Wildlife Pond Calculator — Volume, Liner & Pump Size

A wildlife pond should have a maximum depth of at least 60cm (2ft) to prevent freezing solid in winter. Include shallow margins (10-20cm) for wildlife access and planting shelves at 20-30cm depth for marginal plants. Varied depths create the best habitat diversity.

Liner size = pond length + (2 x max depth) + (2 x overlap). The overlap (usually 30cm each side) allows for securing the liner at the edges. Always round up and buy slightly more than calculated to allow for uneven ground.

A dedicated wildlife pond does not strictly need a pump if it has a good balance of plants and receives some natural water circulation. However, a pump improves water quality and oxygenation. Size it to circulate half the pond volume per hour.

An irregular or kidney shape is most natural-looking and provides varied habitat zones. Include at least one gently sloping side for wildlife access, a shallow shelf for marginal plants, and a deeper central zone. Avoid steep sides.

Aim for around two-thirds of the pond surface covered by plants. Include oxygenating plants (one bunch per square metre), marginal plants on the shelves, and a few floating plants. This creates a balanced, low-maintenance ecosystem.