Dodged a bullet - found a sinkhole

[MHarryE]

It's a cenote - you may find virgins sacrificed by an ancient culture in the bottom. But I remember that from Mexico and the similar holes. You are in MA, aren't you? MA - Salem is in MA - witch trials - definitely onto something more than a simple sinkhole here.

 

[PhysAssist]

I'm glad you weren't seriously injured!

We've experience with sinkholes here in our yard. The builder/prior owner buried tree stumps and other organic in several areas, when he was clearing the area for the house and septic fields These sites were unmarked, but we have been finding them one by one over the past 20 years of living here. First, we'll see a low area develop, then a small hole, and then it will collapse and leave an open pit of variable size. Then we start to fill it in. I found the first one much like you did falling in with one of my legs up to my left hip-luckily without injury.

When I was about 10, we developed an area of quicksand in my parents front yard, when a watermain developed a mild leak. My dad carefully stuck a 12' piece of quarter round molding virtually completely into the area. He had to leave it there because he couldn't pull back hard enough to get it back out. My brother and I had great fun watching the water authority crews trying to dig down through that soupy sandy mess.

I did some extensive reading about sinkholes (cenote, whatever-there are many different terms used interchangably) when that guy in Florida disappeared in the sinkhole that sucked down his bedroom, and all the sources agreed that it is often difficult to tell the true extent of the hole from the surface, so as others have suggested

Be Careful!

Best wishes for safe and inexpensive resolution,

Thomas

 

[caps]

We had a similar thing happen where I used to live West of Baltimore in Maryland. There was a spring that ran steady for at least 15 years that dried up. I remember we used to push a piece of 4 inch vent pipe over the outlet and it would push the water up about a foot or so above the ground level. One of the neighborhood kids was poking around it after it dried up and fell into a hole that was about three foot in diameter and about 6 foot deep with ankle deep water at the bottom. No one was hurt but it sure scared the heck out of him. As kids we used to play in the spring frequently when it was flowing and there was no indication of any sort of cavity. Best guess is that when it dried up the soil settled as the water receded and left the hole.

 

[farmgirl19]

It looks like your foot is close to where you "went in", in the one photo. That is probably too close to be safe. Be careful, please!

 

[Don87]

I did some poking around in the area today, though didn't get a chance to excavate (I had to move a big pile of dirt first). The water in the hole was crystal clear (so maybe a spring?), feeling the bottom with a stick there's rocks in the bottom, some areas are gravel and some are much deeper and mud on the bottom. It extends about 4' in one direction and there are some areas around that are 5' deep mud (can push a stick in 5 foot with minor effort). I think it's been developing for a while now that I look at it. Last fall I cut a tree (you can see the stump in the pictures) because the roots had just pulled out and it was lifting out of the ground with the wind, other trees around had started to die and I lost a couple of others. The whole area is slightly sunken vs the other ground and there's a thick mat of tree roots, which is what's holding the surface up, where I fell through I stepped between the roots. I've roped the area off with flagging tape and will wait for it to dry before digging in further. The stone wall near it is my property line, so I probably will be unable to drain it - but maybe I can fill it with rocks and get a stable surface, my hope was to use the area to park a trailer.

The area of the sinkhole. The hole in the center is where my foot went through.
View attachment 319598

Another view showing where the area is. Note there's a compacted Pad for parking right next to it. The drain pipe is for my downspouts though due to a gutter problem (tree hit it), almost nothing drains out of it, it runs out the other end.
View attachment 319599

where my foot went through, looks innocent enough!
View attachment 319600

Inside the hole. The water is pretty clear and the level is about 6" under the level of the ground, the top level is being supported mostly by tree roots.
View attachment 319601

Not to alarm you, but I would be very concerned after seeing the pictures. The next sinkhole could destabilize the building, depending on the flow direction of that underground stream.

I would consider calling in an expert of some sort right away.

 

[tcreeley]

In my area we have 13' to 25' dug wells lined with stones all the way dating back to the 1800's. They are usually filled in, some are not. Debris could have capped it off, limbs etc and you punched through walking. A lot of western Mass is limestone, but growing up in the Berkshires, I never heard of anything like caverns. Who knows. I think it is an old well. Maybe the house or barn fell in on it 150 years ago and rotted away leaving vegetation. I always look for stones in a pattern, or apple trees nearbye and a bit of mounding.

-Just looked at your pictures- old cesspool/septic.....? Goodluck Just saw story on a sinkhole in Lexington and another in Holyoke.

 

[tractchores]

Thanks. Im monitoring it, but haven't dug it out yet because its so wet. Its a good 20' from the building with a compacted parking area in between, so a good distance. I checked it yesterday and there has been no change and the water isn't moving so i don't think it will grow. I think an old well or something might be the culprit. As far as i know there is no limestone in the area, definitely no mines and there weren't any other dwelling as it was pasture and an orchard back to the 1700's

 

[Pharm]

We have sink holes that pop up every once in a while. It is almost always related to water - be it underground springs or other manifestations. We had a big one open up last year where we suspect an underground spring is located in a field where we plant crops. It was probably about 7 foot deep and big enough to swallow me riding an ATV. I had one about the size of yours just open up again. Last year I filled it with dirt but it's back again this year - we've had heavy rains this year which I suspect is the culprit.

