging as well as long overdue repairs.
Those repairs, which should have started within a year of the dredge ending, could wind up costing Miami-Dade County hundreds of millions of dollars under a 2012 contract signed by the county.
Miami-Dade County officials said Thursday they were reviewing the report. Any estimate on costs to mitigate damage would be premature, they said.
In a statement, Mayor Daniella Levine-Cava said the county was working with the Florida Department of Environmental Protection on a mitigation plan to repair damage.
“I’m deeply concerned about the damage of coral colonies and committed to learning everything we can about what took place and where we go from here,” she said.
The Florida Department of Environmental Protection said Thursday it was still looking into the matter.
The report comes as conditions on Florida’s ailing reef continue to worsen, fueled by pollution and climate change.
An ocean heat wave over the summer triggered widespread bleaching in the Keys, while stony coral disease, which was identified near the dredge site in 2014 and can be spread in sediment, continues to sicken the entire 300-mile long tract.
The reef is the only inshore barrier in the mainland U.S. and provides a powerful barrier to increasingly powerful hurricane storm surge. One study put the price of protection from fierce hurricanes at $1.8 billion just between Fort Lauderdale and Miami.
The Army Corps is also gearing up for more dredging at Port Miami, raising concerns over the delay in addressing damage from the earlier project. Corp officials said this month a tentative plan is due by October 2024.
“How can we be thinking about dredging Port Miami again without having fixed the damage that was done in 2015 and before?” said Miami Waterkeeper executive director Rachel Silverstein, whose nonprofit has repeatedly battled the Corps in court over damaging work.
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In a report prepared in response to the NOAA assessment, Waterkeeper estimated that the county could face up to $400 million in costs if the traditional practice of repairing reefs by dropping boulders on the ocean floor is followed. That work usually costs between one million and $1.5 million dollars per acre, the report said, and provides no guarantee that coral will recover.
Because of the uncertainty, Silverstein said more lasting tactics should be used, including creating a coral restoration center that informs future dredges and scales up coral nurseries racing to keep up with replanting the reef.
“I propose that we do something better and that we negotiate some kind of a plan where we are putting Miami's restoration programs for our reefs on steroids,” she said. “We flush them full of funding to test every scientific method and new idea and pilot and see what works. Scale coral restoration at an industrial level here in Miami-Dade County. Bring our reefs back. Show the world how to do it.”
As the dredge unfolded between 2013 and 2015, it continually raised concerns.
Corps officials estimated the $205 million project would wipe out about seven acres of reef, including five undisturbed acres at the mouth of the channel, and eight acres of seagrass meadows.
Corps officials originally planned on transplanting only threatened species, including 38 staghorn corals. But after environmental groups sued in 2011, Miami-Dade County and the Corps agreed to transplant coral from about 16.6 acres and eventually moved about 1,000.
But within weeks, anglers, divers and scientists started complaining about widespread impacts, even to the transplanted coral.
A charter boat captain photographed a plume of sediment flowing from a barge sailing to an offhsore dump site. Divers, including scientists with the National Marine Fisheries Service sent to inspect the area, found coral smothered in fine sediment.
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Silverstein, who’d just completed a Phd studying coral at the University of Miami, went to confirm the reports.
“This huge dredging ship [was] churning the water and making the water vibrate around us while we were diving,” she said. “ You couldn't see your hand in front of your face here was so much sediment in the water. And the current was just ripping.”
Photographs taken at the time show a moonscape of coral, shrouded in sand. In their report, NOAA officials said dredgers used a method of chopping up the ocean bottom before dredge work followed, which suctioned up sediment. That chopping method was not included in an environmental impact statement. Instead, the report said dredgers planned to use isolated blasting three times a day over the 1,300-day dredge.
“Rock chopping is the practice of using the draghead of the Cutterhead Suction Dredge to grind, pulverize, or pound the rock without the suction function engaged,” the report said.
The chopping created a silty clay-like “rock flour,” that caused the most concern, the report said.
Because of the damage, rock chopping will not be used in the Port Everglades dredge.
As work proceeded, tension mounted among federal and state agencies. Environmentalists made repeated trips to court to clean up work. A lead biologist was found guilty of lying about working for a consultant, which could have jeopardized monitoring and sentenced to two years probation, although she was given time for a Disney Cruise. NOAA divers — told they could assess the damage — were twice blocked by the dredgers.
Despite the warnings, the environmental monitoring firm hired by Corps officials to track problems denied any widespread damage, concluding just six corals were killed.
“Based on what I had seen myself, what I had read, from what others had seen, I knew that that was patently impossible,”Silverstein said.
In 2018, the Corps agreed to settle the lawsuit filed by Waterkeeper, the Miami-Dade Reef Guard Association and Tropical Audubon by paying to replant 10,000 staghorn coral.
Silverstein said the victory was premature.
“Since then, we've now realized that [even more] corals were killed in that project, which was the report that came out this week,” she said. “And the rest of the damage that was done has never been restored.”
A mitigation plan was supposed to be developed based on a year of post-construction monitoring.
“But here we are. The project ended in 2015. We're here in 2023 and we still have no formal impact assessment from the state,” she said.
With another dredge on the horizon, Silverstein said the latest report highlights the need to come up with better dredging and monitoring rules.
“There was still this really big open question of needing a final government report that told the story of what actually happened to the corals at Port Miami. And so this report is critically important,” she said. “It’s even more powerful coming from a government body that is also saying this was a huge amount of damage to a national resource in Miami's backyard.”
