Thanks to SaveH2O, of Supadiverta
This diagram indicates a charged drainage system. These are sometimes called either a “wet” or a “pressure” system.
With this type of system a section of the pipe always remains full unlike a Conventional System.
As the pipes are under pressure it is essential all the joints in above ground and underground pipework are fully watertight
- A neater appearance than having pipes above ground.
- Allows you to discharge water at a height above the ground level at the down pipe.
- It is more likely to block as the flow through the pipes can be fairly slow and the low points can collect silt. Silt will get deposited at flow rates below 0.6m/sec which will be the situation for most rainfall events.
- It is also more difficult to unblock.
- Can cost more with excavation and additional inspection fittings .
- Potential for mosquito breeding in water unless appropriate screes are installed.
Also see Underground Pipes