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→Time to drain internal water storage reservoir
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<imagemap>
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Image:Infiltration.png|thumb|700 px|This is an image map; clicking on components will load the appropriate article.
Image:Infiltration.png|thumb|500 px|This is an image map; clicking on components will load the appropriate article.
poly 315 507 208 555 317 605 423 555 [[Drainage time]]
poly 315 507 208 555 317 605 423 555 [[Drainage time]]
rect 210 658 426 730 [[Details]]
rect 210 658 426 730 [[Details]]
This spreadsheet tool has been set up to perform all of the infiltration practice sizing calculations shown below<br>
This spreadsheet tool has been set up to perform all of the infiltration practice sizing calculations shown below<br>
{{Clickable button|[[Media:Infiltration Sizing 20200525 locked.xlsx|Download the infiltration practice sizing tool]]}}
{{Clickable button|[[Media:Infiltration Sizing 20220617 locked (1).xlsx|Download the infiltration practice sizing tool]]}}
==To calculate the required storage reservoir footprint area where the depth is fixed or constrained (1D drainage)==
==To calculate the required storage reservoir footprint area where the depth is fixed or constrained (1D drainage)==
K<sub>f</sub> is the minimum acceptable saturated hydraulic conductivity of the filter media and growing medium when compacted to 85% maximum dry density (mm/h); minimum of 25 mm/hr is recommended for bioretention filter media; minimum of 15 mm/hr is recommended for enhanced grass swale and stormwater tree trench growing medium.<br>
K<sub>f</sub> is the minimum acceptable saturated hydraulic conductivity of the filter media and growing medium when compacted to 85% maximum dry density (mm/h); minimum of 25 mm/hr is recommended for bioretention filter media; minimum of 15 mm/hr is recommended for enhanced grass swale and stormwater tree trench growing medium.<br>
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For full infiltration design practices that do not feature an underdrain, once the internal water storage capacity has been filled, the length of time required to fully drain surface ponded water is limited by the saturated hydraulic conductivity of the underlying in-situ (native) subsoil.<br>
For full infiltration design practices that do not feature an underdrain, once the internal water storage capacity has been filled, the length of time required to fully drain surface ponded water is limited by the saturated hydraulic conductivity of the underlying in-situ (native) subsoil. To calculate the time (''t'') to fully drain surface ponded water once filled to capacity:
To calculate the time (''t'') to fully drain surface ponded water once filled to capacity:
<math>t=\frac{d_{p}'}{f'}</math> <br>
<math>t=\frac{d_{p}'}{f'}</math> <br>
Where <br>
Where <br>
<math>t=\frac{n\times A_{r}}{f'\times x}ln\left [ \frac{\left (d_{r} + \frac{A_{r}}{x} \right)}{\left (\frac{A_{r}}{x}\right) }\right]</math>
<math>t=\frac{n\times A_{r}}{f'\times x}ln\left [ \frac{\left (d_{r} + \frac{A_{r}}{x} \right)}{\left (\frac{A_{r}}{x}\right) }\right]</math>
Where "ln" means natural logarithm of the term in square brackets <br>
Where "ln" means natural logarithm of the term in square brackets <br>
Adapted from CIRIA, The SUDS Manual C753 (2015).
Adapted from CIRIA, The SUDS Manual C753 (2015)<ref>Construction Industry Research and Information Association (CIRIA). 2015. The SUDS Manual C753. Accessed: 18 November 2021. https://www.ciria.org/CIRIA/Memberships/The_SuDs_Manual_C753_Chapters.aspx</ref>
[[category: modeling]]
[[category: modeling]]
[[category: infiltration]]
[[category: infiltration]]