As heavy rainfall hit Alachua County over the past week, a series of connected sinkholes opened up within Oakmont, a subdivision off SW 122nd Street.
The Oakmont sinkholes are in a stormwater basin on the development with the largest measuring 40 feet by 100 feet. The sinkholes were first reported to the city of Gainesville on Tuesday.
Ted Goodman, a geologist with Alachua County, said sinkholes tend to appear during periods of heavy rain or drought. And the occurrences aren’t unusual in Florida and western Alachua County.
Goodman said he heard of another sinkhole that opened over the weekend within the Town of Tioga in a similar scenario. The Newberry station of the Suwannee River Water Management District reports 11.56 inches of rainfall in the last week.
“I know there have got to be others that we just haven’t heard of that the developers and homeowners’ associations in those areas just deal with them as a matter of course,” Goodman said.
Goodman said the responsibility typically falls on the property owner with Alachua County involved if it threatens a road or other public infrastructure. Oakmont has already hired a geotechnical engineer to work on a remediation plan that will fill the sinkhole, and the county has signed off on the plan.
Florida rests on a limestone shelf, and in western Alachua County, that shelf lies closer to the surface than other parts. As water works through limestone, the stone dissolves some and voids can form. Eventually, the void below can’t hold up whatever is left of the ground and a sinkhole forms.
Goodman said stormwater basins increase the pressure on the ground directly below. If a chimney or crack exists, the water finds that weak point and can exploit it faster.
He said this stormwater basin at Oakmont has had issues before, and once sinkholes form, they tend to reappear at the same location.
After Tropical Storm Elsa in 2021, multiple sinkholes opened in the Jonesville area and in the Tioga Town Center, including in a stormwater basin.