The Lincoln Memorial Reflecting Pool in Washington, D.C. has turned green due to an algae bloom, just weeks after a multi-million dollar renovation project repainted its bottom “American flag blue” under President Trump’s administration.
The pool, which measures 2,030 feet long and has a surface area of approximately 338,000 square feet, was refilled with water earlier this month after the renovation. However, the algae bloom has caused the water to take on a verdant hue, with experts saying it’s a common occurrence in such conditions.
Algae Bloom in Reflecting Pool
According to Steve Goodale, a swimming pool specialist, the algae bloom is a result of “New Pond Syndrome,” which occurs when a natural body of water is started up in an open-air environment. Rosalina Stancheva Christova, a professor of aquatic ecology at George Mason University, confirmed that the algae belongs to the genus Desmodesmus, which is not toxic or harmful.
Christova says the reflecting pool provides “excellent conditions” for algae growth, with shallow, stagnant water, strong sunlight, and no shade. The recent renovations may have affected the balance of nutrients in the pool, potentially accelerating the algae blooms. The new, darker interior surface of the pool is also absorbing more sunlight, resulting in warmer water that’s friendlier to algae growth.
Renovation and Mitigation Efforts
The Trump administration has said the algae came from residual material in supply lines, and its growth was likely exacerbated by extreme temperatures. The administration is using a mix of mitigation strategies, including pouring hydrogen peroxide into the water to kill the algae, and deploying “high-tech nanobubble ozone technology” to neutralize algae and other pathogens.
The Interior Department says hydrogen peroxide is a milder treatment than chlorine and is used in spas and specialty pools, with no harmful side effects to marine life or the environment. The department is working to maintain the pool and prevent future algae blooms, but experts say it’s a common issue that may recur every summer.
