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Wildlife Ponds and Lake Linings

Butyl Products Ltd. offer design, supply and installation services for wildlife ponds and lake linings. We will be pleased to quote for your project.

All lakes tend to become wildlife havens whether you intend it or not!

Special attention is required for wildlife ponds, as to be successful it must be sufficiently natural to provide all the normal habitats and foods required by the wildlife. The lining system must not detract from the natural uses of the pond but must also not be damaged by the wildlife.

Remember: Ducks bite! Deer have sharp hooves! Water voles dig holes to live in!

Kew Gardens wildlife water feature in progress, UK

We recommend the following lining system for all lakes and wildlife ponds.

Below liner: Geotextile liner protection. One layer minimum 2500 CBR and minimum 2.00mm thick to prevent puncture from stones, etc.

Liner: 0.75mm Butyl rubber with all welded joints. This can deal with settlement.

Note: For large lakes PVC and LLDPE liners are often used as they may be considerably cheaper than Butyl rubber. In these cases a high level of ground compaction is required to prevent settlement.

Above liner: Geotextile liner protection. One layer minimum 2500 CBR and minimum 2.00mm thick to prevent puncture from above.

Finally: Add a minimum of 50mm of 'as dug' soil to cover the base of the pond over the geotextile, increase to 100mm thick when the depth of water is below 1.00m. This weights the geotextile and finishes the pond.

Control of water depth is also helpful, maximum depth can be controlled using an overflow weir or pipe. Weirs are achieved by lowering the edge of the liner in one place around the pond.

As with all lined water features you must ensure that the highest level of natural water in the ground (the water table) is at least 0.5m below the liner level. If not, drainage will be required to prevent the likelihood of the liner lifting.

Public Records Office wildlife landscaped pond, Kew, UK

Buxton Park Nature Reserve, UK

Ground specification All surfaces on which the lining is to be laid must be prepared so that no damage to the lining is possible.

The surface shall be free of all rocks, sticks, stones, roots, sharp objects or debris of any kind. The surface should provide a firm unyielding foundation for the membrane with no sudden, sharp or abrupt change or break in gradient. No standing water or excess moisture shall be present. The surface must be constructed to allow the necessary compaction. 90% proctor with a surface tolerance of ±25mm for plastic materials, 80% proctor and ±50mm for rubber materials.

If after inspection of the surface to be laid on it is deemed unsuitable, sand blinding or an approved geotextile may be required as a protection layer.