Ord
1.1 Storages
Supporting information
The volume recognised in the water accounting statements (8,577,385 ML) represents the total volume of water held in storages that are used to administer water access entitlements at 30 June 2013. The volume includes the dead storage volume.
Total volume of water within each storage within the Ord region at 30 June 2012 and 30 June 2013 is given in the following table.
Storage |
Capacity (ML) |
Dead storage |
Volume at 30 June 2013 (ML) |
Volume at 30 June 2012 (ML) |
| Arthur Creek |
65,000 |
Unknown |
60,800 |
60,800 |
Lake Argyle |
10,755,830 |
324,000 |
8,417,183 |
10,599,780 |
Lake Kununurra |
100,825 |
87,000 |
97,587 |
96,990 |
Moochalabra |
2,023 |
175 |
1,815 |
1,826 |
Total |
10,923,678 |
411,175 |
8,577,385 |
10,759,396 |
The water volume in Lake Argyle decreased during the 2012–13 year from 99% full at 30 June 2012 to 78% full at 30 June 2013. The almost capacity volume at the start of the 2012–13 year was due to the record rainfall conditions observed during the 2010–11 year, which resulted in high storage levels throughout the 2011–12 year (see line item note 1.1 in the 2012 Account). The water volumes in the other storages within the region changed very little from the previous year.
Quantification approach
Data source
Provided by
Method
Storage volume at the start and end of the year was calculated using water level data (metres above Australian Height Datum) collected at each storage. Rating tables established for each storage were used to convert the height measurement to a volume.
The volume of individual storages was aggregated to present the total volume for the line item as detailed in the supporting information table.
Assumptions, limitations, caveats and approximations
Storage–volume curves represent specifically surveyed parts of the storage and may not reflect the storage–volume relationship across the entire storage.
Storages are subject to sedimentation and other physical changes over time, which in turn affects the accuracy of the storage–volume curves.
No storage data were available for Arthur Creek at 30 June 2013. Given the storage volumes in Lake Kununurra and Moochalabra changed little during the 2012–13 year, it was assumed that the storage volume in Arthur Creek remained the same as that measured on 30 June 2012.