Difference between revisions of "Notation"

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;A<sub>c</sub> :Area of the catchment, whole contributing drainage area (usually in m<sup>2</sup>).  
;A<sub>c</sub> :Area of the catchment, whole contributing drainage area (usually in m<sup>2</sup>).
 
;A<sub>i</sub> :Area of impervious cover within the catchment (usually in m<sup>2</sup>). 


;A<sub>p</sub> :Area of the practice e.g. footprint area of a bioretention cell (usually in m<sup>2</sup>)
;A<sub>p</sub> :Area of the practice e.g. footprint area of a bioretention cell (usually in m<sup>2</sup>)


;d :Depth e.g. of an infiltration practice (units of length, usually mm or m)
;D :Duration of the design storm event (in units of time, usually hrs)
 
;d<sub>p</sub> :Surface ponding depth of an infiltration practice (unit of length, usually mm or cm)
 
;d<sub>m</sub> :Filter media depth of a bioretention, stormwater planter or soil cell practice (unit of length, usually mm or cm)
 
;d<sub>s</sub> :Storage reservoir depth of an infiltration practice (unit of length, usually mm or cm)
 
;d<sub>T</sub> :Total depth of an infiltration practice (unit of length, usually cm or m)
 
;f :Infiltration rate, measured (usually mm/hr)
 
;f':Design infiltration rate (length per time, usually mm/hr) after application of safety correction factor (SCF)


;f :Infiltration rate (usually mm/hr)
;h :Height (units of length)


;h :height (units of length)
;i :Intensity of the design storm event (in units of depth/time, usually mm/hr)


;i :Thornthwaite monthly heat index (-)
;i :Thornthwaite monthly heat index (-)
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;L :Length, e.g. of a reach, channel or swale (usually in m)
;L :Length, e.g. of a reach, channel or swale (usually in m)


;m :run of side slopes in channel cross sections (length, but usually expressed as a ratio in relation to rise. e.g. side slopes = 1:3, so m = 3)
;m :Run of side slopes in channel cross sections (length, but usually expressed as a ratio in relation to rise. e.g. side slopes = 1:3, so m = 3)
 
;n :Porosity, applies to aggregate and other void-forming materials, filter media and native soils (unit is vol/vol, so dimensionless)


;n :Manning's coefficient (unitless) Note: for clarity porosity is being expressed as 'void ratio' and sharing the notation V<sub>R</sub>
;n :Manning's coefficient (unitless) Note: the symbol n is also used for porosity so it is important to be sure which term is implied.


;N :Number of days in the month
;N :Number of days in the month
;x :Perimeter of infiltration practice or swale x-section (m)
;f':Design infiltration rate (length per time, usually mm/hr) after application of safety correction factor (SCF)


;Q<sub>p</sub> :Peak flow in units of volume per time (e.g. m<sup>3</sup>/s)
;Q<sub>p</sub> :Peak flow in units of volume per time (e.g. m<sup>3</sup>/s)


;R :Ratio of catchment (A<sub>c</sub>) to the practice footprint area (A<sub>p</sub>). ''syn.'' I/P ratio. For [[green roofs]] (and often permeable paving systems) this will be 1:1. In [[bioretention]] it may be 15 or 20 to 1.   
;R :Ratio of catchment impervious area (A<sub>i</sub>) to the practice permeable footprint area (A<sub>p</sub>). ''syn.'' I/P ratio. For [[green roofs]] and often [[permeable pavements|permeable pavement]] systems that do not receive drainage from external impervious areas this will be 0. For [[bioretention]], [[infiltration trenches]] and [[infiltration chambers]] receiving pavement runoff, it is recommended to be kept between 15 to 20.   


;R<sub>a</sub> :Existing rise of swale gradient (length, usually m)
;R<sub>a</sub> :Existing rise of swale gradient (length, usually m)
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;SCF :Safety correction factor (dimensionless)
;SCF :Safety correction factor (dimensionless)


;t :time (usually in hrs)
;t :Drainage time (usually in hrs)


;T :Temperature (°C)
;T :Temperature (°C)
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;V :Volume (usually in m<sup>3</sup>)
;V :Volume (usually in m<sup>3</sup>)


;n :Porosity, applies to aggregate and other void-forming materials, filter media and native soils (unit is vol/vol, so dimensionless)
;x :Perimeter of infiltration practice or swale x-section (m)


;y :Depth of water (L, usually m or sometimes mm)
;y :Depth of water (L, usually m or sometimes mm)

Latest revision as of 18:32, 6 August 2020

Ac
Area of the catchment, whole contributing drainage area (usually in m2).
Ai
Area of impervious cover within the catchment (usually in m2).
Ap
Area of the practice e.g. footprint area of a bioretention cell (usually in m2)
D
Duration of the design storm event (in units of time, usually hrs)
dp
Surface ponding depth of an infiltration practice (unit of length, usually mm or cm)
dm
Filter media depth of a bioretention, stormwater planter or soil cell practice (unit of length, usually mm or cm)
ds
Storage reservoir depth of an infiltration practice (unit of length, usually mm or cm)
dT
Total depth of an infiltration practice (unit of length, usually cm or m)
f
Infiltration rate, measured (usually mm/hr)
f'
Design infiltration rate (length per time, usually mm/hr) after application of safety correction factor (SCF)
h
Height (units of length)
i
Intensity of the design storm event (in units of depth/time, usually mm/hr)
i
Thornthwaite monthly heat index (-)
I
Thornthwaite annual heat index (-)
L
Length, e.g. of a reach, channel or swale (usually in m)
m
Run of side slopes in channel cross sections (length, but usually expressed as a ratio in relation to rise. e.g. side slopes = 1:3, so m = 3)
n
Porosity, applies to aggregate and other void-forming materials, filter media and native soils (unit is vol/vol, so dimensionless)
n
Manning's coefficient (unitless) Note: the symbol n is also used for porosity so it is important to be sure which term is implied.
N
Number of days in the month
Qp
Peak flow in units of volume per time (e.g. m3/s)
R
Ratio of catchment impervious area (Ai) to the practice permeable footprint area (Ap). syn. I/P ratio. For green roofs and often permeable pavement systems that do not receive drainage from external impervious areas this will be 0. For bioretention, infiltration trenches and infiltration chambers receiving pavement runoff, it is recommended to be kept between 15 to 20.
Ra
Existing rise of swale gradient (length, usually m)
Rb
Rise of compensation gradient for an enhanced swale (length, usually m)
RVCT
Runoff volume control target (as outlined by MECP, units are mm)
S0
Longitudinal slope (m/m, i.e. dimensionless)
ST
Storage (m3)
Sx
Cross slope (m/m, i.e. dimensionless)
SCF
Safety correction factor (dimensionless)
t
Drainage time (usually in hrs)
T
Temperature (°C)
V
Volume (usually in m3)
x
Perimeter of infiltration practice or swale x-section (m)
y
Depth of water (L, usually m or sometimes mm)