3.2 Wastewater system

Supporting information

The volume reported (96 ML) includes water held in the wastewater pipes system owned by SA Water, but does not include wastewater treatment lagoons. There was little new wastewater pipe construction in the 2011–12 year. The volumes of water held in the wastewater collection system, itemised by gravity-fed and pumping pipes, are presented in the following table.

Wastewater collection system volumes at the start and end of the 2011–12 year
Wastewater system Storage volume at 30 June 2012 (ML)
Storage volume at 30 June 2012 (ML)
Wastewater pipes—gravity 64 63
Wastewater pipes—pumping 32 32
Total 96 95

Quantification approach

Data source

Geographic Information System (GIS) database, Maximo system.

Provided by

SA Water.


GIS analysis was used to identify wastewater pipes within the Adelaide region. The volume of water held in these pipes was estimated from their total capacity. 

The volumes of water held in pipes were estimated from pipe lengths and nominal diameters (stored in the Maximo system) using the following formula:

π x (D/2) x (D/2) x PL

D = Nominal diameter of the pipe

PL = Pipe length.

Assumptions, limitations, caveats and approximations

  • The volume in gravity and pumping wastewater pipes is assumed to be 20% and 100% of capacity, respectively.
  • Pipes without recorded construction dates are assumed to have been constructed before the 2011–12 year.
  • Nominal diameters of pipes were used for the calculation of volumes.
  • The volume reported does not include volumes of water held within wastewater lagoons.

Uncertainty information

The uncertainty estimate is not quantified.

Comparative year

This line item corresponds to line item 3.2 'Wastewater collection system' reported in the 2011 Account.