This could be the start of a big sinkhole season

Workers with GSE Engineering & Consulting, Inc. survey the large sinkhole that opened in the backyard of Robin and Rhonda Matheny in the Jonesville area, west of Gainesville on Monday. The sinkhole appears to have only grown a little deeper not wider, but with rain to come in the days to follow, conditions could change.

Brad McClenny/Staff photographer
Published: Monday, May 14, 2012 at 7:53 p.m.
Last Modified: Monday, May 14, 2012 at 7:53 p.m.

On the surface, it appeared Monday that little had changed in Robert and Rhonda Matheny's backyard.

The crater-like sinkhole that opened up Saturday, its lip a few yards from the swimming pool, hadn't grown much since Sunday.

But what was happening below the surface on the Mathenys' property in Jonesville was of concern to geologists.

Rhonda Matheny, 62, said they told her that the storage shed on the far side of the yard would likely fall in at some point.

It's just a matter of when.

Sinkholes could become even more of a worry around the state in the coming weeks and months because of the depleting aquifer, thanks to pumping and the drought, exacerbating an already worrisome, naturally occurring phenomenon.

"Even though it's related to the drought, it's really the overpumping of the aquifer that is making matters worse and making conditions such that we're more likely to have sinkholes," said Chris Bird, Alachua County's environmental protection director.

Ironically, when rain comes, it will exacerbate the problem as it will make topsoils heavier.

With the support beneath gone, the soils will cave in, creating sinkholes.

"We can be sure that there will be more," said Anthony Randazzo, a principal at the firm Geohazards Inc., which inspects properties before and after sinkholes develop, and a professor emeritus of geology at the University of Florida. "We can expect a number. I don't really know how many."

According to data from the Florida Geological Survey, 54 sinkholes have been reported in Alachua County since the 1960s, the most recent ones opening on Christmas in 2006 in the Arredondo area.

The sinkhole at the Mathenys' property would make 55, giving Alachua County the 15th most in the state. The counties with the most sinkholes reported are Citrus, with 353, and Marion, with 337, according to the data.

A map of the incidents in Alachua County showed that only one occurred east of U.S. 441.

Jonathan Martin, a professor of geology at UF, said a kind of fault line runs through Gainesville separating an area to the west where limestone, which erodes over time, is close to the surface and an area to the east where the surface is supported by mostly clay.

"There are all kinds of geological hazards around here that people don't really think about," Martin said.

For example, clay can shrink and expand with water, in some cases causing the ground — and whatever is above it — to dip.

"Sinkholes are kind of dramatic because they happen quickly," Martin said. "The net result of both of them is that the house becomes worthless."

Martin knows.

His house was built over some so-called shrink-swell clay, and some windows won't shut and doors won't close because the ground has moved.

The difference is shrink-swell issues can often be fixed if caught early.

There is often little warning of a sinkhole.

Randazzo said his firm looks at about a thousand properties a year in Florida, investigating them for sinkholes or other geological issues.

There are a lot of people, due to the economy, who don't have sinkhole insurance, "which is not very wise in Alachua County, I can tell you that," he said. "That's something you can't afford not to do."

In 2011, the Legislature changed the law on sinkhole insurance mandating insurance companies, including the state's Citizens Property Insurance Corp., to verify damage was caused by an actual sinkhole.

Randazzo said the changes took away protections for policyholders.

In the Mathenys' case, he said, it is a no-brainer — a sinkhole has caused damage on the property.

But other cases are less black and white, as there aren't craters in the ground but the surface is shifting, causing some level of damage to the property.

It remains to be seen how much damage will finally happen at the Mathenys' home, where they lived for 37 years.

"It's an eerie sound when you hear that dirt caving in," said Robert Matheny, 65, who goes by Robin. "An eerie thing."

Contact Chad Smith at 338-3104 or

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