Melbourne: Statement of Changes in Water Assets and Water Liabilities

for the year ended 30 June 2021

  • The volume of water in the region's storages increased during 2020–21 for the second consecutive year.
  • This increase represents the change in water volume in the region's surface water storages.

Schematic representation of the Melbourne region. Total water inflows during 2020–21 was 3,490 GL. Total water outflows was 3,093 GL. Water storage at 30 June 2021 was 223 GL higher than the previous year.

The Statement of Changes in Water Assets and Water Liabilities is provided in the table below. The statement presents the actual water flows associated with the region's water stores, as well as the changes in water assets and water liabilities that occurred during the year.

 

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 2021 ML2020 ML2019 ML2018 ML2017 ML2016 ML
Water inflows
Surface water inflows1,884,2512,007,158783,1961,081,9241,893,529864,165
Precipitation85,19081,00050,069**62,104**74,360**56,263
Inter-region inflow296,432214,818126,955**157,667**196,912**132,079
Runoff1,407,3781,625,851566,395**798,421**1,510,712**626,694
Point return: irrigation51109246576182
Flood return69,49167,63125,522**44,260**90,152**33,501
Discharge: urban supply*0000831281
Discharge: wastewater*23,10516,94113,65318,65817,44314,206
Delivery: inter-region2,604808356**757**3,058**1,059
 
Groundwater inflows774,006708,579290,791319,906385,279301,539
Inter-region coastal inflow28,71538,59629,90328,47128,71328,394
Recharge: landscape346,462302,222119,528**125,443**127,676**119,311
Recharge: surface water*373,331342,171107,763**126,101**195,120**115,239
Leakage: urban system*25,49825,59033,59739,89133,77038,595
 
Urban water system inflows832,175852,922825,973835,015860,976796,474
Wastewater collected391,974396,803359,631361,263377,859350,527
Allocated diversion: surface water*315,125337,915443,896458,708436,848445,845
Allocated extraction: groundwater*7672727260102
Delivery: desalinated water125,000118,13222,37414,97246,2090
 
Total water inflows3,490,4323,568,6591,899,960**2,236,845**3,139,784**1,962,178
Water outflows
Surface water outflows2,111,0862,087,4011,226,3791,448,8141,930,1271,306,307
Evaporation76,03071,30672,833**78,831**78,674**74,096
Outflow1,108,1961,101,543534,774**682,047**1,026,002**584,548
Recharge: groundwater*373,331342,171107,763**126,101**195,120**115,239
Overbank flow215,254211,22941,672**79,644**169,415**63,365
Non-allocated diversion: individual users10,83910,32313,65212,243**12,04214,670
Allocated diversion: individual users8,6648,6517,6187,391**8,2345,004
Allocated diversion: urban system*315,125337,915443,896458,708436,848445,845
Transfer: inter-region3,6474,2634,1713,8493,7923,540
 
Groundwater outflows143,912202,728151,343153,431154,939149,266
Inter-region coastal outflow126,277184,378130,311132,349134,657124,561
Discharge: landscape––––––
Allocated extraction: individual users17,55918,27820,96021,010**20,22224,603
Allocated extraction: urban system*7672727260102
 
Urban water system outflows837,740849,954815,898815,165812,423789,630
Leakage: groundwater*25,49825,59033,59739,89133,77038,595
Delivery: urban users394,040398,582409,913398,598386,147389,989
Discharge: sea316,732322,703268,481277,668301,846267,248
Discharge: landscape00107253190131
Supply system transfer: inter-region7,21212,7855,8362,1591,071431
Supply system delivery: irrigation01021,2561,5077561,365
Supply system discharge: surface water*0000831281
Other supply system decreases14,03512,43913,68614,69913,35512,567
Recycled water delivery: urban users39,82140,42638,42231,48030,63331,440
Recycled water delivery: irrigation8,2437,79312,41512,2248,97011,868
Wastewater discharge: surface water*23,10516,94113,65318,65817,44314,206
Other wastewater decreases9,05412,59318,53218,02817,41121,509
 
Total water outflows3,092,7383,140,0832,193,620**2,417,410**2,897,489**2,245,203
 
Unaccounted-for difference(174,452)**(178,524)142,842**89,999**(144,937)**100,374
 
 
Change in water storage      
Change in surface water storage222,949**250,229(151,208)**(89,959)**98,160**(183,739)
Change in groundwater storage–190000
Change in urban water storage293(196)390(607)(802)1,088
Total change in water storage223,242**250,052(150,818)**(90,566)**97,358**(182,651)
 
Closing water storage1,571,4391,348,197**1,098,145**1,248,963**1,339,529**1,242,171
 
 
Change in water claims      
Change in urban system claims*49,62293,861(40,140)(31,306)31,706(2,585)
Total change in water claims49,62293,861(40,140)(31,306)31,706(2,585)
 
 
Change in water liability
Surface water liability49,84499,132(42,590)(33,893)39,189(5,014)
Allocation remaining: individual users2225,271(2,450)(2,587)7,483(2,429)
Allocation remaining: urban system*49,62293,861(40,140)(31,306)31,706(2,585)
Commitment: inter-region000000
 
Groundwater liability000000
Allocation remaining: individual users000000
Allocation remaining: urban system*000000
Total change in water liability49,84499,132(42,590)(33,893)39,189(5,014)
       
Net change in water assets223,020**244,781(148,368)**(87,979)**89,875**(180,222)
 

 

* between-store flows

** different to published volume in historical accounts (see Governance for more information)

Note: quantification approaches used to derive each item volume are provided in the Methods