Wherever limestone and dolomite are found underground, sinkholes are to be expected, said Ed Osborne, director of the Geological Investigations office at the Geological Survey of Alabama in Tuscaloosa.
“And limestone and dolomite are very common in north Alabama,” Osborne said.
Water eats away at both limestone and dolomite which can create caves that weaken the ground above and can lead to sinkholes, explained Miriam Hill, professor of geography and geographic information systems at Jacksonville State University.
The depressions can occur naturally and during construction, Osborne said.
It cost the city more than $1 million to repair the sinkhole, said Oxford finance director Alton Craft, with another $2.3 million spent to install sewer and water lines and prepare the site for future retail development.
Add those figures to the $7.5 million spent last year for site preparation prior to construction of Publix and the city will have spent around $10.7 million on the project.
City officials note a study, however, which estimates the revenue from sales taxes and other fees will give Oxford a return on that investment in a little more than two years.
More retail, restaurant and business outlets are expected to open atop the spot where the sinkhole once was, but contracts with those businesses have not been signed, said Eric Brewer of WR Oxford, the company developing Oxford Commons.
Brewer declined to name those businesses until the contracts have been completed.
“We’re working on it,” Brewer said.
Oxford’s sinkhole is one of many that have occurred in Calhoun County in recent years, and evidence points to more forming in the future.
The Alabama Department of Transportation was to begin this week a $9.4 million repair of a sinkhole that formed beside Alabama 21 at mile marker 225.
In May, an 80-foot sinkhole was discovered at the intersection of Weaver Road and Glade Road in Anniston. City workers believe heavy rains washed away dirt and a deteriorated drainage pipe, which caused the underground hole.
A sinkhole was discovered in 2009 at the site of a proposed Sam's Club, just across Leon Smith Parkway from Oxford Commons.
In 2005, a sinkhole large enough to drive a bus into formed at the intersection of U.S. 78 West and Mountain Crest Avenue, about 3 miles from downtown Oxford.
Homeowners in a DeArmanville subdivision off of Buckalew Bridge Road discovered three sinkholes in their neighborhood in 1998.
A map from the Geological Survey of Alabama shows at least 20 sinkholes formed across Calhoun County between 1958 and 1986, five of which occurred in the Oxford, Hobson City and Bynum areas.
North Alabama is littered with them, with several thousand sinkholes recorded in Lawrence, Morgan, Madison, Jackson, Marshall, Limestone and Colbert counties, according to those maps.
The death of a man after a sinkhole formed under the bedroom of his Seffner, Fla., home in March drew worldwide attention.
Florida’s terrain — covered with underground caves, streams and drainage systems — is ripe for sinkholes, Osborne explained.
One of the most famous sinkholes in the U.S. occurred in Winter Park, Fla., in 1981, when a 350-foot sinkhole swallowed a home, a laundry, a print shop, part of the city’s swimming pool and five Porsche sports cars from a garage.
The largest sinkhole in Alabama occurred in Shelby County in December 1972. Called the “Golly Hole,” it’s about 325 feet wide and 120 feet deep.
But it’s not clear if there are more sinkholes occurring today than in years past, explained Osborne.
He suspected he’d be fielding calls from reporters asking about sinkholes after a 60-foot wide sinkhole on Monday swallowed part of a condominium in Clermont, Fla., Osborne said.
“My guess is that we’re just paying more attention to them,” Osborne said.
Staff writer Eddie Burkhalter: 256-235-3563. On Twitter @Burkhalter_Star.