Murray-Darling Basin
1.5 Inter-region claim on water
Supporting Information
The volumetric value for the line item at the end of the 2010–11 year was 470,066 ML. This line item includes claims on Snowy Hydro Ltd (Snowy Hydro) for the balance of the required annual release (RAR). The line item applies only to the Southern Basin.
| Description | Tumut River (ML) |
River Murray (ML) |
Total |
|||
As at 30 June 2010 |
As at 30 June 2011 |
As at 30 June 2010 |
As at 30 June 2011 |
As at 30 June 2010 |
As at 30 June 2011 |
|
| Fixed annual calculated yield for the development | 1,026,000 |
1,026,000 |
1,062,000 |
1,062,000 |
2,088,000 |
2,088,000 |
| Add DISV as at 01 March from previous Snowy Water Year | 481,000 |
0 |
784,000 |
299,000 |
1,265,000 |
299,000 |
| Less releases made during previous Snowy Water Year, in excess the previous year's RAR adjusted by DISV at 01 March | 12,000 |
0 |
16,000 |
222,000 |
28,000 |
222,000 |
| Less water allocation from prior Snowy Water Year for environmental releases | 71,000 |
120,788 |
22,000 |
101,146 |
93,000 |
221,934 |
| RAR at the commencement of the Snowy water year (01 May) | 1,424,000 |
905,212 |
1,808,000 |
1,037,854 |
3,232,000 |
1,943,066 |
| Less accountable release to 30 June | 156,000 |
69,000 |
265,000 |
273,000 |
421,000 |
342,000 |
| Less DISV reduction at 30 June | 1,110,000 |
325,000 |
1,292,000 |
806,000 |
2,402,000 |
1,131,000 |
| RAR remaining at 30 June | 158,000 |
511,212 |
251,000 |
-41,146 |
409,000 |
470,066 |
DISV = dry inflow sequence volume, RAR = required annual release
The value of the accountable release at 30 June 2011 is a preliminary estimate only and subject to confirmation and revision.
Claim for Snowy Hydro releases remaining
The Snowy Hydro water year is from 01 May to 30 April (the Snowy Water Year). Each Snowy Water Year, Snowy Hydro must release the RAR to the Tumut River and River Murray. The RAR is set at the commencement of the Snowy Water Year for delivery over the next 12 months.
In drier times, an allowance known as the dry inflow sequence volume (DISV) is made for reduced inflows to the Snowy Mountains Scheme. The DISV reduces the RAR when inflows are low and increases the RAR when inflows recover. These DISV adjustments are made on a monthly basis through the Snowy Water Year up to 01 March.
Environmental water savings transferred from the Murrumbidgee River and River Murray to the Snowy River or the montane streams result from entitlements acquired in the Murray–Darling Basin (MDB) through completion of water saving infrastructure projects or purchases of entitlements. When allocations are announced against these entitlements, the RAR (claim against Snowy Hydro) is reduced. Snowy Hydro subsequently makes these environmental releases to the Snowy River and other montane streams.
Snowy deals with New South Wales irrigators
Included within this line item are the Snowy Hydro deals with New South Wales irrigators. This refers to a dealing whereby water access licence holders in the Murrumbidgee and New South Wales Murray negotiated with Snowy Hydro to release water to Blowering Reservoir and Hume Reservoir earlier than required to provide the water under their RAR. This is not considered a trade, as Snowy Hydro Limited does not own the water; rather, it is just an earlier than required transfer. The licence holder is required to payback Snowy Hydro at a point in the future through a reduction in their allocation water.
The volume is not included in the water accounting statement for this line item as the MDB region does not have a claim on Snowy Hydro or the water access licence holders, but it is disclosed as it will have an impact on the value of the RAR.
The payback to Snowy Hydro is shown in line item 13.1 Adjustment and forfeiture of surface water allocation. During the 2010–11 year, 152,519 ML was repaid by the Murrumbidgee licence holders and 205,205 ML was repaid by Murray licence holders to Snowy Hydro.
| Description | The 2009–10 year |
The 2010–11 year |
||
Tumut River (ML) |
River Murray (ML) |
Tumut River (ML) |
River Murray (ML) |
|
| Balance owing to Snowy Hydro at 01 July | 169,968 |
205,205 |
152,519 |
205,205 |
| Borrowed from Snowy Hydro | 0 |
0 |
0 |
0 |
| Payback to Snowy Hydro | 17,449 |
0 |
152,519 |
205,205 |
| Balance owing to Snowy Hydro at 30 June | 152,519 |
205,205 |
0 |
0 |
Note: The values in this table may vary from those stated in information provided by Snowy Hydro due to variations in reporting years.
Quantification Approach
Data Source
Provided by
Method
Snowy Hydro RAR:
- Snowy Hydro RAR at the commencement of the Snowy Water Year (01 May) is based on the calculations in the Snowy Water Licence.
- Snowy Hydro RAR remaining at 30 June adjusts the RAR at 01 May by the estimated progressive releases (in ML) from 01 May to 30 June.
Inputs to the calculation of the RAR include:
- 1,062 GL for the River Murray and 1,026 GL for the Tumut River – the precorporatisation RAR
- the dry inflow sequence volume
- environmental water savings being transferred from the Murrumbidgee River and River Murray to the Snowy River or the montane streams
- recognising when Snowy Hydro has made a water release in advance of the Snowy Water Year
- transfers between the Tumut River and the River Murray
- recognising water deals between Snowy Hydro and downstream irrigators (both the borrowings and the subsequent paybacks).
Snowy deals with New South Wales irrigators are as recorded by the New South Wales Office of Water.
Assumptions, Limitations, Caveats and Approximations
Uncertainty Information
Snowy Hydro required annual release
The uncertainty estimate was not quantified. 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
The uncertainty estimate was not quantified.