Boston Officials Reveal Reason Behind Mysterious Sinkhole in Neighborhood Park

After the massive sinkhole was discovered in Dorchester's Ronan Park, the Boston Parks and Recreation Department had said an engineering firm would take a look at the hole and bring in a probe to see what’s down below. 

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Many people have been wondering for days now what caused a massive sinkhole to mysteriously appear in a Boston neighborhood park.

They got their answer Thursday morning: it's an old well that dates back to the 1800s.

"What we believe currently is that the well is either built in 1818 by John Pierce for his estate," Boston archaeologist Joe Bagley said. "Or, the well is the new well that Mary L. Pierce built sometime between September 22, 1871, and May 1, 1872."

The Boston Parks and Recreation Department, including Commissioner Ryan Woods and Bagley, held a 10:30 a.m. press conference to provide an update on the gaping hole in Ronan Park that was discovered Sunday in Dorchester, Massachusetts.

The sinkhole was originally estimated to be 40-feet deep and 3.5-feet wide, but Bagley said it is a 16.5-foot opening. City officials said at the time the sinkhole was discovered they suspected it could be an old cracked drain pipe that possibly gave way after the recent rain.

Recent rain was to blame, but it's not an old cracked drain pipe.

Bagley said the well revealed itself after recent rain loosened soil, causing it to slip down into the well, partially filling it.

The well is under 10 feet of fill that was brought to the site to create Ronan Park in 1912, Bagley said. While Bagley says the well is currently 6.5-feet deep, he said there's no way to know how deep it was originally. Only six feet was left in tact when the fill poured in this past weekend.

The stone-lined well is covered in slabs of granite. Bagley says there is an opening in the top of the well that was opened in the not so distant past.

Why? Bagley says it was either the stone covering failing or possibly a historic wooden covering that failed.

"When something like this turns up, it's kind of shining a light on a story that may have been either lost or underrepresented in the history of this neighborhood," Bagley said.

Bagley says his team lowered an iPhone down into the hole, taped to LED flashlights on a rope, to get a look around.

The well either dates back to 1818 when John F. Pierce purchased the land, or 1871/1872 when Mary L Pierce bought the property, according to Bagley.

Bagley said the first thing they looked for was to see if there were any animals or people were at the bottom of it.

"Fortunately nobody's down there," he said.

Boston's archaeologist Joe Bagley held a press conference with the city's parks and recreation department to talk about the massive sinkhole that was discovered Sunday at Dorchester's Ronan Park.

The site has been secure since Sunday, when barriers were put into place. The hole was discovered Dec. 6 by a father walking in the area, Woods said.

The man called the mayor's 24-hour hotline (311) to report his finding, at which time Boston's fire and police departments both responded to the scene, as did the parks and recreation department, Woods said Thursday.

Following the discovery at the base of a steep hill, Boston Parks and Recreation said an engineering firm would take a look at the hole and bring in a probe to see what was down below.

Woods said their current plan is to make sure all the drain is intact, and then it should be backfilled within the next two weeks.

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