WILMINGTON –– A lawsuit filed in federal court against the U.S. Army Corps of Engineers highlights the deadly environmental cost of dredging the Wilmington harbor: bludgeoned sea turtles.
Each year, the corps’ south Atlantic division kills dozens of endangered sea turtles over the course of its federally mandated duties of dredging navigation channels along the coast.
From North Carolina to Alabama, hopper dredging killed at least — and likely well over — 500 endangered sea turtles in the south Atlantic division between 1980 and 2015 (representing only maimed turtles counted and self-reported by USACE, this is considered a conservative estimate, according to a comprehensive 2017 study commissioned by the Bureau of Ocean Energy Management on the practice).
The National Marine Fisheries Service limits the number of sea turtles killed across USACE’s districts so as to not place a species’ survival in jeopardy. Green, loggerhead, and Kemp’s ridley sea turtles are frequently crushed in the process of dredging the roughly 18-mile hope dredge channel along the Wilmington harbor, stretching from beyond Frying Pan Shoals past Ft. Fisher.
This year alone, dredging activity has killed five sea turtles in the Wilmington district (three while clearing the Wilmington harbor for commerce and military activity; one during Oak Island’s renourishment project to beef up the hurricane-depleted shoreline; one tending to the Morehead City port).
A hopper dredge returned to the Wilmington harbor and killed the channel’s third sea turtle of the year last week, according to Ramona McGee, an attorney representing conservation plaintiffs against USACE in a suit filed earlier this month.
“These are only the ones that we know about, or, better yet, the ones that the corps knows about and has decided to count as being attributed to a dredging operation,” McGee said.
Hopper dredges vacuum the maritime floor, sifting material through screens and dumping it on deck to be either disposed of as spoils or fanned out along the region’s beaches if it’s high quality. Dredges frequently come across bulky debris in the Wilmington harbor, often leading to reduced screening size or no screens at all, according to an extensive biological opinion issued last year by the National Marine Fisheries Service.
The impacts on smaller species are unquantified. Biological debris is so unrecognizable on board, observers cannot identify which species are being killed, according to the lawsuit.
Since the ‘90s, the corps has adhered to a self-imposed dredging window, limiting the mud- and sand-disturbing activity to winter months and banning it in warm spring and summer months, when biological activity is known to be more abundant. Environmental windows aren’t a precise science; the 2017 BOEM study found industry stakeholders collectively wished to improve and refine the timeframe based on data and operational logic. Still, it’s undisputed sea turtles are more active in warmer waters, but more research is needed on their specific movements and migration patterns.
All turtles killed by the Wilmington district this year were sucked into the dredge machinery after April 15, a previously off-limits timeframe. Even in cooler months, kills are inevitable when the dragheads are running; in fiscal year 2017, two turtles were killed in November and one in January during a Wilmington harbor maintenance project.
Last year, the corps initiated a process to drop its long-held, self-imposed window at both the Wilmington and Morehead City ports between December 1 and April 15 and open up hopper dredging year-round.
“Removing the historic seasonal dredging window is not intended to allow dredging any time of year in every location,” the corps reported in its “finding of no significant impact” in February. “It is about using the best available information to make informed decisions based on the current situation.”
This spring and summer, the corps dredged along the southeastern coastline, well outside its old window, for the first time in decades (occasionally, projects could get extended slightly beyond the thresholds but only on a case-by-case basis).
A federal judge sided with the environmental group One Hundred Miles in May, barring USACE from dredging in the summer months at the Port of Brunswick in Georgia. By July, USACE’s Savannah district announced it would adhere to its traditional dredging windows. The same month, the corps released a bid solicitation for work in the south Atlantic district in fiscal year 2022 that would restrict dredging to winter months in the Savannah, Brunswick, and Charleston harbors; no such limitation was included for the Wilmington or Morehead City harbors.
On Aug. 4, the nonprofits Cape Fear River Watch, N.C. Wildlife Federation, and Defenders of Wildlife sued USACE and Col. Benjamin Bennett in his official capacity as commander, seeking injunctive relief and requesting a judge vacate the corps’ environmental assessment that led to its decision.
Filing the suit was necessary for the North Carolina harbors “because the harms to wildlife and coastal resources is so severe,” explained McGee, the Southern Environmental Law Center attorney. “The agency’s missteps in completing an inadequate environmental review and engaging in unreasoned agency decision-making are so egregious.”
USACE referred an inquiry to the Department of Justice. A DOJ spokesperson said the agency is aware of the suit and reviewing it.
Regional contract, saving money
An uptick in demand for hopper dredging and a national shortfall in contractors capable of conducting the work has imperiled several contracts in the Wilmington district, according to the corps’ assessment last year, with bids either too high or proposals failing altogether.
