Chiff and Fipple Forums

There seems to be a small sink-hole in my yard. Small, so far... I think one large-ish garbage bag would fill the hole.

So, anyone have advice on filling it?

What I know so far, strictly from some web searching, but it seems like good common sense: Put a layer of larger rocks on the bottom, then a layer of smaller rocks on top of that. Then, layer soil on top of that -- with maybe a layer of sand in between? But in my case the hole is so small I don't know if I'd bother with sand.

And, a layer of something called geotextile fabric, so the soil doesn't just seep down in between the rocks the first time it rains, I assume.

The geotextile fabric has me a little stumped. Is this the same as "weed barrier"?
Can I find this at, say, Home Depot, or a local gardening center, or...? And if they do carry it, will I be able to buy it in small quantities, or is it the kind of thing that's only sold on large rolls?

Should I just use, er... a garbage bag, instead of searching for geotextile fabric? I assume a garbage bag barrier would not be ideal, but it's a very small job.

Thanks in advance for any words of wisdom!

Garden centres will likely have a black mesh fabric, usually made out of some kind of plastic and available by the yard. That'll do, although stuff designed to be used on the surface has additional sunlight resisting stabilizers that you don't need if you're applying it to the bottom of a hole. A dead or dying screen door or window screen will also work, as will a few layers of burlap. Burlap is biodegradable and will eventually rot, and screens will either rust or get brittle and tear after a time. If the sinkhole is above a persistent drainage issue, that might be a problem, but if not, or if you can re-establish grass or anything else with a strong root system on the spot before the fabric rots away, you'll be fine.

They're making sacking out of plastic, too, If you go to the farmer's market or bulkstore and buy a great big bag of onions or a gross of ears of corn (or ask your fave produce manager for an empty one) that'll work, too. If doesn't have to last forever, unless this is where your downspout meets the earth or something.

Where do you live that you're getting sinkholes? What is the cause of the sinkhole?

More than likely it's the space where the roots of a tree were before breaking down. Consider it a backyard dentistry project.

Make sure it's really only that large and isn't the site of a caved-in septic tank. That can be dangerous.

Septic tank! Yikes... no, this street was only developed about 20 years ago and we've always had town water and sewer.

This is upstate New York. I'm not at all sure of the cause. There was a small dip in the lawn for years, and over the last couple of years it's grown deeper.

It's happening near the edge of the property, closer to my neighbor's pool than to my house. I wondered whether there might be a leak in some sort of underground plumbing for his pool, but it seems unlikely the plumbing would extend all the way to my property.

Thanks, all

Sinkholes can be caused by several different underground phenomena, so it is helpful to know a little about the underground geology. Do you have limestone beneath a shallow layer of dirt, for example? Sinkholes in this kind of situation can be serious, as it might decide to suddenly open up and swallow your car. Another cause of surface subsidence has to do with the compaction of the rock grains due to the overpumping of ground water. My advice is to fill it in in the way that you mentioned and keep your fingers crossed that it will be relatively stable.

As for the plastic that was mentioned to hold the rock and soil but allow the water to pass through, I have plenty to give away. We needed some of it to put under a 180 square foot patio. My wife bought a 800 square foot roll of the stuff at Cosco. I'm trying to think creatively and figure what else I could use it for.

If it's white, think blanket of fake snow for Christmas Decorations. If it's black, Halloween.

If it's just a hole, ie the space where a stump rotted away, and not the product of some form of flowing water causing erosion, you can fill it with anything in no particular order. Rocks and earth. For style points, make sure the top 6" is topsoil.

You should park something really ugly on that spot, and the rule of Murphy will make sure it doesn't sink any further.

Until I read your description of your sinkhole. I was thinking along the lines of this-what we have, and wondering how/why in the world you would tackle such a job-


I'm right in that sw part of this sink hole line of counties, and so are Em's kin people.


Come to think of it, everything around here is either a mountain, a valley, or a sinkhole. I was thinking - gee that would be a big project to fill in a sinkhole and then it would not be very stable. We once lost a calf who was unlucky enough to have one fall in with it-but that field is nothing but sink holes.



I figured one of our resident geologist would chime in on this.

cowtime wrote:
I figured one of our resident geologist would chime in on this.

I studied geology in sinkhole country, southern Indiana. I used to do a lot of splunking (cave exploring) when I was in college. Some of the caves we entered by crawling through an opening at the bottom of a sinkhole. I figured, however, that if I started mentioning the fine points of karst topography, people would just yawn and push the back button.

cowtime and Doug - I too thought "why would you fill in a sink hole". But I, too am in sinkhole country (we have one behind our house - not close enough to do any damage for the next million years or so.....)

I'm with crooked tune...sounds like an area that once had a tree or root system under it, the tree died or was removed and then about 10-20 years later you have a hole and/or depression once the wood underneath has thoroughly decomposed. We have real sink holes from time to time in my area, but most o what people call sink holes are NOT sink holes.

Also, rabbits, groundhogs and other critters will dig a den, and that can lead to a small depression, too (with the entrance usually several feet away).

Just dump a bag of dirt in it and move on with your life!

Eric

How can you want to block the portal to another dimension??? I'm shocked, simply shocked I tell ya.