 

[paulharvey]

When ever you collapse it and go to backfill it make sure to use a high plastic clay/fat clay and plug it up. If you can get a couple of feet if nasty plastic clay in there your probably good for another generation.

 

[foote2floor]

My father and i once excavated a small area to extend a side walk for wheelchair access. He found something odd and hopped off the tractor, he fell knee deep in a recently abandoned septic tank with a 1/4 inch plywood lid. Needless to say I let him go home for the day, and he drove home without shoes, socks, or pants that day.

Consider yourself lucky it is "clear water"

 

[BraveheartGN]

Since it's near a stone wall it would appear to be an old farm site at one time. Any possibility it was an old "grave" for horses?

 

[caps]

A pit from a really old outhouse location perhaps? It was not unusual for them to just throw a couple boards and some dirt over them when the outhouse was moved.

 

[tractchores]

Since it's near a stone wall it would appear to be an old farm site at one time. Any possibility it was an old "grave" for horses?

Could be, though the primary use was livestock pasture and the livestock of choice was sheep. It wasn't near any of the barn sites or anything and stopped being used as pasture land probably over 100 years ago and became orchard then ultimately forest. The lot next to it was apparently partially a saw mill site that processed a huge number of trees that fell during the hurricane of 1938, though the actual sawmill was probably 3/4 mi away. Maybe I'll find some clues when it finally dries enough to dig it out. I'm thinking it was a man made cavity via a covered hole or something rotting away as the water does not appear to be flowing or coming up even though we've had huge amounts of rain..

 

[farmgirl19]

Now we ALL want to know what it is! Be neat to "see" what you discover. Just stay safe, doing your excavation.

 

[compact]

Maybe a sunken grave? I worked in a cemetary for a couple years, we all learned to levitate during spring mowing.

 

[Richard]

Glad to hear you're ok. It's a scary moment.

I was on my backhoe once, on the hill next to the house (away from house). I was facing up the hill when all the sudden the machine, a full sized machine, suddently felt light and was teetering. I stopped... looked around, didn't notice anything out of the ordinary.

Put into gear and didn't move. Confused, I jumped off to look.

One of the rear tires was floating in mid air. I had found some form of cavern and the wheel had broken through the top crust. I watched....nothing happened so I got back on the machine, lowered the stabilizers and used the hoe to crab the back around a bit. I got the wheel on solid ground & moved the machine.

Went back to look and I'm guessing the hole was maybe three to five feet deep and maybe five/ten feet across (it's been 10 years so I don't remember)

Turned the backhoe around and used the hoe to dig up & cave the hole in.

Probably the scariest moment I've ever had on the machine, well, other than one time the wife was yelling at me wagging her index finger...saying something about I just crushed her flowers but, that's a different story.

 

[tractchores]

Scary! The rain finally stopped for a few days, so the area may be dry enough to dig out by next weekend

 

[tractchores]

Ok we got some decent weather finally over the last week and the surface water receded enough for me to dig it out at least a little. Here are some pictures, I'm still not certain what it is and there's too much water to see the bottom still.

 

[tractchores]

Ok we got some decent weather finally over the last week and the surface water receded enough for me to dig it out at least a little. Here are some pictures, I'm still not certain what it is and there's too much water to see the bottom still.

View attachment 328196
The hole is probably 3 x 4 at this point, the cavity appears to extend further out from the BH beyond it's reach from the current position, but the hole is smaller and further underground there. When digging water poured in from that direction. The edges are dirt and do not appear to be lined or anything, so this likely is buried material that rotted or a spring (or both). The entire hole seems like it might have been a pit dug out via an excavator as the sides are nearly perfectly vertical and the soil type changes on the site (soil in the pit appears to be consistent with Fill used to build the house and the sides resembles the soil in the area that has not been disturbed)

View attachment 328197
A view of the position. To the right is a tree that had been falling over last year, when I flipped the stump up I discovered that the root system is what was holding the top of the cavity up. When I fell through my foot broke through the root system. The tree is not that old, but may be 20 years (have to count some rings), which would give the minimum age if this were a dump site for woody materials.

View attachment 328198
This is my 'smoking gun' in terms of what I think this is. I found a number of pieces of wood, no big stumps or anything, but chunks of wood that appeared to be chainsaw cut and a length of a few feet maximum. Pictured is a small stump, which was found 4' below the surface, so must have been buried, I can't see how it could have gotten there on its own. There was not much woody material, but definitely some rotted pieces. Anyone know what I'd expect to find in the bottom if someone had buried some wood here?

 

[Dr_Zinj]

Massachusetts doesn't have a whole lot of karst topography, since it doesn't have a lot of limestone, being mostly granite bedrock.
I'm going to guess that this was an old wood-lined well or cistern. I remember several places around the area I grew up where farmers would sink a hole in a wet or damp spot, line it with wood so they'd have a spot out in the fields to water their stock with.