Murray–Darling Basin

23.1 Interbasin claim over water in other regions registered

Supporting information

The volumetric value for the line item is 2,071,991 ML. This line item includes the required annual release (RAR) that Snowy Hydro is required to deliver to the Tumut River and River Murray during the year (2,066,000 ML), and a claim by Grampians Wimmera–Mallee Water in the Glenelg catchment (5,991 ML).

Claim for Snowy Hydro releases

The values shown in the following table is the RAR announced from 01 July 2009 to 30 June 2010 and relates to the Snowy Water Year of 01 May 2010 to 30 April 2011.
It also includes the Dry Inflow Sequence Volume (DISV) adjustments made to the RAR during the year on a month-by-month basis.

RAR for 2009–10 and Snowy Water Year 2010–11
Description	Tumut River (ML)	River Murray (ML)	Total (ML)
Fixed annual calculated yield for development	1,026,000	1,062,000	2,088,000
Minus Snowy Water allocation	71,000	22,000	93,000
Plus Change in DISV reduction over year	45,000	26,000	71,000
Equals RAR for Snowy Hydro Water Year 2010–11	1,000,000	1,066,000	2,066,000

Line item 7.1 Interbasin claim on water – remaining explains in more detail the arrangements for the calculation of the RAR.

Claim by Grampians Wimmera Mallee Water on water in the Glenelg River

Under a Victorian bulk entitlement, Grampians Wimmera–Mallee Water is able to transfer water from the Glenelg River upstream of and including Rocklands Reservoir; and the First and Second Wannon creeks upstream of and including the weirs to the Wimmera–Mallee supply system, located within the Murray–Darling Basin (MDB) region’s boundaries.

As the National Water Account 2010 reports at a retail level for bulk entitlements in Victoria (see notes on ‘Significant water accounting policies’), a claim is recognised for the water transferred in that increases the water assets, from which allocations will be announced by the bulk entitlement holder (Grampians Wimmera–Mallee Water). The total of the water transferred-in during the 2009–10 year was 5,991 ML (see Line item 13.6.3 Delivery of water transferred-in under interbasin agreement to connected surface water) and this is recognised as an increase of a water asset and reported under this line item.

Quantification approach

Data source

Australian Capital Territory: Water Audit Monitoring Report 2009–10 (30 November 2010).
New South Wales: NSW Office of Water’s Water Accounting section.
Queensland: Water Audit Monitoring Report 2009–10 (31 January 2011).
Snowy Hydro: Snowy Hydro Limited Water Operations Report 2009–10.
Snowy deals with New South Wales irrigators: NSW Office of Water’s Water Accounting section.
South Australia: Water Audit Monitoring Report 2009–10 (22 February 2011).
Victoria: Water Audit Monitoring Report 2009–10 (19 January 2011).

Note: Water audit monitoring (WAM) report data are stored in the Murray–Darling Basin Authority (MDBA) HYDRO database.

Data provider

MDBA.

Method

Snowy Hydro required annual release at the beginning of the Snowy Water Year (01 May) is based on the calculations in the Snowy Water Licence.
No description of the method used was attached with the WAM data.

Uncertainty

Snowy Hydro Claim: Uncertainty is ungraded. Numbers are estimated at the commencement of the water year, and subject to revision and confirmation at the end of the year.
Snowy deals with New South Wales irrigators: Ungraded.
WAM data: Ungraded.

Approximations, assumptions, caveats/limitations

Snowy Hydro Claim: Numbers are estimated at the commencement of the water year, and subject to revision and confirmation at the end of the year.
Inflows to Hume Reservoir are subject to a formula for calculating the respective New South Wales and Victorian shares, which is 50% between New South Wales and Victoria with some adjustments. For the purposes of this account, this line item has been treated as a 50% share for Murray – NSW and 50% share for Murray – Vic.

National Water Account 2010