Water Gardening: Planning My First Pond... Any Advice?, 1 by SongsofJoy

SongsofJoy wrote:
This is a picture of the bottom drain installation (sorry it's a little dark):

Once you dig your pond, find the lowest point. All sides should slope toward that point (no hard angles). Dig a small hole at that lowest point where you will install the drain. The drain should be set in a small cement base so that it doesn't shift. Then dig a trench from that point out to where you plan to store your mechanical filter. This is for the pvc line. The mechanical filter can be a barrel like mine or you could make a settling chamber out of leftover pond liner. I like my barrel because it provides a safe place to land for any fish who decide to take a ride through the bottom drain. Once a day I check my barrels and rescue any tourists. After a while, they seem to learn and by mid-summer I seldom find any.

I could go into a lot more detail about the specific things I've learned along the way (mostly as the result of doing it wrong and learning the hard way). If you think you might go with a bottom drain, I'd be happy to explain in more detail.