Pond Boss Forums POND CONSTRUCTION Soil questions Packing clay bottom

I just had a half acre pond built. There is good red clay on bottom but they didn't pack it down very good. Main area that it wasn't packed down was at the deepest end where dam is. Should the bottom be packed? Just got 1st rain since it was built and had small area of water about a foot deep but only lasted 1 day now it's gone.

Welcome to the forum!!

I think you answered your own question. Short answer, yes. Look for any sand/gravel areas, dig those out, fill and pack with clay and try to pack the whole area that will be under water, not just the bottom.

If I didn't pack it down do you think it would hold water if I fill it up? It's all clay no sand. What should I pack it down with? All I have is a 25 hp tractor and 4 wheeler, which is why i paid someone to build the pond.

Call Sunbelt Rentals in Warner Robbins 1-800-667-9328 and see if they have any compaction equipment. I see that they have a compaction plate for a backhoe and for an excavator, but that might be a slow process. Typically the ground would be packed by a multi tired wheel scraper that was loaded or a sheepsfoot roller.

The pond is showing you now that it's not holding water by that foot of water leaking out.

If it doesn't hold water then I'm calling the guy that built it. He can compact it or do whatever it needs. I asked 2 different guys multiple times about packing down the clay and both gave me the same answer which was no. It was ran over by the giant excavator not sure what size it was, so 75% of it is packed, there's just some loose dirt areas at the deep end where the dam is. I was told when we get a hard rain it will make it settle and that red clay will harden. Half an inch of rain is not gonna do it, which is what we got here last week.

I would treat the sand/gravel with quality, high expansion rate bentonite or polymer first then compact 4-6" lifts of high plasticity clay over those areas. One can even treat the sand areas with additive, clay, additive, clay, etc. Lasagna style. I sealed my gravel veins using polymer and compacted clay in this manner. Here to help anytime - tj@hudlandmgmt.com

Theres no sand or gravel, it's all red clay

First rain?

It will take some time for the soil in the pond basin to become fully saturated.

When my pond was filling after renovation it would drop a foot in just a few days after a big rain.
Once it filled up those big, fast drops no longer happened.

That's what I was hoping thanks for responding Augie

A dug pond, with good clay and proper compaction, not a bulldozer, when filled up will stay full very similar to water in a bucket. It requires no time for saturation of the soil. Loose soils and poorly compacted clay will produce or cause a saturation period. When you get the pond full of water it will quickly tell you the nature of the soil and how well the soil was compacted. Sandy and loose soil veins in some areas of a compacted clay basin can cause leakage problems. This is where expert experienced pond construction becomes VERY IMPORTANT.

Well in my area there's not alot of pond builders, and it's not my specialty nor do I have the equipment to do it. Thanks for your input though.

I won't say that it won't hold water just because it soaked up the first small rain, but I will say if you want to compact it you want to do it as soon as you can. It won't take much rain to make it a muddy mess in the bottom, which will make it hard to compact.
How thick do you think your clay is? How long was it dry before you got the rain?

Only clay that's not compacted is in the deep end about 25% of the pond. The clay is very thick throughout the pond. It's been dry over a week after it was dug out. We haven't had much rain.

I had my water table pond excavated last December in gray clay soil. It was filling before the excavator was finished and wasn't compacted. It hasn't rained much in the past month and a half and its only down about a foot. Maybe Maine clay is denser?

There are many different types of clays, and there are clays that are interspersed with sand/gravel veins.

I am renovating a 48 year old pond the clay in my area is light Brown to red Brown. I have owned it for twenty years it is dry because of the drought. I am cleaning out the muck but I don't see any color difference from the muck all the way to the rock layer below. Is it normal for clay to take on the color of the muck. Or could it be that the sediment that washed in could have had some clay content and be black like the muck

I think I would take some of the soil just above the rock layer and play around, do some test with it. Dry some of it up enough to make a ball and see if it holds together, try throwing up against something and see if it holds together ect... . See if it acts like clay.

A true "water table" pond IS NOT clay sealed. It must be hydraulically connected to the groundwater supply.

Of course, there are exceptions. Such a when you have a spring that takes and gives water at a certain pool elevation, with a clay-lined pond basin below that elevation. (This would keep the pond holding some water after the spring dries up during the dry season.)

Mine definitely is not a water table pond fills with runoff during winter and drops about ten to twelve feet during summer I would like to seal it up better to keep it higher.

The material at the bottom has a good clay feel to it but the color is throwing me

cb100,

Bob's advice is spot on. Clay content is difficult to determine by color. The quantity and quality of the clay must be determined by its plasticity. (Can you dry it out and then add some water to make a cohesive ball of clay? If so, can you rub it between your palms and make a "worm" that does not crumble?)

A lot of the "muck" in an old pond is organic material. (Which is typically black or dark gray.) Material with a high organic content usually WILL NOT pack and seal.

Hitting rock is usually fatal when building a pond. However, if your pond held water for 48 years prior to the drought, then it is possible that an impermeable rock layer was the actual bottom seal for the pond.

I would expect your pond to have a clay-cored dam in that situation.

Good luck on your pond renovation project!

cb100,

I was typing a longer response, and missed your post that your pond goes down 10-12 feet during the summer. That is WAY MORE than the expected evaporation loss for your area of California.

You are definitely correct that your pond is not completely sealed!

If the material above your rock turns out to be good, packable clay, then you need to spread your material, moisten it to the correct water content, and then pack it in lifts. (There are lots of threads in the forum for the proper procedure, written by some pond-building experts.)

If it passes the hand-packing tests, but you are going to spend a lot of time/money for the renovation, then the next step would probably be a professional soil analysis. You may have a county farm service agency, or similar resource to perform that test for a nominal fee since you are a landowner in the county.

Fishnrod thanks for the response sorry to say this is California and if you can find a county service there is no service here that is reasonable. I hope to save any material with good quality and I have areas of clay.but I would be interested in treating the bottom first before placing and compacting the clay

cb100 - Would SoilFloc work in your situation? I'd hit up TJ.

Already contacted TJ. I have a bit of work to do before I am ready for that. Right now am trying to dewater the muck it is amazing how much water is locked up in the muck. I dug an area about thirty feet by six feet and a little deeper than the muck with a deeper sump pit put the intake for my pump in it and pump to my forage pond. It fills up about two feet deep after about six hours