Pond Boss Forums POND CONSTRUCTION Soil questions Web Soil Survey says "very limited"

Hi all. I have a 120 acre "recreational" tract of land in west central MO I bought primarily for hunting, but having my own fishing lake would sure be nice.

There is only one suitable place for a pond - in the valley below the future cabin site. I've had the NRCS gals come out and flag out and design a pond for me. Turned out 1.4 acres, 16 foot deep before any digging, with a 6" drain pipe. Gave me a warning to have a backhoe come dig test holes to check for rock and suitable clay.

Looking at it on the web soil survey site, it shows "Norris channery loam is well drained, 20 inches to paralithic bedrock. It's rated as "very limited" for pond reservoirs.

Is this a potential deal killer? I have not had the backhoe out yet, but I can't see any bedrock layer in the creek channel. From reading on this site I will try the bucket test. Anything else I should do at this point?

Welcome back to the forum.

I think the next step is get a backhoe out and dig test holes. Soil survey maps are great for a broad overview, but for pinpointing there's nothing better than actually seeing what's there.

Soil on top could be poor for sealing a pond, but down 5' it might be great. Test and verify.

Even if the soil is poor, if there is a supply of clay somewhere else on the property, that could be used to line the pond and seal it.

Thanks Esshup. I've been around, checking in every now and then. Finally have a potential pond site.

Besides looking for good clay, I assume I should be looking for a problem rock shelf/bedrock. The "ditch" or creek channel is probably 8 foot lower than the bank, and it would be difficult to get a backhoe down there to dig a hole in the bottom of the channel. (water only runs after a rain) Would that be required? Otherwise dig 3/4 holes in what would be the deepest part of the pond, and under where the dam would be?

Thanks

I'd dig test holes in as many areas as you can. Take a look at Mike Otto's article in the latest issue of Pond Boss magazine. That will give you a good reason why to dig as many test holes as you can.

Redon...Are there many other ponds in your immediate area? Look on Google Earth for other ponds. If several ponds are close by, talk to land owners and see if they had issues. As esshup said, nothing beats lots of test holes for the best underground picture on your site.

Those same maps said I had nothing but sand and gravel, unusable for ponds. However I have nothing but clay and larger stones, very heavy soil, which is more than suitable (if properly compacted). Only the very upper layers of soil matched the surveys.
I live in an area of very wildly varying soil types. Just down the road is a large sand and gravel pit. No clay at all. Probably goes clear down many many feet too. Just huge heaps of soil left by glaciers.

Still haven't gotten a backhoe out to dig test holes, but thought I would post some photos of what I have. First is two sample jars, the one on the left was soil from only three feet deep, the right from the side of the creek bank.

The shallow soil appears to be ~20% clay after 48 hours. In the week since it has settled to look like 10%. I placed about 6" loose soil into a bucket with 5 1/4" holes. Packed it down to about 3" by hand. Filled the bucket and all the water ran out in about 12 hours. Then I tamped the bucket onto a concrete floor and refilled it. Lost about 1/2" in 12 hours and slowed to a stop about 2.5" loss in a week. I was unable to find a defined procedure for this test.

The right jar has nearly 100% clay dug from the side of the ditch to be dammed. Was quite interesting how the mud line vs clear water line was very defined as it settled. Water is pretty clear.

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Below is a photo of the side of the ditch bank. Below the soft clay is a layer hard clay shale. While damp I can easily shove a shovel through it. If it dries out its quite hard and you can shave it with a knife to make powder. Can this material be compacted? Is it good for a dam core?

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