Park Service monitoring new algae bloom on National Mall

Park Service monitoring new algae bloom on National Mall. (ABC7)

Last August, a huge algae bloom killed off hundreds of fish in a pond in Constitution Gardens on the National Mall. Now, the National Park Service is keeping a close eye on another big algae bloom there this summer.

Millions of tourists and locals pass by, or through, this part of the National Mall every year; and most probably don't even know its name. But everyone seems to agree that Constitution Gardens needs to be cleaned up.

“There's a lot of trash in the water,” said tourist Preetha Selban.

The bright green stuff on the edge of the pond is actually duckweed, part of the ecosystem that ducks feed on. But what's problematic is the algae in huge clumps a little further out in the middle of the pond.

Tourist Carrie Leblanc said, “I was surprised when you look down in it, it's all very mucky and murky.”

On hot summer days, the smell can be overwhelming.

The National Park Service said, because the pond is only a couple feet deep, algae blooms like this are typical each summer, requiring on-going maintenance with rangers skimming the surface.

Agency spokesperson Mike Litterst said, “This is a 1970s installation built without our 2017 sensibilities when it comes to sustainability or green architecture.”

Long-term, the Park Service and the Trust for the National Mall plan to overhaul this space, with phase one currently underway relocating the historic Lockkeeper's House.

In phase two, crews will build new facilities and restaurants in Constitution Gardens and rehab the pond - making it deeper and adding circulation systems to reduce but not eliminate algae. After all, Litterst said, some algae is good.

“The algae provides cover for fish, provides shade when we get those blazing hot days with the sun,” he said.

Right now, with bluegill fish spawning in the pond, rangers will wait until the fall to drain, clean and refill it.

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