| Brutus-
Make your pond depth at least the depth of the frost lines. "At least" means "or more". In my area that is 42". Your depth requirement will be similar. Find out from the city or just grab a grubby guy at Depot and ask him. (Or girl, of course. This is a modern world I've been transplanted into.)
The tall wall seems awkward to me. I prefer about 20". The appearance still feels like a fish pond with that height of a wall rather than like a water tank. The higher you build your wall the greater will be the likelihood that the wall will fail, so if you want high walls don't also gravitate to the "easy way" of building them. See? Inverse relationship?
Being an old fat guy I believe in things like concrete. It is a great way to give yourself a stable, level starting point. It also causes the wise, or previously scarred, among us to plan a little better because it is such a permanent and heavy material to work with. You will find that many of the most dedicated hobbiests, the folks you love to read here and elsewhere, also have the most concrete in their ponds.
Follows a pic of diggin after the concrete collar and block courses. You can minimize your work inside a hole by doing it this way.
Mickey the windowman |