Changes

{|class="wikitable"

{|class="wikitable"

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!colspan = "2" style="background: darkcyan; color: white; align = center"|Surface

!colspan = "2" align = center"|Surface

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|width = 210px|Berm height (mm)

|width = 210px|Berm height (mm)

|Sometimes referred to as the bowl depth

|Sometimes referred to as the bowl depth or ponding depth (e.g. 300 mm)

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|Surface roughness (Manning’s n)

|Surface roughness (Manning’s n)

|Lower numbers indicate less surface obstruction and result in faster flow

|Lower numbers indicate less surface obstruction and result in faster flow

Suggested ranges:

Suggested ranges:

* Mown grass (dependent on density) 0.03 – 0.06<ref name = SWMM> Oregon State Univ., Corvallis. Dept. of Civil, Construction and Environmental Engineering.; Environmental Protection Agency, Cincinnati ONRMRL. Storm Water Management Model Reference Manual Volume I Hydrology (Revised). 2016:233. https://nepis.epa.gov/Exe/ZyPURL.cgi?Dockey=P100NYRA.txt  Accessed August 23, 2017.</ref>

* [[Turf|Mown grass]] (dependent on density) 0.03 – 0.06<ref name = SWMM> Oregon State Univ., Corvallis. Dept. of Civil, Construction and Environmental Engineering.; Environmental Protection Agency, Cincinnati ONRMRL. Storm Water Management Model Reference Manual Volume I Hydrology (Revised). 2016:233. https://nepis.epa.gov/Exe/ZyPURL.cgi?Dockey=P100NYRA.txt  Accessed August 23, 2017.</ref>

* Rocks 0.03 – 0.05

* [[Stone]] 0.03 – 0.05

* Planted (highly dependent on density) 0.05 – 0.15

* Planted (highly dependent on density) 0.05 – 0.15

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|Surface slope (%)

|Surface slope (%)

|If the slope > 3% a series of [[Checkdams]] or weirs should be included in the design.  

|If the slope > 3% a series of [[Check dams]] or weirs should be included in the design.  

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!colspan = "2" style="background: darkcyan; color: white; align = center"|'''Soil (bioretention filter media)'''

!colspan = "2" align = center"|'''Soil (bioretention filter media)'''

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|Thickness (mm)

|Thickness (mm)

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|Porosity (fraction)

|Porosity (fraction)

|Suggest range 0.35 – 0.4 unless otherwise tested

|Suggest [[Bioretention media storage|0.4]] unless otherwise tested

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|Field capacity (fraction)

|Field capacity (fraction)

|Suggested range 50 - 60 <ref name = SWMM/>

|Suggested range 50 - 60 <ref name = SWMM/>

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!colspan = "2" style="background: darkcyan; color: white; align = center"|'''Storage'''

!colspan = "2" align = center"|'''Storage'''

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|Thickness (mm)

|Thickness (mm)

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|Void ratio

|Void ratio

|Suggest range 0.35 – 0.4 unless otherwise tested

|Suggest value 0.4 unless otherwise tested

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|Seepage rate (mm/hr)

|Seepage rate (mm/hr)

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|Clogging factor

|Clogging factor

|?

|Maybe up to 0.5 to account for some anticipated maturation.

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|Design drawdown time (hrs)

|Design drawdown time (hrs)

|Recommend 48 hours?

|Also known as '[[drainage time]]'

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!colspan = "2" style="background: darkcyan; color: white; align = center"|'''Drain (underdrain)'''

!colspan = "2" align = center"|'''Drain (underdrain)'''

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|Flow coefficient

|Flow coefficient

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|Offset height

|Offset height

|This is the height from the base of the cell to the height at which the drain discharges. In some designs this may be the height of the perforated pipe within the storage layer [[Bioretention: Partial infiltration]]. In other designs this height is adjusted by creating an upturn in the discharge pipe. [[Bioretention: Internal storage]]

|This is the height from the base of the cell to the height at which the drain discharges. In some designs this may be the height of the perforated pipe within the storage layer; in others this height is adjusted by creating an upturn in the discharge pipe.[[Bioretention: Partial infiltration]]

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