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→Size a bioretention cell with no underdrain for constrained ground area
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*''d<sub>T</sub>'' = Total depth of infiltration practice (m).}}
They may be easily applied for any shape and size of infiltration facility, in which the reservoir storage is filled with aggregate. + +
If R is greater than 20, consider decreasing catchment impervious area (A<sub>i</sub>) by draining less area to the practice.
If R is greater than 20, consider decreasing catchment impervious area (A<sub>i</sub>) by draining less area to the practice.
−==Size a bioretention cell with no underdrain for constrained ground area==
+==Size a bioretention cell where drainage area and practice area are fixed==
If the land area is limited, determine the I/P ratio, which is the ratio of catchment impervious area (A<sub>i</sub>) to practice pervious footprint area (A<sub>p</sub>):
If the land area is limited, determine the I/P ratio, which is the ratio of catchment impervious area (A<sub>i</sub>) to practice pervious footprint area (A<sub>p</sub>):
:<math>R=\frac{A_{i}}{A_{p}}</math>
:<math>R=\frac{A_{i}}{A_{p}}</math>
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*''A<sub>i</sub>'' = Catchment impervious area in m<sup>2</sup>}}
*''A<sub>i</sub>'' = Catchment impervious area in m<sup>2</sup>}}
−Then calculate the required depth (''d<sub>T</sub>''), as:
+Then calculate the required storage reservoir depth (''d<sub>r</sub>''), as:
−<math>d_{T}=\frac{D \left[ (R\times i)-f'\right]}{n'}</math>
+<math>d_{r}=\frac{D \left[ (R\times i)-f'\right]}{n'}</math>
{{Plainlist|1=Where:
{{Plainlist|1=Where:
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*''i'' = Intensity of design storm (m/h)
*''i'' = Intensity of design storm (m/h)
*''f''' = Design infiltration rate (m/h)
*''f''' = Design infiltration rate (m/h)
−*''n''' = Effective porosity of the fill materials within the practice, depth weighted mean
+*''n''' = Effective porosity of the storage reservoir fill material}}
−These equations assume that infiltration occurs primarily through the base of the facility.
These equations assume that infiltration occurs primarily through the base of the facility.
−<br>
−This spreadsheet tool has been set up to perform all of the infiltration practice sizing calculations shown above.<br>
−This spreadsheet tool has been set up to perform all of the infiltration BMP sizing calculations shown above<br>
{{Clickable button|[[Media:Infiltration Sizing 20200525 locked.xlsx|Download the infiltration practice sizing tool]]}}
{{Clickable button|[[Media:Infiltration Sizing 20200525 locked.xlsx|Download the infiltration practice sizing tool]]}}