Changes

Jump to navigation Jump to search
m
Line 13: Line 13:     
==Spacing drain pipe==
 
==Spacing drain pipe==
Laterals drains should be spaced between 3 - 4 m apart. <br>
+
Laterals drains should be spaced between 3 - 4 m apart.
 +
----
 
This is based on an analysis of Hooghoudt's equation<ref>H.P.Ritzema, 1994, Subsurface flow to drains. Chapter 8 in: H.P.Ritzema (ed.), Drainage Principles and Applications, Publ. 16, pp. 236-304, International Institute for Land Reclamation and Improvement (ILRI), Wageningen, The Netherlands. ISBN 90-70754-33-9</ref>:
 
This is based on an analysis of Hooghoudt's equation<ref>H.P.Ritzema, 1994, Subsurface flow to drains. Chapter 8 in: H.P.Ritzema (ed.), Drainage Principles and Applications, Publ. 16, pp. 236-304, International Institute for Land Reclamation and Improvement (ILRI), Wageningen, The Netherlands. ISBN 90-70754-33-9</ref>:
 
<math>Drain\ spacing=\sqrt{\frac{8K_{soil}H\left(D_{i}-D_{d}\right)\left(D_{d}-D_{w}\right)+4K_{soil}\left(D_{d}-D_{w}\right)^{2}}{q}}</math>
 
<math>Drain\ spacing=\sqrt{\frac{8K_{soil}H\left(D_{i}-D_{d}\right)\left(D_{d}-D_{w}\right)+4K_{soil}\left(D_{d}-D_{w}\right)^{2}}{q}}</math>
Line 23: Line 24:  
''D<sub>w</sub>'' is the minimum acceptable depth to the water table during infiltration
 
''D<sub>w</sub>'' is the minimum acceptable depth to the water table during infiltration
 
''q'' is the inflow volume expressed as a depth over the entire surface (m)
 
''q'' is the inflow volume expressed as a depth over the entire surface (m)
   
===Example===
 
===Example===
 
During a 25 mm storm event, a bioretention cell receives concentrated flow from a catchment 20 times larger than its own footprint (25 x 20 = 500 mm = 0.5 m).  
 
During a 25 mm storm event, a bioretention cell receives concentrated flow from a catchment 20 times larger than its own footprint (25 x 20 = 500 mm = 0.5 m).  
The bioretention cell comprises 0.6 m filter media laid over 0.6 m clear, coarse reservoir gravel. The pipes are laid within the reservoir, 0.9 m below the surface.  
+
The bioretention cell comprises 0.6 m filter media laid over 0.6 m clear, coarse reservoir gravel. The pipes are laid within the reservoir, 0.9 m below the surface:  
 
<math>Drain\ spacing=\sqrt{\frac{4\times 2.4m\left(0.9m-0.3m\right)^{2}}{0.5}}=3.4 m</math>
 
<math>Drain\ spacing=\sqrt{\frac{4\times 2.4m\left(0.9m-0.3m\right)^{2}}{0.5}}=3.4 m</math>
  
8,255

edits

Navigation menu