Murray–Darling Basin
17.1 Evaporation from surface water

The volumetric value for the line item at the end of the 2012–13 year was 3,036,866 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 the evaporation volumes on surface water assets in the MDB region in the 2012–13 year

Surface WRP area		State/Territory	Volume (ML)
Code	Name
SW20	Warrego–Paroo–Nebine	Qld	–
SW19	Condamine–Balonne	Qld	55,935
SW18	Moonie	Qld	–
SW17	Qld Border Rivers	Qld	34,355
SW16	NSW Border Rivers	NSW	10,867
SW12	Barwon–Darling Watercourse	NSW	–
SW13	NSW Intersecting Streams	NSW	–
SW15	Gwydir	NSW	51,442
SW14	Namoi	NSW	66,883
SW11	Macquarie–Castlereagh	NSW	92,347
Sub-total Northern Basin			311,829
SW10	Lachlan	NSW	141,038
SW9	Murrumbidgee NSW	NSW	98,599
SW8	NSW Murray and Lower Darling	NSW	924,208
SW3	Northern Victoria	Vic.	287,745
SW2	Vic. Murray	Vic.	237,951
SW4	Wimmera–Mallee	Vic.	62,507
SW5 and SW7	SA Murray Region and Eastern Mount Lofty Ranges	SA	–
SW6	SA River Murray	SA	953,358
SW1	ACT	ACT	19,629
Sub-total Southern Basin			2,725,037
Total for the region			3,036,866

 

Specific details of evaporation volumes on individual surface water asset basis in the MDB region in the 2012–13 year

WRP area	SDLarea		State/Territory	Surface water asset	Volume (ML) for the 2012–13 year
	Code	Name
SW19 Condamine–Balonne	SS26	Condamine–Balonne	Qld	Buckinbah Weir1	2,691
				Chinchilla Weir1	4,162
				Connolly Reservoir2	564
				Cooby Creek Reservoir2	3,279
				Jack Taylor Weir1	3,368
				Lake Kajarabie1	28,621
				Lake Leslie1	11,993
				Moolabah Weir1	1,111
				Neil Turner Weir2	147
SW17 Qld Border Rivers	SS24	Qld Border Rivers	Qld	Glenlyon Lake1	19,984
				Lake Coolmunda1	13,116
				Storm King Reservoir2	1,255
SW16 NSW Border Rivers	SS23	NSW Border Rivers	NSW	Lake Inverell2	481
				Pindari Lake1	10,078
				Tenterfield Creek Reservoir2	308
SW15 Gwydir	SS22	Gwydir	NSW	Lake Copeton1	50,315
				Tareelaroi Weir1	1,127
SW14 Namoi	SS21	Namoi	NSW	Chaffey Reservoir1	474
				Dungowen Reservoir2	826
				Gunidgera Weir1	720
				Lake Keepit1	39,093
				Mollee Weir1	1,144
				Quipolly Reservoir2	1,293
				Split Rock Reservoir1	23,333
SW11 Macquarie–Castlereagh	SS20	Macquarie–Castlereagh	NSW	Chifley Reservoir2	2,964
				Lake Burrendong1	62,728
				Lake Oberon2	4,876
				Lake Windamere1	17,460
				Rylstone Reservoir2	1,024
				Spring Creek Reservoir2	960
				Suma Park Reservoir2	1,781
				Timor Reservoir2	250
				Winburndale Reservoir2	304
Sub-total Northern Basin					311,829
SW10 Lachlan	SS16	Lachlan	NSW	Carcoar Lake1	3,554
				Lake Brewster1	67,502
				Lake Cargelligo1	15,335
				Lake Endeavour2	655
				Lake Rowlands2	955
				Lake Wyangala1	53,036
SW9 Murrumbidgee NSW	SS15	Murrumbidgee NSW	NSW	Berembed Weir1	1,072
				Blowering Reservoir1	44,858
				Gogeldrie Weir1	2,222
				Hay Weir1	5,078
				Lake Burrinjuck1	39,635
				Maude Weir1	1,975
				Redbank Weir2	194
				Tombullen Storage1	3,565
SW8 NSW Murray and Lower Darling	SS18	Lower Darling	NSW	Lake Cawndilla1	142,689
				Lake Menindee1	198,977
				Lake Victoria1	123,772
				Lake Wetherell1	90,185
				Pamamaroo Lake1	86,588
				Stephens Creek Reservoir2	8,892
	SS14	NSW Murray	NSW	Lake Hume1	164,220
				Upstream of Lock 7 (Rufus)2	5,277
				Upstream of Lock 8 (Wangumma)2	7,657
				Upstream of Lock 9 (Kulnine)2	12,241
				Upstream of Lock 10 (Wentworth)2	11,417
				Upstream of Lock 15 (Euston)2	72,295
SW2 Vic. Murray	SS3	Kiewa	Vic.	Lake Guy2	116
				Rocky Valley Storage2	2,036
SW3 Northern Victoria	SS4	Ovens	Vic.	Lake Buffalo1	3,870
				Lake William Hovell1	1,603
	SS5	Broken	Vic.	Lake Nillahcootie1	5,374
				McCall Say Reservoir1	313
	SS6	Goulburn	Vic.	Goulburn Weir 1	10,640
				Greens Lake1	6,167
				Lake Eildon1	126,354
				Waranga Basin1	44,830
	SS7	Campaspe	Vic.	Campaspe Weir2	241
				Lake Eppalock1	27,942
				Lauriston Reservoir2	2,163
				Malmsbury Reservoir2	2,994
				Upper Coliban Reservoir2	2,903
	SS8	Loddon	Vic.	Barkers Creek Reservoir2	514
				Cairn Curran Reservoir1	15,615
				Crusoe Reservoir2	295
				Evansford Reservoir2	253
				Hepburn Lagoon2	910
				Kow Swamp2	23,334
				Laanecoorie Reservoir 1	3,667
				McCay Reservoir2	200
				Newlyn Reservoir 1	594
				Sandhurst Reservoir2	296
				Spring Gully Reservoir2	373
				Tullaroop Reservoir1	6,300
SW2 Vic. Murray	SS2	Vic. Murray	Vic.	Kangaroo/Racecourse Lake2	11,772
				Lake Banimboola2	726
				Lake Dartmouth1	76,447
				Lake Mulwala1	42,368
				Mildura Weir2	1,341
				Reedy/Middle Lake2	3,927
				Third Lake2	2,260
				Torrumbarry Weir1	11,097
				Upstream of Lake Mulwala2	42,368
				Upstream of Mildura Weir2	43,492
SW4 Wimmera–Mallee	SS9	Wimmera–Mallee	Vic.	Dock Lake1	5,158
				Green Lake1	6,191
				Lake Batyo Catyo1	505
				Lake Bellfield1	5,624
				Lake Fyans1	4,182
				Lake Lonsdale1	13,669
				Lake Taylor1	3,342
				Lake Whitton2	749
				Pine Lake1	3,477
				Toolondo Reservoir1	8,709
				Wartook Reservoir1	10,900
SW6 SA River Murray	SS11	SA Murray	SA	Blanchetown Weir – Lock 11	40,832
				Bookpurnong Weir – Lock 41	7,590
				Lake Albert1	169,942
				Lake Alexandrina1	640,479
				Overland Weir – Lock 31	13,162
				Renmark Weir – Lock 51	8,984
				Upstream of Lock 6 (Murtho)2	14,004
				Upstream of Lake Alexandrina2	46,280
				Waikerie Weir – Lock 21	12,085
SW1 ACT	SS1	ACT	ACT	Bendora Reservoir1	924
				Corin Reservoir1	3,098
				Cotter Reservoir1	474
				Googong Reservoir1	7,687
				Lake Burley Griffin 2	5,707
				Lake Ginninderra2	1,012
				Lake Tuggeranong2	728
Sub-total Southern Basin					2,725,037
Total for the MDB region					3,036,866

