Each pond needs a liner to prevent water from escaping through the base of the pond. There are natural pond bottoms made of clay and there are artificial pond liners. Both effective in its own way and each with its own advantages. A half-acre pond would be equivalent to a circular pond about 170 feet in diameter or, in a more natural way, about 220 feet long by 100 feet wide.
There are several options for building a new pond without a coating or cement layer. The easiest thing is to excavate the pond in the local water table and use the groundwater. However, for this to work well, you must live in an area with a fairly stable high water table. Choosing the best lining was a task in itself.
That's where McDonald called Colorado Lining's Houston office to help him with engineering and design. If you need a lining, do not go to the local sawmill, garden department and buy a plastic roll. The liner should have a certain thickness with some flexibility and then be properly sized to make sure you have no problems after installation, when the water starts to flow. If the soil proves satisfactory, the next step is to remove all vegetation from the area and dig the pond.
However, privately owned residential ponds benefit both from the use of liners and from any other source of water. This leads them to give up any coating and only compensate for the loss of water through filtration by refilling the pond regularly. Finally, properly lined ponds are less likely to attract tree roots than unlined ponds, since there is no water that constantly seeps through the soil to encourage growth. We installed two 8 bottom drains, added a professional skimmer, a Venturi air supply valve, a natural rock waterfall, a turtle island that supported a 25-foot bridge that spanned the pond, a “Ultima II” high-pressure filter, backwash, ultraviolet light, lighting in the pond and waterfall.
But if the groundwater is 10 feet below the surface, the pond will look more like a quarry, with dangerously steep sides. Some residential pond owners think that trying to install a geomembrane as a liner, or even a clay product, is a waste of time and money. It is true that it is impossible to remove all the mud from a pond full of rocks because of all the voids and openings between the materials. After placing the liner across the bottom of the pond, it was secured around the entire edge of the pond by digging a trench, pulling the edge of the liner into the trench, and then backfilling with good soil.
It's true that the aggressive roots of some plants, such as bamboo, can damage even the toughest pond liner materials. An ultraviolet light is placed in series between the filter and the pond return to kill pathogenic bacteria that can cause disease and turn the pond green. Keeping trees 20 to 50 feet from the edge of the pond also reduces root development toward the water source. Large pond liners are made of PVC (polyvinyl chloride) or RPE (reinforced polyethylene) and are custom made to reduce seams in the field.
Ponds lined with impermeable geomembranes and similar flexible materials can be as natural as those that are only built with clay or soil. This material will also protect the pond from cracks that could result from freezing and thawing.