DEECA Victorian Water Accounts 2021-22

About the area

This page describes the water account for the ‘common’ or wholesale water supply system that Melbourne Water operates for the greater Melbourne metropolitan area as well as for connected regional water authorities. It spans four river basins: Bunyip, Yarra, Maribyrnong and Werribee. Water is harvested from the Bunyip, Yarra, Thomson and Goulburn basins. The water supply system draws from several on-stream storages and includes four significant off-stream storages: the Silvan, Cardinia, Sugarloaf and Greenvale reservoirs.

Most of the inflows come from protected catchments in the Yarra, Bunyip and Thomson basins, and minimal treatment (chlorination) is required. However, about 20% comes from unprotected catchments, and this water is fully treated by treatment plants at the Sugarloaf, Tarago and Yan Yean reservoirs.

Water balance

The table below shows the total volumes of water supplied from water resources in the Melbourne Water system in 2021-22.

Table 1: Water balance, Melbourne Water

Water account component	2021-22 (ML)	2020-21 (ML)
Volume in store
Start volume in store ¹	350,444	355,531
End volume in store ¹	388,627	350,444
Change in store ¹	38,183	(5,087)
Inflows
From Yarra basin to Silvan	240,601	195,805
From Yarra basin to Sugarloaf	119,111	103,346
From Goulburn River to Sugarloaf	0	0
From Tarago Reservoir	10,258	11,475
Inflow of desalinated water	125,000	125,000
Rainfall on four main storages	19,082	20,726
Unaccounted for inflow	-	2,191
Total inflows	514,052	458,543
Outflows
Deliveries
To South East Water	160,399	154,805
To Yarra Valley Water	159,126	156,422
To Greater Western Water	122,857	120,272
To Gippsland Water	2,052	1,974
To Barwon Water	1,280	4,524
To South Gipsland Water	681	714
To Westernport Water	132	253
To Cardinia Creek from Cardinia	1,825	1,825
To Stonyford Creek from Silvan	730	730
Total deliveries	449,082	441,519
Losses
Evaporation from four main storages	20,173	19,462
System losses	743	2,649
Unaccounted for outflow	5,871	-
Total losses	26,787	22,111
Total outflows	475,869	463,630
System efficiency
Distribution system efficiency (%)	94%	95%

Water account component	2021-22 (ML)	2020-21 (ML)
Volume in store
Start volume in store ¹	350,444	355,531
End volume in store ¹	388,627	350,444
Change in store ¹	38,183	(5,087)
Inflows
From Yarra basin to Silvan	240,601	195,805
From Yarra basin to Sugarloaf	119,111	103,346
From Goulburn River to Sugarloaf	0	0
From Tarago Reservoir	10,258	11,475
Inflow of desalinated water	125,000	125,000
Rainfall on four main storages	19,082	20,726
Unaccounted for inflow	-	2,191
Total inflows	514,052	458,543
Outflows
Deliveries
To South East Water	160,399	154,805
To Yarra Valley Water	159,126	156,422
To Greater Western Water	122,857	120,272
To Gippsland Water	2,052	1,974
To Barwon Water	1,280	4,524
To South Gipsland Water	681	714
To Westernport Water	132	253
To Cardinia Creek from Cardinia	1,825	1,825
To Stonyford Creek from Silvan	730	730
Total deliveries	449,082	441,519
Losses
Evaporation from four main storages	20,173	19,462
System losses	743	2,649
Unaccounted for outflow	5,871	-
Total losses	26,787	22,111
Total outflows	475,869	463,630
System efficiency
Distribution system efficiency (%)	94%	95%

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About the area

Water balance

Table 1: Water balance, Melbourne Water

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Victorian Water Accounts 2021-22

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