Once you have settled on a potential site for your pond, you need to decide on the size. If you want fish and a variety of plants, it would be best to have a larger in-ground pond. This doesn’t mean you would not be successful with a half-barrel or other type of patio-deck water container garden. Now is the time to get out paper and pencils. Draw out a base map of your yard then draw in the shape of the pond and then add plantings and other features around it. Draw out several designs. This is also the time to determine what kind of material your pond will be constructed of. Preformed or prefabricated shell, flexible liner or concrete. A pond does not have to be round. You might want to consider a stream, or more than one waterfall. Do you want a formal look to your pond? If you do, then you might want to stick with a square, circle or rectangle design. The geometric shapes with balanced, mirror image plantings are very tranquil and elegant to look at. Most back yard ponds I have encountered have an informal design (ponds designed without strict geometric form) and these tend to suit most landscapes and home designs as well as the owners. Plan your pond to harmonize with the surrounding area. Using a flexible liner offers you an easy way to shape a pond. Planning your pond in stages will be much easier on your budget. For example, the first year – your largest pond, the second year – a stream, the third year – a bog garden.
Preformed or prefabricated shell ponds can be purchased at almost any local store that carries water garden supplies. These stores include Lowes, Home Depot, Meijers and almost any nursery just to name a few. You should look for black or dark gray fiberglass that is at least 1/4 inch thick and will hold water when they are above ground. They should come with a lengthy guarantee. AVOID POOLS WITH FLEXIBLE SIDES THAT DO NOT MAINTAIN THEIR SHAPE WHEN FILLED WITH WATER WITHOUT SUPPORT. These pools tend to change shape as you backfill around them which results in a top edge that is not level. Shapes and sizes can vary. Depth varies from 13 to 18 inches depending on model selected.
Flexible Liners come in two types – PVC and rubber. Both are sold in grades by thickness, measured in mils (one-thousandth of an inch). Thicker liners cost more, but are more durable and last longer. I would strongly recommend the thicker synthetic rubber EPDM that has at least a 45-mil. Check the guarantees and warranties. A 45-mil liner should last 20 years. You can adapt a flexible liner to fit a site because there are no preset sizes or shapes to contend with.
The depth of your pond should be taken into consideration for these reasons. Deeper water helps maintain cool, clear water and a more stable summer temperature. If you keep fish year around, a deeper pond will keep them from freezing. A depth of 18 and 24 inches is okay for Goldfish and mosquito fish. Koi prefer ponds of at least three feet. The Koi enthusiasts recommend as much as five feet. Koi require vertical swimming exercise for optimum health and they grow much larger than goldfish. Goldfish and koi are cold-water fish. Warm water holds less oxygen. In designing your pond you could make part of your pond deep to keep the water cooler.
People who might have problems with bending or kneeling should strongly consider a raised pond and edges. These ponds help to eliminate getting down on the ground to feed and touch your fish, and make it easier to clean your pond and skimmer.
Darlene Jennings (pond Lady) President, Mid-Michigan Pond & Water Garden Club Advanced MSU Master Gardener