Sinkhole Saga: Why are they appearing after Debby?

by Michael Mosher on July 7, 2012

Debby has left a lot of scars on our area between destroyed homes and sinkholes.

Sinkholes can form when a pipe bursts underground and water pushes away the surrounding soil, but that wasn’t the case with the sinkholes after Debby.

Underground cavities form overtime as water eats away at limestone. Once that cavity is created, there is just a thin layer of sand and clay left. The sinkholes suddenly occur when that layer of sand and clay can’t hold its weight anymore and collapses.

Tropical Storm Debby’s torrential rains and heavy flood waters only made the pressure worse.

“The soil gets saturated and heavy up top. That adds some weight and that can help to cave in the top,” says geological sciences professor, Liz Screaton with the University of Florida.

Once a sinkhole has formed, Screaton says there are two ways to fix it. One option is to fill it with cement, but if is forming underneath a building or a house you can put supports down into the solid rock to support the foundation.

So the question now is, if we get another big rain or flood will there be more sinkholes?

It is possible.

“There are cavities underneath our feet in a lot of places in Florida, whether they will form sinkholes or when they will form sinkholes is hard to predict,” tells Screaton.

A contributing factor that was working against the First Coast going into Debby was the low water table. The more water there is inside the underground cavity, the more stability it adds. If there is less water, there is less stability and that means more sinkholes.

Full article…here

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