You will need a pond liner to keep water in your pond. To calculate the size of liner needed, take the pond width, add it to the depth multiplied by two and add 24 inches for overlap. The length is calculated the same way. It is also a good idea to have pond underlayment below to protect the liner from punctures and damage from rocks or roots. You will also need a pump, filter, tubing and possibly a skimmer.
Shade and sun is important to consider. If you plan to have water plants in your pond they will need at least partial sun and a shelf 12 to 18 inches deep with a one foot width. If your pond is in sun or partial sun a UV Light is recommended, and if it is under a tree, you will likely need a skimmer.
Many garden ponds have waterfalls. If you want a waterfall, decide roughly where it will go.
The steps to build a pond are straightforward. First, make a sketch of your design. Take a garden hose to outline your design on the ground. Next, dig out the pond and put in the underlayment and pond liner and fill it with water. Trim the liner and add rock edging. Then install the pump and filter. Finally, de-chlorinate the water and slowly introduce plant life and fish.
A garden pond is an attractive addition to any backyard. Building a pond is a practical project for many homeowners to undertake themselves, and the pond itself can provide enjoyment for years to come.