Line 31: |
Line 31: |
| | | |
| ===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 0.06 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 0.07 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> |
Line 37: |
Line 37: |
| :<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 0.06 = 7.2\ m^{2}</math> | + | :<math>A_{f}=120\times 0.07 = 8.4\ m^{2}</math> |
− | 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: | + | So to meet the target particle removal, the forebay will be 8.4 m² in area. This gives the storage volume of 1.26 m³, which can be returned to the initial equation to determine the minimum cleaning frequency as: |
− | :<math>C_{f}=\frac{1.08}{1.7\times 0.8\times 0.6}=2.2\ years</math> | + | :<math>C_{f}=\frac{1.26}{1.7\times 0.8\times 0.6}=1.5\ years</math> |
| | | |
| ==Gallery== | | ==Gallery== |