Supplier Specific Information

Why are the Bureau's water storage levels or volume different to other published sources?

The Bureau receives data from water authorities and agencies around the country. Some of these organisations also publish the data on their own websites.

In order to provide a consistent set of data, the Bureau has to standardise the data received. Consequently, even though we rely on the same base information, the water levels, volumes and percentages that we publish may differ from the values published elsewhere. Details on specific differences for each of the data providers are provided below.

If you note a difference or would like more information on how we calculate the values we publish please let us know via feedback.

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ACTEW Corporation Limited
Volumes published by ACTEW for Canberra include the dead storage capacity whereas the Bureau publishes Accessible Storage volume, which excludes the dead storage capacity. Consequently, the Bureau's volumes for Canberra will be less than ACTEW's.

The aggregated storage total published by ACTEW includes four storages, whereas the Bureau's total for the Australian Capital Territory (ACT) only includes the three storages that are physically in the ACT.
Barwon Region Water Corporation (Barwon Water)

Most volumes published by Barwon Water include dead storage capacity whereas the Bureau publishes accessible storage volume, which excludes dead storage. This will also cause differences between the percentages reported. There are also differences in rounding of storage capacities, for example Barwon Water uses 7,455 ML as the capacity of Wurdee Boluc Reservoir and the Bureau uses 7,410 ML as the accessible capacity.

Barwon Water publishes a combined total storage volume for the Stony Creek Reservoirs, whereas the Bureau publishes separate volumes and percentages for each storage.

Cairns Regional Council

The volumes published by Cairns Regional Council include dead storage capacity, whereas the Bureau publishes accessible storage volume, which excludes dead storage.

For the publication of storage levels Cairns Regional Council links to the Bureau's Rainfall and River Conditions website. On this site water levels are published in metres relative to a local datum, in this case height above the spillway, whereas on the Bureau's Water Storage website all water level values are published in mAHD (Australian Height Datum).

Central Highlands Regional Water Corporation

Volumes published by Central Highlands Water include dead storage capacity whereas the Bureau publishes accessible volume, which excludes dead storage. This will also cause differences between the percentages reported.

Additionally, Central Highlands Water publishes only 59.9% of the total storage volume of Lal Lal reservoir, with the remaining volume allocated to Barwon Water and environmental requirements. The Bureau publishes the full accessible storage volume used by both providers and the environment. This will cause a substantial difference in both the volume and percentages reported for this storage.

Coliban Region Water Corporation (Coliban Water)

The storage volumes published by Coliban Water, include dead storage capacity, whereas the Bureau publishes accessible storage volume, which excludes dead storage. This will also cause differences between the percentages reported.

There is also a difference between the capacities published for Malmsbury Reservoir. Coliban Water report 12,034 ML as the total storage capacity, whereas the Bureau uses 17,225 ML.

Department for Water

Volumes published by the Department for Water include the dead storage capacity whereas the Bureau publishes accessible storage volume, which excludes dead storage. Differences also occur due to inclusion of River Murray weir volumes in the Bureau's reporting of water information.

Gippsland and Southern Rural Water Corporation (Southern Rural Water)

Storage volumes published by Southern Rural Water include accessible storage plus dead storage capacity, whereas the Bureau publishes accessible storage volume only. The difference in reported volumes may cause differences in percentages reported by each organisation. There are also differences in the assessment of storage capacities. For example, the accessible capacity for Melton Reservoir is reported as 14, 360ML by Southern Rural Water and 14,202ML by the Bureau.

Gladstone Area Water Board

Volumes published by Gladstone Area Water Board include dead storage capacity, whereas the Bureau publishes accessible storage volume, which excludes dead storage. This will also cause differences between the percentages reported.

Gosford City & Wyong Shire Councils

Volumes published by Gosford and Wyong Councils include dead storage capacity, whereas the Bureau publishes accessible storage volume, which excludes dead storage. This will also cause differences between the percentages reported.

There are also minor differences in rounding of storage capacities, for example Gosford and Wyong Councils use 190,000 ML as the total capacity of Mangrove Creek Reservoir and the Bureau uses 189,983 ML as the total capacity.

Goulburn-Murray Rural Water Corporation (Goulburn-Murray Water)

Volumes published by Goulburn-Murray Water include the dead storage capacity whereas the Bureau publishes accessible storage volume, which excludes dead storage. This will also cause differences between the percentages reported. Differences also arise due to rounding of the storage capacity, for example Goulburn-Murray Water use 3,906,000 ML as the capacity of Dartmouth and the Bureau uses 3,827,698 ML.

Grampians Wimmera Mallee Water Corporation (GWMWater)

Volumes published by GWM Water include dead storage capacity whereas the Bureau publishes accessible storage volume, which excludes dead storage. The Bureau also standardises levels to mAHD whereas GWM Water publish some storage levels relative to a local datum.

There are also differences in rounding of storage capacities, for example GWM Water use 18,460 ML as the capacity of Lake Fyans and the Bureau uses 17,450 ML as the accessible capacity.

