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Line 43: − ==To calculate the required depth, where the area of the facility is constrained (1D)== − <math>d=\frac{D\left[\left( \frac{I}{P} \right )i-q \right]}{n}</math> Line 57:
Line 55: − + − (The rearrangement to calculate the required footprint area of the facility for a given depth is not available at this time. Elegant submissions are invited.) + − + + + Line 69:
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Infiltration: Sizing and modeling (view source)
Revision as of 02:13, 12 September 2017
, 6 years agono edit summary
{{Clickable button|[[Media:Infiltration Sizing.xlsx|Download .xlsx calculation tool]]}}
{{Clickable button|[[Media:Infiltration Sizing.xlsx|Download .xlsx calculation tool]]}}
==To calculate required depth (3D)==
==To calculate required depth (3D)==
[[file:Hydraulic radius.png|thumb|Three footprint areas of 9 m<sup>2</sup>.<br>
[[file:Hydraulic radius.png|thumb|Three footprint areas of 9 m<sup>2</sup>.<br>
and
and
<math>b=\frac{xq}{nP}</math>
<math>b=\frac{xq}{nP}</math>
==To calculate the required depth, where the area of the facility is constrained (1D)==
<math>d=\frac{D\left[\left( \frac{I}{P} \right )i-q \right]}{n}</math>
==To calculate the require facility area or footprint where the depth is constrained (1D)==
==To calculate the require facility area or footprint where the depth is constrained (1D)==
<math>P=\frac{IiD}{nd+qD}</math>
<math>P=\frac{IiD}{nd+qD}</math>
==Infiltration of surface ponding time==
(The rearrangement to calculate the required footprint area of the facility for a given depth using three dimensions of underground infiltration is not available at this time. Elegant submissions are invited.)
==Time for infiltration of surface ponded water==
The following equation assumes that infiltration occurs primarily through the footprint of the facility.
The following equation assumes that infiltration occurs primarily through the footprint of the facility.
It is best applied to calculate the limited duration ponding on the surface of [[bioretention cells]], [[bioswales]] and [[enhanced grass swales]].
It is best applied to calculate the limited duration ponding on the surface of [[bioretention cells]], [[bioswales]] and [[enhanced grass swales]].
<math>t=\frac{nd}{K}</math>
<math>t=\frac{nd}{K}</math>
==Drawdown time to empty facility==
==Drawdown time==
The design of infiltration facilities should be checked for [[drawdown time]]. The target drawdown time for the internal storage of an infiltration facility is between 48-72 hours. <br>
The design of infiltration facilities should be checked for [[drawdown time]]. The target drawdown time for the internal storage of an infiltration facility is between 48-72 hours. <br>
To calculate the time (''t'') to fully drain the facility:
To calculate the time (''t'') to fully drain the facility: