Canberra
19.3 Leakage to groundwater

The urban water supply system is one of three sub-components of Canberra's urban water system.  The three sub-components are the:

• Urban water supply system
• Wastewater system
• Recycled water system.

Surface water (11.12) is the main source of water for Canberra's urban water supply system.

Urban water consumption (part of 19.4) was 38,852 ML during the 2011–12 year, representing 93% of all urban water supply system outflows. The remaining urban water was lost through operational losses.

The following figure shows all the inflows and outflows associated with the urban water supply system. For more detail on a particular flow associated with the urban water supply system, refer to the line item notes.

Schematic diagram of water inflows and outflows during the 2011–12 year for Canberra's urban water supply system. Line item numbers are provided in brackets.

This line item volume (2,906 ML) represents the total leakage from the urban supply system to the groundwater system. These losses include leakage from pipes, service reservoirs and service connections prior to the customer water meters.

The ACTEW Water's real losses were calculated in line with the Water Services Association of Australia (WSSA) National Performance Framework. The real losses from the distribution system is the difference between the system input volume (SIV) and the total of the billed water exported (supplied to Queanbeyan), billed metered consumption, billed unmetered consumption, unbilled metered consumption, unbilled unmetered consumption, unauthorised consumption and customer meter under-registration.

• Losses from the water distribution system store cannot be distinguished between leakage to groundwater and leakage to landscape, and therefore a combined estimate is provided.
• Background losses from the potable water supply system include losses from ongoing leakage, pipe bursts and other components.

The uncertainty estimate was not quantified.

The 2011–12 leakage from Queanbeyan potable water supply system was calculated from the estimated leakage from water network. This is calculated by using the difference between what QCC purchases from ACTEW and what QCC sells to its customers.

• Losses from the water distribution system store cannot be distinguished between leakage to groundwater and leakage to landscape, and therefore a combined estimate is provided.
• Background losses from the potable water supply system include losses from ongoing leakage, pipe bursts and other components.

The uncertainty estimate was not quantified.