Melbourne
19.5 Urban water discharge to surface water

Supporting Information

The volume presented (15,390 ML) represents the total volume of wastewater discharged to surface water from South East Water's sewage treatment plants (STPs), Western Water's recycling water plants (RWP) and Yarra Valley Water's local treatment plants (LTPs).

The breakdown of wastewater discharge to surface water in the Melbourne region during 2010–11 is presented in the following table.

Wastewater discharge
Authority Discharge location Volume (ML)
South East Water Pakenham STP to Deep Creek 2,402
Koo Wee Rup STP to Yallock Creek 198
Lang Lang STP to Adams Creek 18
Longwarry STP to King Parrot Creek 184
Subtotal for South East Water 2,802
Western Water Bacchus Marsh RWP to Land lot/Lagoon 144
Gisborne RWP to Jacksons Creek 352
Melton RWP to Werribee River 926
Riddells Creek RWP to Bolinda Creek 256
Romsey RWP to Deep Creek 308
Sunbury RWP to Jacksons Creek 1,760
Subtotal for Western Water 3,746
Yarra Valley Water Brushy Creek LTP to Brushy Creek 3,903
Craigieburn LTP to Merri Creek 1,051
Healesville LTP to Yarra River 333
Upper Yarra LTP to Yarra River 884
Lilydale LTP to Olinda Creek 2,351
Monbulk LTP to Sassafras Creek 21
Wallan LTP to Merri Creek 299
Subtotal for Yarra Valley Water 8,842
Total
 15,390

Quantification Approach

South East Water

Data Source

South East Water.

Provided by

South East Water.

Method

This item represents the daily metered volume of treated wastewater discharged to Deep Creek, Adams Creek, Parrot Creek and Yallock Creek. 

Assumptions, Limitations, Caveats and Approximations

Assumes meters and readings are accurate.

Uncertainty Information

Uncertainty is estimated to be +/– 5% based on meter specifications.

Western Water

Data Source

Western Water: plant data.

Provided by

Western Water.

Method

This item represents the metered volume of treated wastewater discharged to surface water from Western Water's wastewater/recycled water treatment plants in the Melbourne region (i.e excluding discharge at Woodend Recycled Water Treatment Plant to Five Mile Creek). Meters are located at the outlet of the treatment plants and are read daily by the treatment plant operators. 

Assumptions, Limitations, Caveats and Approximations

Nil.

Uncertainty Information

+/– 5% in accordance with Summary Audit Report, October 2010 (Essential Services Commission 2010).

Yarra Valley Water

Data Source

Yarra Valley Water local treatment plants flow database: LTPFLOW.

Provided by

Yarra Valley Water.

Method

This item represents the metered volume of treated wastewater discharged from Yarra Valley Water local treatment plants to surface water. Meters at local treatment plants are read daily.

Assumptions, Limitations, Caveats and Approximations

Nil.

Uncertainty Information

Uncertainty is estimated to be +/– 5% based on meter specifications.

Comparative year

This item corresponds to line items 20.4.1 Discharge of urban wastewater to connected surface water and 20.5.1 Urban recycled water discharge to connected surface water reported in the 2010 Account. In the 2011 Account, the presentation of these line items has changed as they have been merged into one line item: 19.5 Urban water discharge to surface water.

The comparative year volume is 25,262 ML and is the sum of volumes reported at line items 20.4.1 (8,063 ML) and 13.7.2 (17,199 ML).