Changes

==Select a surface ponding depth to begin sizing with==

==Select a surface ponding depth to begin sizing with==

* Step 2: Determine a maximum surface ponding depth (''d_{p, max}'')

* Step 2: Determine a maximum surface ponding depth (''d_{p, max}'')

For practices without underdrains,

For practices without underdrains:

<math>d_{p, max}=f'\times48</math>

<math>d_{p, max}=f'\times48</math>

{{Plainlist|1=Where:

{{Plainlist|1=Where:

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

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

*48 = Maximum permissible drainage time for ponded water (h)

*48 = Maximum permissible drainage time for ponded water (h)}}<br>

*Note that in designs without underdrains, conceptually the drainage of ponded water is limited by infiltration through the base of the practice.}}<br>

*Note that in designs without underdrains, conceptually the drainage of ponded water is limited by infiltration through the base of the practice.}}<br>

For practices with underdrains see recommended maximum surface ponding depth for each filter media blend in the table above.<br>

For practices with underdrains see recommended maximum surface ponding depth for each filter media blend in the table above.<br>