Adelaide
11.2 Entitled diversion of non-allocated surface water to urban water system

Supporting information

a. Entitled diversion of non-allocated surface water to urban water system

The volume reported (101,099 ML) was the volume of water harvested from runoff produced within the Adelaide region that supplied the region's urban water supply system in the 2011–12 year.

b. Urban water system overview

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

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

During the 2011–12 year, the majority (66%) of Adelaide's urban water was sourced from catchments within the region (line item 11.2). Imported River Murray (line item 11.9) water constituted approximately 31% of the urban water supply system's source water. Also, during the 2011–12 year, the Adelaide desalination plant commenced operating and made up the remaining 3% of Adelaide's urban water sources (line item 11.6).

Urban potable water consumption (line item 19.4) was 127,729 ML during the 2011–12 year, representing 84% of all outflows from the urban water supply system. A very small volume of water (2%) was transferred out of the region via normal operations in SA Water's service area (line item 19.11). Non-revenue water, including pipes bursting and background leakage (line item 19.3) and other losses (line item 19.20), made up the remaining urban water supply system outflows.

The following figure shows all the inflows and outflows for 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 for Adelaide's urban water supply system during the 2011–12 year; line item numbers are provided in brackets
Schematic diagram of water inflows and outflows for Adelaide's urban water supply system during the 2011–12 year; line item numbers are provided in brackets

Quantification approach

Data source

SA Water: Readings from either the Supervisory Control and Data Acquisition (SCADA) database or manual field instrument readings, stored in the MetDaily file.

Provided by

Bureau of Meteorology.

Method

The volume of water diverted to the urban water system from Adelaide's surface water (that was harvested from runoff within the region) was calculated by subtracting the volume of River Murray water transferred into the region's urban water system (line item 11.9 Delivery of water to urban water system under inter-region agreement) and the volume of desalinated water transferred from the Adelaide desalination plant (line item 11.6 Delivery of desalinated water to urban water system) from the total volume of inflows into the urban water system, as shown in the following table.


Volume of surface water diverted to the urban water system during the 2011–12

Calculation

Description

Volume (ML)

 

Total volume of inflows into the urban water system

152,392

less

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

47,477

less

11.6 Delivery of desalinated water to urban water system

3,816

 

11.2 Entitled diversion of non-allocated surface water to urban water system

101,099

As detailed in the following tables, the total volume of inflows into the Adelaide region's urban water system (152,392 ML) comprised of:

  • inflows into the regions' water treatment plants (148,915 ML); and
  • direct delivery to urban customers of potable water imported into the region (3,477 ML).
Inflows into the regions' water treatment plants (WTPs) during the 2011–12 year

Water treatment plant

Water source/reservoir

Quantification approach

Volume (ML)

Anstey Hill

Millbrook Tank

Metered inflow

27,439

Barossa

Barossa Reservoir

Metered outflow + 5%

15,030

Happy Valley

Happy Valley Reservoir

Metered inflow

61,070

Happy Valley

Adelaide desalination plant

Metered inflow

3,816

Hope Valley

Hope Valley Reservoir

Metered outflow + 5%

20,103

Little Para

Little Para Reservoir

Metered inflow

10,093

Myponga

Myponga Reservoir

Metered inflow

5,880

Summit Storage

Summit Reservoir

Metered inflow

5,484

Total

148,915

The inflows into the WTPs were either quantified as measured inflows into the WTPs or calculated from measured outflows from the WTPs by adding a 5% factor to account for process losses.

Potable water imported into the region was abstracted from the River Murray and treated in water treatment plants (WTPs) outside the region via the following routes:

  • the Swan Reach–Stockwell Pipeline (SRSPL) after treatment at the Swan Reach WTP
  • the Mount Pleasant WTP that received River Murray water from the Mannum–Adelaide Pipeline (MAPL).

Assumptions, limitations, caveats and approximations

This calculation method assumes the following:

Uncertainty information

The uncertainty estimate is not quantified.

Comparative year

This line item corresponds to line item 11.2 'Non-allocated diversions of surface water' reported in the 2011 Account.

In the 2011 Account, storages used for urban water supply only (located off-stream and which harvested only minimal catchment runoff) were reported at line item 3.1 'Urban water system'. These storages were Barossa Reservoir, Happy Valley Reservoir, Hope Valley Reservoir and Onkaparinga Summit Reservoir. As a consequence, the 2011 Account considered the inflows of water into these storages instead of inflows into the water treatment plants they supplied to quantify the total volume of inflows into the urban water system.

In the 2012 Account, these storages were reported at line item 1.1 Storages in order to be consistent with the classification of storages applied to the other regions of the National Water Account. Inflows into these storages were therefore replaced in the 2012 Account by inflows into the water treatment plants they supplied to quantify the total volume of inflows into the urban water system.

In the 2011 Account, an error was also made when quantifying line item 11.9 'Delivery of water to urban water system under inter-region agreement'.

The 2010–11 year volume of line item 11.2 'Entitled diversion of non-allocated surface water to urban water system' was restated from 120,014 ML in the 2011 Account to 92,965 ML in the 2012 Account to reflect this change of classification of the storages and to correct the quantification error made on line item 11.9. The following tables show how the restated volume was quantified.

Volume of surface water diverted to the urban water system during the 2010–11 year
Calculation

Description

Volume (ML)

  Total volume of inflows into the urban water system

141,264

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

48,299

  11.2 Entitled diversion of non-allocated surface water to urban water system

92,965

Line item 11.9 Delivery of water to urban water system under inter-region agreement was restated from 45,346 ML in the 2011 Account to 48,299 ML in the 2012 Account.

The total volume of inflows into the urban water system constitutes inflows into the water treatment plants and the import of potable water into the region.

 
Inflows into the regions' WTPs during the 2010–11 year
Water treatment plant

Water source - Reservoir

Quantification approach

Volume (ML)

Anstey Hill

Millbrook Tank

Metered inflow

23,039

Barossa Barossa Metered outflow + 5%

10,262

Happy Valley Happy Valley Metered inflow

63,714

Hope Valley Hope Valley Metered outflow + 5%

15,933

Little Para Little Para Metered inflow

14,310

Myponga Myponga Metered inflow

6,052

Summit Storage Summit Storage Metered inflow

4,875

Total

138,184

 

Volume of potable water imported for urban water supply during the 2010–11 year
Source

Volume (ML)

Swan Reach WTP via Swan Reach–Stockwell Pipeline

3,022

Mount Pleasant WTP via Mannum–Adelaide Pipeline

57

Total

3,079