Changes

[[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]].

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,  

*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]]'''

 

==Materials==

==Materials==

==Performance==

==Performance==

{{:Exfiltration: Performance}}

{{:Exfiltration: Performance}}

==External resources==

==External resources==