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Line 108: − + − For practices with no underdrain:<br>+ − <math>d_{s}=(f'\times t \times 1/n) + d{p}</math>+ − {{Plainlist|1=Where:+ − *''f''' = Design infiltration rate (mm/hr), − *''t'' = [[Drainage time]] (hrs). Check local regulations for drainage time requirements; and − *''n'' = Porosity of the reservoir aggregate}}<br> − For practices with an underdrain:<br> − <math>d_{s}=f'\times t \times 1/n</math> − {{Plainlist|1=Where: − *''f''' = Design infiltration rate (mm/hr), − *''t'' = [[Drainage time]] (hrs). Check local regulations for drainage time requirements; and − *''n'' = Porosity of the reservoir aggregate}} − To boost drainage performance on fine-textured, low permeability soils, consider designing storage reservoirs even deeper than those calculated using the above approach, that many not fully drain between storm events, which increases hydraulic head and infiltration rate at the base of the practice. See [[Low permeability soils]] for more information. − − − * Step 2: Determine what the planting needs are and assign an appropriate depth of filter media, using the table above. − − −
→Calculate the total depth of the practice, dT
==Calculate the total depth of the practice, d<sub>T</sub>==
==Calculate the total depth of the practice, d<sub>T</sub>==
* Step 2: Calculate the active storage depth of the storage reservoir (''d<sub>s'', mm):<br>
* Step 6: Determine what the planting needs are and assign an appropriate depth of filter media, using the table above.
* Step 7: Select an underdrain perforated pipe diameter (typically 100 - 200 mm), assign this as an 'embedded' depth equal to the pipe diameter. *Note that this component does not apply if a downstream riser is being used to create the storage reservoir.
* Step 8: Sum total depth of bioretention components, and compare to available depth between the surface grade and the seasonally high water table or top of bedrock elevations.
* Step 9: Adjust component depths to maintain a separation of 1.0 metre between base of the practice and seasonally high water table or top of bedrock elevation, or a lesser or greater value based on groundwater mounding analysis. See below and [[Groundwater]] for more information.
* Step 3: Select an underdrain perforated pipe diameter (typically 100 - 200 mm), assign this as an 'embedded' depth equal to the pipe diameter. *Note that this component does not apply if a downstream riser is being used to create the storage reservoir.
* Step 5: Sum total depth of bioretention components, and compare to available depth between the surface grade and the seasonally high water table or top of bedrock elevations.
* Step 6: Adjust component depths to maintain a separation of 1.0 metre between base of the practice and seasonally high water table or top of bedrock elevation, or a lesser or greater value based on groundwater mounding analysis. See below and [[Groundwater]] for more information.
==Calculate the remaining dimensions==
==Calculate the remaining dimensions==