Pond Boss Forums POND CONSTRUCTION Soil questions Do I need to line the banks of this pond?

I started on the smaller of two ponds last summer, all I had to do the work was my CAT D6C bulldozer.

Pond-01

Pond-02

I hit a layer of wet mushy clay at 7 ft deep, and had to stop digging in fear of getting my dozer stuck.

Pond-03

It rained very hard from August until winter. I bought a CAT 225 Excavator in the fall to help me finish the pond the next summer, along with digging the larger pond.

Pond-04

After about a month of warm dry weather following spring, the pond looked like this:

Pond-05

Once the weather started to get dryer & hotter with very little rain, I could see the water level dropping, and the banks were always wet, like they were soaking up water. I lost about 1 foot per month of water level.

In early July, I pumped out the pond completely and finished it off to about 16-18 ft deep from grade.

Pond-06

It looked like this right after finishing the digging:

Pond-07

There are 3 layers of soil I dug through. The first being 7 ft of E1A sandy loam. The next is about 5-6 ft of gray silty clay, then at about 12-15 ft I hit very dark & hard red clay, mixed with particles of gray clay, mixed with big rocks & some shale. These rocks are round, they were from the Great Lakes (Ontario) when they first formed by glacier 12-14,000 years ago.

Me question is, will I have to line the banks from grade to 7 ft down?

You can see the transition in the last photo from sandy loam to gray, silty clay.

The water level is steadily rising in the pond, mostly from the layer I hit at 15 ft. From what the farmer next door told me, all the ponds in the area (there are many) are fed from below, from this layer of "shale" he called it.

I have seen another pond dug a few houses down, not very deep, and no clay was used to line it... It's all landscaped already.

Should I plan on lining the banks?

I'm taking next week off to start working on the 1 acre pond, and I would like to plan oout where my spoils go...

The clay needs to dry out a bit before I can spread it on the banks...

Should I worry about the rocks mixed in with the red clay, eventhough the water level started filling from the bottom?

I don't understand your area and know absolutely nothing about a pond being fed from below. Maybe the shale and/or rock strata are below some kind of groundwater that is being prevented from moving by the heavy duty clay. Does the neighbor say that the pond will go to full pool from the bottom? That sounds artesian.

I don't know the answers. I'm not sure I have ever heard of that type of pond environment.

Anybody??

Well, that seems to be the case.

The layer under the clay holds the water, when I broke through the clay, the water filled up from the bottom about halfway up the clay layer and stopped.

I'm assuming I will have to line the sandy loam portion of the bank down to the clay layer, so when watershed & rain fill up the pond, the banks wont soak it up...

When I got the pond permit from the county conservation dept. They said I could line the banks if I wanted to, but it was not a requirement...

I was told in my area, most pond builders dig a hole, wait a few years, and that's about it...

I was only given 2 requirements. Go at least 8 ft deep (I went 18 ft in some spots), and stay 50 ft from any property line... That's it...

etd, i'd like to have viewed all yer pics but (apologetically) dont have the time on dial up, and probably cant add anything of great significance anyway. just wanted to chime in and thank you for providing such a detailed posting.

my thoughts just from the text:
you described the soils really well, and it sounds like the shale zone (a glacial till?) has confined water (water under pressure). the mushy clay you initially hit at 7 feet sounds like the natural level (water table for the water emanating from the shale). it sounds like in yer area once the upper soils are soaked in, the pond should be fine. lining would hasten the filling so it sounds like it just depends on yer patience. for insurance, how easily could you doze up some clay rich soils to compact over the sandy loam?

i wouldnt worry about rocks in a clay matrix (if its a true clay matrix).

it also sounds like the amount of pressure underwhich the water flows out from the shale exceeds the back pressure exerted by yer pond on the shale, which is awesome, cause if it was the other way around, you'd never fill up.

i wish i had gushing ground water.....yer lucky!

Here is an updated set of pictures of my progress on the 2nd larger pond:

Pond 2

I'm about 50% complete with the excavation, unfortunately I'm out of vacation days at work, so not sure I can finish before winter...