¹ Dynamic surface area was used in calculations

² Static surface area used (based on boundaries defined for surface water bodies in Bureau of Meteorology's  Australian hydrological geospatial fabric (AHGF)

 

Bureau of Meteorology (the Bureau): National Climate Centre (NCC) daily climate grids (rainfall, temperature and solar radiation), Australian hydological geospatial fabric (AHGF) waterbody feature class, and Australian water resources information system (AWRIS) water storage.

The Bureau.

The potential evaporation estimate produced by the Australian Water Resources Assessment system landscape model (AWRA-L) version 3.0 (Van Dijk 2010) was used to calculate evaporation from the surface water store. The AWRA-L model uses a modified version of the Penman–Monteith method to produce the potential evaporation. Daily AWRA-L potential evaporation grids were produced based on daily gridded climate data that were available on a 0.05⁰ (approximately 5 km) national grid.

Potential evaporation was an estimate of the evaporative demand of the environment. The daily gridded climate data sets used to produce this estimate were generated by the Bureau and included downward solar irradiance, and maximum and minimum air temperature. The methods used to generate these gridded data-sets have been 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, where this relationship was not available the static AHGF surface area was used.

• The AWRA-L 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.
• The use of the static default AHGF surface area is an approximation only. It represents the waterbody at capacity and therefore likely results in an overestimation of precipitation on those features.

The uncertainty estimate was not quantified.

There was a prior period error in the line item volume reported in the 2012 Account. The prior period error was a result of using solar radiation data with bias correction errors. Solar radiation is an input for line item volume calculation. The line item volume for the 2011–12 year has been recalculated accommodating the prior period error correction. 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

Segment	2013 Account volume for the 2011–12 year (ML)	2012 Account volume for the 2011–12 year (ML)	Difference due to a prior period error (ML)
Northern Basin	313,670	366,255	(52,585)
Southern Basin	2,672,732	2,892,164	(219,432)
Whole region	2,986,402	3,258,419	(272,017)