Lee and Leah Mansfield, their 2-year-old son Marshall and a goat named Loretta are standing near the edge of a 15-foot gaping hole in the ground in their backyard pasture in Archer.
The couple moved to the property in February from Citra and brought their whole farm with them, including three horses, chickens, pigs, dogs and some kittens.
Just before Tropical Storm Elsa arrived, the couple noticed a 3-foot wide depression in that back pasture about 20 feet away from a 24-by-12-foot shed where their teenage son sleeps.
At first, they thought they could use the depression as a fire pit, Leah said, but it quickly expanded beyond that: “It was so deep and more collapsed, I couldn’t see the bottom.”
The next day it was twice the size, Leah said, and by day four it was this size it is now, about 15 feet in diameter and 12 feet deep. At one point Lee tried to measure how deep the hole was so he set a 6-foot-long board in the center and now it has disappeared about 10 feet below the exposed bottom of the hole.
“There’s not much clay between the sand and limestone [in western Alachua County],” Olson said.
He said clay helps insulate limestone from the direct impact of water and heavy rain events that cause wet sand to rush to fill in the gaps in the limestone, which is when the ground caves in.
Olson said that sinkholes happening in retention ponds and at least 50 to 100 feet away from structures could be filled in with gravel and dirt as the first step to stabilize them.
But Olson said if sinkholes are near where people will be driving or walking or near buildings, remediation usually involves compaction grouting and that entails, “pumping concrete into the ground at a high pressure.”
Jen Grice, acting director of Emergency Management for Alachua County said she refers homeowners with an active depression or sinkhole to the Florida Department of Environmental Protection’s Sinkhole FAQ web page.
The website walks homeowners through steps they should take for safety.
“Take notes of its dimensions; take photographs; note and photograph changes over time; and keep children and pets away,” the site states. “If the hole is directly impacting a house, and sinking, sagging, or cracking walls are apparent, stay out of the dwelling.”
The FDEP suggests that if a hole suddenly appears, fill it with clayey sand to slow the water movement because any water moving into the hole can cause it to expand and remain active.
The Mansfields said that is their next step, and they are trying to arrange for the shed to be moved away from the area as soon as possible.
For now, the horses have been moved to the front yard and the gate to the back pasture is secured shut.