View source for Template:Drainage variants reference

A Drainage can be a(n):
* [[Drainage (Water Overlay)#Passive Drainage|Passive Drainage]] lets water flow from the drainage pipes into the waterway.
* [[Drainage (Water Overlay)#Active Drainage Negative Q|Active Drainage with a negative Q]] can pump water from from the waterway (with a lower level) into the drainage pipes. 
* [[Drainage (Water Overlay)#Active Drainage Positive Q|Active Drainage with a positive Q]] can pump water from the drainage pipes up into a waterway (with a higher level).