Enjoying a game of frisbee, taking a scenic stroll or relaxing on a grassy hillside sound like pleasant activities, and many people across the United States often participate in all of them – on top of massive piles of trash.
Many beautiful parks and preserves in the U.S. were once landfills, and while the exact number of these is uncertain, the Center for City Park Excellence has noted that there may already be as many as 4,500 acres of landfill parks in major U.S. cities.
Landfill parks date back to at least 1916, years before the term “landfill” was coined, according to the Trust for Public Land. That was the year Seattle converted its former Rainier Dump into the Rainier Playfield.
As many as 3,500 U.S. landfills have closed since 1991, according to the Environmental Protection Agency (EPA), and landfills that are no longer in use are considered good locations to build new parks due to their size, cost and location.
“Landfills fill vast spaces, often near dense metro areas, where open land is scarce, [and] in many cases, landfills/brownfields are city-owned, and therefore ‘free’ to purchase,” said Dr. B.D. Wortham-Galvin, director of Clemson University’s Master of Resilient Urban Design program.
“This helps to offset construction costs, which the Center for City Park Excellence calculates average around $300,000 per acre for landfill parks,” Wortham-Galvin told AccuWeather.
A landfill’s unique characteristics make it difficult to be used in many other ways, according to Wortham-Galvin. “A park or open nature-filled area is one of the best options,” she said. “So, why not turn it into a park?”
How it benefits the environment
Environmental benefits are largely connected to the gas produced by landfills, according to Wortham-Galvin.
“When landfills sit open, these harmful gases – mainly methane, carbon dioxide, ammonia and hydrogen sulfide – leak straight into the air,” she said. “When a landfill is capped in order to be turned into a park, the majority of gases cannot be released.”
Because of this, vents are put in specific areas to allow gas to be released. From these vents, the gases can be monitored and even captured for other energy uses instead of being released directly into the atmosphere, Wortham-Galvin added.
Ensuring safety for visitors
Since November 1991, the EPA has regulated the construction of municipal landfills, and many new safeguards have been established since then, according to the Trust for Public Land.
The process of ensuring that the space is made safe for humans begins with assessment of the landfill, including its age and contents; the amount of groundwater or soil contamination; planned recreational use; topography; and availability of materials, according to Wortham-Galvin.
From there, the project continues to the phases of research, design and construction. The EPA requires monitoring of groundwater and leachate collection for at least three decades after a landfill closes.
“The EPA requires gas collection systems, as methane may be released for 30 or more years after closure and is flammable,” Wortham-Galvin said. “Pre-1991, landfill projects often just had vents to release the gas; now, many sites collect and sell the gas to create a revenue for the park department.”
While there are many regulations in place to make landfills safer for humans, inevitable issues like erosion and gas leaks could still occur. The 50-acre Mabel Davis Park, located 4 miles south of downtown Austin, Texas, experienced issues for years after being converted to a park in 1979, before adequate regulations were in effect, according to the Trust for Public Land.
Problems including erosion and leachate pollution from illegally dumped fertilizer and battery casings eventually led to its closure in 2000 in order to redesign it and bring it up to current EPA standards. The park re-opened in 2005.
“Regulations make landfill parks safe enough to enjoy and use, as long as you don’t dig too deep in the sandbox,” Wortham-Galvin said.
Potential visitors need not worry about unpleasant smells lingering from former landfills, as an odor is highly unlikely to occur if the park is cared for properly.
“The smell from landfills comes from the gases created as the refuge attempts to decompose,” Wortham-Galvin said. “When the landfill is covered properly, the smell is greatly reduced, in some cases, to almost nothing.”
The landfill smell decreases as the ground cover increases, and clay, which creates a waterproof barrier and is now required per EPA regulations, is the most helpful way to eliminating smell.
Controlling gas vents is also key in eliminating any potential stench, Wortham-Galvin added.