Cleanup set to begin on massive sinkhole

Barring unforeseen developments, cleanup is expected to begin this week on the massive sinkhole that recently swallowed two homes in the Lake Padgett community of Land O’ Lakes.

As of July 20, Pasco County was entering the final stages of securing bids from contractors for debris removal at the sinkhole site, which now measures 235 feet wide and approximately 50 feet deep — believed to be the largest in the county’s history.

While the sinkhole is labeled ‘dormant,’ recent activity has been documented. On July 19, the sinkhole’s perimeter widened by approximately 10 feet, after sand erosion just below the ground surface dried out and collapsed into the hole.
The movement along the bank resulted in a hot tub and slab of concrete falling into the hole, along with about 10 feet of dirt and grass. (Courtesy of Pasco County)

Before cleanup and repair work can begin, however, engineers must perform additional testing to ensure the ground around the sinkhole is stable enough for heavy equipment. One of the county’s contracted engineers, Intertek-PSI, is currently using ground penetrating radar and core sampling to measure the structural integrity of Ocean Pines Drive and county easements leading up to the sinkhole.

Kevin Guthrie, Pasco County’s assistant county administrator for public safety, said recovery work could take months, with costs ranging from $750,000 to more than $2 million.

“It’s going to be a very slow and methodical process,” Guthrie said.

The county already has spent about $100,000 responding to the sinkhole, through contractual and departmental costs.

The county’s goal is to have a debris removal company in place in case homeowner’s insurance companies don’t accept responsibility to clean up the sinkhole.

The fastest, most economical cleanup tactic being considered is what’s called a dragline — a cable-operated system that would extend out and collect debris from the surface of the sinkhole.

Other possible options include using a float barge or large crane, with an excavator, to remove debris and decontaminate the sinkhole site.

“We’re trying to look for the most cost-effective, but safe option, so that we don’t put other homes in danger,” Guthrie said. “If we can employ a tactic that does not cause harm to the (sinkhole) banks, that’s the big deal right now.

“There’s a possibility using that dragline may actually destabilize those banks and cause further damage,” he said.

The assistant county administrator estimates filling the entire sinkhole would require approximately 135,000 cubic yards of dirt, though plans that far ahead are not yet in place.

The sinkhole originally opened on July 14 at 21825 Ocean Pines Drive, where it engulfed two homes and a boat.

Despite extensive property damage, no injuries have been reported.

The sinkhole is currently labeled “dormant,” but activity has been documented.

On July 19, the sinkhole’s perimeter widened by approximately 10 feet, after sand erosion just below the ground surface dried and collapsed into the hole.

The movement along the bank resulted in a hot tub and slab of concrete falling into the hole, along with about 10 feet of dirt and grass.

As a precaution, two homeowners along Canal Street were advised to gather their belongings for possible evacuation in the future.

Guthrie has reassured the activity is not an indication of the sinkhole becoming deeper.

“The sinkhole is not growing,” he said, assuredly.

In resolving the erosion issue, Guthrie said the edges of the sinkhole must be reshaped with dirt, from a 90-degree angle to a 45-degree slope.

“There is no support for that sand. As the water table goes down, that sand has nothing to hold it in place. So, that sand is falling out which then causes the grass and top soil to collapse,” Guthrie explained.

Once engineers deem the area safe, the county will bring in dump truck loads of dirt to shore up the banks of the sinkhole, before the large-scale cleanup process begins.

“We’re trying to determine if there are any sinkholes or any other activity under the ground before we bring the dump trucks in. Once we have figured that out, then we will start bringing that dirt in,” Guthrie said.

Elsewhere, water tests of the sinkhole turned up negative for E. Coli, officials said last week.

Further testing did come up positive for total coliform bacteria, in some of the water surrounding the sinkhole, officials said.

Greg Crumpton, a county health official, said it’s likely the result of older, dirty wells, some of which are upwards of 10 years to 20 years old in the Lake Padgett and Lake Saxon communities.

He said a confirmatory test and resample is underway.

If those tests come back positive, nearby homeowners are advised to use bottled or boiled water until the wells are disinfected.

Water tests
Due to the positive bacterial results, Pasco County announced it is waiving the fees for well water for testing more than 400 homes along Lake Padgett and Lake Saxon through July 28.

All residents living on the following streets qualify for free well water testing: Bronze Leaf Place, Canal Place, Clover Leaf Lane, Flat Rock Place, Grove Place, Heatherwood Lane, Lake Padgett Drive, Lake Saxon Drive, Ocean Pines Drive, Panther Way, Peninsular Drive, Pine Shadow Drive, Rain Forest Place, Snook Circle, Swans Landing Drive and Wilsky Road.

Residents who would like their well water tested should do the following:

  • Go to the Pasco County Environmental Laboratory located at 8864 Government Drive in New Port Richey and request a test kit for Total Coliform.
  • Present proof of address and receive lab instructions to collect water.
  • Take a sample of their tap water according to lab protocols, and bring the sample and associated paperwork back to the laboratory.
  • Results will be available in two days.

 

Help still available
Help remains available for sinkhole victims. Those needing help should reach out to the American Red Cross, The Salvation Army of Pasco County, Pasco County Human Services or United Way of Pasco County.

Published July 26, 2017

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