Changes

   

   

*The overflow must be situated at the far end of the facility to prevent any localised ponding to cause bypassing of the infiltration facility.  

*The overflow must be situated at the far end of the facility to prevent any localised ponding to cause bypassing of the infiltration facility.  

*Offline facilities use flow splitters or bypass channels that only allow the design storm runoff storage volume to enter the facility. Higher flows are conveyed to a downstream storm sewer or other BMP by a flow splitting manhole weir or pipe, or by by-passing the surcharging curb opening and flowing into a downstream catchbasin.

*Offline facilities use flow splitters or bypass channels that only allow the design storm runoff storage volume to enter the facility. Higher flows are conveyed to a downstream storm sewer or other BMP by a flow splitting manhole weir or pipe, or by by-passing the curb opening and flowing into a downstream catchbasin connected to a storm sewer.

===Overflow elevation===

===Overflow elevation===

The invert of the overflow should be placed at the maximum water surface elevation of the practice. i.e. the maximum ponding level.  

The invert of the overflow should be placed at the maximum water surface elevation of the practice. i.e. the maximum surface ponding level.  

A good starting point is 150 to 350 mm above the surface of the mulch cover. However, consideration should be given to public safety, whether or not an underdrain is included, and the time required for ponded water to drain through the filter bed surface (must drain within 48 hours).  

A good starting point is 150 to 350 mm above the surface of the mulch cover. However, consideration should be given to public safety, whether or not an underdrain is included, and the time required for ponded water to drain through the filter bed surface, and if no underdrain is present, through the underlying native soil (must drain within 48 hours).  

See [[Bioretention: Sizing]] and [[Stormwater planters]] for more details.

See [[Bioretention: Sizing]] and [[Stormwater planters]] for more details.