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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>


==Gallery==
==Gallery==

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