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[[file:Hydraulic radius.png|thumb|Three footprint areas of 9 m<sup>2</sup>.<br>From left to right x = 12 m, x = 14 m, and x = 16 m]]For some geometries (e.g. particularly deep facilities or linear facilities), it may be preferred to also account for lateral infiltration. The 3 dimensional equations make use of the hydraulic radius (''P''/''x''), where ''x'' is the perimeter (m) of the facility. <br>Maximizing the perimeter of the facility directs designers towards longer, linear shapes such as [[infiltration trenches]] and [[bioswales]]. Line 70:
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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>
Infiltration: Sizing and modeling (view source)
Revision as of 02:17, 12 September 2017
, 7 years agono edit summary
==To calculate the required depth, where the area of the facility is constrained (3D)==
==To calculate the required depth, where the area of the facility is constrained (3D)==
To calculate the required depth:
To calculate the required depth:
:<math>d=a[e^{\left ( -bD \right )} -1]</math>
:<math>d=a[e^{\left ( -bD \right )} -1]</math>
==Drawdown time to empty facility==
==Drawdown time to empty facility==
[[file:Hydraulic radius.png|thumb|Three footprint areas of 9 m<sup>2</sup>.<br>
From left to right x = 12 m, x = 14 m, and x = 16 m]]
The target [[drawdown time]] for the internal storage of an infiltration facility is between 48-72 hours. <br>
For some geometries (e.g. particularly deep facilities or linear facilities), it preferable to account for lateral infiltration.
The 3D equation make use of the hydraulic radius (''P''/''x''), where ''x'' is the perimeter (m) of the facility. <br>
'''Maximizing the perimeter of the facility directs designers towards longer, linear shapes such as [[infiltration trenches]] and [[bioswales]].'''
To calculate the time (''t'') to fully drain the facility:
To calculate the time (''t'') to fully drain the facility:
<math>t=\frac{nP}{qx}ln\left [ \frac{\left (d+ \frac{P}{x} \right )}{\left(\frac{P}{x}\right)}\right]</math>
<math>t=\frac{nP}{qx}ln\left [ \frac{\left (d+ \frac{P}{x} \right )}{\left(\frac{P}{x}\right)}\right]</math>