In article ,
"BAC" wrote:

An alternative to digging a full sized hole is to install the rigid liner
into the equivalent of a raised bed. If you excavate a hole for the deep
water section, the spoil can be used to help support the marginal section.
Something like log-roll screwed to timber stakes can be used as a temporary
retaining wall when you're backfilling under the margins.

I definitely like this idea. I've had a few ponds by now; the one time
I tried with a rigid liner, I followed all the advice and instructions
carefully, but despite all my best efforts, the liner "settled" at one
edge a few days after I'd filled it, and I was left with an awful
unsightly edge of the liner poking up for at least half the
circumference of the pond. It was a very big liner, so I was greatly
disinclined to empty it and start all over again (especially as I'd
transferred all my ongoing pond mud, complete with creatures). Yes, I
like the built-up idea -- doesn't have to be very built-up, does it.

John