Florida residents were allowed to return to their homes on Tuesday after they had been forced to evacuate when a breach in a 79-acre reservoir holding wastewater south of Tampa raised the threat of a collapse that could unleash a 20-foot wall of water.
The announcement came after officials spent Monday assessing the potential of a second breach in the leaking reservoir, which was ruled out by the end of the day.
As a news conference Tuesday afternoon, Scott Hopes, the acting Manatee County administrator, said that because of additional pumps and rerouting of water from an uncontrolled breach, residents would be allowed to return to their homes. More than 300 homes were under a mandatory evacuation order.
“We believe that risk has been successfully mitigated and lessened,” Mr. Hopes said.
On March 26, when the leak was reported, the reservoir, part of a system of ponds connected to a former phosphate mine in Piney Point, Fla., held about 480 million gallons of wastewater.
With the water volume at 340 million gallons on Sunday, Mr. Hopes warned that models suggested that if the reservoir were to give way at that volume, it could result in a “20-foot wall of water” cascading across residential and commercial areas.
The Florida Department of Environmental Protection said Tuesday that about 303 million gallons of water remained in the reservoir and that through Tuesday afternoon about 165 million gallons had been discharged. The department also said that water in the area would be sampled to assess its quality.
At the news conference, Vanessa Baugh, chair of the Manatee County Commission, said that the county’s board had unanimously authorized the use of a deep injection well on county-owned property. That would give county commissioners total control over the well in the future and allow the county to dictate water quality before it goes into the well.
“In other words, the residents and business owners of north Manatee can rest assured,” Ms. Baugh said. “I am so pleased that the interruption of life — or to life — as usual in north Manatee is minimal.”
Mr. Hopes said that while there were lingering concerns about the leak’s impact on the environment, the flow of the water appeared to be at a rate that officials were hopeful could be diluted and handled properly.
“We are very, very optimistic that we have been able to successfully minimize the impact,” Mr. Hopes said, adding that drinking water was safe. “I think everybody should be rest assured that this is very much under control now. The risk has been lessened.”
At the news conference, Mr. Hopes empathized with residents who were forced to evacuate, but was thankful there was not a major breach.
“It’s been hard on everybody involved. It’s been stressful for the residents of Manatee County,” Mr. Hopes said. “I hope that tonight many of us — I know I’m going to — sleep better. I may actually sleep, and I’m sure the others that have been involved.”