Sydney
11.9 Delivery of water to urban water system under inter-region agreement

Supporting information

a. Urban water supply system overview

The urban water supply system is one of three subcomponents of Sydney's urban water system. The three subcomponents are the:

  • urban water supply system
  • wastewater system
  • recycled water system.

In the 2012–13 year, all water supplied to the urban water supply system was sourced from surface water (11.12 Allocation diversion of surface water to urban water system) with a small volume of 596 ML sourced from the Fish River Water Supply Scheme by Lithgow City Council (11.9 Delivery of water to urban water system under inter-region agreement). Sydney Water Corporation in the past has also sourced water from desalinated water (11.6 Delivery of desalinated water to urban water system); however, no desalinated water was reported this year.

Potable and nonpotable urban water consumption (part of 19.4 Delivery to urban water system users) was 472,541 ML during the 2012–13 year, representing 88% of all urban water supply system outflows.The remaining outflows are reported as being lost through leakage (19.3 Leakage to groundwater) as well as other operational losses (19.20 Other urban water decreases), and a small volume was exported outside the region (19.11 Transfer of water outside of region).

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 2012–13 year for Sydney's urban water supply system; line item numbers are provided in brackets
Schematic diagram of water inflows and outflows during the 2012–13 year for Sydney's urban water supply system; line item numbers are provided in brackets

Supporting information

The volume of 596 ML stated in this line item represents the diversion made by Lithgow City Council from the Fish River Water Supply Scheme. Further details of the Fish River Water Supply Scheme are available under line item 3.4 Urban inter-region claim on water.

Quantification approach

Data source

Lithgow City Council spreadsheets; New South Wales Office of Water Fish River Water Supply Scheme Weekly Use Report 2012–13.

Provided by

Lithgow City Council; New South Wales Office of Water.

Method

The metered supply volume is based on flow measurements by New South Wales State Water Corporation using ABB magflow meters.

Assumptions, limitations, caveats and approximations

Nil.

Uncertainty information

The volume is based on measured data. Estimated uncertainty based on meter accuracy is +/–2%.

Comparative year

In previous accounts, the volume diverted by Lithgow City Council was included in 9.11 Delivery of water under inter-region agreement. As Lithgow City Council is considered an urban water supplier, line items attributed to them have been moved to the urban water store.

Therefore the volume reported in the 2011–12 year has been restated as 17 ML, which is equal to the diversions made by Lithgow City Council in that year.