Florida Sinkholes Cause

Florida Sinkholes

Florida Sinkholes Causes

A sinkhole on Shoal Drive in Hudson that buried the backside of a house in 2012. Pasco County Fire officials claimed the sinkhole was 40 feet wide and 20 feet deep at the time the photo was taken. Read more

The Villages Sinkhole

The Villages is characterized as “Disney for Seniors” for a variety of reasons.

The Villages, the world’s biggest retirement community, is also one of America’s safest and most relaxing places to live. Sumter County, which is nearly completely made up of Villagers, ranks 62nd out of 67 counties in Florida for violent crime, owing to the county’s median age of 66.6, the highest in the country.

The presence of gates, guard booths, and required visitor identification cards contributes to the low crime rate. The number of vehicular deaths is quite low, which makes sense considering that Villagers prefer to commute by golf cart rather than automobile. The Villages is also in the safest hurricane-prone area of Florida.

Villagers, on the other hand, are growing increasingly afraid of a strange threat: the ground suddenly opening up and swallowing them whole.

This March, a 10-year homeowner of the Village of Calumet Grove told me, “Everybody is scared,” pointing to a saucer-sized hole at his curb where sinkhole specialists excavated to check for weak spots. Seven sinkholes formed across the street and into a golf course a month earlier, producing a zig-zag fracture over the exterior of one house and forcing the evacuation of four residences. One has been sentenced. A town hall meeting that week drew five times the normal number of Villagers. With a tired laugh, the elderly neighbor adds, “It’s not a good time to sell.”

The Villages, despite its generally peaceful reputation, is a hotspot of sinkholes. They’re more common in Florida than anywhere else, yet we’ve spotted them on Maryland highways and even in front of the White House this week. And The Villages sits right in the midst of Sinkhole Alley, a region of Central Florida counties with the highest risk of sinkholes.

Florida Sinkhole

Florida Sinkholes Map By City, County and Address

Sinkholes in Florida

Sinkholes are usually just a pain in the neck for property owners, but when tragedy strikes, it’s the stuff of nightmares. Jeffrey Bush, who was asleep in his bedroom when a sinkhole pulled him 20 feet down, is one of Florida’s six known sinkhole deaths. His remains were never found.

In recent years, the frequency of recorded sinkholes in The Villages has increased. Residents reported “many” sinkholes in 2016, but none harming homes, according to an official with The Villages Public Safety Department, according to the Orlando Sentinel. The same is true for 2015; three sinkholes impacted six properties in 2014.

That independent news source, on the other hand, recorded at least 32 sinkholes in 2017. At least eight residences were damaged, as well as a country club, a busy junction, a Lowe’s home improvement shop, and the world’s largest American Legion post.

(The Villages’ developer’s newspaper, The Daily Sun, commented on none of them save the one near the major junction, saying merely that it was “later found not probable” to be a sinkhole.) Villages-News reported at least 11 sinkholes in the first three months of 2018, damaging eight homes—all before sinkhole season began in early April. This week, four additional sinkholes appeared.

Florida Sinkhole Season

The fact that there is a “sinkhole season,” just as there is a “tornado season” and a “hurricane season,” demonstrates the complexity of the danger. The fact that Florida is constructed on a carbonate base, mostly limestone, underpins all of them. Rainwater, which turns acidic as it seeps through the soil, dissolves that rock very readily.

The resultant landscape is honeycombed with cavities, known as “karst.” When a hollow gets too large to maintain its roof, the clay, and sand above it collapses, leaving a gaping hole at the surface.

Primary Cause of Sinkholes

Water—either too much or too little—is the primary cause of sinkholes. Florida’s typically wet soil has a karst-stabilizing impact. During a drought, however, cavities that were previously supported by groundwater dry out, making them unstable. The weight of pooled water can strain the soil after a severe downpour, and the quick rush of groundwater can wipe out voids.

At the start of 2017, Central Florida was experiencing a severe drought, which was followed by Hurricane Irma’s torrential rains, which reached The Villages in September—and a deluge following a drought is the ideal setting for a sinkhole epidemic.

However, Mother Nature’s significant events in 2017 do not explain for the current epidemic of sinkholes. Sumter County’s weather has been very average. So, what exactly is going on here?

Mand-Made Growth

The greatest consistent reason for rising sinkholes, it turns out, is man-made growth. The weight of new structures bears down on weak places; underground infrastructure can lead to leaking pipes; and, perhaps most importantly, groundwater pumping disturbs the delicate water table that keeps the karst stable.

And The Villages has been on a construction frenzy. It was the United States’ fastest expanding metropolitan region. It’s been in the top ten for four years in a row (2013-16), and it’s still there. Journalist Andrew Blechman predicted in his 2008 book Leisureville that The Villages will “end its build-out—an industry phrase for the point at which a project is complete—in the very near future,” with a population of “110,000 inhabitants.” However, a decade later, the population had surpassed 125,000 people.

