Difference between revisions of "Choker layer"
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[[File:Gravel.jpg|thumb]] | [[File:Gravel.jpg|thumb|medium sized granular, free from fines]] | ||
In [[bioretention]] systems a choking layer of ≥ 100 mm is the recommended method to prevent migration of finer [[filter media]] into an underlying reservoir of [[Reservoir gravel|coarse aggregate]]. | In [[bioretention]] systems a choking layer of ≥ 100 mm is the recommended method to prevent migration of finer [[filter media]] into an underlying reservoir of [[Reservoir gravel|coarse aggregate]]. | ||
Suitable materials include: | Suitable materials include: | ||
Revision as of 20:29, 6 March 2018
In bioretention systems a choking layer of ≥ 100 mm is the recommended method to prevent migration of finer filter media into an underlying reservoir of coarse aggregate. Suitable materials include:
- High performance bedding (HPB)
- Clean, angular aggregate screened to between 6 - 10 mm. Widely available and designed specifically for drainage applications. Free from fines by definition.
- HL 6
- Is a clean, angular aggregate screened between 10 - 20 mm. Free from fines by definition.
- Pea Gravel
- Rounded natural aggregate, screened between 5 - 15 mm, and washed free from fines.
In most scenarios, a geotextile layer is unnecessary and have been associated with rapid decline and clogging in some circumstances.