19.3 Leakage to groundwater
a. Leakage to groundwater
The volume reported (14,718 ML) represents background leakage from the mains water network.
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
Geographic Information System (GIS) database; National Water Commission 2013.
GIS analysis was used to calculate the length of SA Water pipes within the Adelaide region. The leakage volume was calculated by multiplying this length and the 2011–12 mains loss rate for Adelaide, which was 3.74 kL/km/day (National Water Commission 2013).
Assumptions, limitations, caveats and approximations
- Assumes length of water mains at 30 June 2012.
- Leakage from bulk transport pipelines (Mannum–Adelaide Pipeline, Murray Bridge–Onkaparinga Pipeline and Swan Reach–Stockwell Pipeline) and wastewater pipelines is assumed to be negligible.
- Leakage from fire services and recycled water pipes are not considered.
- All leakage is assumed to be to groundwater.
Derived from measured data. Estimated in the range +/– 30% to +/– 50%.