Changes

Jump to navigation Jump to search
Line 86: Line 86:  
It is best applied to calculate the maximum duration of ponding on the surface of [[bioretention cells]], and upstream of the [[check dams]] of [[bioswales]] and [[enhanced grass swales]] to ensure all surface ponding drains within 48 hours.  
 
It is best applied to calculate the maximum duration of ponding on the surface of [[bioretention cells]], and upstream of the [[check dams]] of [[bioswales]] and [[enhanced grass swales]] to ensure all surface ponding drains within 48 hours.  
 
To calculate the time (''t'') to fully drain surface ponded water through the filter media or planting soil:  
 
To calculate the time (''t'') to fully drain surface ponded water through the filter media or planting soil:  
<math>t=\frac{dp'}{K_{f}}</math>
+
<math>t=\frac{d_{p}'}{K_{f}}</math>
 
Where <br>  
 
Where <br>  
 
d<sub>p</sub>' is the effective or mean surface ponding depth (mm).<br>
 
d<sub>p</sub>' is the effective or mean surface ponding depth (mm).<br>
Line 104: Line 104:  
<br>
 
<br>
 
To calculate the time (''t'') to fully drain the facility assuming three-dimensional drainage:  
 
To calculate the time (''t'') to fully drain the facility assuming three-dimensional drainage:  
<math>t=\frac{nAr}{f'x}ln\left [ \frac{\left (d+ \frac{Ar}{x} \right )}{\left(\frac{Ar}{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).

Navigation menu