Miami Will Be Underwater Soon. Its Drinking Water Could Go First

The city has another serious water problem.

Bloomberg Businessweek Christopher Flavelle

One morning in June 2018, Douglas Yoder climbed into a white government SUV on the edge of Miami and headed northwest, away from the glittering coastline and into the maze of water infrastructure that makes this city possible. He drove past drainage canals that sever backyards and industrial lots, ancient water-treatment plants peeking out from behind run-down bungalows, and immense rectangular pools tracing the outlines of limestone quarries. Finally, he reached a locked gate at the edge of the Everglades. Once through, he pointed out the row of 15 wells that make up the Northwest Wellfield, Miami-Dade County’s clean water source of last resort.

Yoder, 71, is deputy director of the county’s water and sewer department; his job is to think about how to defend the county’s fresh drinking water against the effects of climate change. A large man with an ambling gait, Yoder exudes the calm of somebody who’s lived with bad news for a long time.

“We have a very delicate balance in a highly managed system,” he said in his rumbly voice. “That balance is very likely to get upset by sea-level rise.” What nobody knows is when that will happen, or what happens next.

From ground level, greater Miami looks like any American megacity—a mostly dry expanse of buildings, roads, and lawns, sprinkled with the occasional canal or ornamental lake. But from above, the proportions of water and land are reversed. The glimmering metropolis between Biscayne Bay and the Everglades reveals itself to be a thin lattice of earth and concrete laid across a puddle that never stops forming. Water seeps up through the gravel under construction sites, nibbles at the edges of fresh subdivisions, and shimmers through the cracks and in-between places of the city above it.

Miami-Dade is built on the Biscayne Aquifer, 4,000 square miles of unusually shallow and porous limestone whose tiny air pockets are filled with rainwater and rivers running from the swamp to the ocean. The aquifer and the infrastructure that draws from it, cleans its water, and keeps it from overrunning the city combine to form a giant but fragile machine. Without this abundant source of fresh water, made cheap by its proximity to the surface, this hot, remote city could become uninhabitable.

Climate change is slowly pulling that machine apart. Barring a stupendous reversal in greenhouse gas emissions, the rising Atlantic will cover much of Miami by the end of this century. The economic effects will be devastating: Zillow Inc. estimates that six feet of sea-level rise would put a quarter of Miami’s homes underwater, rendering $200 billion of real estate worthless. But global warming poses a more immediate danger: The permeability that makes the aquifer so easily accessible also makes it vulnerable. “It’s very easy to contaminate our aquifer,” says Rachel Silverstein, executive director of Miami Waterkeeper, a local environmental protection group. And the consequences could be sweeping. “Drinking water supply is always an existential question.”

County officials agree with her. “The minute the world thinks your water supply is in danger, you’ve got a problem,” says James Murley, chief resilience officer for Miami-Dade, although he adds that the county’s water system remains “one of the best” in the U.S. The questions hanging over Miami and the rest of Southeast Florida are how long it can keep its water safe, and at what cost. As the region struggles with more visible climate problems, including increasingly frequent flooding and this summer’s toxic algae blooms, the risks to the aquifer grow, and they’re all the more insidious for being out of sight. If Miami-Dade can’t protect its water supply, whether it can handle the other manifestations of climate change won’t matter.

The threats to the Biscayne Aquifer are unfolding simultaneously, but from different directions and at different speeds. In that way, Miami’s predicament is at once unique and typical: Climate change probes a city’s weaknesses much as standing water finds cracks in the foundation of a house.

Twenty minutes east of the Northwest Wellfield sits the Hialeah Water Treatment Plant. With its walls built of coral rock in 1924, Hialeah was Miami’s first major water processing facility. The water drawn from the Northwest Wellfield is piped here to be cleaned along with water from another cluster of wells that pull from straight beneath the plant. As climate change worsens, this plant will matter more and more.

A few blocks from the Hialeah plant, buried beneath what’s now a maintenance yard for the county’s Metrorail trains, lies a 1.2-acre zone that the Environmental Protection Agency has ranked the second-most hazardous Superfund site in Miami-Dade. From 1966 until 1981, the land was used by Miami Drum Services Inc., a company that rinsed containers for an assortment of toxic chemicals, then disposed of the residue on-site.

County and state officials concluded in 1981 that the operations were contaminating the aquifer;the EPA later said the space was leaching arsenic, cyanide, mercury, nickel, lead, cadmium, chromium, chloroform, and oil into the groundwater. The county forced Miami Drum Services to abandon the property and spent two months removing all “visibly contaminated soils.”

