11.9 Delivery of water to urban water system under inter-region agreement
The volume reported (45,346 ML) was the volume of water transferred into the Adelaide region under the Class 6 water access entitlement to River Murray water. This included non-potable and potable transfers as described in the following table.
|Murray Bridge–Onkaparinga Pipeline||Pipeline releases – metered flow||18,502|
|Mannum–Adelaide Pipeline||Pipeline releases – metered flow||23,761|
|Swan Reach–Stockwell Pipeline||Pipeline releases – metered flow||4|
|Swan Reach WTP via Swan Reach–Stockwell Pipeline||Potable consumption||3,022|
|Mount Pleasant WTP via Mannum–Adelaide Pipeline||Potable consumption||57|
WTP = Water treatment plant
River Murray water abstracted under the entitlement is provided to users via the Swan Reach and Mt Pleasant WTPs.
- The Mt Pleasant WTP is located just outside the Adelaide region boundary and received River Murray water from the Mannum–Adelaide Pipeline. Water treated at Mt Pleasant WTP services users both inside and outside the Adelaide region. Water servicing users within the Adelaide region is reported as water abstracted under the entitlement.
- The Swan Reach WTP treats all River Murray water abstracted via the Swan Reach–Stockwell Pipeline and is located to the northeast of the Adelaide region. Following treatment at the Swan Reach WTP, potable water is transferred by the pipeline to supply the Barossa Valley, Lower North and Yorke Peninsula. A second pipeline diverts water from the Swan Reach–Stockwell Pipeline south to users in the Adelaide region.
The total volume of water abstracted from the River Murray under the entitlement in 2010–11 was 56,463 ML as reported in the 2010–11 Water Audit Monitoring Report. Therefore, 11,090 ML (19.7%) of water abstracted under the entitlement was not delivered to and used in the Adelaide region.
More information on the entitlement can be found at line item 3.4 Urban inter-region claim on water.
Pipeline releases – metered flow
Non-potable water transfers through the Murray Bridge–Onkaparinga Pipeline and the Mannum–Adelaide Pipeline were metered with a flow gauge.
Potable water transfers (non-consumption) through the Swan Reach–Stockwell Pipeline were measured by the metered flow of discharge from the pipeline to the South Para River.
Metered flows for the 2010–11 year were extracted from the SA Water's SCADA database and/or MetDaily file.
Assumptions, Limitations, Caveats and Approximations
- The inter-region claim to River Murray water is held on behalf of the Adelaide region. However, there is offtake from the three pipelines before entering the Adelaide region. Therefore the volume reported underestimates the actual volume of water diverted from the River Murray under the inter-region claim.
- The volume reported for delivery from the Swan Reach–Stockwell Pipeline was the volume subsequently discharged to surface water. For clarity, this flow is represented as an urban water inflow from outside the region. The flow from the urban water system to surface water store is not reported in the statements, but disclosed in the notes.
Potable water consumption
The volume of River Murray water transferred into the Adelaide region from the Swan Reach–Stockwell Pipeline is not metered a the point it enters the region, therefore potable consumption data were used to measure this volume. Similarly, potable consumption data were also used to measure the volume of River Murray transferred into the region folllowing treatment at Mt Pleasant WTP.
A shapefile of the Adelaide region was used to extract the service point numbers (SPNs) of meters within the Adelaide region from the SA Water GIS database. Only meters that were supplied with potable water from the Swan Reach and Mt Pleasant WTPs were considered. The SPNs were then used to extract water meter readings for the 2010–11 reporting period for individual water meters from the SA Water CSIS database.
Water consumption was calculated by analysing the difference between consecutive meter readings and summed for 2010–11. To account for meter readings that occurred immediately before or after 2010–11, metered consumption was apportioned based on the following equation:
Vr = ( tr / tm ) × Vm
Vr = volume for metered period within 2010–11 (kL)
tm = length of period between meter readings (days)
tr = length of metered period within 2010–11 (days)
Vm = volume for metered period (kL).
Assumptions, Limitations, Caveats and Approximations
Both the Mt Pleasant and Swan Reach WTPs supply water to users outside the region. Therefore the volume reported underestimates the total volume of water abstracted from the River Murray under the entitlement.
This item corresponds to line item 13.6.5 Other lumped delivery of water transferred-in to connected surface water reported in the 2010 Account. In the 2011 Account the following changes were made that caused the 2009–10 year value to be restated:
- In the 2010 Account the Class 6 water access entitlement for River Murray water (the entitlement) was reported as an inter-region claim held by the Adelaide region's surface water store. However, in the 2011 Account the entitlement was reported as a claim held on behalf of the Adelaide region's urban water system. This change was made because River Murray water abstracted under the entitlement is transferred directly into the Adelaide urban water system (although there is some subsequent discharge to surface water). Thus, representing the entitlement as a claim held by the urban water system provides clearer information for the user. This change did not affect the volume reported.
- In the 2011 Account the volume of water that was actually delivered to the Adelaide region was reported instead of the volume that was abstracted under the entitlement (as reported in the 2010 Account) to provide better information to users. If the latter (volume of water abstracted under the entitlement) was reported this would overestimate the volume of River Murray water used to supply the Adelaide region's urban water system. This change resulted in a decrease (3,979 ML) in the volume reported for 30 June 2010.
These changes and their respective volumes are detailed in the following table. The restated comparative year volume is 52,991 ML.
|2010 Account line item name||Source||Volume at 30 June 2010 reported in 2010 Account (ML)||Change from the 2010 Account to the 2011 Account due to change in methodology (ML)||Volume at 30 June 2010 reported in 2011 Account (ML)|
|13.6.5 Other lumped delivery of water transferred-in to connected surface water||Murray Bridge Onkaparinga Pipeline||56,970||(3,979)||22,683|
|Swan Reach–Stockwell Pipeline||264|
|Swan Reach WTP via Swan Reach–Stockwell Pipeline||3,664|
|Mount Pleasant WTP via Mannum-Adelaide Pipeline||66|