Visitors to the National Mall will have to once again imagine water in the reflecting pool near the Lincoln Memorial.
On Thursday, more than a hundred workers were scrubbing and cleaning the bottom of the now-empty reflecting pool, using brooms, shovels, hoses and high-powered vacuums -- and it's proving to be a larger task than anyone had anticipated, reports NBC4's Tony Tull.
"It's slippery when you walk on it, but when you try to grind it up with a shovel, it just sticks to the bottom," one worker said of the algae.
The $100,000 job is probably the last thing the National Park Service wanted to take onto the $34 million renovation project.
"It's of course frustrating to the National Park Service," said a NPS spokesperson. "We did not expect to do this so quickly, but this is a maintenance problem."
After an ongoing battle with the algae, the NPS took the advice of aquatic biologists and water management expects and drained the pool Wednesday.
This comes only five weeks after the reflecting pool reopened Aug. 31, with a new circulation and filtration system that draws in water from the Tidal Basin.
"We came here to see, and we are very disappointed," said a tourist who otherwise appeared in good spirits.
Prior to the renovation, the pool had been leaking and had trouble with stagnant water.
When the pool is eventually refilled, workers will increase the ozone level in to the water to prevent the algae from growing again.
"We weren't quote sure how much ozone to inject into the water to kill the nutrients that feed the algae," said the NPS spokesperson. "We started out at one level, we've more than doubled that level, and we think we've got it right."
Crews expect the cleaning and refilling to take another few days.