Pond Liner Anti-Buoyancy Calculations

Liner Design

• Pond liner manufacturers design liners not to float. If installed properly, you don't need to worry about anti-buoyancy calculations for your liner. Basic principles of physics ensure that pond liners stay at the bottom of a pond. When you install a pond liner, you install it on top of soil, with neither air nor water underneath it. The weight of water in a pond sinks the liner and holds it in place. Because nothing pushes the pond liner from underneath, it stays within the ground thanks to the weight of water -- liners are not in ponds, but under them.

Problems

• When used improperly or somehow damaged, pond liners may float up from the bottom of a pond. For instance, if a rip appears somewhere in a pond liner, water drains through that leak. As it drains into soil, some water may become trapped between the liner and soil, causing the liner to rise, or float, within the water. Or, during or after a heavy rainfall, water may seep around the sides of a pond and get underneath the liner. In this case, the liner may rise, or float, within the pond. A dramatic rise in the level of groundwater due to flooding may also induce floating in a pond liner. In every case of floating liners, water somehow gets underneath the liner and causes it to rise up from the soil.

Solutions

• Various anti-buoyancy solutions exist to help prevent liners from floating in ponds. Always use an underlay when installing pond liner. An underlay sits underneath the pond liner, proving extra protection against leaking water and sharp objects in the soil from tearing the liner. You can also use weights to prevent floating liners. Weights can assume the form of concrete blocks underneath a liner that you attach the liner and underlay to, or stones or bricks placed on top of the liner around the lip of the pond. Placing heavy objects around the lip of a pond can also help prevent water from leaking under or around the liner. You can also simply replace a floating liner with a more effective one.

Alternative Liners

• A few alternative types of liners exist that rarely suffer problems from floating, namely organic and concrete linings. Organic liners made from clay or a similar substance coat the recess into which you plan on pouring water to coat a pond. These liners become part of the soil structure and harden the soil to prevent water from leaking through it. Clay liners may erode, but they most likely won't float. Concrete liners apply like organic liners, as a layer of wet material slathered across soil. Once dry, a concrete liner forms a very hard, durable surface large impervious to water damage.