Murray-Darling Basin
17.1 Evaporation from surface water

Supporting Information

The volumetric value for the line item at the end of the 2010–11 year was 3,505,568 ML.

The line item represents evaporation volumes from surface water assets within the Murray–Darling Basin (MDB) region. Evaporation from storages (included in line item 1.1); regulated river channels, locks and weirs (included in line item 1.3); lakes (included in line item 1.4); and other known water bodies within the region were taken into account in the line item. Information on evaporation from other surface water assets (mainly unregulated rivers and unknown water bodies) is not available.

Evaporation volumes from surface water assets on water resources plan (WRP) area basis are summarised in the following table. Specific details of evaporation from individual asset basis are included in the table thereafter. In the tables, volumes shown against a WRP or sustainable diversion limit (SDL) area are based on surface water assets geographically located within that area.


Summary of evaporation volumes on surface water assets in the MDB region in the 2010–11 year
Surface water resource plan area


 Volume (ML) for the 2010–11 year  



SW18 Condamine–Balonne Qld 76,744
SW16 Qld Border Rivers Qld 46,482
SW15 NSW Border Rivers NSW 14,798
SW14 Gwydir NSW 38,835
SW13 Namoi NSW 76,713
SW10 Macquarie–Castlereagh NSW 118,824
Sub-total Northern Basin 372,396
SW9 Lachlan NSW 137,885
SW8 Murrumbidgee NSW NSW 129,225
SW7 NSW Murray and Lower Darling NSW 1,153,414
SW3 Northern Victoria Vic 325,367
SW2 Vic Murray Vic 229,451
SW4 Wimmera–Mallee Vic 49,578
SW5 SA Murray SA 1,086,563
SW1 ACT ACT 21,689
Sub-total Southern Basin 3,133,172
Total for the region 3,505,568


Specific details of evaporation volumes on individual surface water asset basis in the MDB region in the 2010–11 year
Water resource plan area

SDL area


Surface water asset

 Volume (ML) for the 2010–11 year 



Condamine–Balonne SS26 Condamine–Balonne Qld Buckinbah Weir1 3,228
Chinchilla Weir1 4,395
Connolly Dam2 606
Cooby Creek Reservoir2 3,407
Jack Taylor Weir1 4,847
Lake Kajarabie1  44,965
Lake Leslie1  13,474
Moolabah Weir1 1,647
Neil Turner Weir2 175
Qld Border Rivers SS24 Qld Border Rivers Qld Glenlyon Lake1 22,377
Lake Coolmunda1  22,824
Storm King Dam2 1,281
NSW Border Rivers SS23 NSW Border Rivers NSW Lake Inverell2  516
Pindari Lake1 13,974
Tenterfield Creek2 308
Gwydir SS22 Gwydir NSW Lake Copeton1  37,533
Tareelaroi Weir1 1,302
Namoi  SS21 Namoi  NSW Chaffey Dam1 6,742
Dungowen2 612
Gunidgera Weir1 928
Lake Keepit1  55,688
Mollee Weir1 1,413
Quipolly Dam2 1,500
Split Rock Reservoir1 9,830
Macquarie–Castlereagh SS20 Macquarie–Castlereagh NSW Chifley Dam2 3,205
Lake Burrendong1  92,771
Lake Oberon2  4,749
Lake Windamere1  13,538
Rylstone Reservoir2 1,134
Spring Creek Reservoir2 969
Suma Park Reservoir2 1,955
Timor Dam2 246
Winburndale Dam2 257
Northern Basin 372,396
Lachlan  SS16 Lachlan  NSW Carcoar Lake1 2,665
Lake Brewster1  62,120
Lake Cargelligo1  20,403
Lake Endeavour2  708
Lake Rowlands2  943
Lake Wyangala1  51,046
Murrumbidgee NSW SS15 Murrumbidgee  NSW Berembed Weir1 1,445
Blowering Reservoir1 51,008
Gogeldrie Weir1 2,738
Hay Weir1 5,358
Lake Burrinjuck1  62,238
Maude Weir1 2,221
Redbank Weir2 231
Tombullen Storage1 3,986
NSW Murray and Lower Darling SS18 Lower Darling NSW Lake Cawndilla1  176,014
Lake Menindee1  242,027
Lake Victoria1  152,419
Lake Wetherell1  114,882
Pamamaroo Lake1 103,364
Stephens Creek Reservoir2 10,644
SS14 NSW Murray NSW Lake Hume1  228,973
Upstream of Lock 7 (Rufus)2 6,334
Upstream of Lock 8 (Wangumma)2 9,141
Upstream of Lock 9 (Kulnine)2 14,583
Upstream of Lock 10 (Wentworth)2 13,087
Upstream of Lock 15 (Euston)2 81,946
Vic Murray SS3 Kiewa Vic Lake Guy2  98
Rocky Valley Storage2 2,048
Northern Victoria SS4 Ovens Vic Lake Buffalo1  2,929
Lake William Hovell1 1,461
SS5 Broken Vic Lake Nillahcootie1  6,162
SS6  Goulburn  Vic Goulburn Weir 1 13,130
Greens Lake1 9,480
Lake Eildon1  117,508
Waranga Basin1 67,444
SS7 Campaspe Vic Campaspe Weir2 284
Lake Eppalock1  33,563
Lauriston Reservoir2 2,362
Malmsbury Reservoir2 3,167
Upper Coliban Reservoir2 3,082
SS8 Loddon Vic Barkers Creek Reservoir2 632
Cairn Curran Reservoir1 18,908
Crusoe Reservoir2 332
Evansford Reservoir2 283
Hepburn Lagoon2 986
Kow Swamp2 29,262
Laanecoorie Reservoir1 4,995
Mccay2 198
Newlyn Reservoir1 639
Sandhurst Reservoir2 328
Spring Gully Reservoir2 431
Tullaroop Reservoir1 7,801
Vic Murray SS2 Vic Murray Vic Kangaroo/Racecourse Lake2 14,432
Lake Banimboola2  708
Lake Dartmouth1  56,094
Lake Mulwala1 52,584
Mildura Weir2  1,572
Reedy/Middle Lake2 4,747
Third Lake2 2,750
Torrumbarry Weir1 10,539
Upstream of Lake Mulwala2 33,272
Upstream of Mildura Weir2 50,607
Wimmera–Mallee SS9 Wimmera–Mallee  Vic Lake Bellfield1  3,825
Lake Fyans1  4,359
Lake Lonsdale1  25,552
Lake Taylor1  5,505
Lake Whitton2  882
Toolondo Reservoir1 61
Wartook Reservoir1 9,394
SA Murray SS11 SA Murray SA Blanchetown Weir – Lock 11 17,010
Bookpurnong Weir – Lock 41 9,099
Lake Albert1 191,187
Lake Alexandrina1 755,299
Overland Weir – Lock 31 16,784
Renmark Weir – Lock 51 10,905
Upstream of Lock 6 (Murtho)2 17,238
Upstream of Lake Alexandrina2 54,774
Waikerie Weir  – Lock 21 14,267
ACT SS1 ACT ACT Bendora Dam1 856
Corin Dam1 2,948
Cotter Dam1 471
Googong Reservoir1 8,065
Lake Burley Griffin2 7,241
Lake Ginninderra2  1,249
Lake Tuggeranong2 859
Southern Basin 3,133,172
Total for the region 3,505,568

