Murray–Darling Basin
9.9 Discharge from urban water system

Supporting information

The volumetric value for the line item for the 2011–12 year was 34,325 ML. The volume represents treated urban wastewater discharge to surface water within ACT and Murrumbidgee NSW surface water resource plan areas. Information from other urban water systems, particularly within the Northern Basin, was not available. The line item value splits as follows:

  • Lower Molonglo water quality control centre: 31,255 ML
  • Uriarra wastewater treatment plant: 9 ML
  • Queanbeyan wastewater treatment plant: 3,061 ML

When there is storage capacity, water diverted from the rivers is treated at Mount Stromlo water treatment plant and then transferred to Googong Reservoir via the water reticulation network. This transfer volume is not included in this line item value because this volume has already been accounted in line item 9.4 Runoff to surface water. Transfer volume reported for 2011–12 year was zero.

Quantification approach

Data source

ACTEW Water: data warehouse; and Queanbeyan City Council: database.

Provided by

ACTEW Water and Queanbeyan City Council.


Treated wastewater discharged to the surface water store was measured at wastewater treatment plant outflow flow meters.

Assumptions, limitations, caveats and approximations


Uncertainty information

Volumes were derived from measured data. Estimated uncertainty is +/– 5%.