Murray–Darling Basin
1.4 Lakes and wetlands

Supporting information

The volumetric value for the line item for the 2011–12 year was 1,811,372 ML.

This line item represents the volume of water held in lakes and wetlands that are connected either seasonally or perennially to the river channel system. Specific details of individual lakes and wetlands are provided in the following table. Information is provided only for selected lakes and wetlands in the Southern Basin of the Murray–Darling Basin (MDB) region. For other lakes and wetlands, particularly in the Northern Basin, the volumetric values were not available.

Water from lakes and wetlands listed for the line item is not used primarily to supply water for licensed entitlements. Line item 1.1 Storages includes storages that are used to supply water for licensed entitlements.


Details of lakes and wetlands in the MDB region at the start and end of the 2011–12 year
Water resource plan area

Sustainable diversion limit area

State/Territory

Lake name

Total capacity1 (ML)

Total storage2 volume on 30 June 2012 (ML)

Total storage3 volume on 30 June 2011 (ML)

Code

Name

SW4 Wimmera–Mallee SS9 Wimmera–Mallee Vic. Dock Lake  4,430 0 0
Vic. Green Lake  5,350 3,591 4,462
Vic. Lake Batyo Catyo 2,250 479 1,837
Vic. Pine Lake  62,380 7,830 10,770
SW5 SA Murray SS11 SA Murray SA Lake Albert 279,583 250,889 273,937
SA Lake Alexandrina 1,644,884 1,513,961 1,594,916
SW1 ACT SS1 ACT ACT Lake Burley Griffin 33,723 29,122 33,723
ACT Lake Ginninderra 3,700 3,700 3,700
ACT Lake Tuggeranong 1,800 1,800 1,800
Southern Basin  2,038,100 1,811,372 1,925,145
Whole MDB region 2,038,100 1,811,372 1,925,145

1–3Dead storage volumes are included except for Dock Lake, Lake Batyo Catyo, Green Lake and Pine Lake.

Lakes Burley Griffin, Ginninderra and Tuggeranong are used primarily for recreation, conservation and aesthetic purposes, and are not formally associated with the urban water supply system; however, water from these lakes can be abstracted or released to maintain environmental flows and for small-scale irrigation.

At present, abstraction from Lake Ginninderra and Lake Tuggeranong is limited to volumes that would have negligible effect on the volume of the lakes (less than 50 ML).

Quantification approach

Data source

(1) Environment and Sustainable Development Directorate of the ACT Government: Lakes Ginninderra and Tuggeranong, (2) National Capital Authority: Lake Burley Griffin, and (3) Bureau of Meteorology (the Bureau)'s Water Storages, Australian Water Resources Information System (AWRIS): other lakes.

 

Provided by

Environment and Sustainable Development Directorate of the ACT Government, National Capital Authority and the Bureau.

 

Method

Lakes Ginninderra and Tuggeranong

No storage volume or level information was available for these lakes; however, their capacity is known. Therefore, the total storage within these lakes was estimated based on the assumption that these water bodies were full at the start and end of the year.

Lake Burley Griffin

The volume was as estimated by National Capital Authority.

Other lakes

Storage volume was estimated at the start and end of the year by using gauged water level height(s) (metres Australian height datum) for individual storages. The height measurement was converted to a volume using the storage-volume curve(s) of the storage.

Assumptions, limitations, caveats and approximations

Lakes Ginninderra and Tuggeranong

Water levels in Lake Ginninderra and Lake Tuggeranong are generally managed within 200 mm of full supply level throughout the year. Therefore, the estimated storage volumes of these lakes in the water account are considered to be only slightly overestimated.

Lake Burley Griffin

The capacity of Lake Burley Griffin is based on survey data collected at the time of construction and fill in 1964.

Other lakes

Storage-volume curves represent specifically surveyed parts of the water storage and may not reflect the storage-volume relationship across the entire storage.

Water storages are subject to sedimentation and other physical changes over time, which in turn affect the accuracy of the storage-volume curves.

Uncertainty information

The uncertainty estimate was not quantified.

Comparative year

The following changes resulted in the restatement of the 2010–11 year volume:

  • updated information
  • scope change.

The scope of the line item was changed as additional storages were added to the 2012 Account in order to provide more complete information to the users of the National Water Account. The added storages were Lake Batyo Catyo, Dock Lake, Green Lake and Pine Lake, resulting in a 17,069 ML increase for the 2010–11 year.

As a result of updated information, Lake Burley Griffin volume was increased by 723 ML for the 2010–11 year.

The changes and their respective values are detailed in the table below:

 

Restatement of comparative year information made for the line item 1.4 Lakes and Wetlands
Segment

2012 Account volume at 30 June 2011 (ML)

2011 Account volume at 30 June 2011 (ML)

Difference due to scope change and updated information (ML)

Northern Basin
Southern Basin 1,925,145 1,907,353 17,792
Whole region 1,925,145 1,907,353 17,792