I'm going to be building a pond on my new deck this summer. It'll
(probably) be about 8' x 3' x 3' deep.
It may be a little shallower, but not much, because I really think you need
that deep for lilies (I know you can grow them in less - my first was a
dwarf in a tub - but you should see the lilies in the 5' deep part of my
second pond). It could be a little wider too. It will be a formal pond,
and I'm thinking of building it with vertical wood sides (lined), and
hanging planters off the side (like window boxes - but inside the pond) for
shallower plants.

Has anyone else done something like this? Is there anything in particular
to watch out for? Freeze thaw cycles could be hard on it (and my deck) if
it isn't done right.
--
derek