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?