Murray–Darling Basin
9.15 Increase of inter-region surface water claim on water

Supporting information

The line item applies only to the Southern Basin of the Murray–Darling Basin (MDB) region. The volumetric value for the line item for the 2011–12 year was 2,560,022 ML. The line item includes the required annual release (RAR) that Snowy Hydro Limited (Snowy Hydro) was required to deliver to the Tumut River and the Murray River (2,525,776 ML), and a claim by Grampians Wimmera–Mallee Water in the Glenelg catchment (34,246 ML) for the 2011–12 year.

Claim for Snowy Hydro releases:

The values shown in the following table was the RAR announced from 1 July 2011 – 30 June 2012 and related to the Snowy water year of 1 May 2012 – 30 April 2013. It also includes the dry inflow sequence volume (DISV) adjustments made to the RAR during the year on a month-by-month basis and other RAR adjustments.

 

Required annual release for the 2011–12 year and Snowy water year 2012–13
Description

 Volume (ML) for the 2011–12 year 

Tumut River (ML)

Murray River (ML)

Total (ML)

Fixed annual calculated yield for development

1,026,000

1,062,000

2,088,000
minus Snowy water allocation

127,352

96,872

224,224
plus Change in DISV reduction over year 325,000 259,000 584,000
plus other RAR adjustment1 39,000 39,000 78,000
equals RAR for Snowy Hydro Water Year 2011–12 1,262,648 1,263,128 2,525,776


1Release volume from the Tumut River was reduced by 78,000 ML, under Clause 13.2 of the Snowy Water licence, in the 2011–12 Snowy water year.  The same volume has been nominated for release during the 2012–13 Snowy water year. At this stage the release is nominated from the Murray River and the Tumut River equally. Line item 1.5 Inter-region claim on water explains in more detail the arrangements for the calculation of the RAR.

Claim by Grampians WimmeraMallee 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 MDB region's boundaries.

The total of the water transferred-in during the 2011–12 year was 34,246 ML reported under line item 9.11 Delivery of water under inter-region agreement to surface water.

 

Quantification approach

Data source

(1) Snowy Hydro Limited: Snowy Hydro transfers from the Snowy Hydro Water Operations Report 2011–12; (2) New South Wales Office of Water's water accounting section: Snowy deals with New South Wales irrigators; and (3) Murray–Darling Basin Authority: water audit monitoring (WAM) data received from Victoria (21 March 2013) and stored in the HYDRO database.

Provided by

Bureau of Meteorology (the Bureau), NSW Office of Water and Snowy Hydro.

Method

  • The Snowy Hydro required annual release at the beginning of the Snowy water year (1 May) was based on the calculations in the Snowy Water licence.
  • The quantification method was not available for the WAM data received for this line item.

Assumptions, limitations, caveats and approximations

Snowy Hydro claim: Numbers were estimated at the commencement of the water year, and subject to revision and confirmation at the end of the year.

Inflows to Lake Hume for the Murray River 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.

Uncertainty information

The uncertainty estimate was not quantified.

Comparative year

This line item corresponds to line item 9.15 'Increase of inter-region claim on water' reported in the 2011 Account.