THE VILLAGES - Nearly two months after promising to repair a sinkhole in one of its retention ponds, The Villages is in the final stages of installing a synthetic liner - a solution debated by some experts.

The Southwest Florida Water Management District warned The Villages in March to find a remedy for a large sinkhole plaguing a retention pond, called Lago Bonito, in northeast Sumter County's Santo Domingo Village. Water district spokesman Michael Molligan said the liner - which was recommended by the district - is in place, but that the district has yet to complete final inspections.

Molligan said the water district will review the final engineering plans to affirm that the plastic liner has been installed correctly.

"Once the plans are received, our compliance staff will visit the site," Molligan said. "My understanding is that (The Villages has) completed the liner."

Thick synthetic liners are commonly used to repair sinkholes, which are usually formed when acidic rainwater flushes through the soil and erodes underlying rock such as limestone. This process forms gaping holes and can potentially contaminate the underlying aquifer. Sinkholes are common in Florida, as the underlying rock tends to be especially porous.

University of Florida geology professor James Channell said that although a synthetic liner is an effective solution to sinkholes, and one that will protect the aquifier for a few decades - longer, if carefully monitored - it is not a long-term solution.

"If we're trying to preserve the aquifier for the next century, we're going to have to do a little bit better than a plastic liner," Channell said.

Geologist Sandy Nettles of groundwater consulting firm N.S. Nettles and Associates in Tarpon Springs agrees, and goes even further, calling the use of a synthetic liner to repair a sinkhole "a joke." Nettles said that although liners prevent surface water from flowing directly into the sinkhole and underlying rock, they can't stop groundwater from seeping into the holes, or caverns, underground, which are the real problem.

Nettles said the only long-tern solution to sinkholes is to identify the cavern system and then fill the openings with cement - a process that is very expensive.

"To stop a sinkhole, you have to close those voids up," he said.

Villages Community Development District 2 administrator Pete Wahl told The Reporter in May that he has confidence that the liner - which cost CDD 2 $127,000, paid for out of excess revenues - is an effective solution to the sinkhole.

"Based on history and with past liners, we seem to have eliminated the problem with sinkholes," Wahl said.

Molligan said that while there is always a chance that the sinkhole could reopen or that another one could occur, the synthetic liner is, for now, the best solution - and one that will be manned carefully by the water district.

"We'll keep an eye on it and make sure it does what it's supposed to do," he said.