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| [[Overflow|Overflows]] are features of inline facilities and convey larger storm events out of the LID feature.<br> | | [[Overflow|Overflows]] are features of inline facilities and convey larger storm events out of the LID feature. |
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| Construction Steps:<br> | | '''Construction Steps:''' |
| #Connect the overflow drain to the underdrain | | #Connect the overflow drain to the underdrain. |
| #Install overflow pit to grade at the location specified in the contract documents | | #Fit a metal, domed grate to the overflow. |
| #Fit a metal, domed grate to the overflow<br>
| | #Install overflow pit to grade at the location specified in the contract documents. |
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| Key Inspection Points:<br> | | '''Key Inspection Points:''' |
| *Overflow drain matches design specifications | | *Overflow drain matches design specifications. |
| *Overflow pit is positioned at the maximum water surface elevation of the practice, as per the contract documents | | *Overflow pit is positioned at the maximum water surface elevation of the practice, as per the contract documents. |
| *Sufficient freeboard is provided between the overflow and inlet such that the inlet is not inundated by design storm flows | | *Sufficient freeboard is provided between the overflow and inlet such that the inlet is not inundated by design storm flows. |
| *Overflow grate matches design specifications | | *Overflow grate matches design specifications. |
| *Overflow grates located in high-traffic areas are screwed on or equipped with locks<br> | | *Overflow grates located in high-traffic areas are screwed on or equipped with locks. |
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| Mistakes to Avoid:<br> | | '''Mistakes to Avoid:''' |
| *Backflows – ensure that backflows are avoided by confirming that inlet and overflow elevations match design specifications with surveys | | *Backflows: Ensure that backflows are avoided by confirming that inlet and overflow elevations match design specifications with surveys. |
| *Incorrect sequencing – install overflow drain prior to backfilling with granular material and engineered soil | | *Incorrect sequencing: Install overflow drain prior to backfilling with granular material and engineered soil. |
| *Incorrect grate material – avoid using plastic overflow grates due to breakages and UV degradation<br> | | *Incorrect grate material: Avoid using plastic overflow grates due to breakages and UV degradation. |
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| <gallery mode="packed" widths=300px heights=300px> | | <gallery mode="packed" widths=300px heights=300px> |
| overflow-pipe-install.jpg | Overflow pipe installed to an underdrain T-connection. | | overflow-pipe-install.jpg | Overflow pipe installed to an underdrain T-connection. (Photo Source: CVC, 2010) |
| overflow-plastic-cap.jpg | Overflow installed with a plastic cap. Note that the use of plastic grates is discouraged. | | overflow-plastic-cap.jpg | Overflow installed with a plastic cap. Note that the use of plastic grates is discouraged. (Photo Source: CVC, 2012) |
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| </gallery> | | </gallery> |