USA-Florida: Miami Will Be Underwater Soon. Its Drinking Water Could Go First - by 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. 

The state requires at least two feet of dry soil between the bottom of the drainage field and the top of the water table, but Lapointe says that during the wet season, the groundwater in parts of southern Florida already comes above that two-foot threshold. More intense flooding and rainstorms will swell the water table further, on top of the gains caused by sea level rise, sending partially treated human waste into the aquifer. That waste can contain E. coli bacteria, which cause diarrhea, vomiting, and even kidney failure. High levels of nitrates, another component of untreated waste, cause what’s called blue baby syndrome, in which infants’ blood can no longer carry sufficient oxygen.  

How long does Miami have before the water table overwhelms the septic system? Officials, including the South Miami mayor, worry that the point of failure is closer than people realize. Says Stoddard, “I’m convinced that some of those septic systems are working by force of habit rather than by the laws of physics.”

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