Terry Arko: Why the Lincoln Memorial Reflecting Pool Keeps Turning Green
About this episode
Ravi Kurani interviews Terry Arko about the historical and environmental factors contributing to the green color of the Lincoln Memorial Reflecting Pool.
The Lincoln Memorial Reflecting Pool has been turning green since the 1920s, and the reason is baked into its original design. The pool stretches roughly a third of a mile, sits one and a half to two and a half feet deep, holds about 6.5 million gallons, and was built on Washington D.C. marshland that has been slowly sinking ever since. Ravi Kurani brought in Terry Arko, Product Training and Content Manager at HASA Pool with over 45 years in the industry, to diagnose what is really going on and whether it can actually be fixed. What we cover: Still water is algae's best friend. The pool was intentionally designed to stay still to function as a mirror, which means strong surface circulation, the intervention that would help most, directly conflicts with the pool's purpose. The 1920s design got the basics wrong. Built on unstable marshland with asphalt paving and no meaningful filtration, the ground shifted so badly that engineers later had to drive large timber beams beneath the basin to stop it from sinking. The pool has been leaking roughly 16 million gallons of water per year. Nutrients have gotten worse over a century. Phosphates and nitrates in the Potomac watershed are…
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