USACE has packaged its dredging contracts across its entire south Atlantic district to save costs, using the same company tasked with working their way up the coast on a single contract. Each fiscal year, USACE oversees $4.1 million in maintenance dredging work at the Port of Wilmington; it reported it could save a quarter-million in the harbor annually if the dredging windows were eliminated.
Keeping the window could mean Wilmington and Morehead City decoupling from the regional contract, “putting them at risk of not being dredged on a regular basis or at a reasonable cost,” the corps concluded in its February environmental impact assessment.
The Wilmington district’s funding allotment for maitaining the harbor is often inadequate, the corps reported in its assessment, “so maintenance dredging has to be reduced to the bare minimum to keep channels open to navigation.” On occasion, this has interfered with safe navigation of the channel.
The assessment acknowledges important fish species are more abundant in warmer temperatures, but also states “it is unknown how effective these windows are and whether they are a necessary tool for avoiding impacts.”
A majority of turtle deaths in the Wilmington and Morehead City harbors between 2016 and 2020 occurred during March and April (inside the window), according to a corps assessment.
In reviewing the draft assessment, the N.C. Department of Environmental Quality concluded the corps didn’t compile enough data to justify the change; to satisfy this concern, the corps and DEQ agreed to drop windows for a three-year trial period.
Conservation agencies, which meticulously followed and reviewed the rule-change, aren’t satisfied.
“Agencies have the duty to objectively and fairly assess a reasonable range of alternatives and to not simply justify decisions already made,” McGee said. “It’s concerning about whether the agency was objectively approaching the drawing board, so to speak, to say, ‘OK, what is our best solution here?’ Or whether they just decided to remove dredging windows and kind of reverse-engineered everything around that.”
The corps solicited bids for its regional harbor dredging contract in August 2020 –– before the public comment window on the rule change elapsed –– advertising no spring or summer bans to companies it was soliciting. It awarded the windowless contract mid-September 2020 to Great Lakes Dredge & Dock Company, before the public comment period had ended.
Efforts to reduce sea turtle kills and other adverse environmental impacts while dredging have been explored since the ‘80s. Employing a range of costly mitigation measures, contractors use various tactics to avoid sucking up sea turtles. Vessels run trawls, designed to gently capture and dissuade larger species from congregating in an area ahead of dredging. However, even trawls –– intended to save large species in a dredge’s path –– can and have killed turtles in the process.
The corps hires onboard observers, which look out for turtles and detail when the reptiles get entrapped in dredge equipment. All turtle “takes,” as it’s called, are documented on a corps database, including detailed incident reports for each encounter.
Clusters of horseshoe crabs, wood, and seagrass frequently accumulate on intake screens, intended to shield large objects from entering. Two-foot-wide pipes suction the ocean floor with up to 10,000 horsepower, causing blunt-force trauma to most marine life caught in their path.
Turtles become entrained when they get sucked into a dredge’s draghead and their bodies course through a centrifugal pump before getting dumped onto the vessel — if they don’t clog the equipment.
Reports include images of dismembered turtles, their barnacle-covered shells crushed, pink flesh peeking through. Some depict just a fin or two –– the rest of the creature still somewhere at sea. Rarely, turtles survive the upheaval and are promptly delivered to nearby rehabilitation facilities.
Many die in the process. A study last year found gas emboli, the precursor to decompression sickness, in turtles that both died and recovered after being found alive after hopper dredging activities in North Carolina. Researchers note massive tissue trauma likely caused the deaths, but gas emboli could have complicated recovery.
An author of that study, Dr. Craig Harms, a doctor of veterinary medicine at N.C. State University, told the Carteret County News-Times he wasn’t opposed to dredging –– the maintenance is vital to the region’s economic health, he said.
“But this is a cost that shouldn’t be glossed over. ‘Lethal take’ is an antiseptic euphemism for running a live sea turtle through a wood-chipper, and there are ways to minimize the number of turtles making that trip,” he told the paper. Harms added in recent years, the corps has not covered the cost to rehabilitate the few turtles that manage to survive entrainment.
Sea turtles aren’t the only endangered species killed by federally funded dredging contracts. Atlantic and shortnose sturgeon are known to traverse the harbor, but these interactions are rare. The corps recognized dredging in spring and fall migration season could increase lethal takes of sturgeon but also concluded impacts to the species would be insignificant, the conservationists point out in their filing.
“Limiting dredging to a certain season has worked for decades without an issue. Any time dredging happens, there are possible harms,” McGee said. “The point here is that spring and summer are just very biologically active times of year.”
“It makes sense to avoid those times of year. It really comes down to using the best avoidance and mitigation measures to ensure that dredging is done in as safe a way as possible,” she said.
Send tips and comments to Johanna F. Still at email@example.com