# Clay soil



## Jamesaboy (Mar 8, 2017)

Our dirt is all basically clay with very little sand. Would it help at all by adding sand over the trails where it becomes very slick and greasy?

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## Clayncedar (Aug 25, 2016)

All clay soil where I am and a wet climate too. It's a little hard to get away from a greasy reality with that combo.

That said, small berming in turns with pipes underneath to remove drainage; keeping drains open and maintaining rollers on straightaways to shed rain efficiently; and having park management that's willing to close trails officially in wet seasons all helps minimize the slimey mess. It's a lot if work though.

As for the sand - I guess so but I can't picture having enough sand, manpower to spread it, or budget to fund it all on a trail of any decent size.


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## Cotharyus (Jun 21, 2012)

I'd say no, not just for the reasons mentioned above, but also consider possible environmental impacts of any sand getting washed off and into local streams (I know, it's sand right? But a new sandbar might raise some eyebrows.) and affecting trail drainages after heavy rains. 

Focus instead on proper drainage on the trails. We have a lot of clay as well, and some places if the water sits on it for too long it can get slick, or it might stay slick for a few hours after a slow soaking rain. At those times you just have to stay off them. Otherwise we have some slightly exaggerated outslopes in some places, and large drainages to ensure water doesn't get backed up on the trail. Where these things work, our trails don't really get soft, just a mm or so of slick on top until it dries out, which usually only takes a couple of hours.


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## BonkedAgain (Aug 23, 2005)

I don't think I would add sand since it has its own issues. It will tend to simply slide off the clay base during dry times or float to the top when the clay is wet. Not to mention it is slippery as snot and would make traction inconsistent.

If I were to try and amend the soil my first choice would be crusher fines since it holds together well and drains efficiently, and is pretty commonly used in trail applications. Another choice might be some kind of paving aggregate base. 

Regardless of what you use, a big factor is how to get it onsite. If you have a wide trail then you can probably truck it out using a gator or power wheelbarrow. We had one project here in town where they actually helicoptered in crusher fine - crazy expensive! In any case, if you are going to do it right then expect it to require a lot of time and expense.


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## Harold (Dec 23, 2003)

Locally, we tend to rock armor the clayey spots with poor drainage. In some parks, that rock has to be imported because there's not enough suitable rock for the purpose.

It seems to me that to get enough sand, you'd have to bring in an awful lot more of the stuff to do the job right. Agree that crusher fines would be more effective than sand, anyway.


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## Jamesaboy (Mar 8, 2017)

Thanks guys just got back in from working on some more drainage can never do enough! We have been doing some work with rock to help out the last year. All the rock has been brought in due to the lack of it in the area. Was just thinking about the sand idea since there is a bank full near by I could use but will probably forget about that idea.. thanks! Will always accept advice 

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## Oh My Sack! (Aug 21, 2006)

You can seldom ever modify soil structure on a permanent basis. The soils will trend back to their natural state as the different components eventually stratify. It would be an incredibly complex operation to sufficiently blend the soils and that would likely still have short termed success. 

Hopefully you have a supply of native rock in the area that you could utilize for proper armoring. It's a very tough situation and one that I'd guess many are battling with as this years rains have really created a lot of new problems...at least out here in the west.


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## Gigantic (Aug 31, 2012)

Harold said:


> Locally, we tend to rock armor the clayey spots with poor drainage. In some parks, that rock has to be imported because there's not enough suitable rock for the purpose.
> 
> It seems to me that to get enough sand, you'd have to bring in an awful lot more of the stuff to do the job right. Agree that crusher fines would be more effective than sand, anyway.


+1 in areas where we don't have rock in our parks, we've armored with corduroy, using black locust saplings, which are resistant to rot and can abate the wet areas until the trails can be rerouted or made more sustainable. Our rain in the midatlantic tends to be seasonal; I'd almost rather have clay soils than the loamy soils we tend to have in our urban forests.


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## Clayncedar (Aug 25, 2016)

Gigantic said:


> +1 in areas where we don't have rock in our parks, we've armored with corduroy, using black locust saplings, which are resistant to rot and can abate the wet areas until the trails can be rerouted or made more sustainable. Our rain in the midatlantic tends to be seasonal; I'd almost rather have clay soils than the loamy soils we tend to have in our urban forests.


I get to work with eastern red cedar corduroy which works pretty well too.