The Villages announced a 93 percent increase in house development last year, as well as a new property purchase that would generate up to 20,000 units. Another property transaction for 8,000 additional houses is about to be finalized.

Golf Courses

More golf courses will be built as a result of the additional houses, which will increase the total number of golf courses in The Villages to 49 (the second most per capita in the United States). Retention ponds created on those courses have the potential to seep into the karst, causing sinkholes. Irrigating The Villages’ 49 golf courses and tens of thousands of lawns is also a big danger concern.

Veteran writer Craig Pittman recalls in his 2016 book Oh, Florida how a buddy who worked at the Daily Sun told him that the staff was never to publish two things: 2) “The countless sinkholes that open up due of all the water being drained from the aquifer to keep lawns and golf courses green.”

Lauren Ritchie of the Orlando Sentinel writes in a critical piece that the nascent neighborhood had a water permit to consume 65 million gallons per year in 1991, but by 2017 that rate had risen to “a staggering 12.4 billion gallons per year.”

A contentious plan by a bottling firm to pump almost half a million gallons of water per day—and quadruple that pace during peak months—is also threatening the local aquifer in Sumter County. Pumping will begin shortly, despite Villagers’ objections that a lowering water table could cause sinkholes.

Sumter County Sinkholes

When it comes to sinkholes, the Villages should not be singled out. The Villages is located in Marion and Lake counties, which are ranked #4 and #10 on RiskMeter’s 2011 list of the most sinkhole-prone areas in Florida. The first is Pasco, which is bordered to the south by Sumter. A 260-foot-wide sinkhole opened beneath a Pasco neighborhood this summer, devouring two houses and condemning seven more, making it the county’s biggest sinkhole in 30 years. For RiskMeter, an online program that provides hazard assessments for insurers, the huge chasm equaled the legendary Winter Park sinkhole in Orange County, which was ranked #8.

Citrus County Sinkholes

Citrus County, located just west of Sumter, is ranked #6 in RiskMeter and the fourth “grayest” county in the United States, based on the percentage of inhabitants over 65. Pasco and Marion are also among the top ten counties in the US for both the number and concentration of senior citizens.

Ocala County Sinkholes

A sinkhole in a fast-food lot in Ocala, near The Villages, swallowed a car, forcing the elderly couple inside to climb out. A man standing on the grass in The Villages slid through a five-foot hole’s trapdoor. A elderly couple in Glenbrook discovered a sinkhole just outside their front door.

Another Villager called 911 to report a “prowler,” only to find a black emptiness instead. Half of a couple’s house in the adjacent city of Apopka fell, taking with it “almost 50 years of memories.”

On the same day he returned from a trip to The Villages to check a possible sinkhole, I chatted with geologist and sinkhole specialist David Wilshaw. The little dip was created by a leaky irrigation line, but the terrified homeowner informed Wilshaw she hadn’t slept all night because she was afraid the ground might swallow her.

Sinkhole injuries are uncommon, but “perception is crucial,” according to Wilshaw, “especially with the older population.” They’re also worried that they’ll lose their “greatest investment”—their home—”during their golden years,” when they’re at their most vulnerable.

ground penetrating radar (GPR)

The unpredictability of sinkholes is at the heart of that anxiety element. They generally appear out of nowhere, and detecting weak places in the earth is difficult. “Drilling exploratory holes in The Villages is difficult because rock can be 5 feet down in certain areas and 100 feet down if you go 20 feet to the side,” Wilshaw explains.

Wilshaw, who owns a firm that specializes in analyzing sinkhole danger, is frequently recruited to examine properties using ground penetrating radar (GPR), the most effective method of detecting holes. However, because Florida law does not mandate it, he claims that many homebuilders “will do absolutely nothing and instead rely on the end user” to check for cavities. He describes it as “a little bit of the Wild West.

NASA’s technology

Is there any other technology that can assist anticipate sinkholes than GPR? NASA’s technology has demonstrated its worth: When an interferometric synthetic aperture radar (InSAR) sensor is flown repeatedly over a region prone to sinkholes, especially the slow-forming ones known as “cover-subsidence,” it detects minute changes in ground elevation over time.

The Florida Department of Environmental Protection (DEP) reached out to NASA for assistance after that usage of InSAR became public in 2014, but when I checked in with a DEP representative, she stated it wasn’t going to happen anytime soon.

Homeowners Insurance

Given the fragile nature of karst, a sinkhole can occur even after a location has been studied and certified secure from sinkholes. Wilshaw advises, “It’s better to just cross your fingers and get insurance.” However, homeowners insurance only covers “catastrophic earth collapse,” which occurs when a sinkhole renders a property inhabitable.

