Part 4 – Stormwater Drainage

4.10    The Hydraulic Design of Pipelines

The hydraulic capacity of stormwater pipelines shall be sufficient to convey the design flow as determined by the procedure outlined in Section 4.8.1

All pipes shall be of adequate size to carry the designed flow without surcharge.

The design shall provide that:

• No stormwater pipeline, other than connections to individual lots, shall be less than 300mm diameter pipes.  This will be dependent on pipe hydraulic design.
• All public stormwater pipes shall be adequate for all potential loadings and proposed construction methods based on pipe location and depth. The preferred method of demonstrating the pipe strength grade is a software printout from the Concrete Pipe Association of Australasia for Concrete Pipes.  For other accepted pipe materials the relevant manufacturer’s strength recommendations shall be provided with the pipe design.
• Catch pit outlets (leads) shall not be less than 200 mm diameter and shall be of sufficient strength dependent on the proposed location and potential loadings. The minimum velocity for pipes flowing full shall be 0.7 m/s.
• The maximum velocity for pipe flow shall be 4.0 m/s.

Special measures to dissipate energy shall be designed at all outfalls to natural and constructed receiving waterways.