My bog filters were upflow gravel filters with plants as a veggie filter.
It was a slightly raised pond about 18 inches deep with about a foot of
gravel. The gravel is now gone, but the veggies are still there. I run
some other massive filtration, so the gravel was redundant, and gravel is
hard to clean. For one of my ponds, I used landscape timbers to frame it
up, for the other, I used retaining wall block. Line with liner. Leave a
small depression in the side you want as a waterfall. One that I think
would look good is to run a 2 foot or there abouts, ring about half way
around to the pond and plant that with all kinds of water plants. Would
help get some of the plants out of the pond providing more room for the
fish, and lots of filtration.

Thanks for the comments on my ponds.
--
RichToyBox
http://www.geocities.com/richtoybox/pondintro.html

"moe" wrote in message
oups.com...
Wow Rich those are some nice looking ponds you have there. I've thought
about a bog. Was it hard to do? Where we live we don't have a backyard
to use so I am using a section of the front yard that grass refused to
grow in. I'm limited on space but could fit a bog in.