Editing Dartmouth Dam

{{Use dmy dates|date=April 2022}}
{{Use Australian English|date=March 2014}}
{{Infobox dam
| name = Dartmouth Dam
| name_official = 
| image = dartmouthdam2.jpg
| image_size = 270px
| image_caption = Dartmouth Dam wall, pictured in April 2003
| image_alt = 
| location_map = Victoria
| location_map_size = 270px
| location_map_caption = Location of the Dartmouth Dam in [[Victoria, Australia|Victoria]]
| coordinates = {{coord|36|33|29|S|147|31|25|E|type:landmark|display=inline,title}}
| country = Australia
| location = [[Victoria (state)|Victoria]]
| status = O
| construction_began = 1973
| opening = 1979
| demolished = 
| cost = A$139&nbsp;million
| operator = [[Goulburn–Murray Water]]
| owner = [[Murray Darling Basin Authority]]
| dam_type = E
| dam_height = 
| dam_height_thalweg = {{cvt|180|m|0}}
| dam_height_foundation = 
| dam_length = {{cvt|92|m|0}}
| dam_elevation_crest = {{cvt|486|m|0}} {{AHD}}
| dam_width_crest = {{cvt|670|m|0}}
| dam_width_base = {{cvt|700|m|0}}
| dam_volume = {{convert|14.1|e6m3|abbr=unit|0}}
| dam_crosses = {{unbulleted list|[[Mitta Mitta River]]|[[Gibbo River]]|[[Dart River (Victoria)|Dart River]]|Morass Creek and others}}
| spillway_count = 
| spillway_type = [[spillway#Types|Uncontrolled chute]]
| spillway_capacity = {{cvt|2750|m3/s|0}}
| res_name = Dartmouth Reservoir
| res_capacity_total = {{convert|3856|GL|e9impgal+e12USgal|abbr=unit|0}}
| res_capacity_active = 
| res_capacity_inactive = {{convert|71|GL|e9impgal+e9USgal|abbr=unit|0}}
| res_catchment = {{cvt|3600|km2|0}}
| res_surface = {{cvt|6300|ha|0}}
| res_elevation = 
| res_max_depth = 
| res_max_length = 
| res_max_width = 
| res_tidal_range = 
| plant_name = Dartmouth Power Station
| plant_coordinates = 
| plant_operator = [[AGL Energy]]
| plant_commission = January 1981
| plant_decommission = 
| plant_type = [[Francis-type]]
| plant_turbines = 1 × {{cvt|180|MW|0}}
| plant_capacity = {{cvt|150|MW|0}}
| plant_annual_gen = {{cvt|310|GWh|TJ|0}}
| website = [http://www.mdba.gov.au/river-information/running-river-murray/dartmouth-dam Dartmouth Dam] at the [[Murray–Darling Basin Authority]]
| extra = 
}}

'''Dartmouth Dam''' is a large rock-fill [[embankment dam]] with an [[spillway#type|uncontrolled chute spillway]] across the [[Mitta Mitta River|Mitta Mitta]], [[Gibbo River|Gibbo]] and [[Dart River (Victoria)|Dart]] rivers, the Morass Creek and a number of small tributaries. The dam is located near [[Mount Bogong]] in the north-east of the [[Australia]]n state of [[Victoria (state)|Victoria]]. The dam's purpose includes [[irrigation]], the generation of [[hydro-electric power]], [[water supply]] and conservation. The impounded [[reservoir (water)|reservoir]] is called '''Dartmouth Reservoir''', sometimes called '''Lake Dartmouth'''. The '''Dartmouth Power Station''', a hydro-electric power station that generates power to the national grid, is located near the dam wall. The dam is Australia's tallest dam, at {{convert|180|m}}.

A smaller pond, called the '''Dartmouth Dam Regulating Pond''' or '''Banimboola Pondage''', approximately {{convert|9|km|0}} downstream of the main dam, also across the Mitta Mitta River, is located adjacent the [[Banimboola Hydroelectric Power Station]] and forms part of the Dartmouth Dam complex of facilities.