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## iceboxsteve (Feb 22, 2012)

I'm surprised no one gave the most obvious, responsible, and cost effective answer.

Don't ride when its wet.

If the trail is greasy stay off it. As many have said, you will never be able to amend the soil, trying is lots of wasted money. Some areas may require armoring, but if your whole tread is clay and slick when wet, consider forgoing riding.


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## DaveVt (Jun 13, 2005)

We have clay, and therefore slate. Many old quarries on our hill. We have 12kms excavator built trail and successfully surfaced with slate quarry tailings (crushed slate). It has been 5 years and shows no signs of degradation. One local is a dirt scientist. He had some interesting things to say about clay and water and how clay has the ability to super saturate due to a molecular charge that bonds with H2O. He is one of the nations leading experts in working on clay when building highways and large buildings. 

The bottom line is clay with aggregate is ideal in terms of compaction and erosion resistance UNTIL this super saturation occurs, then you just have to stay off it. Uphill ditching has worked extremely well. Extreme shapes like high berms need reshaping virtually every year after Mud Season in Vt, but once that is over our trails do resist erosion due to extreme dry periods better than other areas. Pluses and minuses but after spring our clay with slate chips rides awesome and holds up really well. I'll take it over sandy soils any day.


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## HypNoTic (Jan 30, 2007)

DaveVt said:


> We have clay, and therefore slate. Many old quarries on our hill. We have 12kms excavator built trail and successfully surfaced with slate quarry tailings (crushed slate). It has been 5 years and shows no signs of degradation. One local is a dirt scientist. He had some interesting things to say about clay and water and how clay has the ability to super saturate due to a molecular charge that bonds with H2O. He is one of the nations leading experts in working on clay when building highways and large buildings.
> 
> The bottom line is clay with aggregate is ideal in terms of compaction and erosion resistance UNTIL this super saturation occurs, then you just have to stay off it. Uphill ditching has worked extremely well. Extreme shapes like high berms need reshaping virtually every year after Mud Season in Vt, but once that is over our trails do resist erosion due to extreme dry periods better than other areas. Pluses and minuses but after spring our clay with slate chips rides awesome and holds up really well. I'll take it over sandy soils any day.


The other important factor to consider in the northeast is the heavy vegetation cover that help maintain humidity in the soil, therefor the water act as chemico-mechanical binder between the very fine clay particulates and hold very, very well to bike riding. Put the exact same clay in central Oregon (where I was last week for the PTBA) and you'll have a dusty mess in about 3-4 weeks.


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## tbmaddux (May 22, 2012)

HypNoTic said:


> Put the exact same clay in central Oregon (where I was last week for the PTBA) and you'll have a dusty mess in about 3-4 weeks.


That was in Bend, which is typically thought of as sandy or volcanic. Unless I'm mistaken, clay is a fine, cohesive, sedimentary soil and quite old compared to the young volcanic soils east of the Cascades.

Here in the Willamette Valley we have a lot of clay, much of which is expansive, or maybe silty soils at best, and it's wonderful when dried to the consistency of concrete but if we don't build our drains well it'll get soft and stay that way for months after the rains end, and then suddenly the ruts are hard as a rock.


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## DaveVt (Jun 13, 2005)

HypNoTic said:


> The other important factor to consider in the northeast is the heavy vegetation cover that help maintain humidity in the soil, therefor the water act as chemico-mechanical binder between the very fine clay particulates and hold very, very well to bike riding. Put the exact same clay in central Oregon (where I was last week for the PTBA) and you'll have a dusty mess in about 3-4 weeks.


For this reason, I also don't abide by the new school habit of leaf blowing everything down to mineral dirt every spring. Some organic material ground in or floating on top of the trail keeps moisture in and help avoid the dust-bowl scenario that I have seen responsible for high-use trails losing a lot of material in this area. Trail turns to moon dust, then a summer gully washer takes the dry fine soil types down the river.


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## iceboxsteve (Feb 22, 2012)

tbmaddux said:


> That was in Bend, which is typically thought of as sandy or volcanic. Unless I'm mistaken, clay is a fine, cohesive, sedimentary soil and quite old compared to the young volcanic soils east of the Cascades.


From my limited knowledge of soils, there isn't much clay in the northeast either. Not like other parts of the world (southeast). Clays typical indicate old soils, or a parent material that has been seriously weathered. And as noted are quite small particles.

New England soils are considerably young due to glaciation. That said VT does have clays from the glacial lake. I've heard marine clay deposits are quite interesting.

