Perth
1.1 Storages
Supporting information
The volume reported in the water accounting statements (183,415 ML) represents the total volume of water held in surface water storages within the Perth region at 30 June 2013. These storages are used for urban water supply and irrigation water supply (refer to Table P2 in the Physical information).
Total volume of water within each storage at 30 June 2012 and 30 June 2013 is given below. The individual storage volumes include the volume of dead storage.
Storage |
Capacity (ML) |
Dead storage (ML) |
Storage at 30 June 2013 (ML) |
Storage at 30 June 2012 (ML) |
Canning |
90,300 |
60 |
16,652 |
26,279 |
Churchman Brook |
2,200 |
40 |
893 |
911 |
Drakes Brook |
2,300 |
20 |
1,508 |
1,995 |
Harvey |
55,700 |
780 |
18,603 |
21,942 |
Logue Brook |
24,200 |
380 |
3,703 |
3,512 |
Mundaring |
43,000 |
20,560 |
23,923 |
25,454 |
North Dandalup |
73,800 |
1,020 |
12,960 |
20,317 |
Samson Brook |
7,900 |
90 |
521 |
377 |
Serpentine |
136,700 |
1,010 |
31,880 |
33,819 |
Serpentine Pipehead |
2,200 |
460 |
2,103 |
27 |
South Dandalup |
125,100 |
12,940 |
12,937 |
11,953 |
Stirling |
54,300 |
1,800 |
23,139 |
21,810 |
Victoria |
9,400 |
50 |
4,275 |
4,821 |
Waroona |
14,800 |
170 |
4,085 |
2,991 |
Wungong |
56,400 |
3,430 |
26,233 |
33,247 |
Total |
698,300 |
42,810 |
183,415 |
209,455 |
Overall storage volume for the Perth region at 30 June 2013 was 26% of capacity, a decrease of 4% from 30 June 2012. The figure below shows that water volume in most of the storages within the Perth region at the end of the 2012–13 year are less than that at the end of the 2011–12 year.
The decrease in surface water storage is primarily attributed to the decrease in inflows into the storages during the 2012–13 year compared to the comparison year (see Water Corporation website).
Graph of water volumes for each storage within the Perth region at the end of the 2011–12 and 2012–13 years. Capacity of each storage is also shown.
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 by the Water Corporation 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.