Muck Disposal Raises Alarm: A Plan to Dump Excavated Muck in a State Park and Tree Farms is Adding to the Growing Environmental Questions Surrounding the 18-Mile Stretch Widening Project
By Curtis Morgan, The Miami Herald
Nov. 24–Work to widen the 18-Mile Stretch, already under a multiagency microscope because of a massive algae bloom tainting surrounding waters, has a new problem: Tons of excavated muck and mulched mangrove are fast piling up along the main road into the Keys.
Contractors, backed by the Florida Department of Transportation, want to truck part of it to a nearby state park in North Key Largo, where it would be used to help fill illegally dug rock pits. The rest would be spread in vacant tree farms in Florida City.
The disposal plans have been held up by questions from South Florida water managers and federal and Miami-Dade County regulators.
They have also alarmed environmental groups, who have clamored for the soggy mounds to be hauled away, but are now worried about ripple effects from depositing as much as 20,000 cubic yards of suspect stuff into rock pits a megayacht’s length away from the Atlantic Ocean.
The three-acre, 36-foot-deep basins were dredged by developers of the long-defunct Carysfort marina, and are now part of Dagny Johnson Hammock Botanical State Park off Card Sound Road.
Residual contaminants could flow through porous coral bedrock with every tidal change, potentially harming sea grass, reefs and marine life and even spreading the algae bloom to a new and unaffected area, said Alex Score, a marine conservation specialist with the World Wildlife Fund in Key Largo.
“It’s all connected down here. That’s why we have such a big issue with treating our waste water in Monroe County,” Score said. “This doesn’t seem like it would fall under the best management practices of a state park.”
But officials with the DOT and the Florida Department of Environmental Protection, which issued a letter on Nov. 16 authorizing the Key Largo disposal, said they would first require that the soil be tested and then accept only uncontaminated “clean fill.”
“If there were any negative impacts anticipated, of course we don’t want to use it for the restoration project,” said Sarah Williams, a DEP spokeswoman.
Alice Bravo, a planning and environmental manager for the DOT, said the agency has asked the contractors on the U.S. 1 project — California-based Granite Construction in Monroe County and Hialeah-based Community Asphalt in Miami-Dade — to delay moving any material until environmental consultants could analyze potential impacts. Bravo didn’t have an estimate of when that work might be completed.
“We’re trying to answer the questions,” she said. “I don’t know what people think of the DOT, but we consider ourselves stewards of the environment.”
CENTER OF SCRUTINY
The $270 million project to widen the dangerous two-lane road between Florida City and Key Largo has been at the center of scrutiny — geographically and figuratively — regarding a blue-green algae explosion that has perplexed scientists with its unprecedented size and persistence.
The bloom has clouded as much as 95 square miles of northeast Florida Bay and southern Biscayne Bay for more than a year, causing a decline in sea grass and raising concerns about the kind of massive die-off that slammed Florida Bay a decade ago.
After six months of stepped-up research and monitoring by seven agencies, scientists know what caused the algae bloom — a surge of the nutrient phosphorous. But they’re still sorting out where it came from and what’s continuing to feed it.
A study by the South Florida Water Management District in July pointed to a number of possible causes, including a string of hurricanes, runoff from farm fields through the C-111 drainage canal and the on-going road work.
In a first phase in Monroe, contractors chopped up 28 acres of mangroves, then mixed it with the muck and marl, cement and a metal “slag” to form a stabilizing layer under the roadbed.
In a first four-mile leg in Miami-Dade, 10 acres of mangroves and a 10-foot deep layer of muck are being scooped out and replaced with lime rock.
The key concern about the road work is just how much troublesome stuff might be unlocked from the mulched mangroves and thick marl and muck under the highway.
Miami-Dade’s Department of Environmental Resource Management records show water samples taken at construction sites didn’t detect levels of any chemical that violated water quality standards.
But the tests have shown traces of heavy metals, elevated amounts of petroleum compounds in water and, of most concern, phosphate spikes ranging from twice to nearly 200 times normal concentrations in the surrounding bays.
Bravo said such high readings doesn’t mean the road work is to blame for the bloom. She said DOT consultants have calculated that road work is too limited to produce the huge nutrient loads needed to fuel such a massive bloom.
Bravo said the rock-pit disposal plan was not just concocted as a quick and easy solution, but has been discussed with state environment regulators for years as a potential benefit for both the park restoration and the road project.
But with the bloom enduring so long, regional water managers have raised new questions. Two federal agencies with a say over what can be dumped there — the Army Corps of Engineers and the Environmental Protection Agency — also have concerns, and apparently were unaware the DEP signed off on the proposal last week.
‘A DEAD ISSUE’
In an e-mail, Paul Kruger, a Corps environmental specialist in Miami, called it “a dead issue and the Corps never approved or would approve of making a restoration site into a solid waste disposal site.”
Bill Kruczynski, an EPA water-quality scientist for the Florida Keys National Marine Sanctuary, said the restoration project still needs about one million cubic yards of fill. But, he said, what was piled along U.S. 1 appears too mixed with branches, roots and other decaying organics to qualify as “clean.”
“If they put unsuitable fill material in either of those pits, it could be a source of pollutants to the Atlantic Ocean,” Kruczynski said. “They’d have to give us some assurance the fill material had been screened.”
Williams said the DEP letter, signed by Florida Park Service Director Mike Bullock, along with further soil testing would provide that assurance.
In addition, Bravo said the more problematic material — thick with rotting branches and peppered with bottles, tires and other roadside trash — isn’t bound for the sensitive state property, but for five parcels owned by Manuel Diaz Farms near Florida City.
A plan developed by an environmental consultant for Community Asphalt, calls for the material to be spread over barren fields located west of U.S. 1 and well away from wetlands. It would then be raked to separate organic matter and trash. The remaining muck would be plowed into planting rows, wood debris would be mulched and leftover trash would be trucked to a landfill.
The county hasn’t made a decision on the plan yet, said Wilbur Mayorga, chief of DERM’s pollution remediation section, but expected to send a letter to contractors asking for a formal permit application and more details on how the waste would be processed.
Cynthia Guerra, executive director of the Tropical Audubon Society of Miami-Dade, said there are too many questions about the fill to feel comfortable with either disposal plan. It’s not clear the material can be classified “clean,” how the fill would be tested and whether any agency would monitor what winds up in rock pits and tree farms, she said.
“The devil is in the details here,” Guerra said. “I’m just concerned by the mess it seems to have created along Florida Bay.”
Copyright (c) 2006, The Miami Herald
Distributed by McClatchy-Tribune Business News.
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