(Reuters)

Crews were working around the clock on Monday to prevent the collapse of a waste water reservoir’s leaky containment wall near Tampa Bay, Florida, making steady progress after officials warned of an imminent threat of flooding over the weekend.

The worsening leak in the containment wall at Piney Point waste water reservoir, which holds 480 million gallons, prompted Florida Governor Ron DeSantis to declare a state of emergency on Saturday over concerns that stacks of phosphogypsum waste, primarily from fertilizer manufacturing, could collapse and cause dangerous flooding at the site.

At least 30 people had been evacuated to local hotels for shelter, Manatee County Public Safety Director Jacob Saur said on Sunday. A full breach could have flooded the surrounding area with a 20-foot wall of water, officials said.

The situation was improving by Sunday as state agencies had managed to expedite a pumping system that was draining polluted water from the property, which is owned by a company called HRK Holdings, acting Manatee County administrator Scott Hopes told reporters.

While officials initially expected draining to take 10-12 days, with the new pumping system and pipes, the threat of catastrophic flooding could be avoided as soon as early this week, Hopes said at a Sunday news conference.

“With the additional pumps we’ll probably be able to nearly double the amount of water that we’re taking out,” Hopes said. “We believe that probably by Tuesday we’re going to be in a much better position and the risk level will have decreased significantly.”

Engineers are pumping the water to Port Manatee to ease pressure on the reservoir’s retaining wall and avoid the catastrophe of a sudden breach. But environmental advocates worry the drainage of nutrient-dense water will cause ecological trouble, including possibly spawning algal blooms that could kill marine life in Tampa Bay.

“The biggest concern from our standpoint right now is the amount of nutrients being loaded into the lower Tampa Bay,” Ed Sherwood, executive director of the Tampa Bay Estuary Program, told radio station WMNF on Sunday. “This event, in probably five to 10 days, is introducing the amount of nutrients into the bay that we would want to see over an entire year.”  

By Sunday, the 480 million gallon reservoir had already been drained to fewer than 300 million gallons, Hopes told reporters on Sunday.

Officials said the reservoir’s structural lapse poses no threat to area residents’ drinking water, which primarily comes from Lake Manatee.