Sydney

Interbasin claim on water

Claim to water in the Fish River Water Supply Scheme

The Fish River Water Supply Scheme (FRWSS) is located outside the Sydney Region and managed by NSW State Water Corporation. Organisations within the Sydney Region receiving FRWSS water and details of their maximum annual quantities (MAQ) are shown under ‘Surface Water’ in the contextual statement.

The FRWSS supplies chlorinated water via a pipeline to the Sydney Catchment Authority’s (SCA) Upper Cascade Reservoir or Sydney Water Corporation’s (SWC) Cascades Water Treatment Plant. Under gravity alone, the FRWSS can supply 9.5 ML/d. The supply can be boosted, via a pumping station, to 14 ML/d. The FRWSS also supplies treated water from Duckmaloi Water Treatment Plant to Lithgow City Council’s distribution system and Delta Electricity’s Mt Piper and Wallerawang power stations.

The carry-over volumes from the previous year and allocation announced at the beginning of any year from the FRWSS are contingent on several operating rules as detailed below.

• MAQ is generally available for extraction whenever the storage volume of Oberon Reservoir is > 50% capacity.
• When reservoir volume falls below 50%, the water allocation for major consumers is restricted (commensurate with the storage volume).
• Water abstracted for one customer may affect the water allocated to others because a customer can abstract all allocated water early in the year, thus drawing down the reservoir volume below the 50% threshold.
• Allocations announced early in the year may be reduced later in that year depending on the reservoir volume.
• A permitted carry-over volume constitutes a future water right of a customer, as well as a contingent water asset of the region.

The 2009–10 reporting period

Three entitlement holders operating in the region had opportunity to access carry-over volumes prior to March 2010, but none of them did. Access to these carry-over volumes, plus any savings from 2009–10, was suspended in March 2010 because Oberon Reservoir (FRWSS supply reservoir) fell below 10% capacity. Therefore, no carry-over volume was available for abstraction at the end of 2009–10.

The following table presents details of restricted allocation and carry-over volumes for the three organisations operating in the Sydney Region for 2009–10.

Because allocation announced at the beginning of the year is contingent on several operating rules, the 2009–10 allocation from the FRWSS has been classed as a contingent water asset of the region. However, the 2009–10 the FRWSS carry-over volumes have been classed as a water asset because the volumes were available to the region at the beginning of 2009–10.

• Details of quantification approaches for the values presented in the above table are available in following notes:
• Line item 7.1 Interbasin claim on water: remaining for allocation and carry-over volumes for the Sydney Catchment Authority
• Line item 7.15 Nonphysical water distribution system asset: other lumped for allocation and carry-over volumes for Delta Electricity and Lithgow City Council
• Line item 19.5.6 Other lumped delivery of water transferred-in to water distribution system for volumes supplied for Delta Electricity and Lithgow City Council.

Groundwater assets in the Sydney Region: Kangaloon aquifer

One of the physical groundwater assets that is connected to the entitlement system in the Sydney Region is the Kangaloon aquifer. Feasibility studies have been undertaken to build a bore field to supplement the surface water supplies of Sydney in extreme droughts. The plans include a licence to extract 30,000 ML each year for a period of up to three years, after which the aquifer would be left to recharge. Development of the bore field was shelved in 2008 and was to be halted at the point where land acquisitions, planning approval and tender design are complete, to enable reactivation without delay in future emergencies. These plans have not yet been approved. The groundwater asset associated with the Kangaloon aquifer is classed as a contingent water asset.

Desalinated water supply to Sydney Water Corporation’s distribution system

Sydney’s desalination plant at Kurnell has the capacity to produce 91,250 ML per year (Sydney Water Corporation). However, the plant’s delivery capacity depends on storage volume of reservoirs supplying water to Sydney (see ‘Other water resources’ in the contextual statement). Therefore, desalinated water supply volume is contingent on the storage volume of reservoirs. More details on Sydney’s desalinated water supply are provided in the note Significant water accounting policies.

Therefore, only 19,952 ML of desalinated water was transferred into the Sydney Region. This volume is recognised on the Statement of Changes in Water Assets and Water Liabilities and the Statement of Physical Water Flows.