11.12 Entitled diversion of allocated surface water to urban water system
a. Entitled diversion of allocated surface water to urban water system
The volume reported (57,281 ML) was the volume of water diverted under SA Water's licence to surface water for the purposes of public water supply, from the Western Mount Lofty Ranges Prescribed Water Resources Area.
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
Assumptions, limitations, caveats and approximations
The uncertainty estimate was not quantified.