Sydney
19.20 Other urban water decreases

Supporting Information

The total volume for this line item is 4,936 ML.

This volume calculated for this line item is Delta Electricity's total discharged metered volume of treated industrial wastewater (4,885 ML) from Wallerawang Power Station to the Coxs River (upstream of Lake Lyell) plus the calculated volume of non-revenue potable water (51 ML) from Shoalhaven City Council.

Quantification Approach

Delta Electricity

Data Source

Delta Electricity data spreadsheets.

Provided by

Delta Electricity.

Method

Ultrasonic flow meters were used to measure discharge from the power stations.

Assumptions, Limitations, Caveats and Approximations

Discharge from power stations flows to the Coxs River and its tributaries.

Uncertainty Information

The volume is based on measured data. Estimated uncertainty based on meter accuracy is +/– 2%. Meters are regularly calibrated. The NSW Office of Water conducts an annual verification review on Delta Electricity's water data.

Shoalhaven City Council

Data Source

NSW Office of Water calculations.

Provided by

Shoalhaven City Council.

Method

A leakage value is derived by a calculation of the total water treated less authorised potable supply (line item 19.4). The NSW Office of Water will make adjustments if the calculation produces a figure that is outside a specified percentage of total water supplied.

Assumptions, Limitations, Caveats and Approximations

Nil.

Uncertainty Information

Estimated uncertainty, based on meter accuracy and professional judgment on determination of boundaries of water supply areas beyond the Sydney region, is +/– 5%.

Comparative year

The following table compares the value at 30 June 2010 reported in this account with the corresponding value reported in the 2010 Account.

 

Comparative year information from the 2010 Account for line item 19.20

2011 Account line item

2010 Account line item

Value reported in the 2010 Account (ML)

Value reported in the 2011 Account (ML)

Additional information

19.20 Other urban water decreases

13.7.3 Discharge after use of water diverted by industries

6,160

6,160

Change in line item name