The people of Plant City, FL sometimes refer to 2010 as the “year of the sinkhole.” While there are incidences of sinkholes in Plant City, the winter of 2010 was a literal sinkhole bonanza. Record cold temperatures in January, collided with Plant City’s strawberry season. To protect their strawberries from the freeze, farmers pumped billions of gallons of water out of the ground. Within a matter of days, sinkholes began to appear. The city alone had to pay $7 million to repair roads that had been swallowed up by sinkholes. Many homeowners who lived within the vicinity of strawberry fields found themselves dealing with sinkhole damage which, in some cases, left their homes uninhabitable.
What happened in Plant City in 2010, is a perfect example human activity triggering the occurrence of sinkholes. In this instance, the over-pumping of groundwater was the triggering mechanism. For a more scientific explanation of what happened, I spoke with Ralph Meder, geologist at MCD of Central Florida.
“When there is rapid withdrawal of groundwater,” Ralph explained, “groundwater fluid pressure decreases significantly. The subsurface limestone cavities that once had water pressure to hold the topsoils in place, suddenly fill with air. The soils above ground, called the “overburden,” become more compact and dense as moisture is pulled out. Soon, the limestone walls of cavities underground, unable to sustain the weight of the soil layer above them collapse, forming sinkholes.”
People can trigger sinkhole conditions even in areas that are not naturally prone to sinkholes. For example, in urban areas a water main break can wash away underground soils causing a cavity to form. In Florida, where sinkholes are already a natural occurrence, pumping groundwater without restraint leads to a higher incidence of sinkhole formation. The ramifications of over-pumping goes well beyond an increase in sinkholes — it also affects both the quantity and quality of water.
Florida’s new SB 408 property insurance law may put the brakes on the number sinkhole claims — maybe. The fact remains, however, that there will be more sinkholes as Florida’s natural karst landscape clashes with inevitable and often destructive human activity.
If you suspect you have a sinkhole, call the experts at Helicon Foundation Repair. As a recognized leader in sinkhole remediation and with over a decade of experience, Helicon Foundation Repair has completed thousands of successful projects.