South East Queensland
3.1 Urban water supply system

The volumetric value for the line item at the end of the 2012–13 year was 3,727 ML.

This line item represents the volume of water held within potable water supply pipes and tanks (balancing reservoirs) by urban utilities within the South East Queensland (SEQ) region. Urban utilities included under this line item are: Seqwater, Queensland Urban Utilities (QUU), Council of the City of Gold Coast, Logan City Council, Redland City Council, Unitywater, and Toowoomba Regional Council.

The potable water supply system consists of large diameter bulk transmission mains that transport potable water from the water treatment plant to key water tanks and distribution points within the urban potable water supply system. Smaller distribution mains distribute water to end users from these tanks and distribution points. Seqwater manages large diameter bulk transmission mains and the three urban retailers manage distribution mains.

The volume of water within pipes and tanks can be seen in the following table.

Table Notes:

1. QUU previously (2011-12) reported 332 ML for pipe volume, however this was readjusted in 2012/13 to 1182 ML. QUU engineer believes the 332ML volume may just include trunk volumes that feed the reservoir whereas 1,182 ML volume includes all pipes owned by QUU.

2. Toowoomba Regional Council reported that there are two tanks at Crow's Nest and Yarraman within the SEQ region having a total capacity of 2.4 ML and the pipe length of 58 km having diameters  of 100–150 mm. Assuming average cross section area, the capacity of the pipes was 0.71 ML.

3. Where data were not available this has been represented with a dash (–).

Although data were not available for various components, some additional information was provided on these water assets:

• The total length of potable water supply pipes (including bulk suppliers and retailers) in the SEQ region is approximately 14,837 km.

Seqwater: pipe volumes; Queensland Urban Utilities (QUU): pipe and tank volumes; Council of the City of Gold Coast: pipe and tank volumes; Logan City Council: tank volume; Redland City Council; pipe and tank volumes; Unitywater; pipe and tank volumes; Toowoomba Regional Council; pipe and tank volumes.

Seqwater, QUU, Council of the City of Gold Coast, Logan City Council, Redland City Council, Unitywater, Toowoomba Regional Council.

The volumes of water in the pipes and tanks were obtained from Seqwater, QUU, Council of the City of Gold Coast, Logan City Council, Redland City Council, Unitywater, Toowoomba Regional Council.

Due to lack of availability of actual storage volumes on 30 June 2013, the entire capacity for each tank and water main for the utilities in the South East Queensland (SEQ) region was included for this line item as the volume; however, QUU have incuded all the pipes owned by the QUU. The pipe volumes for the portion of Toowoomba Regional Council within SEQ region was approximated using average pipe capacity.

The uncertainty estimate was not quantified.