WATERFOWL TECHNIQUE SUMMARY PAGE

Pond Construction (Synthetic Liner) (Managing Wetlands for Wildlife - Implementing Management Plan)

Summary Information
Type of technique Health & Management / Managing Wetlands for Wildlife / Implementing Management Plan / Techniques:
Synonyms and Keywords --
Description Synthetic pond liners have become popular as an alternative to either premoulded ponds or concrete for constructing ponds in recent years. Liners vary from polythene sheeting to butyl rubber matting.
  • The area for the pond must be excavated, allowing for the depth of underlay and protective capping material to be used.
  • A layer of sand or matting should be laid down: 15cm deep recommended (B93).
  • The liner is put in place.
  • Should be capped with minimum 15cm protective material/soil and at least 40cm to allow for growth of roots of wetland plants (B93).
  • Edges should be covered e.g. with a surround of paving stones or similar, slightly overhanging.
Appropriate Use (?)
  • Liners are flexible and will follow contours; they may be used to construct ponds of any shape or size.
  • Laying a liner takes less time than construction with concrete.
Notes
  • Polythene liners may least 10 years, butyl rubber liners may last 20-25 years.
  • Stronger more durable liners such as thick butyl rubber are preferred; they are less likely to develop leaks.
  • Overhanging edging slabs are aesthetically pleasing as well as protecting the liner.
  • The length of liner required may be calculated as the longest length of the pond plus twice its greatest depth.
Complications / Limitations / Risk
  • Polythene liners are suitable only for small ponds .
  • Polythene liners perish where exposed to sunlight.
  • Shallow slopes (maximum gradient one in three) are essential if the liner is to be adequately covered with soil and this is to remain stable.
  • Liners are vulnerable to puncture.
  • Exposed liners are vulnerable to damage by waterfowl.
Equipment / Chemicals required and Suppliers
  • Liner.
  • Sand or matting as underlay.
  • Soil for capping.
  • Excavation machinery for large areas (spades for small ponds)
Expertise level / Ease of Use Depends on pond size - expertise required for handling very large liners and for large-scale excavation.
Cost / Availability Cost of liners is variable. Polythene or PVC sheeting is inexpensive but more durable materials such as butyl rubber are expensive, particularly for use on large areas.
Legal and Ethical Considerations  
Author Debra Bourne
Referee  
References B93, B94, B96, B108

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