Adelaide
19.4 Delivery to urban water system users

Supporting information

a. Delivery to urban water system users

The volume reported (141,892 ML) represents delivery of potable and recycled water to users by SA Water in the Adelaide region during the 2012–13 year. The total volume delivered is itemised for various uses in the following table.

Urban water use in the Adelaide region during the 2012–13 year
Purpose Type of water (ML)
Potable Recycled
residential use 92,308 203
commercial, industrial, municipal use 26,756 2,918
agricultural / individual irrigation use 3,896 344
other use—urban use 14,068 44
recycled water on-site outdoor / irrigation use n/a
208
recycled water on-site in-door use  n/a n/a
recycled water on-site within process use (no-recirculation)  n/a 1,147
Subtotal 137,028 4,864
Total 141,892

Recycled water supplied by SA Water to the Willunga Basin Water Company and Virginia Pipeline Scheme is reported at line item 19.6 Urban water discharge to irrigation schemes.

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
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

c. Recycled water system overview

The recycled water 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.

In the Adelaide region, the majority of wastewater treatment plants produce recycled water which is subsequently provided to users (including irrigation schemes) or used on-site.

During the 2012–13 year, the majority of recycled water produced (75%) was provided to the region's irrigation schemes (line item 19.6 Discharge from urban water system to irrigation scheme). Approximately 17% was supplied for urban consumption (part of line item 19.4 Delivery to urban water system users) and a very small volume (113 ML) was injected to groundwater for later use (line item 19.9 Managed aquifer recharge).  The remaining recycled water (approximately 8%) was recirculated back into the wastewater system (and therefore not reported in the water accounting statements). 

The following figure presents the inflows and outflows associated with the recycled water system.

For more detail on a particular flow associated with the recycled water system, refer to the line item notes. Note that volumes annotated with an asterisk (*) indicate flows between urban subcomponents and are not reported in the Account 2012. As such, these flows do not have an associated line item number or note.


Schematic diagram of water inflows and outflows for Adelaide's wastewater system during the 2012–13 year; line item numbers are provided in brackets
Schematic diagram of water inflows and outflows for Adelaide's wastewater system during the 2012–13 year; line item numbers are provided in brackets

Quantification approach

Potable water

Data source

Supervisory Control and Data Acquisition, geographic information system (GIS) and customer service information system (CSIS) databases.

Provided by

SA Water.

Method

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. The SPNs were then used to extract water meter readings for 2012–13 and primary land use codes for each meter from CSIS.

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

Where:

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).

The primary land use codes were reclassified as residential; commercial/industrial/municipal; agricultural/individual irrigation; or other urban use. Then total water consumption for the Adelaide region was calculated by summing the 2012–13 water consumption for each meter based on the 2013 Account land use classes.

Assumptions, limitations, caveats and approximations

  • Apportionment: the method used for apportionment assumes that consumption is constant over the period between meter readings. This may not reflect the actual consumption, which may vary based on seasonal patterns.
  • SPNs: the method assumes that all relevant SPNs have been captured in the GIS accurately and completely.
  • Primary land use: the method assumes that all SPNs have an accurate allocation of primary land use codes and each SPN represents a single land use; however, it is likely that each SPN is providing water for several land uses.

Uncertainty information

The uncertainty estimate was not quantified.

Recycled water

Data source

Wastewater Treatment Plant Records (WWTP) records and Supervisory Control and Data Acquisition database (SCADA).

Provided by

SA Water.

Method

The metered volume of recycled water delivered to users was obtained from SA Water's WWTP records. Metered flows are either automatically logged by SCADA or manually read and recorded by plant operators. 

Assumptions, limitations, caveats and approximations

  • The volume reported does not include any recycled water from community waste management systems managed by local councils.
  • The volume reported as supply from Bolivar WWTP to Mawson Lakes is the total volume supplied. It is mixed with stormwater and potable water, and supplied to residential and municipal uses.

Uncertainty information

Uncertainty is +/– 10% based on meter calibrations.