DeSantis' declaration of a state of emergency allocates more pumps and cranes to the area.
Manatee County Administrator Scott Hopes said the models show the area could be covered with between 30 centimeters (1 foot) to 1.5 meters (1.5 feet) of water, and the second floor is 10 feet above ground.
"So what we're looking at now, is trying to prevent and respond to, if need be, a real catastrophic flood situation", DeSantis stated.
The entire Piney Point reservoir site, about 20 miles south of Tampa, and surrounding areas has been evacuated.
Parts of US-41 have also been closed due to the breach. "It is slightly acidic, but not at a level that is expected to be a concern".
Aerial images aired on local television showed water pouring from leaks in the walls of the retention pond.
"Collapse of Piney Point Stack Imminent!" an alert from county officials released at 11 a.m. Saturday said.
DeSantis insisted the water being discharged has tested as not radioactive, a common byproduct of the phosphate mining process, but rather comprises a mix of saltwater, mining "legacy process water", and stormwater runoff.
Hopes said he could not rule out that a full breach could destabilize the walls of the other ponds at the Piney Point site.
Hopes says that if the pond collapses, there is a risk it could destabilise the walls of other areas in the plant.
"This is not acceptable and it's not something we will allow to persist", he said, adding that he has ordered the Florida Department of Environmental Regulation to find a permanent fix at the site.
Officials are rolling out a response plan that includes controlled discharges of mixed seawater into Port Manatee to relieve pressure and maintain the integrity of the stack system, according to the Florida Department of Environmental Protection. The water meets "water quality standards for marine waters with the exception of pH, total phosphorus, total nitrogen and total ammonia nitrogen", according to the Florida DEP.
DeSantis vowed to hold HRK Holdings, the owners of the property, accountable for the failure.
"The pond is basically salt water".
In 2016, more than 200 million gallons of contaminated waste water from another fertiliser plant in central Florida leaked into one of the state's main aquifers after a massive sinkhole opened up in a pond of a phosphogypsum stack.
"This is my community, too", Barath said.