To over winter, a deep spot must be planned that will go just past the frost line in your area of the country. The deeper section only needs to be large enough to accommodate whatever fish and pots you would like to keep in the pond during the winter. In warmer parts of the country, deeper pools will help keep water temperature down during the hot days of summer. Very shallow water can heat up quickly in the hot sun and this could kill your fish. We recommend flexible liners.
Flexible liners allow for an easy and a very forgiving installation.
Other choices include concrete and preformed ponds. Concrete installations usually require a professional installation as well as being a medium that tends to crack as the ground freezes and thaws. Preformed ponds are good for some indoor installations, but are difficult to install outdoors as the hole must match the shape to avoid shifting and cracking.