Changes

*Waterproof containment can be created using a plastic membrane/liner (HDPE or EPDM are common materials).

*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.  

**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.

**Alternatively, a manufactured cushion fabric (geotextile) can be employed for this purpose. 

**The top surface of the membrane must also be protected from stone and gravel being used for inside the BMP. Again, sand or a cushion fabric may be used.

*When a pipe is used to provide drainage from the BMP cell, a 'pipe boot' should be sealed to both the pipe and the liner to prevent leaks.  

[[Category:Materials]]

[[Category:Materials]]