1 Dynamic surface area was used in calculations

2 Static surface area was used in calculations (based on boundaries defined for surface water bodies in Bureau of Meteorology's Australian Hydrological Geospatial Fabric)


Quantification Approach

Data Source

Bureau of Meteorology (the Bureau): (1) Rainfall, temperature and solar radiation grids, (2) Australian Hydrological Geospatial Fabric (AHGF) waterbody feature class and (3) Australian Water Resources Information System (AWRIS) water storage.

Provided by

The Bureau.


The Priestly and Taylor method to estimate potential evaporation (as calculated by the WaterDyn model [Raupach 2008]) was used to estimate evaporation from the surface water assets. Monthly potential evaporation data produced by the Bureau were used, based on daily gridded climate data that is available on a 0.05 degree (approximately 5 km) national grid.

Potential evaporation is an estimate of the evaporative demand of the environment. The daily gridded climate data sets used to produce this estimate are generated by the Bureau and include downward solar irradiance, and maximum and minimum air temperature. The methods used to generate these gridded data-sets are outlined in Jones et al. (2007).

The evaporation at each waterbody was estimated from the proportionally weighted average of grid-pixels cells that intersected each water feature. The volume was then estimated using the monthly average surface area of each waterbody. The surface area varied dynamically with changing level for storages where the relationship between storage level and surface area had been derived.

Assumptions, Limitations, Caveats and Approximations

The Priestly and Taylor method potential evaporation estimates are subject to approximations associated with interpolating the observation point input data to a national grid as described in Jones et al. (2007).

The dynamic storage surface areas calculated from the levels and storage rating tables represent a monthly average and therefore do not capture changes that occur on a shorter time-scale.

Uncertainty Information

The uncertainty estimate was not quantified.

Comparative year

This line item corresponds to line item 14.1 Evaporation from connected surface water, reported in the 2010 Account. In the 2011 Account, the following changes were made that caused the 2009–10 year value to be restated:

  •  The scope of the line item was changed.

  • An error was committed in the values reported in the 2010 Account.

  • The methodology used to quantify the line item was improved and resulted in a material change in volume.

The changes and their respective values are detailed in the following table.


Restatement of comparative year information made for the line item 17.1 Evaporation from surface water
2010 Account line items


Volume for the 2009–10 year reported in the 2010 Account (ML)

Difference due to scope, prior period error correction and calculation method change (ML)

Volume for the 2009–10 year reported in the 2011 Account (ML)

14.1 Evaporation from connected surface water Northern Basin 261,749 –57,603 204,146
Southern Basin 2,896,721 –423,914 2,472,807
Whole region 3,158,470 –481,517 2,676,953

Scope change was due to the following reasons:

  • Lake Mokoan, Lake Batyo Catyo, Pine Lake, Dock Lake and Green Lake (included in the 2010 Account) were excluded for the 2011 Account.  Information for Lake Mokoan was not available.  Qualification of other four storages as surface water asset was not verified at the data collection phase for the 2011 Account (they were considered as abandoned after the construction of Wimmera pipeline).  For 2012 Account, these storages will be investigated for their inclusion.

  • Regulated river reaches upstream of Lock 10 and Lock 15 in the River Murray were included for the 2011 Account.

Prior period error correction was due to the following reason:

  • Barren Box Swamp was included in the 2010 Account.  However, it is not a surface water asset for the 2011 Account because this storage is located in a water distribution system.  Barren Box Swamp was excluded in the 2011 Account.

Calculation method change was due to the following reason:

  • Penman open water evaporation method was used for the 2010 Account. For the 2011 Account, Priestly and Taylor potential evaporation method was used.  The change was made for better estimate of evaporation.