At long last, the dirtiest waterway in Florida is about to get a good scrubbing.
Fourteen years after concentrations of dioxins, a deadly family of cancer-causing chemicals, were discovered in sediment at the bottom of Miami’s Wagner Creek, the city is getting around to cleaning it up. The waterway snakes for 1.6 miles from Allapattah through Jackson Memorial and past the historic neighborhoods of Overtown and Spring Garden before emptying into the Miami River.
The city has signed a contractor, Sevenson Environmental Services, and expects to issue a issue a notice to proceed on the $18 million project this week, said Jeovanny Rodriguez, chief of the city’s office of capital improvements. After 90 days of planning and design work, Niagara Falls, N.Y.-based Sevenson should begin dredging the creek. The Seybold Canal, a channelized length of the waterway that connects to the river, will be part of the project.
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The dredging is designed to safely remove several feet of sediment at the bottom of the waterway that’s laced with dioxins, arsenic and other pollutants, said Horacio Stuart Aguirre, chairman of the Miami River Commission. The state-chartered watchdog agency has been pushing the city to clean up Wagner Creek for years, but there has been little urgency to do so because the toxins are contained within the sediment and are not believed to be leaking out. Still, there is a risk that a storm could break it loose and push contaminants into the Miami River, he said.
“It has some really horrible stuff in it, and some of that stuff is highly toxic,” Aguirre said. “We want to scoop it out while it’s still contained. If that sediment breaks loose and washes out, then a huge amount of toxic sediment will spread along the river. We don’t want that to happen.”
The dredging work, expected to take 15 months, carries other benefits, including increasing the waterway’s flood-protection capacity and improving its navigability.
Sedimentation and shoaling from stormwater discharge into the creek has drastically reduced its depth over the years. At places, the waterway is so shallow at low tide that marine businesses on the Seybold Canal must wait for high tide before it can accommodate larger boats, according to the river commission. One commercial fishing operator reported two boat propellers were damaged after hitting the bottom of the canal.
Meanwhile, recreational boats docked behind homes along the canal rest directly on the bottom at low tide, the commission says.
As the mud from the bottom of the creek is removed, it will be collected in deposits along the waterway and tested, Rodriguez said. The level of toxicity will determine precisely how the dredge material is disposed, he said.
Dioxins were discovered in the creek bed in 2003, prompting the city to put up signs warning people not to fish in the waterway because fish or shellfish taken from it could be unsafe to eat. Exposure to even small amounts of dioxins, which can travel through the marine food chain, is believed to cause cancer, immunological problems and learning and behavioral deficiencies in children, among other health problems.
Environmental officials believe the dioxins came from an old city incinerator that operated for 30 years on Northwest 20th Street and from which waste may have flowed into the creek through a drainage pipe. The incinerator was shut down as an environmental hazard in the 1970s; the site has since been cleaned up.
Cleaning up the creek was delayed while a five-year-long, $89 million dredging of the Miami River overseen by the U.S. Army Corps of Engineers took place. The project, completed in 2008, removed several feet of contaminated bottom silt. Two years ago, the city announced it was ready to tackle the creek after years of permitting reviews by federal, state and Miami-Dade County environmental regulators, but that was delayed after a first round of bids was discarded. Sevenson was one of two bidders in a new round.
The project will be funded principally through city stormwater fees, a state loan and a grant from the Florida Inland Navigation District.
The natural creek is fed by the Biscayne Aquifer and once connected the long-gone Allapattah prairie to the river. In 1919, baker John Seybold purchased land at the spot where the creek met the river. He straightened the creek from 11th Street to the river to create the canal named after him, and began building Spring Garden, today a designated historic neighborhood, on its western bank.
But the waterway became heavily contaminated as Miami grew and the river and its tributaries became industrial arteries. A 2011 survey found numerous stormwater pipes dumping into the creek, even though by law property owners must keep stormwater on site or route it to the aquifer. Most of those “unfortunately” remain in place, Aguirre said.
Tests have also at times found elevated levels of coliform bacteria in the water, likely from improper sewage connections and, according to Aguirre, the daily use of the waterway as a toilet by homeless people. Continued rainstorm runoff from parking lots and streets as the creek flows past auto-repair shops, hospitals and jails will also continue to affect water quality, he said.
But the dredging project will result in a cleaner waterway, better flood protection and even higher property values for homeowners along the waterway, Aquirre said.