Melbourne
1.5 Inter-region claim on water

Supporting information

The volume presented in the water accounting statements (794,979 ML) represents the total volume of water that Melbourne retail authorities City West Water, South East Water and Yarra Valley Water were entitled to under:

  • bulk entitlement for Thomson Reservoir
  • bulk entitlement for Silver and Wallaby creeks
  • agreement for water held in Lake Eildon.

The following table presents the breakdown of inter-region claim remaining in the Melbourne region at the start and end of the 2012–13 year.

Inter-region claim on water

Source

30 June 2013 (ML)

30 June 2012 (ML)

Thomson Reservoir

754,560

638,899

Silver and Wallaby creeks

0

0

Lake Eildon

40,419

54,313

Total

794,979

693,212

Thomson Reservoir

Collectively, City West Water, South East Water, and Yarra Valley Water hold a bulk entitlement to a share of storage in the Thomson Reservoir. This bulk entitlement allows Melbourne's retail water authorities to hold a share of the Thomson Reservoir up to its capacity 1,068,000 ML. Storage volume is shared with other users in adjacent regions, who hold the following bulk entitlements:

  • Thomson River–Victorian Environmental Water Holder (10,000 ML)
  • Thomson Macalister–Southern Rural Water (45,000 ML).

The Melbourne retail water authorities' share of storage volume in the Thomson Reservoir at the end of the 2012–13 year (inter-region claim remaining) was derived from the Thomson Reservoir share of storage opening volume, inflows, diversions, and outflows or losses from the reservoir. This calculation is presented in the following table.

Inter-region claim on Thomson Reservoir
Thomson Reservoir Volume (ML)
Opening balance at 1 July 2012                        638,899
9.15 Increase of inter-region surface water claim on water 159,955
9.11 Delivery of water under inter-region agreement to surface water                           (25,148)
17.17 Decrease of inter-region surface water claim on water                          (19,146)
Closing balance at 30 June 2013                        754,560

Water stored in Thomson Reservoir is delivered to Upper Yarra Reservoir for distribution to Melbourne's water supply system.

Silver and Wallaby creeks

Collectively, City West Water, South East Water, and Yarra Valley Water hold a bulk entitlement to divert surface water from Silver and Wallaby creeks. The bulk entitlement specifies that a maximum volume of 66,000 ML may be diverted from Silver and Wallaby creeks over a three-year period (subject to rules specified in the bulk entitlements). If less than the maximum volume is diverted, the remaining volume is not carried over to the following year. Subsequently the opening and closing balance of the claim remains zero.

Water is diverted from Silver and Wallaby creeks and delivered to Tooroorung Reservoir and Yan Yean Reservoir for distribution to Melbourne's water supply system. The total volume of water delivered from Silver and Wallaby creeks is presented as part of 9.11 Delivery of water under inter-region agreement to surface water.

Lake Eildon

Melbourne retail authorities have claim to water from Lake Eildon under a water savings supply and transfer agreement (an unpublished document). Under the agreement, water savings from Stage 1 of the Northern Victoria Irrigation Renewal Project were allocated to Melbourne retail authorities and stored in Lake Eildon.

The calculation of the inter-region claim remaining on water stored in Lake Eildon is presented in the following table.

Inter-region claim on Lake Eildon
Lake Eildon
Volume (ML)
Opening balance at 1 July 2012 54,313

9.15 Increase of inter-region surface water claim on water

27,042

9.11 Delivery of water under inter-region agreement to surface water

(18)

17.17 Decrease of inter-region surface water claim on water

(40,918)
Closing balance at 30 June 2013 40,419

Water stored in Lake Eildon is delivered to Sugarloaf Reservoir via the north–south Pipeline for distribution to Melbourne's water supply system. 

Further information on bulk entitlements can be found at the Victorian Water Register.