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|  | ===Example calculation=== |  | ===Example calculation=== | 
| − | A parking lot catchment of 1.7 ha is being routed through a small forebay into a bioretention cell. The design flow rate is 0.02 m³/s. The system should be designed to require cleaning no more often than once per year. | + | A parking lot catchment of 1.7 ha is being routed through a small forebay into a bioretention cell. The design flow rate is 0.06 m³/s. The system should be designed to require cleaning no more often than once per year.    | 
|  | The volume is calculated as: |  | The volume is calculated as: | 
|  | :<math>V_{f}=1.7\times 0.8\times 0.6\times 1=0.816\ m^{3}</math> |  | :<math>V_{f}=1.7\times 0.8\times 0.6\times 1=0.816\ m^{3}</math> | 
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|  | :<math>A_{f}=\frac{0.816}{0.15}=5.44\ m^{2}</math> |  | :<math>A_{f}=\frac{0.816}{0.15}=5.44\ m^{2}</math> | 
|  | The area required to settle the 1 mm particles is calculated as: |  | The area required to settle the 1 mm particles is calculated as: | 
| − | :<math>A_{f}=120\times 0.02 = 2.4\ m^{2}</math> | + | :<math>A_{f}=120\times 0.06 = 7.2\ m^{2}</math> | 
| − | So to meet the target particle removal, the forebay will be 5.44 m² in area. This gives the storage volume of 1.8 m³, which can be returned to the initial equation to determine the minimum cleaning frequency as: | + | So to meet the target particle removal, the forebay will be 7.2 m² in area. This gives the storage volume of 1.08 m³, which can be returned to the initial equation to determine the minimum cleaning frequency as: | 
| − | :<math>C_{f}=\frac{1.8}{1.7\times 0.8\times 0.6}=2.2\ years</math> | + | :<math>C_{f}=\frac{1.08}{1.7\times 0.8\times 0.6}=2.2\ years</math> | 
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|  | ==Gallery== |  | ==Gallery== |