==Location and features==
Designed by the State Rivers & Water Supply Commission of Victoria, construction commenced in 1973 and was completed in 1979 by [[Thiess (company)|Thiess Brothers]], at a cost of A$179&nbsp;million.<ref>{{cite web|url=https://portal.engineersaustralia.org.au/system/files/engineering-heritage-australia/nomination-title/Dartmouth_Dam_nomination.pdf |archive-url=https://web.archive.org/web/20200103160302/https://portal.engineersaustralia.org.au/system/files/engineering-heritage-australia/nomination-title/Dartmouth_Dam_nomination.pdf |archive-date=2020-01-03 |url-status=live|title=Nomination of Dartmouth Dam as a National Engineering Landmark|publisher=Engineering Heritage Australia (Victoria)|date=1 June 2004|page=6|access-date=3 January 2019}}</ref> The embankment dam wall is constructed with an earth core and rock fill, rising to a height of {{convert|180|m|0}} from the lowest part of the foundation to the roadway across the top of the dam, making the dam wall the highest in Australia.<ref name=ancold>{{cite web|url=http://www.ancold.org.au/wp-content/uploads/2012/10/Dams-Australia-2010-v1-for-website.xls|format=Excel (requires download)|title=Register of Large Dams in Australia|publisher=The Australian National Committee on Large Dams Incorporated|year=2010|access-date=4 March 2014|work=Dams information|archive-date=12 December 2013|archive-url=https://web.archive.org/web/20131212120804/http://www.ancold.org.au/wp-content/uploads/2012/10/Dams-Australia-2010-v1-for-website.xls|url-status=dead}}</ref> 

The core component materials of the wall include {{convert|10.5|e6m3|abbr=unit}} of rock, {{convert|0.8|e6m3|abbr=unit}} of filter material made from crushed quarried rock, and {{convert|2.8|e6m3|abbr=unit}} of earth for the core.<ref name=mdba/> The reservoir has a capacity of {{convert|3856|GL|e12gal|0|abbr=unit}},<ref>{{cite web|url=http://www.mdbc.gov.au/rmw/river_murray_system/dartmouth_reservoir |publisher=Murray Darling Basin Commission |title=Dartmouth Dam |access-date=5 November 2006 |url-status=dead |archive-url=https://web.archive.org/web/20060908101830/http://www.mdbc.gov.au/rmw/river_murray_system/dartmouth_reservoir/ |archive-date=8 September 2006 }}</ref> or approximately 6.7 times the capacity of [[Port Jackson|Sydney Harbour]]; and can release a maximum outflow of approximately {{convert|12|GL|e9gal|1|abbr=unit}} per day in normal operation.<ref name=mdba>{{cite web|title=Dartmouth Dam|url=http://www.mdba.gov.au/what-we-do/managing-rivers/river-murray-system/dams-weirs/dartmouth-dam|publisher=[[Murray–Darling Basin Authority]]|access-date=10 February 2014|archive-url=https://web.archive.org/web/20140212195425/http://www.mdba.gov.au/what-we-do/managing-rivers/river-murray-system/dams-weirs/dartmouth-dam|archive-date=12 February 2014|url-status=dead}}</ref>

The crest of the uncontrolled spillway is {{convert|486|m|0}} {{AHD}} and is approximately {{convert|92|m|0}} long. When full, flood flows spill over the crest and down an {{convert|80|m|ft|-long|adj=mid}} concrete chute. The water then returns to the river via an open rock cascade which gradually widens to {{convert|300|m|0}} at river level. Once Dartmouth Reservoir reaches 99% capacity, it is considered to be 'operationally full'. Releases are then set to pass inflows downstream to prevent the level rising further.<ref name=mdba/>

Releases are passed through the outlet works and power station whenever possible. Water will only flow over the spillway if significant flood inflows enter from upstream when the storage is close to full. This approach reduces the chance of downstream flooding, maximises operating flexibility for hydro-power generation, and protects the spillway.<ref name=mdba/>

The Dartmouth Dam stores water from the [[Victorian Alps|Victorian High Country's]] snow fields for summer release into the Mitta Mitta, and the downstream [[Lake Hume]], and into the greater [[Murray River]] for irrigation. The reservoir's inflow and outflow capacity is quite small considering its size, meaning that its levels vary little compared with some other dams on the Murray and their tributaries.<ref>{{cite web |url=http://www.mdbc.gov.au/rmw/river_murray_system/dartmouth_reservoir/hume_and_dartmouth_dams_operations_review/backgrounder_4:_lake_dartmouth:_overview_of_operation |publisher=Murray Darling Basin Commission |title=Backgrounder 4: Lake Dartmouth – Overview of Operation |access-date=5 November 2006 |url-status=dead |archive-url=https://web.archive.org/web/20060911064244/http://www.mdbc.gov.au/rmw/river_murray_system/dartmouth_reservoir/hume_and_dartmouth_dams_operations_review/backgrounder_4%3A_lake_dartmouth%3A_overview_of_operation/ |archive-date=11 September 2006 }}</ref>

The reservoir is a popular recreational [[trout]] fishery, being regularly restocked by the Victorian Department of Primary Industries.

