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Line 36: − + − *''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. + − + −
→Size a bioretention cell with no underdrain for constrained ground area
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>
*''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:
*''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]]}}