Commonwealth Environmental Water
This is an annual report on the volume of water that has been carried over from 2011-12 by the Commonwealth Environmental Water Office.
Commonwealth environmental water in River Murray System storages totaled 196 gigalitres on 1 July 2012. The capacity of the storages in the River Murray System totals 9,269 gigalitres. (Hume Dam)
- The Commonwealth Environmental Water Office operates under the same rules associated with water entitlements as all other water users, including with respect to carryover.
- On 1 July 2012 the Commonwealth held water equivalent to 2.8 per cent of public storage capacity across the Murray-Darling Basin. This was 615 gigalitres (GL) of carryover. Like any other water user, the Commonwealth Environmental Water Office cannot fill up dams to the exclusion of other water users.
- Across the Murray-Darling Basin, on a proportional basis, the Commonwealth used more and carried over less of its available water than the average of other water users in 2011-12 for the fourth successive year.
- This has created additional airspace for storage and allocation to all users than would have been the case if Commonwealth environmental water had been used to the same extent as average use.
Carryover is water available in one year that is held in storage for possible use in the following year. Carryover provides water users with greater flexibility to manage their own water availability across years. For example, for an environmental manager, carryover provides the opportunity to water wetlands or river red gums in late winter and early spring ahead of increases to seasonal allocations for many entitlement types.
This is an annual report on the volume of water that has been carried over from 2011-12 by the Commonwealth Environmental Water Office. The Commonwealth Environmental Water Office operates under the same rules and pays the fees and charges associated with its water as other water licence holders. Carryover was previously available to entitlements now held by the Commonwealth Environmental Water Office. Further background information on the carry over of Commonwealth environmental water is given in these factsheets:
- Carryover of Commonwealth Water - Northern NSW
- Carryover of Commonwealth Water - Northern Victoria
- Carryover of Commonwealth Water - NSW Murray and Murrumbidgee
The carryover from 2011-12 to 2012-13 was 615 GL, after some deductions for evaporation under State rules in northern Victoria. The distribution of carryover across catchments is shown in Table 1. 41 per cent of the carryover was held in the southern connected Murray-Darling Basin. 59 per cent of the carryover was held in the northern Basin, with the highest volumes being in the Gwydir, Lachlan and Macquarie catchments. There was no Commonwealth environmental water in Victorian spillable water accounts on 1 July 2012.
|Catchment||Carryover total (GL) (net of evaporative losses)||Utilisation of water available in 2011-12 (%)||Carryover limit (%)|
|Murray (Victoria)||163||65||100 + Spillable1|
|Macquarie and Cudgegong (NSW)||94||30||100|
|Namoi (NSW)||12||0||100 (Upper Namoi)
200 (Lower Namoi)
|Border Rivers (NSW and Queensland)||9||0||85 (Queensland)
In 2011-12, the Commonwealth used 53 per cent of its available water in 2011-12, and used 65 per cent of its available water in the southern connected Basin. Based on preliminary figures, the use in New South Wales and Victoria by all entitlement holders is likely to be around 45 per cent. The Commonwealth Environmental Water Office has used a higher proportion of the water available to it over its four years of operations than most other water users as shown on Figure 1. This means that more airspace has been created for further in-flows than would have been the case if water from these entitlements had been used to the same extent as average use.
Over the longer term it is expected that the percentage of Commonwealth environmental water carried over will be similar to other water users – although, like all water users, it will vary from year to year.
Figure 1 - Utilisation of allocated water as a percentage of the allocated volume
Data for NSW and Victoria for 2008-09 to 2010-11 are from the MDBA Water Audit Monitoring Report 2010-11. Use in 2011-12 in NSW and Victoria is expected to be around 45 percent.
At 30 June 2012, the Commonwealth held 0.1 GL in accounts for which carryover was unavailable, and this water was re-allocated under State rules.
The Commonwealth Environmental Water Office makes decisions on water use in accordance with its annual plans and taking account of environmental opportunities from time to time. Carryover provides flexibility to respond to these opportunities. Large scale actions that this carryover water could be used for in 2012-13 include enhancement of:
- environmental flows in rivers, such as in the Goulburn River;
- wetland waterings, such as the Macquarie Marshes, Lowbidgee, and Gwydir Wetlands;
- floodplain waterings, including into the Gunbower Forest; and
- enhanced flows for the full length of the River Murray, including to the Coorong, lower lakes,and Murray mouth.
Carryover of Commonwealth environmental water as a percentage of major storage capacity in each catchment is shown on Figure 2. The Commonwealth carried over is equivalent to 2.8 per cent of the public storage capacity across the Basin. Whilst this gives a sense of proportion, it is a simplification that overstates the amount of Commonwealth environmental water in storage, because water orders can be supplied from storages or from tributary inflows downstream of storages. Like any other water user, the Commonwealth Environmental Water Office cannot fill up dams to the exclusion of other water users.
Figure 2 - Carryover of Commonwealth environmental water as a percentage of major storage capacity (on 1 July 2012)
Please notice: This is a simplification that overstates the amount of Commonwealth environmental water in storage, because water orders can be supplied from storages or from tributary inflows downstream of storages.
|Catchment||Major Storages (Volume GL)|
|Lake Victoria (667GL)|
|Waranga Basin (432GL)|
|Broken||Lake Nillahcootie (40GL)|
|Ovens||Lake Buffalo (24GL)|
|Lake William Hovell (13GL)|
|Namoi||Split Rock (397GL)|
|Border Rivers||Pindari (312GL)|
|Cooby Dam (21GL)|
|Chincilla Weir (10GL)|
|Jack Taylor (10GL)|
Lindsay Island by Arthur Mostead
MDBA - used with permission