Perth

1.1 Storages—entitlement system

Supporting information

This line item refers to the total volume of water within the major reservoirs within the Perth region. These reservoirs are used for urban water supply and irrigation water supply.

Total volume of water within each major reservoir on 1 July 2009 and 30 June 2010 is given below. The individual reservoir volumes include the volume of dead storage.

Reservoir	Capacity (ML)	Dead storage (ML)	Storage at 30 Jun 2010 (ML)	Storage at 01 Jul 2009 (ML)
Canning	90,300	60	24,537	24,544
Churchman Brook	2,200	40	855	1,007
Drakes Brook	2,300	20	740	359
Harvey	55,700	780	21,022	19,638
Logue Brook	24,200	380	10,014	10,663
Mundaring	43,000	20,560	28,853	26,400
North Dandalup	73,800	1,020	25,695	20,331
Samson Brook	7,900	90	1,362	2,096
Serpentine	136,700	1,010	43,536	49,683
Serpentine Pipehead	2,200	460	2,209	2,209
South Dandalup	125,100	12,940	28,230	20,256
Stirling	54,300	1,800	25,049	14,692
Victoria	9,400	50	2,327	3,318
Waroona	14,800	170	4,038	5,848
Wungong	56,400	3,430	35,411	22,731
Total	698,300	42,810	253,878	223,775

The total water volumes for each reservoir within the Perth region on 1 July 2009 and 30 June 2010 are shown in the figure below. The water volume within most reservoirs at the end of the 2009-10 reporting period is greater than that at the start (1 July 2009).

Except for three reservoirs (Mundaring, Serpentine Pipehead and Wungong), storage within the Perth region was less than 50% of capacity on 30 June 2010, as shown in the figure below.

Graph of water volumes for each reservoir within the Perth region at the start and end of the 2009-10 reporting period

Quantification approach

Data source

Water Corporation: Operational Data Storage System database.

Data provider

Water Corporation.

Method

Storage volume at the start and end of the reporting period was calculated using water level data (metres above Australian Height Datum [mAHD]) collected at each reservoir. Storage rating tables established for each reservoir were used to convert the height measurement to a volume.

The storage volume of individual reservoirs was aggregated to present the total volume for the line item as detailed in the Supporting information table.

Uncertainty

Derived from measured data. Estimated uncertainty is +/- 5%.

Approximations, assumptions, caveats/limitations

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 affects the accuracy of the storage-volume curves.