Washington DC Reflecting Pool algae bloom prompts emergency cleanup before July 4

The U.S. Interior Department and the National Park Service have labeled the algae bloom in Washington’s Reflecting Pool a regional and national priority ahead of Independence Day celebrations. The bloom, covering roughly 15,000 square feet, is linked to a 2023 renovation that replaced the pool’s original stone filtration with a concrete basin, reducing natural water circulation and leaving sediment that feeds algae. Water samples taken in May showed algae levels about 400 % higher than pre‑renovation benchmarks.

In response, officials are implementing emergency measures: a copper‑sulfate chemical treatment to kill the algae, emergency dredging to remove sediment, and restrictions on public access to the pool’s edges. The agency warned that the sight could damage the optics of the July 4 fireworks ceremony.

Media coverage has included a Fox News segment that mocked criticism of the pool’s condition, coining the phrase “Algae Derangement Syndrome.” Tourists have been reported taking pieces of the pool’s surface as souvenirs amid the heightened attention.