Goo Grief

There's a million cubic yards of toxic sludge on the bottom of the Miami River and you may as well get used to it

During a recent tour of the Miami River, Dade County's chief biologist Susan Markley reported a highly unusual sighting. "Look!" she said, sounding alarmed. "There's a guy in the water. Over there."

Indeed, just east of the NW Fifth Street bridge, a shirtless man was sitting quietly in the shallows near the sloping bank, submerged to his ribs. Seeing the county motorboat and its passengers staring at him, the man smiled broadly and waved a vigorous two-armed salute.

"Yuck," Markley muttered as she returned the greeting, knowing all too well what the man was digging his toes into: "Trace metals: lead, copper, cadmium, zinc, sometimes mercury and other metals. Occasionally organic chemicals like PCBs, PAHs, pesticides, and petroleum hydrocarbons." Not to mention what's in the water itself (raw sewage, for starters).

Thick, silty, and toxic, sediments have been accumulating ever since Miami's early inhabitants began the ignominious tradition of wantonly dumping their refuse in the waterway. Contaminated stormwater and untreated sewage, as well as shoreline erosion, fuel spills, and industrial waste have caused the buildup, "a long-term historic record of the pollution climate," in Markleyspeak. The deposits now impede the largest freighters that use the cargo terminals at the western end of the river. There's also widespread concern -- although not much confirming data -- that the contaminated sediments threaten the environmental health of Biscayne Bay.

For decades regulators and politicians have debated whether, and how, to dredge the river. In the process they've demonstrated a remarkable ability to exhaustively study the issue -- convening committees, organizing meetings, conducting studies, reviewing the studies, convening more committees to order more studies -- without managing to agree on a solution.

The U.S. Army Corps of Engineers, which is responsible for maintaining the river, says it needs to be dredged for navigational reasons. But the process is mired in knotty questions of disposal methods and cost. One option would be to dump the crud in the open ocean. But that would require a unique federal waiver that could set a fateful environmental precedent. Another possibility would be to deposit the stuff at a special site on land. Estimated costs hover around $100 million, almost all of which would come from local government coffers.

This unsavory dilemma begs a closer look at the nature of the river's shipping industry and the necessity of dredging. Two companies control an estimated 75 percent of the river's freight trade and operate the largest vessels that are now scraping the river's sludge-filled bottom. Clearing the river would certainly help keep these companies afloat. The benefits to the community, though, are far more questionable.

The sight of half-clothed people paddling around the Miami River was common once, back when it was a shallow waterway that meandered through the South Florida wilderness. The stream's natural headwaters were located just west of today's 29th Avenue, which, until the mid-Twentieth Century, was still part of the Everglades. Its width varied from about 300 feet at Biscayne Bay to about 20 feet where it joined the wetlands; its depth ranged from about 14 feet at its mouth to only a few feet in other places. The Tequesta Indians and, later, Spanish missionaries, lived on its banks. The first Europeans to settle in Miami built their homes next to the river in the early 1800s. It was only natural that Henry Flagler would build his hotel, the Royal Palm, at the prime location of the river's mouth, near where the far less picturesque Dupont Plaza stands today.

In 1933 the U.S. Army Corps of Engineers dredged the river, creating a 5.5-mile-long rectilinear channel 15 feet deep and between 90 and 150 feet wide. The Corps also built a salinity dam at NW 36th Street that essentially shut down the river's natural current and helped stop the intrusion of saltwater into the young city's underground drinking-water supply. The effort also allowed larger boats to sail up the entire length of the river; as the river's users increased, so did the pollution. Besides the growing boat traffic and its attendant waste, the city's sewage emptied directly into the river: It was an open sewer.

Talk about redredging the Miami River began in the 1960s. In the 1970s the Corps concluded that it wouldn't do a whole lot of good to dredge if the sedimentation problem were to continue. In response, the county and the City of Miami began to attack the problem at its source, retrofitting inadequate stormwater connections, shoring up sea walls and the riverbank. Finally the Corps concluded in a 1990 study that there was a navigational justification to dredge.

How contaminated are the sediments? To find out, EPA scientists bury microscopic organisms in sediment samples and measure the critters' ability to withstand the trace metals and organic chemicals therein. Says Bob Howard, the acting chief of EPA's wetlands section: "We had a lower survival rate in those sediments than any we've ever tested."

Scientists also know that the sediments are migrating out of the river into the bay: Natural currents, as well as boat hulls and propellers, kick up clouds of polluted muck, which float out with the tide. But neither the Corps nor anyone else has been able to determine what biological impact the sediments might be having on the bay's ecosystem. (Several agencies, including the EPA and Florida's Department of Environmental Protection, are researching that issue now.)

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