Changes

*''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)}}

Note that in designs without underdrains, conceptually the drainage of ponded water can be limited by infiltration through the base of the practice when filled to capacity.<br>

Note that in designs without underdrains, the drainage of ponded water can be limited by infiltration through the base of the practice when filled to capacity.<br>

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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>