==Hydro-electric power generation==
Designed by the [[State Electricity Commission of Victoria]], and constructed by Lewis Constructions, and commissioned in January 1981, Dartmouth Power Station has one [[Francis turbine]]-[[Electric generator|generator]], with a generating capacity of {{convert|180|MW}}, the largest single installed hydroelectric turbine in Australia. It is owned and operated by [[AGL Energy]].<ref name=agl>{{cite web|url=http://www.agl.com.au/AGLNew/About+AGL/Generation+assets/Hydro+electric+power/Dartmouth.htm |publisher=[[AGL Energy]] |title=Dartmouth Power Station |access-date=13 October 2006 |archive-url=https://web.archive.org/web/20060918180303/http://www.agl.com.au/AGLNew/About+AGL/Generation+assets/Hydro+electric+power/Dartmouth.htm |archive-date=18 September 2006 |url-status=dead }}</ref>

===Power station damage===
On 2 May 1990, the 180 MW Francis turbine-generator running at full speed was instantaneously stopped by a foreign body left in the penstock following maintenance.<ref>SECV, "Report of Investigation into the cause of damage of Dartmouth Power Station on 2 May 1990", State Electricity Commission of Victoria, Power Grid and Distribution Department Publications, June 1990</ref> The installation shifted about 2 m within the base of the {{Convert|180|m|ft|-high|adj=mid}} earth and rock fill gravity dam wall of the 3,906 GL reservoir. After initial consternation regarding the integrity of the wall, declared safe after lengthy assessment), the hydro installation was repaired/replaced, but was off-line for several years. 

A breach of the wall would have obliterated a couple of small towns and a sparsely settled agricultural area in the relatively narrow 120&nbsp;km Mitta Mitta valley below the dam. More significantly, it would have resulted in the over-topping and probable failure of the earthen walls of the {{Convert|40|m|ft|-high|adj=mid}}, 3,038 GL [[Hume Dam|Lake Hume]], 200&nbsp;km downstream on the Murray River. This is immediately upstream of the regional cities of [[Albury]] and [[Wodonga]], and a much more intensively settled irrigation area, and consequences would have been disastrous.

In May 1990, the turbine casing and concrete machine block surrounding the power station were destroyed, when two steel beams entered the turbine. The resulting force ruined the power station and the dam's control systems, making it impossible to gradually release water from the near-capacity dam by conventional means. An improvised system, placing large pipes over the spillway to siphon water over it, was soon installed. The inflow from an unusually wet spring meant that the dam would have overflowed anyway, leading to a spectacular cascade over the huge rock steps, formed when the rock used for the dam was quarried from the valley walls. The station was re-built and recommissioned in 1993.<ref>{{cite web|title=Newsletter of Engineering Heritage |url=http://www.engineersaustralia.org.au/sites/default/files/shado/Learned%20Groups/Interest%20Groups/Engineering%20Heritage/EHA%20No_%2017%20Nov05_1.pdf |publisher=The Institution of Engineers, Australia |access-date=8 February 2012 |date=November 2005 |archive-url=https://web.archive.org/web/20140303002952/https://www.engineersaustralia.org.au/sites/default/files/shado/Learned%20Groups/Interest%20Groups/Engineering%20Heritage/EHA%20No_%2017%20Nov05_1.pdf |archive-date=2014-03-03}}</ref>

===Pondage expansion===
In 2003, the capacity of the regulating pondage was increased to further optimise the power station's generation flexibility. The station is connected to the electricity grid via a 220 kV transmission line to [[Mount Beauty]], {{convert|40|km|0}} away.<ref name=agl/>

==Ecological impact on the Murray–Darling Basin==
The construction and operation of Dartmouth Dam has caused significant changes to the flow patterns and ecology of the Mitta Mitta and [[Murray River|Murray]] rivers. In particular, the unnaturally cold water released from the dam, up to 10 degrees C (18 degrees F) colder than it naturally should be, contributed directly to the disappearance of the [[Murray cod]], [[trout cod]] and [[Macquarie perch]] from the Mitta Mitta River within the first few years of the start of the dam's existence. Cold water pollution caused by Dartmouth Dam is also considered to have contributed to the disappearance of the [[Eel-tailed catfish|freshwater catfish]] from the upper reaches of the Murray River.<ref>NSW Cold Water Pollution Interagency Group (2012) ''Cold Water Pollution Strategy in NSW – report on the implementation of stage one'', NSW Department of Primary Industries, a division of NSW Department of Trade and Investment, Regional Infrastructure and Services, Sydney, New South Wales, {{ISBN|9781742563107}}</ref>

==Climate==

Climate data for the region are sourced at the bottom of the dam wall, in a relatively sheltered spot at {{convert|365|m}} above sea level. Rainfall records began in 1918. Temperature records began in 1975. Winter is twice as wet as summer, and occasionally it may snow. 

