I'm a bit worried about the clay at my site.

I read up on the ball & pencil test, as well as the bucket test.

I have yet to try them.

You can see my pond plan here:
http://www.flickr.com/photos/etd66ss/

I plan to buy a 10-15 ton Dozer this spring to build the pond in conjunction with my Ford 575D Backhoe.

You can see the layers of soil I found while digging my test hole.

The clay I hit seemed sandy-clay at first, and then silty-clay when it turned gray.

When dry, the clay crumbles very easily.

The gray clay was moist when I dug into it, but was had fine layers that sheared apart really easily.

I plan to go 20-25ft deep with this pond. I was assured by the county civil engineer I will have absolutely no problems with the pond holding water.

My lot used to be at the bottom of Lake Ontario 30,000 years ago...

I'm new to pond building, and new to soil analysis.

Any and all advice on my project is welcome.

Thanks!

EDT,

I can’t comment specifically on your soil, however, I would suggest (in general) I have had good success with the advice of local government agencies. They have the relevant information/experience you need for those types of decisions.

Question: If you plan to dig 20', why not dig a few 20' holes and test the soil to be positive of the soil content? That would be a cheap insurance policy before starting major work...just a thought.

Did you have any discussions about watershed for your site?

(BTW - good thinking so far)

Gator

"Did you have any discussions about watershed for your site?"

The county civil engineer came out and inspected our site, and gave us a permit.

He suggested a pond with a berm perimeter, and NOT to use runoff and existing drainage ditches to fill the pond.

He told us the ground water/springs in the area will be sufficient. We told him we'd be going 20ft deep, and he said we will not have a problem holding water, that we'd hit the clay we need.

He gave us soil maps of the area (I have yet to get my hands on them, my brother has them).

However, they clay I hit at 12ft was not the type of clay I expected, it seemed more like compacted & layered silt.

I guess I need to dig a few more holes, and try to get to 20ft.

From what this Engineer said, we have 6-7 different soil types on our 63 acres...

I have some more digging to do, plus try some of the clay tests I read on this site...

hey, what part of the country are you located?

I did another soil test tonight.

Please look at the updated pictures here( http://www.flickr.com/photos/etd66ss/ ), and let me know what you guys think!

I seem to have a variety of clay types.

I am located in Western New York seashores.

This pond site is about 40 miles north of Buffalo NY.

I'm being told by some that 20ft deep is too deep:

"If you don't mind me asking, ETD66SS, why is your proposed pond going to be 20 feet deep ? The oxygen content of any stagnant pond is highest at the surface, but then tapers off as depth increases such that beyond 8 to 10 feet water depth you are looking at a virtual dead zone with insufficient oxygen to sustain aquatic life.

If you plan to feed your fish stock, a good deal of that feed will sink to the pond floor without being eaten if the pond is too deep, and will rot there, polluting the water. When cold weather sets in, the surface water of a deep pond will increase in density and move downwards, displacing poorly oxygenated water up from the depths to the surface - a phenomenom which can cause sudden fish stock die-off.

Finally the cost of excavating a very deep pond will be orders of magnitude higher than the cost of digging a shallow pond, with no advantages that I can see, other than providing deeper refuge for the fish if the pond is located in an area where the surface is likely to freeze over in the winter."

Is 20ft too deep for the size pond that I plan to dig?