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→Geometry and Site Layout
===Geometry and Site Layout===
===Geometry and Site Layout===
Infiltration chambers and soakaways can be designed in a variety of shapes, although facilities should have level or nearly level bottoms to spread flow evenly throughout. Typically designed with an impervious drainage area to pervious facility footprint area ratio (i.e. I:P ratio) between 5:1 on low permeability soils (HSG C & D) to 20:1 on high permeability soils (HSG A & B). Not typically deeper than 4 m.
Infiltration chambers and soakaways can be designed in a variety of shapes, although facilities should have level or nearly level bottoms to spread flow evenly throughout. Typically designed with an impervious drainage area to pervious facility footprint area ratio (i.e. I:P ratio) between 5:1 on low permeability soils (HSG C & D) to 20:1 on high permeability soils (HSG A & B). Not typically deeper than 4 m.
{|class="wikitable"
|+ Site Layout Requirements for Infiltration Chambers, Trenches and Soakaways
|-
!style="background: darkcyan; color: white"|LID Stormwater Management Practice
!style="background: darkcyan; color: white"|Depth to high water
table or bedrock (m)
!style="background: darkcyan; color: white"|Typical Ratio of
Impervious Drainage Area
to Treatment Facility Area
!style="background: darkcyan; color: white"|Native Soil Infiltration Rate
(mm/hr)<sup>3</sup>
!style="background: darkcyan; color: white"|Head
!style="background: darkcyan; color: white"|Space
!style="background: darkcyan; color: white"|Slope
!style="background: darkcyan; color: white"|Pollution Hotspots*
!style="background: darkcyan; color: white"|Set backs**
|-
!Soakaway,
infiltration trench
or infiltration chamber
|1||5:1 to 20:1||Not a constraint||1 to 2||0 to 1||< 15%||No||B, U, T, W
|}
<small><sup>*</sup>Is the LID SWM BMP practice suitable to be located in known pollution hot spots or runoff source areas where land uses or activities have the potential to generate highly contaminated runoff? This could include fueling centers, demolition zones, outdoor storage or handling areas that house hazardous materials, etc.
fueling, servicing or demolition areas, outdoor storage or handling areas for hazardous materials and some heavy industry sites).
<sup>**</sup>Setback codes: B = Building foundation; U = Underground utilities; T = Trees; W = drinking water wellhead protection areas.</small>
===Inlets===
===Inlets===