Sydney
17.17 Decrease of inter-region surface water claim on water

The decrease in the inter-region claim on the Fish River Water Supply Scheme for Sydney Catchment Authority and Delta Electricity for the 2012–13 year was 4,955 ML.

Sydney Catchment Authority: internal databases; New South Wales Office of Water: Fish River Water Supply Scheme Weekly Use Report 2012–13.

Sydney Catchment Authority; New South Wales Office of Water.

Total adjustment and forfeiture on the inter-region claim on surface water is calculated by summing the total carry-over and entitlement for the 2012–13 year, and subtracting any diversions made during that year and any carry-over into the 2013–14 year.

Both Sydney Catchment Authority and Delta Electricity have an annual maximum allocation entitlement from the Fish River Water Supply Scheme to supply water to their storages. This entitlement is subject to a number of operating rules and restrictions depending on levels in the supply storages (Oberon Dam and Duckmaloi Weir).

The carry-over volume available at the beginning of a year from the Fish River Water Supply Scheme is calculated from entitlement holder's allocation and metered supply volume for the previous two years (carry-over volume is a two-year rolling average computed every six months; the carry-over volume is capped at 50% of the maximum annual quantity).

Total forfeiture is calculated as shown in the following table.

 

Total decrease of claim on inter-region surface water during the 2012–13 year

		Volume (ML)
	Opening balance 1.5 Inter-region claim on water  (as at 30 June 2012)	2,367
add	9.15 Increase of inter-region surface water claim on water	11,834
less	9.11 Delivery of water under inter-region agreement to surface water	6,879
less	Closing balance 1.5 Inter-region claim on water (as at 30 June 2013)	2,367
	Total decrease on claim (as at 30 June 2013)	4,955

It is assumed that the maximum allocation entitlement held by each organisation for the Fish River Water Supply Scheme represents the total allocation for the region.

Carryover volume is based on measured data. Estimated uncertainty based on meter accuracy is +/– 2%.

In the 2011–12 year, this line item included Lithgow City Council's decrease of inter-region claim on the Fish River Water Supply Scheme. As Lithgow City Council diversions are now part of the urban water store this volume is now accounted for in 19.14 Decrease of urban inter-region claim on water.

Therefore, the volume reported for this line item has been restated to 5,636 ML for the 2011–12 year.