A blue pool that turned green overnight
The long rectangular Reflecting Pool that stretches across the National Mall was supposed to gleam in patriotic colour for the United States' 250th birthday. Instead, the water has gone a vivid, unmistakable green. The culprit is an algae bloom, and it has shrugged off the Trump administration's costly effort to make the pool what the president called "American flag blue" in time for the milestone. Warm temperatures and a warming climate are among the risk factors experts believe are feeding the outbreak.
A $14 million job, handed out without a bid
The administration poured more than $14 million into refreshing the pool ahead of the festivities planned across the nation's capital. The contract was awarded without competitive bidding to a firm that had never previously done work for the federal government. The same company has, however, carried out work on Donald Trump's golf courses, according to TrendKia.
Green within a day
The trouble appeared almost immediately. Algae started forming less than a day after the renovated pool was unveiled last week. An Interior Department spokesperson told TrendKia that the bloom came from "residual algae from the supply lines, which have been sitting dormant for eight weeks."
It may start with the water
Part of the explanation appears to lie in where the pool gets its water. The Reflecting Pool usually draws from the nearby Tidal Basin, a body of water that is itself frequently choked with algae. When algae levels run high, the supply is switched over to municipal drinking water instead. The Interior Department did not immediately answer TrendKia's questions about which source is feeding the pool right now.
Heat, still water and a hotter planet
Weather is the other big driver. High temperatures create "a perfect storm for [algae] to bloom," says Hans Paerl, a former professor at the University of North Carolina's Institute of Marine Sciences. Water that sits still, he adds, only makes things worse. "Lakes and reservoirs around the world, they all have this problem during this time of year." Washington, DC, is forecast to see hotter-than-normal weather as the week closes, which could make the bloom even harder to bring under control.
Paerl points to a deeper, connected cause that the administration has been in no hurry to tackle: climate change. "It's just getting hotter, and these blooms are expanding globally, they're moving up into higher latitudes," he says. "It's clearly a temperature effect allowing them to optimize their growth."
The fixes on the table
Hydrogen peroxide is one weapon. Beyond that, the Interior Department is "deploying high-tech nanobubble ozone technology" to hold the algae back, an agency spokesperson told TrendKia by email. Trump has praised the overhaul, which included painting the pool blue and sealing leaks, and has claimed the firm the government brought on could handle repairs "in much less time, for much less money."
A fight over who let it slip
The pool's recent history has become a political talking point. The Obama administration spent $34 million on a two-year renovation in the early 2010s, while the Biden administration carried out no major work on it. Trump has falsely claimed that both spent "hundreds of millions of dollars" on the pool, and has shared artificial-intelligence-generated images to pin blame on Democrats for letting the centerpiece of the National Mall fall into neglect. The Interior Department spokesperson, for its part, said the Obama-era work "resulted in massive algae clumps taking over the pool's surface following years of construction that cost taxpayers millions upon millions only to be broken and disgusting days later."
Will it be blue for the big day?
With two weeks left before the anniversary celebrations, whether the pool can be coaxed back to blue in time remains an open question. Given how closely the president has followed the project, even as his administration spars with Anthropic over Fable 5 and works to broker a fragile ceasefire with Iran, more rounds of repairs look likely if the hydrogen peroxide and nanobubbles fail to do the job.
