Pond Boss
Posted By: Crazy_Jay Blue Clay - 01/27/10 10:28 PM
The land I am wanting to build a pond on has a layer of blue clay. After much googling I didnt find much info on this relating to pond construction. Is this a potential positive or negative?


nrcs web soil survey

Typical profile
· 0 to 4 inches: Fine sandy loam
· 4 to 8 inches: Clay loam
· 8 to 36 inches: Clay
· 36 to 60 inches: Loam
Posted By: esshup Re: Blue Clay - 01/28/10 12:26 AM
What is below the 60 inch mark? To properly seal the bottom of a pond, ideally you should have a 2' thick layer of clay, compacting it with a sheepsfoot roller in 6" lifts. That blue clay is good stuff.
Posted By: Crazy_Jay Re: Blue Clay - 01/28/10 01:17 AM
 Originally Posted By: esshup
What is below the 60 inch mark? To properly seal the bottom of a pond, ideally you should have a 2' thick layer of clay, compacting it with a sheepsfoot roller in 6" lifts. That blue clay is good stuff.


Honestly I have no idea, it could be bedrock or gold for all I know. Hopefully I won't have to excavate too much (The land is actually a sloping valley between 2 mountains)

What I do know is that on this same land about 30 years ago my dad tried to build a small spring-fed excavation pond for his horses and cattle. The guy brought a small dozer in and went down a few feet. He freaked out when he hit the blue clay layer, and refused to go any further saying he would get hopelessly stuck.

Anyways the old pond ended up being about 1/8 an acre and even though it was only halfway built it managed to hold water until silt filled it up and the old the spring dried up.
Posted By: esshup Re: Blue Clay - 01/28/10 01:20 AM
That blue clay if it's wet is slicker than owl you know what. I'd stockpile the blue clay and use it to pack in the areas that don't hold water that well. Do a bucket test to see how well the soil in a particular area will hold water.
Posted By: Crazy_Jay Re: Blue Clay - 01/28/10 01:45 AM
 Originally Posted By: esshup
That blue clay if it's wet is slicker than owl you know what. I'd stockpile the blue clay and use it to pack in the areas that don't hold water that well. Do a bucket test to see how well the soil in a particular area will hold water.


\:D Hehe here we say slicker than owl snot, or more often slicker than a "minners" ****. That's hillbilly for minnow.

The dozer guy was a very experienced heavy equipment operator as he was a lifer doing that for the local copper mines. I realize i am going to have do like you said, and soil sample/test excavate before I can move forward. I was just curious if blue clay is going to help me or hurt me. I am more thinking cost wise here.
Posted By: esshup Re: Blue Clay - 01/28/10 02:20 AM
I think help, because having good clay to seal the pond is sometimes very hard to find on site, and it gets really expensive really quick if you want to truck enough in to do the job right.

In my case, I had a pond on the property, and needed to make it deeper if I wanted any sort of fish to live longer than a year. I dug deeper and bigger, but still have to put up with a water level that drops 5' in a year due to the porus soil. There's good clay 20 miles to the East of me, but I couldn't afford to truck enough of it to do the job correctly.
Posted By: STU801 Re: Blue Clay - 01/29/10 01:46 PM
you say to uses a sheeps foot from compaction... is there a good way to "make your own"...? dont have one.. and need one.. but can not find one at a decent price
Posted By: jeffhasapond Re: Blue Clay - 01/29/10 02:33 PM
Can you rent one STU801? If there was a place near you that rented construction equipment they should be able to rent you one I would think.
Posted By: STU801 Re: Blue Clay - 01/29/10 03:24 PM
yeah.. There are a few places around.. but my schedule wont allow a long block of time to complete any project... I usually get 2-3 hours per week of work done.. and that make renting costly..
Posted By: Michael Gray Re: Blue Clay - 01/29/10 08:34 PM
Blue clay is excellent material, might need to dry out a bit. What makes it blue or sometimes green is water passing through the material very slowly over time. As mentioned above proper compaction and the processing of the material will make an excellent seal.
Posted By: TMK Re: Blue Clay - 02/11/10 12:12 AM
My pond was dug in blue clay to a depth of 20 feet and it holds water really great! Id say dig some test sites to your desired depth, and if it isn't clay then stock pile the clay and line the pond with it after you Finish the dig.
Posted By: otto Re: Blue Clay - 02/11/10 03:55 PM
The info you get from the soil maps are great---Before you spend much money get a shovel--post hole digger---backhoe and dig some holes. The time you spend finding what is below the surface will be well spent.

