Changes

[[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]], vegetated systems that do not infiltrate water to the native soil. <br>

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]].

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 play critical roles for flow control.

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 saturated hydraulic conductivity of the filter media and the number and size of perforations of the [[underdrain]] pipe play critical roles for flow control. Options for maintaining separation between filter media and clear stone aggregate surrounding the perforated pipe include a 100 mm deep choker layer or sheet of geotextile filter fabric.

{| class="wikitable"

{| class="wikitable"

! Component

! Component

! Recommended depth (with underdrain pipe)

! Recommended depth (with underdrain pipe)

! Typical void ratio (''V_R'')

! Typical porosity (''n'')

|-

|-

| Ponding (''d_p'')

| Ponding (''d_p'')

| ≥ 300 mm

| 150 to 450 mm

| 1

| 1

|-

|-

|  

|  

* 0.7 for wood based

* 0.7 for wood based

* 0.4 for aggregate

* 0.4 for stone

|-

|-

| [[Bioretention: Filter media|filter media]] (''d_m'')

| [[Bioretention: Filter media|Filter media]] (''d_m'')

|  

|  

* 300 mm to support turf grass (and accept only rainwater/roof runoff)

* 300 mm to support turf grass (and accept only rainwater/roof runoff)

* 600 mm to support flowering [[perennials]] and decorative [[grasses]]

* 600 mm to support shrubs, flowering [[perennials]] and decorative [[grasses]]

* 1000 mm to support [[trees]]

* 1000 mm to support [[trees]]

| 0.3

|

* 0.4 for sandier Blend A - Drainage rate priority;

|-

|-

| Pipe diameter reservoir

| Choker layer

| Is equal to underdrain [[pipe]] diameter

| Perforated pipe diameter

| 150 to 200 mm

| 0.4  

| 0.4  

|-

|-

| [[Choker course|Pipe bedding]] (''d_b'')

| Clear stone aggregate layer below perforated pipe

| 50 mm (although commonly omitted altogether).  

| 50 mm (although commonly omitted altogether).  

| 0.4

| 0.4

|}

|}