Until then, water from the Biscayne Aquifer required minimal treatment: The plant would add lime to soften it and chlorine and ammonia to disinfect it, then filter out remaining particles. Once fluoride was added to help prevent tooth decay, the water would be piped to people’s taps. In 1992, in response to the risks posed by toxins from the Miami Drum Service site and others near it, the county added a new stage, running the water through “air stripping” towers designed to remove toxic contaminants.

In 2014 an EPA report warned that “flooding from more intense and frequent storms” could push toxins from Superfund sites into underground water sources like the Biscayne Aquifer. Anna Michalak, a researcher at the Carnegie Institution for Science in Stanford, Calif., says climate change means that U.S. cities are “entering a state that these systems were not built for.” She adds: “As the incoming water quality becomes either worse or just less predictable, you have to have more and more systems in place to deal with all of that.”

In South Florida that new state is already here. The amount of precipitation that falls during the heaviest storms has increased by about 7 percent in Miami-Dade County since the 1960s, according to research by Constantine Samaras, an associate professor of civil and environmental engineering at Carnegie Mellon University. Although the disparity might not seem like much, it could mean the difference between a lot of rain and an outright flood. The Union of Concerned Scientists estimates that by 2045, as much as 29 percent of Miami Beach and 26 percent of Key Biscayne could be “chronically inundated,” which UCS defines as flooding twice a month.

Earlier in 2018, Pamela Cabrera, a graduate student at Harvard, mapped the Superfund sites in Miami-Dade County and their proximity to wellfields. Her hypothesis was simple: Increased flooding could dislodge the toxic chemicals that remain on Superfund and other industrial sites, pushing them into the aquifer. According to Cabrera’s map, the Miami Drum site is 750 feet from the Hialeah Wellfield. A dozen other Superfund sites are scattered throughout the county. More severe flooding or rainstorms could overwhelm Hialeah’s controls or move toxins through the aquifer in new ways, sending them into one of the wellfields not equipped with the same controls.

In 2014 a storage tank in West Virginia leaked methylcyclohexane methanol, a chemical used to process coal, into the Elk River just upstream from Charleston’s water intake center. The spill rendered the city’s water undrinkable, leaving 300,000 people with no water for days. “It’s extremely important for everybody to look upstream of their drinking water systems and protect them,” says Gina McCarthy, who ran the EPA under President Obama and now directs the Center for Climate, Health & the Environment at Harvard. She cites Charleston, as well as Toledo, Ohio, which had to shut down its drinking water supply later in 2014 because of an outbreak of cyanobacteria, as evidence of how a shock to the drinking water supply can thrust a city into chaos.

Miami-Dade has regulations and testing procedures in place to prevent or detect contamination of the aquifer. Asked about the risk, Yoder chooses his words carefully. “I think it’s a fair question to ask,” he says, but adds that the county at least has a history of dealing with those threats, noting its experience with the Miami Drum Services site.

Michalak warns that’s too easy. “Invariably,” she says, “we discover that we’re not quite as clever as we thought.”

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In 1997 the state approved large-scale limestone mining on the border between Miami-Dade and the Everglades. Pulling the rock out of the ground entails blasting holes in the aquifer, which almost immediately fill with groundwater to become dusty blue pools. Locals refer to them as “rock lakes,” although they’re not the kind that draw families for weekend picnics.

The mines happen to surround the Northwest Wellfields. The same conditions that made the area suitable for water wells—vast open space with no development in sight—also made it ideal for massive rock pits. Environmentalists have warned that the rock lakes act as a superhighway for pollutants from the mining, driving them straight to the heart of the aquifer. In 2005 one of the Northwest wells registered five times the federal limit for benzene, a chemical used to blast out rock that’s been linked to leukemia, according to the American Cancer Society. The county ordered the well, along with four adjoining ones, temporarily shut down. Yet regulators never successfully identified the source of the benzene, and the mining continued.

Yoder pulled over beside a rock lake that was lined by gravel roads and surrounded by swamp. The photographer with us made a half-hearted joke about alligators and then got out. Yoder and I stayed in the truck; the air outside was dusty and hot, and neither of us was particularly keen to take our chances with whatever might crawl out of the ditch.

The decision to surround the county’s most pristine wellfields with rock mines reflected a compromise, Yoder said. The Miami-Dade Limestone Products Association Inc., which represents some of the area’s biggest mining outfits, insists mining has no effect on the aquifer. Better that than to surround the wellfields with houses, Yoder said, adding: “More developed areas had higher contaminants.”

...continued in PART 2