20.3 Leakage to groundwater
The volume reported in the water accounting statement (62 ML) represents background leakage from the pipes in the irrigation water supply system to groundwater.
|Irrigation scheme||Volume (ML)|
|Barossa Infrastructure Limited||62|
|Virginia Pipeline Scheme||–
|Willunga Water Basin Company||0|
Data regarding leakage were not available for the Virginia Pipeline Scheme. This volume is assumed to be small, and its omission is unlikely to have a material impact on the irrigation scheme balance.
Leakage from the Willunga Water Basin Company pipes was assumed to be negligible. Numerous pressure monitoring sites will rapidly identify leaks and leaks are fixed quickly.
The leakage from BIL's irrigation scheme (62 ML) was derived from the difference between water supplied to the irrigation scheme and water delivered to the customers.
Assumptions, Limitations, Caveats and Approximations
- The area serviced by BIL extends beyond the boundary of the Adelaide region. It was assumed that the length of BIL infrastructure outside the Adelaide region is insignificant.
- Estimates of unaccounted-for irrigation water were provided for the 2010–11 water year (October – September). It was assumed that these estimates apply to the reporting year.
- It was assumed that leakage from infrastructure caused the difference between water supplied to the irigation scheme and water delivered to customers. However a significant proportion of this difference is likely due to metering errors. During the 2010–11 year BIL upgraded some customer meters and noticed a significant reduction in the difference between water supplied to the irrigation scheme and water delivered to customers.
In the 2010 Account the irrigation water supply system was reported as part of the urban water system; therefore there is no corresponding line item. However, the volume of leakage from the irrigation water supply system was reported at line item 15.2.4 Leakage from water distribution system to groundwater in the 2010 Account. The restated comparative year volume is 182 ML.