Miami-Dade County

Say bye to Virginia Key’s toxic old landfill, and hi to Miami’s biggest park

The site of a closed landfill on Virginia Key is at the center of this aerial view taken in 2011. The Miami-Dade sewage-treatment plant is at upper right. The green section at the upper left is a state nature preserve.
The site of a closed landfill on Virginia Key is at the center of this aerial view taken in 2011. The Miami-Dade sewage-treatment plant is at upper right. The green section at the upper left is a state nature preserve.

This was Miami’s idea of environmental management circa 1961: Take a placid natural lake on a lush barrier island teeming with wildlife. Fill it with a mountain of garbage and sewage-treatment sludge over the next 16 years, until it reaches a height of 30 feet above ground.

When the state orders it shut down, toss some dirt on top of the mess. Then leave the toxic stew to fester for 40 more years, sending a plume of ammonia and other contaminants into the groundwater just yards away from beachgoers and a critical conservation area in the middle of Biscayne Bay.

Now the bill has come due, and there’s good news and bad. The bad: The cost of properly capping and sealing off the old dump on environmentally sensitive Virginia Key will top $45 million, to be borne fully by Miami-Dade taxpayers.

The good: After years of talking, analyzing and bickering, the county is finally ready to tackle the job. And once that’s done, around 2020, the 125-acre stretch of wasteland at the heart of the publicly owned island will be completely transformed. The plan then is to turn the landfill into the biggest park in the city of Miami, fulfilling a decade-old promise.

“It should be a beautiful site. Magnificent,” said Paul Mauriello, deputy director of Miami-Dade’s public works and solid waste management department, which is running the reclamation project. “A great asset for all of the county.”

By September, the county expects to have a final, fleshed-out closure plan that will render the site utterly safe for people and nature alike, said Wilbur Mayorga, chief of the county’s environmental monitoring and restoration division.

The blueprint, developed for the county by engineering giant URS, will include a system of pumps to extract contaminated groundwater from the landfill site and send it thousands of feet below ground, into a new deep-injection well at the sewage-treatment plant next door. Tests of the pumps are slated to begin later this month, Mayorga said.

The entire site will be capped by two feet of lime-rock fill produced by the boring of the PortMiami tunnel. The free fill, which has been stockpiled on the island, will save taxpayers several million dollars, Mauriello and Mayorga said. The rock was rigorously tested and found free of contaminants.

The cap will be largely impermeable and contoured so that rainwater runs off into clean ground around the site’s perimeter, and doesn’t pond or penetrate into the waste material beneath. Acting in concert, the cap and the pumps will effectively seal contamination under ground and keep it from spreading, Mayorga said.

That job will literally lay the groundwork for the new park.

Exactly what will be in the park is as yet undecided. A conceptual 2010 master plan for the island, developed by the administration of then-Mayor Manny Diaz, called for a combination of natural areas, trails and athletic fields and facilities spread across the landfill site. But planning and design for the actual park will come as reclamation work proceeds, and only after extensive public consultation, Miami parks director Kevin Kirwin said.

“It’s a great opportunity, and we need to do it right,” Kirwin said. “And to do it right is going to take everybody’s input.”

One section of the site, on the southwest corner, is a relatively undisturbed and uncontaminated mangrove wetland that will be preserved, Mayorga said.

The new park would cap a years-long effort by the city and county to restore and preserve the much-abused 1,000-acre island, most of which sits north of the Rickenbacker Causeway. The goal: to turn it into Miami’s equivalent of Manhattan’s Central Park, although surrounded by water instead of city streets.

Off the busy causeway is a ring of underappreciated recreational and natural jewels that would be augmented by the new park at the center. To the west of the landfill site lies a largely pristine state-designated wildlife and conservation zone that’s mostly off-limits to people.

To the east are two city beach parks, one the historic former blacks-only beach that’s been restored by a private trust. Along the shoreline, the county has undertaken significant mangrove restoration, while the city parks department has painstakingly removed exotic trees and plants and resuscitated an upland hammock that’s now traversed by a nature trail. Beach and dune restoration has brought back nesting turtles and even attracted nesting crocodiles.

North of the landfill, on the other side of the big county sewage plant that remains a blot on the key, is a network of mountain-bike trails built and maintained by volunteers, and the adjacent cove that was once home to the legendary Jimbo’s fish shack. The Jimbo’s site has been cleared and is now a popular spot for paddlers and manatee-watchers, though the city and conservationists are at odds over how to repair the lagoon’s deteriorated seawall.