Soils vary greatly, and its a great discussion. I once read that all clays are expansive, some are just more expansive than others. Clays are unlike any other soil particle. Cool stuff.


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## DaveVt (Jun 13, 2005)

Stumbled onto this. Notice where the "Nightmare Project" X is marked. 





This is what I was talking about....




Certain clay are worse than others. All about the Isomorphic Substitution.


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## indytrekracer (Feb 13, 2004)

Indiana clay is bomb proof when dry and fully compacted. It is also a nightmare when fully saturated. Are biggest issues are due to seeps. When we encounter seeps, we dig back channels or in-slope the tread to collect the water before it gets to the tread. The inside drains lead down to the grade reversal. At the low points we rock armor to get the water across the trail.

Back Channel Cut, rocks and gravel on left will be used to armor drain.


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## DaveVt (Jun 13, 2005)

^ Exactly. Even better if you can ditch like 2 feet farther uphill, and deeper. Keep a berm of undisturbed earth between your tread and the water course, then bring it across as you said, either an armored low spot before a grade reversal or culvert, gravel, fabric, then good dirt with aggregate.....maybe.


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## Jamesaboy (Mar 8, 2017)

Nice pics. I'm always in Indiana so you know what I'm dealing with. What trail is that?

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## Clayncedar (Aug 25, 2016)

iceboxsteve said:


> From my limited knowledge of soils, there isn't much clay in the northeast either. Not like other parts of the world (southeast). Clays typical indicate old soils, or a parent material that has been seriously weathered. And as noted are quite small particles.


You haven't been to Southeast Pennsylvania in the Appalachian foothills where sediment from the oldest mountains in North America all seems to have been deposited.

The trail where I build on is nothing but red clay. 
Fast summer riding but makes for wet conditions and closed trails all winter.


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## DaveVt (Jun 13, 2005)

Clayncedar said:


> You haven't been to Southeast Pennsylvania in the Appalachian foothills where sediment from the oldest mountains in North America all seems to have been deposited.
> 
> The trail where I build on is nothing but red clay.
> Fast summer riding but makes for wet conditions and closed trails all winter.


I did spend some time in Western South Carolina. A place called Issaqueena Dam was the local ride spot. Red Clay hard-pack with a line so burned in there was a black smudge. If you got caught in the rain the trail would turn into the slickest surface ever creates. Like riding on wet glass. It also destroyed derailleurs in a day if you rode in the wet. Tiny particles got right in there.


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## iceboxsteve (Feb 22, 2012)

DaveVt said:


> ^ Exactly. Even better if you can ditch like 2 feet farther uphill, and deeper. Keep a berm of undisturbed earth between your tread and the water course, then bring it across as you said, either an armored low spot before a grade reversal or culvert, gravel, fabric, then good dirt with aggregate.....maybe.


Geez Dave, sounds like you're building a road up there in those Vermont woods...


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## DaveVt (Jun 13, 2005)

iceboxsteve said:


> Geez Dave, sounds like you're building a road up there in those Vermont woods...


Haha. We were. Excavator built multi-use.


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## iceboxsteve (Feb 22, 2012)

DaveVt said:


> Haha. We were. Excavator built multi-use.


Leave it to a New Englander to appreciate a good jab of sarcasm.



Clayncedar said:


> You haven't been to Southeast Pennsylvania in the Appalachian foothills where sediment from the oldest mountains in North America all seems to have been deposited.
> 
> The trail where I build on is nothing but red clay.
> Fast summer riding but makes for wet conditions and closed trails all winter.


Go a little northwest and you'll hit the glaciated dessicated plateau. I think of further south when I think of true red clays.



DaveVt said:


> I did spend some time in Western South Carolina. A place called Issaqueena Dam was the local ride spot. Red Clay hard-pack with a line so burned in there was a black smudge. If you got caught in the rain the trail would turn into the slickest surface ever creates. Like riding on wet glass. It also destroyed derailleurs in a day if you rode in the wet. Tiny particles got right in there.


Yeah, southeast red clay is a different than typical New England glacial till/outwash/etc. and bedrock. Weathered for eons into tiny particles.

I've ridden O'Bannon Woods and have seen examples of said gutter drains. I prefer rock everywhere I can if its wet. I really like rock. I can see liking Dave's method of hiding the drain uphill more. Of course that's a bit more work and area of disturbance. The trade offs.


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