Changes

* Step 5: Calculate the active storage depth of the practice (''d<sub>a'', mm):<br>

* Step 5: Calculate the active storage depth of the practice (''d<sub>a'', mm):<br>

For practices with no underdrain:<br>

For practices with no underdrain:

<math>d_{a}=(f'\times t \times 1/n) + d_{p}'</math>

<math>d_{a}=(f'\times t \times 1/n) + d_{p}'</math>

{{Plainlist|1=Where:

{{Plainlist|1=Where:

*''n'' = Porosity of the reservoir aggregate

*''n'' = Porosity of the reservoir aggregate

*''d_p''= design surface ponding depth}}<br>

*''d_p''= design surface ponding depth}}<br>

For practices with an underdrain:<br>

For practices with an underdrain:

<math>d_{a}=f'\times t \times 1/n</math>

<math>d_{a}=f'\times t \times 1/n</math>

{{Plainlist|1=Where:

{{Plainlist|1=Where:

*''f''' = Design infiltration rate (mm/hr),

*''f''' = Design infiltration rate (mm/h),

*''t'' = [[Drainage time]] (hrs). Check local regulations for drainage time requirements; and

*''t'' = [[Drainage time]] (h). Check local criteria for drainage time requirements; and

*''n'' = Porosity of the reservoir aggregate}}

*''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.  

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.

==Calculate the total depth of the practice, d_T==

==Calculate the total depth of the practice, d_T==