Strange 'percolation' of clay through grass

[BigTank]

I'm not sure if this is the correct forum, or if anyone can help with this without seeing a picture (working on it), but there is something strange happening in my mothers lawn.

In a roughly 15-foot square area there are small mounds of clay and other fine soil that seem to be produced by a 'perolating' action up through the grass.

There are approximately 18-25 mounds of dirt, 6-10 inches in diameter and 2-4 inches high. They look similar to when you would build 'drip castles' out of sand. Turning over several that were strong enough to stay in one piece showed that there was a fluid of some kind flowing out of the ground into the mound creating a very definite upside-down semi-spherical hole where the percolating fluid was hitting the underside of the mound.

In my 36 years I have NEVER seen anything like this on our property. (I don't live there now, thus the difficulty with taking pictures...trying to get my mother do send me some.)

Here is what I can tell you about what's under this area:

There is a creek nearby...30ft away. The grassy surface I'm speaking of is approximately 3-4 ft higher in elevation than the water flow of the creek. This area does get soft with a hard rain.

There are MANY underground mine shafts in the area (central PA). I am not sure where they are relative to our property.

There was a large (2ft dia. at the base) maple tree that fell a couple of years ago. The stump is left in the ground and thus the root system as well. This phenomena is occurring very near (2-3 ft away) the stump.

There are Macellus shale wells all over the nearby mountain. These wells are probably 5-8 miles away.

That's about all I can say. This is very strange. Anyone have any theories off the top of their heads? This is nowhere near my area of expertise.

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Fitter, happier, more productive

 

[IRstuff]

My first thought would have been ant hills. I get mounds of loose soil in my lawn from ants. I can't explain why they would be hard, or why you wouldn't see ants.

TTFN
faq731-376

 

[BigTank]

Yes, I've seen this, too, IR. But what's happening here isn't ants. The action that made these mounds seems very clearly indicated by the shape and structure of the mounds themselves. And it's been between 30 and 50°F here lately. No ants about just yet.

And these mounds aren't exactly 'loose'. A few of them are clay, a few are mixed clay and soil, but all are made of fines. It seems very clear to me that water is carrying the fines and depositing them in these mounds.

Removing some of them carefully even reveal a hole in the ground underneath approx. 1 inch in dia or less.

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Fitter, happier, more productive

 

[fattdad]

crawdaddies?

¡papá gordo ain’t no madre flaca!

 

[GeoPaveTraffic]

I agree with fattdad, sounds like crawdads to me.

Mike Lambert

 

[BigTank]

For real? This time of year? Isn't it too cold? If they've been there (they couldn't have just appeared suddenly this year), why have they never done this before?

If it is crawdads, should I be able to see them exiting these mounds?

And why is it isolated to such a small area when there's another 100 yds of 'nesting' area? And why so far from the creek?

I know...lots of questions, but this is really out of the ordinary.

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Fitter, happier, more productive

 

[IRstuff]

Seems like this type of problem is not uncommon:

http://www.helpfulgardener.com/phpBB2/viewtopic.php?t=22649

http://www.icwdm.org/Inspection/gardengrass.asp

http://www.lawnsite.com/showthread.php?t=103959

TTFN
faq731-376

 

[BigTank]

Interesting...googled some pictures and a bit of research about crawfish...

I used to catch them in that creek when I was a kid, but haven't noticed them in a very long time. I think they may have migrated to avoid the mine runoff, but the creek is very clean these days.

I also noticed that, in the pictures I did find, there was always a hole for the crawfish to exit the burrow. These mounds did not have a through hole, just the semi-spherical underside where that the water seemed to percolate against. But aside from that, seems pretty spot-on!

Weird!

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Fitter, happier, more productive

 

[Ron]

Moles! Sounds similar to the mole mounds I see in my yard. Get rid of their food source and they will go away. Trapping the little buggers is a waste of time and the wive's tale solutions don't work. Spray for grub worms and chinch bugs.

 

[BigTank]

Other areas of that property were once riddle with moles, but that when it was unkempt and owned by the county. It's been a few years since it's come back into the family, and taken care of since. The moles don't like the lawn tractor.

And I've never seen them pile soil in that manner...as if it were 'dripped' into place (water as a carrier).

Not that it CAN'T be moles, this is just nothing like I've ever seen. Crawfish seem to be the most logical explanation. Preliminary research suggests that they're getting ready to lay eggs in the next month or so. The mild winter has given them a nice soft area of ground into which they've burrowed. We may have never noticed before because the ground is almost always (this is the first winter I've seen like this in the northeast) frozen and/or snow-covered.

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[Compositepro]

It could be termite activity on the tree roots.

 

[Drumchaser]

the dripped part sounds like crayfish mounds.....but the ones I am familiar with are not as large as your description.....how bout a picture....it should say a thousand words. (sorry)

 

[fattdad]

sand boils from a recent earthquake?

f-d

¡papá gordo ain’t no madre flaca!

 

[BigTank]

'Tis true, drum. I need to put some pics up here. They're on my phone, just haven't posted them yet.

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Fitter, happier, more productive