Otto
Posted By: andedammen Re: Blue Clay - 02/11/10 05:07 PM
The clay is exelente media, hovewer it has a weaknes.
If it dries including freeze dries it looses its quality.
Meaning it starts seeping and/or looses strengt.
Easy to overcome if you are awere of it, just cover the clay in the areas that might be exposed to drought/frost with other soils to keep clay moist and thawd.
Thats my experience anyhow.
I know that oversatureted clay (quick clay) can/has caused landslides, so if used on steep hills or biger scale dam, that might be an isue, deepending on the shape/profiles/scale on your pond.
Posted By: otto Re: Blue Clay - 02/12/10 04:03 PM
Sounds like if you get it filled with water it will be o.k.
Posted By: hollowpondwv Re: Blue Clay - 03/18/10 03:04 AM
We dug some test holes for a pond we want to build, and our excavator was very happy to find blue clay. The test hole he dug (20' by 15') was done very quickly and messily and has held it's water for about a year now with no real effort put into it. I'd say blue clay is a good thing!
Posted By: Turtlemike Re: Blue Clay - 03/18/10 09:15 PM

I live in western WV. and around here, on hillsides and heads of hollows we have layers of blue clay that occur in what pond builders around here call " slip seams ". These seams are places where the land has slid or slipped over a deeper layer, possibly thousands of years ago usually because of an up hill spring or seep. The water flow either deposits the layer of blue clay or colors it blue. These layers are wet and slippery and always slope downhill.

This layer is a very poor foundation for possibly hundreds of tons of dam.
Always dig down below this layer until you find rock or brown or multi colored clay.

Another thing that needs to be remembered is that a hillside hollow pond needs more than just a dam crossing the slope. It also needs to be dug back into the hill and to the sides because if this clay is not dug up and repacked, just like you did the dam material, the water that fills your pond will go to the side and seep through the hill around your dam and cause your pond to leak or even cause a major slip of the slip seam your pond is built on on either side of your dam. EVERYTHING that is going to be under water MUST be dug out to an appropriate depth and repacked. The appropriate depth is below all slip seams and when replaced and packed, the clay is thick enough for the depth of water it must retain.

If when you dig into the uphill side you find a spring that is below water level I think you should pipe it through the clay to the water in your pond or just jeave it uncovered with clay because if you block it it will back up into the hill and find a way around your pond and lead to a slip.
Piping it into the pond will only help a little as the back pressure from the water column above the spring will tend to force the water to seek an other path to relieve the new back pressure. You could pipe it under the pond and through the dam,or to the surface to the side of the dam bypassing the whole situation.

Another problem with this below water level spring is that most springs during a dry time disappear and the spring them becomes basically a hole in the bottom or side of your pond. This will make your pond drop just when you want water most.
Ideally you want your water level below any springs, and the spring flows down into the pond.

Also if this slip seam does not disappear or run up to the surface uphill from your dam before it reaches the future water level then when you cut out the bottom of this seam in building the pond the remaining top portion of the old slip has nothing to hold it up anymore and may slide down into your pond

In some ways water can be a ponds worst enemy.

Most of my ponds are on the top of the hill with nothing above them but sky and no source of water except the rain that falls into them. They stay full and overflowing with clear water all year long except during sevier drought years in summer.

How do I post pics ? I'll show you.
Posted By: CJBS2003 Re: Blue Clay - 03/18/10 09:48 PM
How to post pics:

http://www.pondboss.com/forums/ubbthreads.php?ubb=showflat&Number=92443#Post92443
Posted By: rcn11thacr Re: Blue Clay - 03/19/10 12:31 AM
Welcome turtlemike, thats a heck of a first post. Looks like you will fit in well around here, good to have you.
Posted By: Turtlemike Re: Blue Clay - 03/19/10 08:54 PM

Thanks I'll post some pics when I have time.
Posted By: otto Re: Blue Clay - 03/25/10 03:53 PM
Way to go turtlemike glad to have you.
Posted By: Turtlemike Re: Blue Clay - 04/16/10 05:30 PM
[img]http://picasaweb.google.com/ih/photo/UI6XFE1[/img]
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