The volume reported for the opening (136,915 ML) and closing (97,182 ML) balance for storages represents the sum of individual storage volumes (including dead storage) for surface water storages operated by SA Water at 30 June 2011 and 30 June 2012 respectively.
For more information on major surface water storages, refer to the Surface water section of the 'Contextual information'.
The surface water storage volume, total storage capacity and dead storage are provided in the following table.
|Surface water storage||Total storage capacity (ML)||Dead storage capacity (ML)||Storage volume at 30 June 2012 (ML)||Storage volume at 30 June 2011 (ML)|
|Kangaroo Creek Reservoir||19,000||300||5,544||13,897|
|Little Para Reservoir||20,800||188||4,600||9,416|
|Mount Bold Reservoir||45,900||27||11,496||21,847|
|South Para Reservoir||44,800||310||26,157||38,501|
|Happy Valley Reservoir||11,600||71||8,924||10,399|
|Hope Valley Reservoir||2,764||123||2,257||2,141|
|Onkaparinga Summit Reservoir||427||64||64||80|
Surface water storage volume was measured using gauged water level height(s) in metres with respect to the Australian height datum for individual storages. The height measurement was converted to a volume using the storage-volume relationship(s) provided by SA Water. The storage volume of individual surface water storages was aggregated to present the total volume for this line item.
Assumptions, limitations, caveats and approximations
- Storage-volume relationships were derived from surveys of specific parts of the surface water storage, and may not reflect the storage-volume relationship across the entire storage.
- Surface water storages are subject to sedimentation and other physical changes over time that in turn may affect the accuracy of the storage-volume relationships.
In the 2011 Account, storages used for urban water supply only (located off-stream and which harvested only minimal catchment runoff) were reported at line item 3.1 'Urban water system'. These storages were Barossa Reservoir, Happy Valley Reservoir, Hope Valley Reservoir and Onkaparinga Summit Reservoir.
In the 2012 Account, these storages were reported at line item 1.1 'Storages', in order to be consistent with the classification of storages applied to the other regions of the National Water Account. As a consequence, the 2010–11 volume was restated as per the following table.
2012 Account volume at 30 June 2011 (ML)
2011 Account volume at 30 June 2011 (ML)
|Kangaroo Creek Reservoir||
|Little Para Reservoir||
|Mount Bold Reservoir||21,847||21,847|
|South Para Reservoir||38,501||38,501|
|Happy Valley Reservoir||10,399||
|Hope Valley Reservoir||2,141||
|Onkaparinga Summit Reservoir||80||