Originally Posted by
Grumpy
I can't find the forum discussion about depth that happened awhile back here, but, I remember folks documented their successful ponds that are very deep. The only drawback as I recall is netting fish when the depth is so great.
I started with the intent of a liner pond 4 feet deep, but during excavation I ran into a seasonal spring that needed to be handled. By the time I got the spring controlled with piping I was over 6 feet. Alot of digging, but the soil was OK for it.
In your case you are closer to the house than I, so I would consider that as you dig down. Monitor the soil conditions and remember the load into the ground from your house foundation is considered to spread out on a 45 degree angle from the house footing.
If you start digging vertically on the inside edge of your bond beam, if the soil walls don't want to stand up on their own and start caving that will be your indication how deep you will be able to go. The maximum slope of the excavation can be determined by how long will the walls remain remain stable. Quite often when the soil is wet it will stand up well, but as the excavation continues, and the exposed soil dries out, the "natural angle of repose" of the soil will become apparent as the walls cave in.
When hand digging inside the bond beam, the difficulty is removing the soil as you get deeper, how to transport it, and where to put it!