{{Weather box
|location = Dartmouth Reservoir (1975–2022, rainfall to 1918); 365 m AMSL; 36.54° S, 147.50° E
|metric first = yes
|single line = yes
|precipitation colour = green
|unit precipitation days = 0.2 mm
|Jan record high C = 42.2
|Feb record high C = 43.0
|Mar record high C = 39.0
|Apr record high C = 33.4
|May record high C = 24.7
|Jun record high C = 20.0
|Jul record high C = 19.6
|Aug record high C = 27.2
|Sep record high C = 28.4
|Oct record high C = 33.2
|Nov record high C = 37.9
|Dec record high C = 39.2
|year record high C = 
|Jan high C = 29.5
|Feb high C = 29.0
|Mar high C = 25.8
|Apr high C = 20.7
|May high C = 15.9
|Jun high C = 12.5
|Jul high C = 11.8
|Aug high C = 13.4
|Sep high C = 16.6
|Oct high C = 20.5
|Nov high C = 24.0
|Dec high C = 26.9
|year high C =
|Jan low C = 14.0
|Feb low C = 13.7
|Mar low C = 11.1
|Apr low C = 7.3
|May low C = 4.7
|Jun low C = 3.1
|Jul low C = 2.3
|Aug low C = 2.8
|Sep low C = 4.6
|Oct low C = 7.0
|Nov low C = 9.9
|Dec low C = 11.8
|year low C = 
|Jan record low C = 2.8
|Feb record low C = 2.3
|Mar record low C = 1.9
|Apr record low C = -1.6
|May record low C = -3.5
|Jun record low C = -5.0
|Jul record low C = -5.4
|Aug record low C = -5.0
|Sep record low C = -3.7
|Oct record low C = -1.5
|Nov record low C = -0.2
|Dec record low C = 1.4
|Jan precipitation mm = 65.1
|Feb precipitation mm = 55.6
|Mar precipitation mm = 61.2
|Apr precipitation mm = 57.9
|May precipitation mm = 85.8
|Jun precipitation mm = 100.6
|Jul precipitation mm = 111.3
|Aug precipitation mm = 121.4
|Sep precipitation mm = 102.5
|Oct precipitation mm = 97.4
|Nov precipitation mm = 71.8
|Dec precipitation mm = 73.9
|year precipitation mm = 1006.2
|Jan precipitation days = 6.3
|Feb precipitation days = 5.9
|Mar precipitation days = 6.7
|Apr precipitation days = 7.7
|May precipitation days = 10.5
|Jun precipitation days = 12.5
|Jul precipitation days = 14.8
|Aug precipitation days = 14.6
|Sep precipitation days = 12.9
|Oct precipitation days = 11.0
|Nov precipitation days = 8.8
|Dec precipitation days = 7.6
|year precipitation days = 
|source 1 = [http://www.bom.gov.au/climate/averages/tables/cw_082076_All.shtml Australian Bureau of Meteorology; Dartmouth Reservoir]
}}

==See also==
{{stack|{{Portal|Renewable Energy|Australia|Water}}}}
* [[Banimboola Hydroelectric Power Station]]
* [[Hume Dam]]
* [[Irrigation in Australia]]

==Gallery==
<gallery>
Dartmouth Dam 08032007 single01.jpg|Upper intake tower exposed
Dartmouth Dam 08032007 panorama01.jpg|Power station, wall and spillway
Dartmouth Dam 08032007 panorama02.jpg|First sight of the reservoir
Dartmouth Dam 08032007 panorama03.jpg|The shore opposite entrance point
</gallery>

==References==
{{reflist}}

==External links==
{{Commons category}}
*[http://www.g-mwater.com.au/water-resources/storage-levels Current water storage levels]
*[http://www.sweetwaterfishing.com.au/Dartmouth.htm Lake Dartmouth Fishing Information + Lake Maps. Sweetwater Fishing Australia]

{{Rivers of the North-East catchment of the Murray-Darling basin}}
{{WaterVictoria|state=collapsed}}
{{Lakes of Victoria|state=collapsed}}
{{EnergyVictoria}}

[[Category:Dams in Victoria (state)]]
[[Category:Lakes of Victoria (state)]]
[[Category:North-East catchment]]
[[Category:Rivers of Hume (region)]]
[[Category:Dams completed in 1979]]
[[Category:Dams in the Murray River basin]]
[[Category:Embankment dams]]
[[Category:Hydroelectric power stations in Victoria (state)]]
[[Category:River regulation in Australia]]
[[Category:Energy infrastructure completed in 1971]]
[[Category:1971 establishments in Australia]]