Ord
17.11 Surface water allocation diversion

Supporting Information

The volume recognised in the water accounting statements (12,339 ML) represents the allocation diverted for surface water entitlements in the Ord region during the 2011 Account.

During the 2010–11 year, the Western Australian Department of Water administered 100 licences in this category. Licences relate to water sourced from the Main Ord River, Upper Ord River, Dunham River or King River. Licences are categorised by use below.

Surface water allocation diversion by use in Ord region during the 2010–11 year
Licence category
Volume diverted (ML)
Agriculture 9,835
Commercial and institutional 107
Industry and power generation 7
Mining 1,447
Parks, gardens and recreation 392
Stock and domestic 551
Total
12,339

Quantification Approach

Data Source

Department of Water: Water Resource Licensing database and Annual Reports/Meter Card readings from licensees.

Provided by

Department of Water.

Method

The volume presented for this line item is a combination of metered data and estimates.
Where metered data are available, the abstraction is calculated as the actual abstraction for the 2011 Account. Where metered data are not available, the volume of abstraction is estimated to be the full annual entitlement, divided by the number of days that each licence was active during the 2011 Account. The number of days the licences were active is calculated using the annual renewal date of each individual licence:

  • for licences that expired during the reporting year, the volume of abstraction is estimated to be the full entitlement, divided by the number of days from 1 July 2010 until its expiry date
  • for new licences that were created during the reporting year, the volume of abstraction is estimated to be the full entitlement, divided by the number of days from the licence start date until 30 June 2011.

Some licences are issued in perpetuity and do not have an annual renewal date. In these cases, the volume of abstraction is estimated as the amount of one full year's allocation for licences in force during the reporting year.

Assumptions, Limitations, Caveats and Approximations

There is not sufficient information relating to actual abstraction to provide more accurate estimates of abstraction for all licences. The pro-rata estimates of abstraction assume that the full annual entitlement is abstracted each year, and that the rate of abstraction is uniform throughout the year. It is unlikely on both counts that this will be the case for all licences.

For licences that are metered, the licencee is required to install a cumulative water meter of a type approved under the Rights in Water and Irrigation (Approved Meters) Order 2009 for each water draw point under the licence. The licencee must ensure the installed meter(s) accuracy is maintained to within +/–5% of the volume metered, in field conditions.

Meters must be installed in accordance with the provisions of the  Guidelines for Water Meter Installation(Department of Water 2009).

Uncertainty Information

For estimated data: uncertainty is unquantified.
For measured data: uncertainty range +/– 5%.

Comparative year

The following table compares the value for the 2009–10 year reported in this account with the corresponding value reported in the 2010 Account.

Comparative information from the 2010 Account for line item 17.11

2011 Account line item

2010 Account line item

Value reported in the 2010 Account (ML)

Value reported in the 2011 Account (ML)

Additional information

17.11 Surface water allocation diversion

14.7.9.7 Allocation diversion of regulated flows – Other lumped holders

9,428

9,353

Volume restated due to subsequent availability of actual meter readings

The Bureau of Meteorology reclassified the Lake Argyle Village licence (SWL166420) to urban supply. This amendment caused Line item 17.11 Surface water allocation diversion to be overstated previously.