Hydro-electric Corporation (Hydro Tasmania)

Differences occur in reported level due to reporting by Hydro Tasmania of variation from full supply level, whereas the Bureau report water level against the Australian Height Datum.

Hunter Water

The Bureau reports accessible storage volume for Seaham Weir. Hunter Water does not report storage volume for Seaham weir as water from the offtake weir is transferred to Grahamstown Lake.

The Bureau does not publish volumes for Tomago and Anna Bay as they are underground storages. Storage volumes for these aquifers are shown on the Hunter Water website.

Melbourne Water Corporation (Melbourne Water)

The Bureau and Melbourne Water both report accessible storage volume. However, Melbourne Water cap the 'percent full' value they report to 100%, whereas the Bureau will report values higher than this when storages overflow. Minor differences may also occur due to timing of reports and differences in rounding of values used in calculations.

Murray-Darling Basin Authority

Volumes published by the Murray-Darling Basin Authority (MDBA) include dead storage capacity whereas the Bureau publishes accessible storage volume, which excludes dead storage. Differences in the reported total basin volume occur due to inclusion by the Bureau of smaller storages such as weirs. The Bureau reports on 84 storages in the Basin.

NSW Office of Water

Volumes published by NSW Office of Water include the dead storage capacity whereas the Bureau publishes accessible storage volume, which excludes dead storage. The Bureau also standardises levels to mAHD (Australian Height Datum) whereas the NSW Office of Water publish levels in some storages relative to a local datum. Small differences may also occur in all values, including percentages, as the Bureau uses a different method to calculate daily values than the NSW Office of Water.

North East Region Water Corporation (North East Water)

Volumes published by North East Water include dead storage capacity whereas the Bureau publishes accessible storage volume, which excludes dead storage. This will lead to differences in both the volume and percentages published.

North East Water publishes the combined volume and percentage for the water supply system of the townships that are supplied from storages, whereas the Bureau publishes storage volumes for the individual storages supplying these towns.

Power and Water Corporation (Power and Water)

Power and Water publish percentages which are calculated based on total storage capacity, whereas the Bureau publishes volumes and percentages based on accessible storage capacity (which excludes dead storage).

Queensland Bulk Water Supply Authority (Seqwater)

The Bureau and Seqwater use the same basis for calculating accessible volume. Minor differences may occur due to calculation accuracy.

Rockhampton Regional Council

Individual storage volumes reported by Fitzroy River Water, the business unit of Rockhampton Regional Council responsible for water and sewer assets, include dead storage capacity, whereas the Bureau publishes accessible storage volume, which excludes dead storage.

There are also differences in the rounding of storage capacities, for example Fitzroy River Water use 3000 ML as the total storage capacity of Mount Morgan No. 7 whereas the Bureau uses 2926 ML.

Snowy Hydro Limited

Percentages published by Snowy Hydro Limited are calculated based on total storage capacity, whereas the Bureau publishes storage volumes and percentages based on accessible storage capacity, which excludes dead storage. Minor differences may also arise due to estimation methods for determining daily values.

South Australian Water Corporation (SA Water)

Volumes published by SA Water include dead storage capacity whereas the Bureau publishes accessible storage volume, which excludes dead storage. This will lead to differences in both the volume and percentages published. As the dead storage capacities are large, differences may be greater than 50% for some storages.

Southern Water

Nil. Southern Water do not appear to publish storage volumes

SunWater

SunWater report total storage capacity where as the Bureau report accessible storage capacity. Consequently there will be differences in the published values for volume and percentage full. For storages with perched dead storage, Beardmore and Jack Taylor Weir, the Bureau will only include dead storage below the minimum supply level. This will mean that dead storage values used will be lower than those reported by SunWater.

Sydney Catchment Authority

The Bureau and Sydney Catchment Authority both report accessible storage volume. Minor differences may occur due to timing of reports, differences in rounding of values used in calculations and smoothing of data. Sydney Catchment Authority publishes level below Full Supply Level, whereas the Bureau publishes level relative to the Australian Height Datum (AHD).

Toowoomba Regional Council

Toowoomba Regional Council and the Bureau both report accessible storage volumes.
Differences in the published values may occur due to rounding of capacities, for example Toowoomba Regional Council uses 78,850 ML as the capacity of Cressbrook Reservoir and the Bureau uses 78,847 ML, and also due to differences in the calculation methods used to derive daily storage volumes.

Townsville City Council

The volumes published by Townsville City Council include dead storage capacity, whereas the Bureau publishes accessible storage volume, which excludes dead storage. This will also cause differences between the percentages reported.

Water Corporation

Volumes published by Water Corporation include dead storage capacity whereas the Bureau publishes accessible storage volume, which excludes dead storage. Minor differences may also arise due to estimation methods for determining daily values. To calculate the water storage value for Perth, Water Corporation uses an account-type system to allocate water from Stirling and Samson Brook. At this stage the Bureau can only use simple percentages to allocate the water in these storages to Perth (66% of Stirling and 75% of Samson Brook). Consequently there will be small differences in the calculated volume and percentage full values for Perth.


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