Any damage that falls short of that must be covered by sinkhole insurance, which in Florida generally has a deductible of 10% of the home’s value.

Even after a sinkhole has been fixed (or “remediated,” as the technical phrase goes), it might resurface. The Villages’ most spectacular sinkhole, near Buttonwood (just look at this shot), burst out many months after repair began. The sinkhole that killed Jeffrey Bush did the same.

Florida Division of Emergency Management (DEM)

Sumter County is conspicuously absent from RiskMeter’s top ten list. However, that 2011 list was based on sinkhole insurance claims, and a large number of them were erroneously filed in the years leading up to 2011, when Florida lawmakers reformed the misused system.

The 2013 Hazard Mitigation Plan, prepared by the Florida Division of Emergency Management (DEM), gave Sumter a “medium” risk for sinkholes, which came two years later (just as The Villages was commencing its four-year development run). Only eight other counties were rated as being at a higher risk.

However, as DEM admitted, the 2013 assessment was “imperfect and inadequately justified by existing geologic data” since it was based largely on public reports of sinkholes that had not been validated by geologists.

Clint Kromhout of the Florida Geological Survey won more than $1 million in government money in 2013 to travel throughout Florida verifying sinkholes and creating a prediction map indicating which regions are most “relatively vulnerable.”

“The goal for the scale of the state map is at least the county level,” Kromhout said, “but Kromhout said he hopes they will be able to get to a neighborhood-by-neighborhood detail,” according to James L. Rosica of the Tampa Bay Times, who was one of the many reporters Kromhout spoke with during the three-year study.”

Sinkhole Alley

Kromhout’s 2017 paper, according to Veni, the karst expert I spoke with, is “the most extensive, comprehensive examination of sinkhole risk that I’m aware of.” (Kromhout, as well as a spokesperson for The Villages, declined to be interviewed for this article.) The 2018 Hazard Mitigation Plan, which was released in February, featured its long-awaited prediction map.

That’s the extent of the map’s detail. “Most significantly, the favorability map is not of sufficient detail to offer site specific information on sinkhole development,” according to the Sinkhole Report. The Villages are mostly in Sumter County’s northern half, which is virtually entirely in the red zone.

Is the Sinkhole Report really that useful? “It isn’t the prediction model that some hoped for (it would be quite difficult to construct one), but it does improve the science,” says Robert Brinkmann, a geology professor at Hofstra University who co-authored Florida Sinkholes: Science and Policy and owns a home in Sinkhole Alley.

Sinkhole Research

“The major problem here is that the state doesn’t really support much sinkhole research,” Brinkmann says, “especially since real estate remains one of the state’s primary economic engines.”

“With the exception of this tiny study, the federal government has not actually financed any substantial studies on the issue. Every year, millions of dollars are spent on tsunamis, earthquakes, volcanoes, and hurricanes, yet little, if any, is spent on sinkhole research. [The former] are indeed heinous, but they are one-time theatrical happenings. Sinkholes are a continual hazard, and the majority of the harm occurs over time. The annual property loss caused by sinkholes is staggering”—a conservative estimate of $300 million is used.

As climate change worsens, the impact might become far worse. “As sea levels rise as a result of climate change, groundwater levels in near-coastal locations will rise as well, resulting in more sinkhole flooding,” Veni forecasts. “Studies on the possible degree of such flooding and its ability to induce fresh sinkhole collapses are just getting started,” he says, adding that he’s working on one with a colleague in Florida.

Some Villagers are on the verge of giving up. “We thought we’d be here for the rest of our days when we moved [to the Village of Glenbrook] in 2012,” a member of the “Talk of the Villages” web forum wrote on March 5 after a sinkhole forced his neighbors to evacuate, but “now we’re considering moving again, which is the last thing I wanted to do.”

(A dozen sinkholes developed in an Ocala community not far from Glenbrook, garnering national headlines, less than two months later, forcing another eight family to from their homes.) “I am dreading when the rainy season comes,” another Villager said ominously, referring to the commencement of the rainy season, which is expected to begin on May 27 in the region.

However, the rainy season arrived early this year: on May 20, four sinkholes erupted in Calumet Grove, the Village that had been hit by seven sinkholes in February. Due to a subtropical storm system developing off the coast, thunderstorms are anticipated to persist.

Frank Neumann, an 80-year-old resident who was evicted from his house in February, talked with Villages-News. According to the website, “Prior to Monday’s sinkhole activity, Neumann said he hoped to have his house restored and continue in the area he’s lived in for 14 years—largely because of the friendships he and his wife had established there.” “However, as he stood in his front yard, gazing at the second wave of damage to hit his home in 95 days, he said he wasn’t so sure staying in The Villages was a smart choice.”

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