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| <math>d_{s}=\frac{f'\times 96}{0.4}</math> | | <math>d_{s}=\frac{f'\times 96}{0.4}</math> |
| {{Plainlist|1=Where: | | {{Plainlist|1=Where: |
| *''f''' = Design infiltration rate in mm/hr, and | | *''f''' = Design infiltration rate (mm/hr), and |
| *96 is the desired drainage time in hours | | *96 is the desired drainage time (hrs) |
| *0.4 is the void ratio of [[reservoir gravel|clear stone]]}} | | *0.4 is the Void ratio of [[reservoir gravel|clear stone]]}} |
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| ===Additional step for system without underdrain=== | | ===Additional step for system without underdrain=== |
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| <math>d_{p}=\frac{f'\times48}{0.4}</math> | | <math>d_{p}=\frac{f'\times48}{0.4}</math> |
| {{Plainlist|1=Where: | | {{Plainlist|1=Where: |
| *''f''' = Design infiltration rate in mm/hr, and | | *''f''' = Design infiltration rate (mm/hr), and |
| *48 is the desired drainage time of the ponding in hours | | *48 is the desired drainage time of the ponding (hrs) |
| *0.4 is the void ratio of [[reservoir gravel|clear stone]] *Note that conceptually the drainage of the ponded area is limited by ex-filtration at the base of the practice.}} | | *0.4 is the void ratio of [[reservoir gravel|clear stone]] *Note that conceptually the drainage of the ponded area is limited by ex-filtration at the base of the practice.}} |
| * Step 5: Sum total depth of bioretention, and compare to available space above water table and bedrock. Adjust if necessary. | | * Step 5: Sum total depth of bioretention, and compare to available space above water table and bedrock. Adjust if necessary. |