South East Queensland
11.2 Non-allocated diversion of surface water

Supporting Information

This line item consists of diversions from surface water based on unsupplemented entitlements held by urban utilities and the South East Queensland (SEQ) Water Grid Manager. These diversions may be to Water Treatment Plants (WTPs) that supply the SEQ Water Grid or are off-grid.

Urban unsupplemented diversions from surface water
Water resource plan (WRP) area SEQ Water Grid Water treatment plant Volume
Gold Coast Total Gold Coast WRP area 0
Logan Basin On-grid Capalaba  3,851
Off-grid Canungra  73
Total Logan Basin WRP area 3,924
Moreton On-grid Caboolture  1,361
Enoggera  0
Off-grid Blackbutt & Bernarkin 72
Lockyer 1,900
Preston 3
Somerset Dam Recreation 0
Warrill View 112
Yarraman 86
Total Moreton WRP area 3,534
Total SEQ  region 7,458

Quantification Approach

Data Source

Queensland Department of Environment and Resource Management (DERM) WTP diversion or outflow data from Scenic Rim, Toowoomba and South Burnett Regional Councils and Queensland Urban Utilities. Queensland Water Commission (QWC) Water Hub WTP outflow data. Seqwater supplemented / unsupplemented WTP list.

Provided by

Bureau of Meteorology.


Metered diversion to WTP or output from WTP data were obtained from various regional councils and QWC. Where available diversion data were used in preference to WTP output data. WTPs were selected where the source was surface water and the entitlement was unsupplemented. WTP were then separated in to the water resource plan (WRP) areas and on-grid (form part of the SEQ Water Grid) and off-grid.

Assumptions, Limitations, Caveats and Approximations

Communities with a population of less than 50 were not captured and reported. Off-grid communities within the Gold Coast WRP area were therefore not captured.

As WTP data were compiled from several sources, there were some instances where data were conflicting. In these instances the WTP output was reported as the diversion where this was larger than the diversion values obtained from DERM. This may have resulted in a misrepresentation of unsupplemented WTP diversions, but is expected not to be material to the account.

Uncertainty Information

The uncertainty estimate was not quantified.

Comparative year

This line item corresponds to line item 19.3.1 Unregulated inflow of surface water into the urban water supply system reported in the 2010 Account. The provision of data on which WTP utilised supplemented and unsupplemented entitlements was obtained for the 2011 Account from Seqwater. This showed that the entitlement type has no direct linkage to the WTP forming part of the SEQ Water Grid and identified a number of WTP listed as supplemented that were in fact unsupplemented (and vice versa). In addition to this, data for a number of WTP was not available for the 2010 Account but were available for 2011 Account.

This has resulted in the numbers between the two years not being comparable due to additional WTP data, and a reallocation of WTP between this line item and line item 11.12 Allocation diversion of surface water to urban water system. As data were not available to completely rectify the volumes presented in the 2010 Account, the 2011 Account comparison year used the data reported in the 2010 Account (18,258 ML) and it is noted that direct comparisons should not be made between the volumes.