Aquatic Ponds

The pond liner used to create a pond has a huge impact on water quality, the biological balance of aquatic life, and the longevity of the pond. These are all important factors to consider when designing a pond and selecting the most appropriate liner for the design.

For small ponds sized 300 gallons or less, preformed polymer tubs are the perfect starting point. Preformed ponds can be inset into the ground, or they can be placed on top of the ground and landscaped to blend in with the surrounding terrain. They are usually made from stiff HDPE or fiberglass, and it is uncommon for them to be larger than six feet wide or long. They are available in a variety of shapes.

Ponds larger than six feet in any dimension can be constructed to order, especially from fiberglass, but they are expensive. Most homeowners construct large ponds using a flexible pond liner. These liners are usually made from EPDM, but they can also be made from PVC or butyl rubber. Most pond builders consider EPDM to be the ideal pond construction material. It is flexible, is appropriate for wide temperature ranges, is resistant to punctures, and is not degraded by exposure to UV light. Some types of EPDM rubbers contain chemicals that can leach into the pond and kill fish, so specially branded fish-safe liner should always be selected. EPDM rubber liners will last for approximately 20 years.

Flexible PVC liners are lighter, less expensive, and easier to put into place than EPDM liners, but they are also less puncture resistant, less appropriate in freezing temperatures, and quickly degrade when exposed to the UV rays in sunlight. PVC liners have a useful life of about 10 years if properly installed. That may seem like a long time, but keep in mind that replacement will involve removal of all of the water and relocation of all aquatic life during the replacement process. Rolled or folded PVC liner is usually the material provided in a complete pond kit sold in the garden centers of large package stores.

Butyl rubber liners have a long useful life, but they are quite heavy and not nearly as flexible as EPDM liners. They are still used for some purposes, but have fallen out of favor for decorative pond and water garden use. Some butyl rubbers contain chemicals that can leach into the water and kill aquatic life.

Most small ponds use a submersible pond pump to circulate the water. The circulation aids in water aeration, provides flow to the biological filter, and feeds decorative features such as water spitters, waterfalls, artificial streams and fountains.