Adelaide
4.1 Irrigation water supply system

The irrigation water supply system included volumes of water held within the pipe and tanks infrastructure from the three major irrigation schemes located within the Adelaide region. The opening and closing balances reported (29 ML) did not change as there was no new infrastructure added to these irrigation schemes in the 2010–11 year. The volumes of water held in irrigation schemes are provided in the following table.

Volume of water stored in Adelaide region irrigation scheme's pipes and tanks infrastructure

Irrigation Scheme	Storage volume at 30 June 2010 (ML)	Storage volume at 30 June 2011 (ML)
Barossa Infrastructure Limited (BIL)	19	19
Virginia Pipeline Scheme (VPS)	9.5	9.5
Willunga Basin Water Company (WBWC)	0	0
Total	29	29

 

Barossa Infrastructure Limited (BIL): hard copy map of pipe network.

South Australian Department for Water.

BIL operate a network of approximately 189 km of pipes. The total pipe lengths and corresponding pipe diameters were obtained from a 2009 hard copy map of the BIL pipe network. Lengths and diameters were then used to calculate the total volume stored in the pipes if 100% full, according to the equation:

V = (π × (d/2)2 × (L/1000)
where:
  V = volume (ML)
  d = nominal pipe diameter (m)
  L = length of section (m).

• Pipes were under pressure and therefore were 100% full at all times.
• The 2009 hard copy map of the BIL pipe network was an accurate depiction of the network for the 2010–11 year.
• The nominal pipeline diameters recorded on the map represent the internal diameter of the pipeline.
• An analysis determined that 96% of BIL's pipe network was within the Adelaide region. This discrepancy was assumed to be negligible.

The uncertainty estimate was not quantified.

Water Infrastructure Group.

Water Infrastructure Group.

The Virginia Pipeline Scheme includes approximately 130 km of pipes and a storage pond which receives water directly from Bolivar Wastewater Treatment Plant. The volumes of water held in these pipes and the storage pond were estimated from their total capacity. The storage pond holds approximately 5 ML of water and the pipeline network holds 4.5 ML.

• Pipes were under pressure and therefore were 100% full at all times.
• The storage pond was assumed to be at 100% capacity.
  

The uncertainty estimate was not quantified.

Willunga Basin Water Company.

Willunga Basin Water Company.

Pipes and storages that form part of the Willunga Basin Water Company's (WBWC) infrastructure are emptied between May and October.

• The residual water in the WBWC's pipes and tanks following drainage is negligible.

• WBWC uses the community wastewater management system as an operational storage. They pump water into and out of the lagoons to balance out fluctuations in customer demands and address pipe capacity issues. The volume of wastewater in the treatment lagoons is not counted as part of the irrigation scheme.

•  Pipes and tanks are completely empty.

The uncertainty estimate was not quantified.

This line item corresponds to line item 5.4 Irrigation water supply system, reported in the 2010 Account. In the 2011 Account, the following changes were made that caused the 2009–10 year value to be restated:

• In the 2011 Account a separate irrigation scheme store has been included. In the 2010 Account, this line item was reported as part of the water distribution system store (Urban water supply system). this change was made to provide users with clearer information. This change in scope did not affect the volume reported.
  
• In the 2011 Account, two additional irrigation schemes were reported on. Although the change to the volume reported was small, the volume was restated to provide users with clearer information and comparability between years.

These changes and their respective volumes are detailed in the following table. The restated comparative year volume is 29 ML.

Restatement of comparative year information forline item 4.1 Irrigation water supply system

2010 Account line item name	Irrigation water supply system	Opening/closing volume at 30 June 2010 reported in 2010 Account (ML)	Value difference to volume reported due to inclusion of additional irrigation schemes (ML)	Opening/closing volume at 30 June 2010 reported in 2011 Account (ML)
5.4 Irrigation water supply system	Barossa Infrastructure Limited (BIL)	19		19
	Virginia Pipeline Scheme (VPS)		9.5	9.5
	Willunga Basin Water Company (WBWC)			0
Total		19	9.5	29