Canberra
9.9 Discharge from urban water system

The volume reported in the water accounting statements (34,325 ML) represents the total volume of water discharged from the urban water system to surface water within the Canberra region during the 2011–12 year. In Canberra, it is through the discharge to surface water from the wastewater system.

This line item is made up of several components. When capacity at Googong Reservoir becomes available, treated water is transferred from Mount Stromlo water treatment plant (WTP) into Googong Reservoir via the water reticulation network. In addition to this there are two wastewater treatment plants (WWTPs) within the Canberra region that discharge treated water into the Molonglo River: the Lower Molonglo Water Quality Control Centre (LMWQCC) upstream from the confluence with the Murrumbidgee, and the Queanbeyan wastewater treatment plant upstream of Lake Burley Griffin and Uriarra WWTP.

The table below provides a breakdown of the volume of water discharged to surface water at each wastewater treatment plant and the volume of water transferred to the Googong reservoir.

Volume of treated water discharged to surface water in the Canberra region

	Plant	Volume treated (ML)
Non Potable	Lower Molonglo Water Quality Control Centre	31,255
	Uriarra WWTP	9
	Queanbeyan WWTP	3,061
	Subtotal	34,325
Potable	Mount Stromlo WTP	0
	Subtotal	0
Total		34,325

The table above provides a breakdown of the volume of wastewater discharge to surface water at each WWTP in the Canberra region for the 2011–12 reporting period. Only the LMWQCC, Uriarra WWTP and the Queanbeyan WWTP discharge treated wastewater to the surface water store. The volume reported for LMWQCC includes 670 ML which spilled from storage dams prior to treatment in the 2011–12 year.

Under the urban water utility water access entitlement, ACTEW abstracts water from the regulated storages of Bendora and Cotter reservoirs, and the unregulated system of the Murrumbidgee River and transfers this water to Mount Stromlo WTP. If capacity is available, it is also possible to transfer treated water from Mount Stromlo WTP into Googong Reservoir via the water reticulation network.

Water Data Warehouse.

ACTEW Water.

ACTEW Water's flow meter measures the release from the water distribution system to Googong Reservoir.

Nil.

Derived from measured data. Estimated uncertainty is +/– 5%.

 

Water Data Warehouse.

ACTEW Water.

ACTEW Water's flow meter measures the release from the water distribution system to Googong Reservoir.

Nil.

Derived from measured data. Estimated uncertainty is +/– 5%.

Database.

QCC.

Treated wastewater discharged to the surface water store was measured by WWTP outflow flow meters. The 2011–12 discharge volume was extracted from the QCC database. The Queanbeyan WWTP is the only QCC WWTP that discharges treated wastewater to the surface water store.

Nil.

Derived from measured data. Estimated uncertainty is +/– 5%.