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− | ;A<sub>c</sub> | + | ;A<sub>c</sub> :Area of the catchment, whole contributing drainage area (usually in m<sup>2</sup>). |
− | :Area of the catchment, whole contributing drainage area (usually in m<sup>2</sup>). | |
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− | ;A<sub>p</sub> | + | ;A<sub>i</sub> :Area of impervious cover within the catchment (usually in m<sup>2</sup>). |
− | :Area of the practice e.g. footprint area of a bioretention cell (usually in m<sup>2</sup>) | |
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− | ;d | + | ;A<sub>p</sub> :Area of the practice e.g. footprint area of a bioretention cell (usually in m<sup>2</sup>) |
− | :Depth e.g. of an infiltration practice (units of length, usually m) | |
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− | ;f | + | ;D :Duration of the design storm event (in units of time, usually hrs) |
− | :Infiltration rate (usually mm/hr) | |
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− | ;h | + | ;d<sub>p</sub> :Surface ponding depth of an infiltration practice (unit of length, usually mm or cm) |
− | :height (units of length) | |
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− | i;
| + | ;d<sub>m</sub> :Filter media depth of a bioretention, stormwater planter or soil cell practice (unit of length, usually mm or cm) |
− | Thornthwaite Heat Index (-)
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− | ;L | + | ;d<sub>s</sub> :Storage reservoir depth of an infiltration practice (unit of length, usually mm or cm) |
− | :Length, e.g. of a reach, channel or swale (usually in m) | |
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− | ;m | + | ;d<sub>T</sub> :Total depth of an infiltration practice (unit of length, usually cm or 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) | |
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− | ;n | + | ;f :Infiltration rate, measured (usually mm/hr) |
− | :Manning's coefficient (unitless) Note: for clarity porosity is being expressed as 'void ratio' and sharing the notation V<sub>R</sub> | |
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− | ;P | + | ;f':Design infiltration rate (length per time, usually mm/hr) after application of safety correction factor (SCF) |
− | :Perimeter of infiltration practice or swale x-section (m) | |
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− | ;q | + | ;h :Height (units of length) |
− | :Infiltration rate in (length per time, usually mm/hr) | |
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− | ;q' | + | ;i :Intensity of the design storm event (in units of depth/time, usually mm/hr) |
− | :Infiltration coefficient in (length per time, usually mm/hr) after application of safety correction factor (SCF) | |
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− | ;Q<sub>p</sub> | + | ;i :Thornthwaite monthly heat index (-) |
− | :Peak flow in units of volume per time (e.g. m<sup>3</sup>/s) | |
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− | ;R | + | ;I :Thornthwaite annual heat index (-) |
− | :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. | |
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− | ;R<sub>a</sub> | + | ;L :Length, e.g. of a reach, channel or swale (usually in m) |
− | :Existing rise of swale gradient (length, usually m) | |
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− | ;R<sub>b</sub> | + | ;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) |
− | :Rise of compensation gradient for an enhanced swale (length, usually m) | |
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− | ;RVC<sub>T</sub> | + | ;n :Porosity, applies to aggregate and other void-forming materials, filter media and native soils (unit is vol/vol, so dimensionless) |
− | :Runoff volume control target (as outlined by MOECC, units are mm) | |
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− | ;S<sub>0</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. |
− | :Longitudinal slope (m/m, i.e. dimensionless) | |
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− | ;S<sub>x</sub> | + | ;N :Number of days in the month |
− | :Cross slope (m/m, i.e. dimensionless) | |
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− | ;SCF | + | ;Q<sub>p</sub> :Peak flow in units of volume per time (e.g. m<sup>3</sup>/s) |
− | :Safety correction factor (dimensionless) | |
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− | ;t | + | ;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. |
− | :time (usually in hrs) | |
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− | ;T | + | ;R<sub>a</sub> :Existing rise of swale gradient (length, usually m) |
− | :Temperature (°C) | |
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− | ;V | + | ;R<sub>b</sub> :Rise of compensation gradient for an enhanced swale (length, usually m) |
− | :Volume (usually in m<sup>3</sup>)
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− | ;V<sub>R</sub> | + | ;RVC<sub>T</sub> :Runoff volume control target (as outlined by MECP, units are mm) |
− | :Void ratio, as usually applied to aggregates and yard materials. In this guide, it is also applied to native soils in lieu of porosity (unit for both are vol/vol, i.e. dimensionless) | |
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− | ;y | + | ;S<sub>0</sub> :Longitudinal slope (m/m, i.e. dimensionless) |
− | :Depth of water (length, usually m or sometimes mm) | + | |
| + | ;S<sub>T</sub> :Storage (m<sup>3</sup>) |
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| + | ;S<sub>x</sub> :Cross slope (m/m, i.e. dimensionless) |
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| + | ;SCF :Safety correction factor (dimensionless) |
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| + | ;t :Drainage time (usually in hrs) |
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| + | ;T :Temperature (°C) |
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| + | ;V :Volume (usually in m<sup>3</sup>) |
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| + | ;x :Perimeter of infiltration practice or swale x-section (m) |
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| + | ;y :Depth of water (L, usually m or sometimes mm) |