Sydney
17.11 Entitled diversion of allocated surface water to users

Users diverted 32,165 ML from streams in the Sydney region during 2011–12.

Diversions in this line item are made under water access licences in the Sydney region as specified in 21.1 Surface water allocation announcements.

Delta Electricity was estimated to divert 19,562 ML from Thomsons Creek Reservoir, Lake Lyell and Lake Wallace for the Mt Piper and Wallerawang power stations. The New South Wales Office of Water estimated the diversions from Individual Stock and domestic and Other lumped holder water access entitlements.

Details of the water rights associated with these diversions can be found under Water access and use information.

The following table provides a breakdown of the diversions made under this category.

Volume of water diverted from surface water by entitlement holders during the 2011–12 year

Entitlement  holder	Water source	Water diverted during 2011–12 (ML)
Major utility (power generation)	Cox River	19,562
Individual holder for stock and domestic	Hawkesbury and Lower Nepean rivers	2301
Other lumped holders	Hawkesbury and Lower Nepean rivers	12,3731
Total		32,165

1 Estimated by the New South Wales Office of Water

Delta Electricity 2011-12 Annual and Sustainability Report

Bureau of Meteorology

The volumetric value estimated for the diversion of allocated flows for the industrial and commercial holder category was derived from the 2011-12 Annual and Sustainability Report and the volume stated for the entitlement was derived from Delta Electricity's water management licence.

The diversion stated by Delta Electricity was taken from their 2011-12 Annual and Sustainability Report

The volume is based on estimated data. The uncertainty associated with this volume is +/- 100%.

Water Sharing Plan for the Greater Metropolitan Unregulated River Water Sources and water use records in the spreadsheets managed by licensing field officers of the New South Wales Office of Water.

New South Wales Office of Water.

Water use was estimated by applying a 9.8% entitlement-use factor for 2011–12 to the total entitlement value for the categories of Individual Stock and Domestic and Other Lumped holders (see line item 21.1). The entitlement-use factor is based on metered usages from 204 licence holders covering approximately 21% of total unregulated and domestic and stock access licence holders in the Hawkesbury-Nepean system.

The calculation method is applied only to the categories of 'Individual holder for stock and domestic' and 'Other lumped holders' from unregulated flow for 2011–12. The metered area (used to calculate entitlement-use factor) represents only a sample of the Sydney region. The sample includes 204 licences in the Hawkesbury and Nepean catchment representing 21% of the total entitlement for that catchment.

The volume was estimated. Estimated uncertainty is +/– 30% to 50% based on professional judgment and established practice within the New South Wales Office of Water.

This line item corresponds to line item 17.11 Surface water allocation diversion reported in the 2011 Account.

In the 2010–11 Account, diversions of 5,768 ML were incorrectly stated in this line item. These include Goulburn Mulwaree Council's diversions for the Marulan Water Treatment Plant, Palerang City Council's diversions from the Shoalhaven River and Sydney Water Corporations diversions from the Hawkesbury and Lower Nepean rivers. As these water rights are held for the urban water store, the diversion is now recognised under 17.12 Entitled diversion of allocated surface water to urban water system. This line item also includes a diversion of 21,308 ML made from the Cox River by Delta Electricity, previously reported under 11.14 Other delivery of water to urban water system. Consequently, the value for this line item has been restated from 23,797 ML to 39,337 ML.