Perth
10.7 Leakage from irrigation scheme

This line item refers to leakage from the irrigation water supply system into groundwater aquifers.

Harvey Water: spreadsheet database.

Harvey Water.

Leakage from the irrigation water supply system was estimated as the difference between the water inflow into the system and the volume of water sold or used by the various customers.

It is assumed that the leakage from the irrigation water supply system is the difference between the volume released from the storages and what is sold to the customers. However, water not used by the customer that drains into a downstream surface water channel (return flow) is not metered and is not included in this calculation. Therefore, it is likely that this leakage value is an overestimate.

There is no differentiation between leakage to the landscape and leakage to the groundwater store, it is simply assumed, in this case, that all losses go to the groundwater store.

It is assumed that most of the losses in the irrigation water supply system are attributed to metering error, rather than actual leakage from the system.

The uncertainty estimate was not quantified.

The following table presents substantive changes in the line item reported in this 2011 Account with the corresponding line item in the 2010 Account.

Comparative year information for line item 10.7

2011 Account line item	2010 Account line item	2011 Account volume for the 2009–10 year (ML)	2010 Account volume for the 2009–10 year (ML)	Change from the 2010 Account to the 2011 Account
10.7 Leakage from irrigation scheme	15.2.4 Leakage from water distribution system to groundwater	2,972	2,972	Change in line item name and number