Article Courtesy of Sumter County Times Online
|By Jim Gibson
“When they opened up, we could hear the thunder of the water draining into them. It sounded like a waterfall…” Dalton Drive resident Barbara Down Torrential rains saturated The Villages Saturday and 13 sinkholes developed in a retention pond that serves Higgins Lake on the Glenview Golf Course in the Villas of St. Simons, according to residents.
The pond area has been plagued with sinkhole problems since last September. Dalton drive resident Barbara Down has documented 10 times that sinkholes have formed in the pond area, but this is the first time one has developed on the property of a resident.
Dennis and Bobbie Ketcham live on Richmond Street, which overlooks the pond and golf course. Mrs. Ketcham returned home from vacation Sunday night, “I just came in last night from the airport at nine o’clock and found a couple of yellow notes on the door that said ‘Don’t go into the back yard you’ve got sinkholes.’ Well we’ve always got sinkholes out in the pond, but I turned on the floodlight and there was one in my backyard.”
The sinkhole opened about 20 feet from the Ketchams’ home and swallowed up several hedge plants that adorned their backyard. “The firemen came out last night and told me to keep a flashlight handy and to watch this during the night and if I’m missing a tree or if the hole gets any bigger to get a taxi and leave my house. I was up all night watching, said Mrs. Ketcham.
“I was wondering where we could get a for sale sign,” said neighbor John Sabol.
Dalton Drive residents said that during the heavy rains Saturday, the retention pond quickly filled with the overflow from nearby Lake Higgins and water coming in from several huge culverts. The pond filled to capacity and then the water spread several hundred feet up onto the golf course.
Once this happened the sinkholes began to develop. “When they opened up we could hear the thunder of the water draining into them. It sounded like a waterfall with the water rushing into it,” said Dalton Drive resident Barbara Down.
“I watched the one in front of my home form. At first the water shot up like a mini geyser, and then the next morning the hole was there,” said Down.
She and other residents are worried the sinkholes are spreading toward their homes. “I’m afraid I’m in the line of this, because you can see almost a straight line of sinkholes heading out into the bed of the pond toward my home,” she said.
Dalton Drive resident Les Johnson said, “I think this is beneficial to them (Villages engineers). You get so much water in here and this is designed so poorly, and they don’t know what to do with the excess water. So here nature comes along and solves their problem. It opens up all these sinkholes and away the water goes down into the aquifer.
Then they’re safe, just dump a little dirt down in the hole and wait for the next one.”
Monday morning geotechnical engineer Nicholas Andreyev, of Andreyev Engineering in Sanford, came out to view the sinkholes. “We are going to bore test holes to determine where the problem is,” he said.
Andreyev said they will be looking for caverns or fissures that have opened up under the ground and will then fill them with concrete. “We are going to fix this problem,” he said.
According to Andreyev, in this type of situation the water in the pond is normally kept from sinking into the ground by a layer of clay that supports and holds it like a clay cup.
This clay cup is sitting on top of a limestone base. The limestone base is not always solid; it may contain many caverns. These caverns are usually full of water, but when water levels drop the caverns become hollow. When water rises in the pond during a heavy rain, the weight of the water may cause the limestone base to give way and collapse into one of the hollow caverns.
The only way to fix this specific problem in The Villages is to find the caverns into which everything is collapsing and fill it with concrete.
“There will be more sinkholes if this is not fixed,” Andreyev said.
He also noted that the water, which drained out of the retention pond when the sinkholes formed, went directly into the aquifer. This water possibly contained pollutants such as fertilizer run-off from the golf course. He said anyone living northwest of the site could possibly have contaminants in their drinking water if they had a private well and it was 35 feet deep or less.
Southwest Florida Water Management District geologist Tony Gilboy verified Andreyev’s statements saying, “You certainly don’t want a direct discharge such as this. You would get a slug of pollutants.”
Gilboy went on to point out that any pollutants should be naturally filtered out by the aquifer system within a one-half mile radius of the site. He also said Village residents do not have to worry about the pollutants because they are on a municipal water supply system.