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− | [[File:perf pipe.gif|thumb|500 px|Exfiltration trench under high flow and exfiltration conditions]] | + | {{float right|[[File:perf pipe.gif|border|600 px|Exfiltration trench under high flow and exfiltration conditions]]}} |
| Exfiltration trenches are similar to [[infiltration trenches]] but differ primarily in the the manner in which stormwater is delivered to the trench.<br> | | Exfiltration trenches are similar to [[infiltration trenches]] but differ primarily in the the manner in which stormwater is delivered to the trench.<br> |
| Runoff enters infiltration trenches directly by infiltration from the surface. In exfiltration systems, surface runoff is collected by drainage [[inlets]] and delivered to the trench via subsurface perforated [[pipes]]. | | Runoff enters infiltration trenches directly by infiltration from the surface. In exfiltration systems, surface runoff is collected by drainage [[inlets]] and delivered to the trench via subsurface perforated [[pipes]]. |
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| Exfiltration systems can be thought of as linear soakaways; designed for both conveyance and [[infiltration]] of excess stormwater. | | Exfiltration systems can be thought of as linear soakaways; designed for both conveyance and [[infiltration]] of excess stormwater. |
| By attenuating runoff volume, they reduce contaminant loads delivered to downstream BMPs, end-of-pipe facilities or receiving waterbodies. | | By attenuating runoff volume, they reduce contaminant loads delivered to downstream BMPs, end-of-pipe facilities or receiving waterbodies. |
− | {{textbox|Rainwater harvesting is an ideal technology for: | + | {{textbox|Exfiltration pipe systems are an ideal technology for: |
| *Road retrofits where sewer lines are being replaced, | | *Road retrofits where sewer lines are being replaced, |
| *All new road/storm sewer constructions where no constraints to infiltration exist, | | *All new road/storm sewer constructions where no constraints to infiltration exist, |
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| *Gravel beds in which exfiltration systems are installed are typically rectangular excavations with a bottom width between 0.6 and 2.4 m <ref>Greater Vancouver Regional District. 2005. Stormwater Source Control Design | | *Gravel beds in which exfiltration systems are installed are typically rectangular excavations with a bottom width between 0.6 and 2.4 m <ref>Greater Vancouver Regional District. 2005. Stormwater Source Control Design |
| Guidelines 2005. Prepared by Lanarc Consultants Limited, Kerr Wood Leidal Associates Limited and Goya Ngan</ref>. | | Guidelines 2005. Prepared by Lanarc Consultants Limited, Kerr Wood Leidal Associates Limited and Goya Ngan</ref>. |
− | *The gravel beds should have gentle slopes between 0.5 - 1%. | + | *The gravel beds should have gentle slopes between 0.5 - 1 %. |
− | *'''[[Maximum flow rate through perforated pipe]]''' | + | *Calculate maximum '''[[flow through perforated pipe]]''' |
| + | |
| + | ===Drawings=== |
| + | Standard details for exfiltration trenches have been produced by City of Kitchener and City of Barrie. See [[Drawings]] |
| + | ==Gallery== |
| + | {{:Exfiltration:_Gallery}} |
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| ==Materials== | | ==Materials== |
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| ==Performance== | | ==Performance== |
| {{:Exfiltration: Performance}} | | {{:Exfiltration: Performance}} |
| + | ===See also=== |
| + | [https://sustainabletechnologies.ca/home/urban-runoff-green-infrastructure/low-impact-development/perforated-pipe-systems/ STEP and partners research and reports on exfiltration systems] |
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| ==External resources== | | ==External resources== |