Liner

• Waterproof containment can be created using a plastic membrane/liner (HDPE or EPDM are common materials).
  • When the membrane is being used directly in the ground, punctures from stones can be prevented by compacting a layer sand (30 - 50 mm) over the soil prior to installing the membrane.
  • Similarly, a 50 mm sand layer should be applied on top of the membrane to protect it from the clear stone being used for drainage inside the BMP.
• Some designs include a concrete cell to prevent infiltration. The longevity of this type of construction may be improved with a coating of liquid waterproofing compound.

Mineral particles which are smaller than 2 mm, and which are free of appreciable quantities of clay and silt. Coarse sand usually designates sand grains with particle size between 0.2 and 0.02 mm.

Best management practice. State of the art methods or techniques used to manage the quantity and improve the quality of wet weather flow. BMPs include: source, conveyance and end-of-pipe controls.

The slow movement of water into or through a soil or drainage system.

Penetration of water through the ground surface.