Question
Hello! I would like to build a large pond in my back yard with some kind of waterfall feature and in the near future have fish. So my question is what are the absolute necessities in building a pond? As far as liner, pump, filters, pretty much anything that is important in building one and ensuring the fish have what they need. I don't have allot of excess money so just the necessities and recommendations.

Thanks You

Answer
Hello Mathew

Pond building is a complicated affair and it would not be easy to explain everything in just a short mail. However, the essentials are clearly...

Firstly dig a hole with a perfectly level ledge (footing) dug around the edges at about 1 foot lower than the height that you wish the water to rise to. This ledge will form the base for rocks or bricks to hold the liner etc in place.    

Remove all sharp stones and glass etc that could puncture the liner

Firstly, line the hole and ledge with builder's nylon to prevent any remaining  sharp objects from puncturing the pond liner, leaving some nylon overlapping the edges of the hole

Lay the pond liner over this nylon, again so that it overlaps the edges of the hole

Lay bricks or rocks on the ledges (on the inside of the pool!) with another builder's nylon strip between them and the liner. Lay these perfectly level as the water will rise to them when the pond is finished.

Fold the overlapping liner and nylon back over the rocks or bricks towards the centre of the pond.

Haunch up the nylon and liner against the rocks with cement and cover with soil. Cut the liner and nylon at the height of the level rocks and backfill with soil. The water will then rise to the level of the rocks, at the height that you cut the liner.

This is how you make a pond!

Good luck!

Jonathan