Even the sewage plant, which the county says would be prohibitively expensive to move, has seen improvements. Fill from the PortMiami tunnel dig was used to create a planted berm along its eastern perimeter to reduce the visual blight on the Jimbo’s and bike-trail areas. And aerial spraying, prompted by a lawsuit by residents of nearby Fisher Island, has virtually eliminated odors wafting out from the plant.

The plant and the landfill are the unfortunate legacy of an age when Virginia Key’s rich natural environment was not appreciated, Mauriello said.

“That’s what people did back in those days. It was considered a waste island.” he said. “It seems very ironic now.”

The landfill, opened in 1961, obliterated Duck Lake, filling the 25-foot-deep body of water with a largely unregulated mix of sludge from the plant next door and household garbage. The area was also plagued by illegal dumping long after the state shut it down in 1977.

The dump was covered by soil in 1980, but the cap was not maintained, and after decades of rain has worn down in spots to just a few inches, Mayorga said. Nothing was done about groundwater contamination, either, he added.

Because tons of waste was buried in the lake, it sits at and below the level of the water table, leaching ammonia and other contaminants into it, Muriello said. But the county decided years ago that cleaning out the area was both unaffordable and impractical, and settled on the cap-and-seal concept instead.

This sort of reuse of a dump site is not novel. The county has turned another closed landfill in North Miami-Dade into the highly engineered Ives Estate Park, today 100 acres of rolling green topography. New York City is gradually transforming its largest trash dump, Fresh Kills on Staten Island, into a vast expanse of parkland and restored natural areas.

The Virginia Key reclamation has taken years to come to fruition even though the county set the money aside for the job from bond sales in the mid-2000s. The county, embroiled in a long-running dispute with the city over a trash contract, declined to release the money until an agreement was struck.

Meanwhile, preparation for the reclamation required extensive water and soil tests that ran from 2009 to 2014. Contractors sank 37 monitoring wells to test water quality, and ground-penetrating radar and seismic testing were used to determine the precise location and density of waste and the underlying bedrock.

Crews also made 96 borings, systematically laid out in a grid, to test the soil, and found concentrations of contaminants. One hot spot is contaminated with hydrocarbons, suggesting someone may have dumped oil or other petroleum products. All those spots will be safely covered by the fill cap, Mayorga said.

Mauriello said he expects selecting a contractor through competitive bids will take about a year and remediation work would take at a year to 18 months.

Once the reclamation is completed, monitoring equipment around the site will continually check on groundwater quality for any toxins that could seep out. Because the dump lets off methane, a product of the decomposition of organic waste, any enclosed park buildings erected on the site must have special venting systems to prevent a deadly gas buildup.

Some preliminary work on the site has begun. Earlier this year, crews cleared scores of exotic trees and plants from the eastern side of the landfill and began spreading fill across the area. The county is now awaiting permits from the city to remove native trees as well. The landfill area must be completely cleared to allow for a consistent cap, but can later be replanted, Mauriello said.

The county is also working with the city on a grading plan so that the site can accommodate the park. The county will sod the area and turn over a green field to the city, Mauriello said.

Miami Commissioner Ken Russell, whose district includes Virginia Key, has said he wants the city to start planning for the park as soon as possible. Russell strongly endorsed the concept of playing fields, though he stopped short of naming specific sports or uses. Nearby built-out Key Biscayne has long wanted to use the site for athletic fields for its residents, while Kirwin said the city has a severe shortage of soccer fields.

Parks advocates and environmentalists have pressed for most of the site to be restored to a natural state with hardwood trees, wetlands and nature trails. They also support sports fields so long as they don’t overwhelm the area or include lighting that would interfere with turtle nesting. The inclusion of a parking garage and baseball fields in the original draft of the Virginia Key master plan provoked a public uproar that sent the plan back to the drawing board.

Hitting the right balance between nature and recreation will be tricky but critical, said Gary Milano, a biologist who directed shoreline restoration on Virginia Key for the county and now sits on the city’s Virginia Key Advisory Board.

He said soccer fields, as opposed to basketball or tennis courts, would be “fantastic” for the site since they’re mostly grass. And he would also like to see those blended into an extension of the adjacent restored hammock into the new park to fulfill the vision of the approved master plan.

“The devil’s in the details as to what’s going to happen on the footprint of the landfill,” Milano said. “We need to make sure we follow through with an open and public process. It’s everyone’s central park.”