11.9 Delivery of water to urban water system under inter-region agreement
a. Delivery of water to urban water system under inter-region agreement
The volume reported (68,420 ML) was the volume of water imported into the Adelaide region during the 2012–13 year under SA Water's Class 6 water access entitlement (WAE) to River Murray water. This included non-potable and potable transfers as described in the following table.
|Imported water||Source||Quantification||Volume (ML)|
|non-potable||Murray Bridge–Onkaparinga Pipeline||pipeline releases—metered flow||25,094|
|Mannum–Adelaide Pipeline||pipeline releases—metered flow||36,547|
|potable||Swan Reach–Stockwell Pipeline||pipeline releases—metered flow||2,423|
|Swan Reach Water Treatment Plant (WTP) via Swan Reach–Stockwell Pipeline||consumption||4,283|
|Mount Pleasant WTP sourced from Mannum–Adelaide Pipeline||consumption||73|
The volume reported was different from the total volume of water abstracted from the River Murray (81,673 ML) under the Class 6 WAE during the 2012–13 year, due to off-takes of water to users located outside the Adelaide region, transfer losses and quantification errors. The volume of water abstracted from the River Murray under Class 6 WAE was sourced from the Department of Environment, Water and Natural Resources Water Information and Licence Management Administration database.
Potable 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. Potable 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 branching from the Swan Reach–Stockwell Pipeline discharges into the South Para River upstream of the South Para Reservoir, where water is stored to supply the Barossa WTP. From that second pipeline, water can also be transferred to the Barossa Infrastructure Limited irrigation scheme in case of need.
More information on the entitlement can be found at line item 3.4 Urban inter-region claim on water.
b. Urban water system overview
The urban water supply system is one of three subcomponents of Adelaide's urban water system. The three subcomponents are the:
- urban water supply system
- wastewater system
- recycled water system.
During the 2012–13 year, Adelaide's urban water supply system relied on three important water sources. Imported River Murray water (line item 11.9 Delivery of water to urban water system under inter-region agreement) and surface water harvested from catchments within the Adelaide region (line item 11.12 Entitled diversion of allocated surface water to urban water system) made up the majority of the water sourced for urban supply; 42% and 35% respectively. Desalinated water (line item 11.6 Delivery of desalinated water to urban water system) made up the remaining 23% of inflows to the urban water supply system in the Adelaide region.
Potable water consumption within the region (line item 19.4 Delivery to urban water system users) was 137,028 ML during the 2012–13 year, representing 86% of all outflows from the urban water supply system. Smaller volumes of potable water were discharged to South Para Reservoir (line item 19.5 Discharge from urban water system to surface water: 2% of outflows) and transferred out of the region via normal operations in SA Water's service area (line item 19.11 Transfer of water outside region: 3% of outflows). Leakage from the water mains (line item 19.3 urban water system leakage to groundwater: 10%) 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. A misbalance of 2,140 ML or 1.3% was calculated for the urban water supply system. This misbalance may be due to a number of factors such as metering inaccuracies, unaccounted losses and inaccuracies in the estimation of certain volumes.
Schematic diagram of water inflows and outflows for Adelaide's urban water supply system during the 2012–13 year; line item numbers are provided in brackets
Pipeline releases—metered flow
Supervisory Control and Data Acquisition (SCADA) database or manual field instrument readings, stored in the MetDaily file.
Metered flows for non-potable water transfers through the Murray Bridge–Onkaparinga Pipeline and the Mannum–Adelaide Pipeline and potable water transfers from Swan Reach–Stockwell Pipeline to the South Para River for the 2012–13 year were obtained from SA Water's SCADA database and/or MetDaily file.
Assumptions, limitations, caveats and approximations
- Water imported from the River Murray is used in the year when it is imported and not stored for later years
- All non-potable water transferred into the region under the Class 6 WAE was included, although part of it does transit through rivers and storages before diversion to the WTPs. Evaporation and leakage from rivers and storages prior to diversion to the WTPs is not considered.
- 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 is less than the actual volume of water diverted from the River Murray under the Class 6 WAE held by SA Water.
Potable water consumption
Supervisory Control and Data Acquisition database or manual field instrument readings, stored in the MetDaily file, Geographic Information System (GIS) and customer service information system (CSIS) databases.
The volume of River Murray water transferred into the Adelaide region from the Swan Reach–Stockwell Pipeline is not metered at 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 2012–13 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 2012–13. To account for meter readings that occurred immediately before or after 2012–13, metered consumption was apportioned based on the following equation:
Vr = ( tr / tm ) × Vm
Vr = volume for metered period within 2012–13 (kL)
tm = length of period between meter readings (days)
tr = length of metered period within 2012–13 (days)
Vm = volume for metered period (kL).
Assumptions, limitations, caveats and approximations
- The inter-region claim to River Murray water is held on behalf of the Adelaide region; however, both the Mt Pleasant and Swan Reach WTPs supply water to users outside the region.Therefore the volume reported is less than the actual volume of water diverted from the River Murray under the Class 6 WAE held by SA Water.