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| [[File:Sizing flow-through planter.jpg|thumb|A flow-through planter comprises a ponding zone, mulch layer, filter media for planting, and a supporting gravel drainage layer]] | | [[File:Sizing flow-through planter.jpg|thumb|A flow-through planter comprises a ponding zone, mulch layer, filter media for planting, and a supporting gravel drainage layer]] |
| | This article is specific to flow-through [[Stormwater planters|stormwater planters]], vegetated systems that do not infiltrate water to the native soil. <br> |
| | If you are designing a planted system which does infiltrate water, see advice on [[Bioretention: Sizing]]. |
| | |
| | The dimensions of a stormwater planter are largely predetermined according to the function of the component. As they do not contain a storage reservoir the planters rely more upon careful selection of materials. Both the filter media and the perforations of the [[Pipe| pipe]] play critical roles for flow control. |
| | |
| | {| class="wikitable" |
| | |- |
| | ! Component |
| | ! Recommended depth (with underdrain pipe) |
| | ! Typical porosity (''n'') |
| | |- |
| | | Ponding (''d<sub>p</sub>'') |
| | | 150 to 450 mm |
| | | 1 |
| | |- |
| | | [[Mulch]] |
| | | 75 ± 25 mm |
| | | |
| | * 0.7 for wood based |
| | * 0.4 for stone |
| | |- |
| | | [[Bioretention: Filter media|Filter media]] (''d<sub>m</sub>'') |
| | | |
| | * 300 mm to support turf grass (and accept only rainwater/roof runoff) |
| | * 600 mm to support shrubs, flowering [[perennials]] and decorative [[grasses]] |
| | * 1000 mm to support [[trees]] |
| | | |
| | * 0.35 for Blend A - Drainage rate priority; |
| | * 0.4 for Blend B - Water quality treatment priority |
| | |- |
| | | Pipe diameter reservoir |
| | | Is equal to underdrain [[pipe]] diameter |
| | | 0.4 |
| | |- |
| | | [[Choker course|Pipe bedding]] (''d<sub>b</sub>'') |
| | | 50 mm (although commonly omitted altogether). |
| | | 0.4 |
| | |} |