Pre-formed ponds can be built in a wide variety of shapes, sizes and depths. Many come with pre-contoured shelves and steps. Choose a style that best suits your garden and selected location. Another point to consider when selecting your pre-formed pond is water depth. If you wish to winter your fish in a harsh climate you will need to select a pond with a depth of at least 4 feet (1.2 m) therefore a liner may be more suitable.
Building a pre-formed pond
1. Position pond and mark out its shape
Place the pond in position and carefully mark out its shape with pegs. DO NOT place the pre-formed pond upside down to outline the shape, or your hole will not match the shape of the form. Position the pond right side up in the exact place you want it and use it as a guide or template while digging around the stakes. Make your outline 4 - 6 inches (10 - 15 cm) larger than the pond itself.
2. Check the first level
Check the first level and start digging down to the shelves.
3. Dig out to the bottom
Reposition the pond, mark out the inner deeper section and continue digging out to the bottom. Be sure that the hole is slightly deeper than the actual depth of the preformed pond and verify that the bottom is level. Remove any stones or roots that may pierce the pre-formed pond when the weight of the water is added.
4. Add sand to the base level and shelves
Once you are satisfied that the hole is the proper size, depth and orientation, add about 2 inches (5 cm) of sand to the base level and shelves. This will protect the liner from damage due to exposed roots or rocks.
5. Insert pre-formed pond lining
Insert the pre-formed pond and make a final check to make sure it is level. Back-fill any spaces left from digging with sand.
6. Add water
Now you are ready to add water. The weight of the water as it is added will help the pre- formed pond settle into place