HDPE pond liner

For farm ponds, water pans and aquaculture, 0.75 mm and 1.00 mm cover the great majority of work. Move to 1.50 mm where the subgrade is rough, where machinery will work near the liner, where the water is deep, or where the pond is a long term asset rather than seasonal storage. Decorative lakes and landscape water features are usually 1.00 mm because the subgrade is prepared and loading is light. Full properties per grade are in the specification table.

More than the water surface area. The sheet covers the floor, climbs every batter, and runs into an anchor trench at the top, and a sloped face is longer than the depth because it is a hypotenuse. Our pond liner calculator does the arithmetic from your top dimensions, depth and batter slope, and returns area, roll count and seam length.

Wherever the subgrade is anything other than smooth, fine and stone free, yes. A cushion geotextile sits between the ground and the liner and absorbs the point loading from stones and angular material that would otherwise puncture the sheet, particularly once water depth presses the liner down onto it. On a properly prepared, rolled and picked subgrade it can sometimes be omitted, but the geotextile is far cheaper than draining a pond to find a puncture.

Only for a pond small enough to be covered by a single panel with no joints, which in practice means under about 7 m in one direction because that is the roll width. Beyond that there are seams, and seams in HDPE have to be welded. There is no adhesive or tape that gives a durable watertight joint in polyethylene. That means a wedge welder for the panel seams and a hand extruder for the inlet and outlet detail.

Covered or submerged liner protected from sunlight lasts decades. Exposed liner on the batters above waterline ages considerably faster, because ultraviolet light and heat deplete the antioxidant package in the polymer, and in Gulf conditions that exposure is severe. Where the design allows, covering the exposed batters with soil, gravel or concrete matting is the single largest thing you can do to extend service life.

For anything of scale, yes. HDPE has far better chemical resistance and a longer service life, and it is what specifications call for in agricultural, industrial and municipal work. PVC and EPDM are more flexible and easier to fit around complex shapes without welding equipment, which makes them common in small garden ponds. The trade-off is a shorter life, particularly under strong sunlight. For anything from a farm reservoir upward, HDPE is the correct material.