Crotty Dam

Crotty Dam
Crotty Dam (at right) aerial shot from the east
Crotty Dam is located in Tasmania
Crotty Dam
Crotty Dam
Location of the dam in Tasmania
Interactive map of Crotty Dam
CountryAustralia
LocationWest Coast Tasmania
Coordinates42°09′37″S 145°37′00″E / 42.160151°S 145.61657°E / -42.160151; 145.61657
PurposePower
StatusOperational
Opening date1991
OwnerHydro Tasmania
Dam and spillways
Type of damRock-fill dam
ImpoundsKing River
Height83 m (272 ft)
Length245 m (804 ft)
Width (crest)300 mm (12 in)
Dam volume770×10^3 m3 (27×10^6 cu ft)
Spillways1
Spillway typeControlled and uncontrolled
Spillway capacity
  • 245 m3/s (8,700 cu ft/s) chute on dam face
  • 190 m3/s (6,700 cu ft/s) valve in tunnel
Reservoir
CreatesLake Burbury
Total capacity1,081,420 ML (876,720 acre⋅ft)
Active capacity1,065,000 ML (863,000 acre⋅ft)
Catchment area559 km2 (216 sq mi)
Surface area5,325 ha (13,160 acres)
Normal elevation229 m (751 ft) AHD
John Butters Power Station
Coordinates42°09′21″S 145°32′04″E / 42.15583°S 145.53444°E / -42.15583; 145.53444
OperatorHydro Tasmania
Commission date1992 (1992)
TypeConventional
Hydraulic head184 m (604 ft)
Turbines1 x 144 MW (193,000 hp)
Fuji Frnacis-type
Installed capacity144 MW (193,000 hp)
Capacity factor0.9
Annual generation576 GWh (2,070 TJ)
Website
hydro.com.au
[1]

The Crotty Dam, also known during construction as the King Dam,[2] or the King River Dam on initial approval,[3] is a concrete-faced rockfill embankment dam across the King River, between Mount Jukes and Mount Huxley, located in the West Coast region of Tasmania, Australia. Completed in 1991, the resultant reservoir, Lake Burbury, was established for the purpose of generating hydro-electric power via the John Butters Power Station. The dam, its reservoir, and the power station are owned and operated by Hydro Tasmania.

Dam and reservoir overview

History

In the 1910s the Mount Lyell Mining & Railway Company had investigated and surveyed a site very close to this dam for a proposed hydro electric scheme.[4] Charles Whitham also wrote of the inevitability of the dam in 1927 and even proposed "Lake Dorothy" as a name for the reservoir.[5][6]: 482, 465–472 

Construction of the dam commenced in the 1980s following the Franklin Dam controversy, and the reservoir was flooded in 1991. The dam was named in honour of James Crotty who founded the North Mount Lyell Copper Mine at the turn of the 20th century. A ghost town site of the eponymous Crotty was submerged by the waters of Lake Burbury; as was the settlement of Darwin.

Technical details

The Crotty Dam, together with the Darwin Dam, are two major dams that form the headwaters for the King River Hydroelectric Power Development. The dam is located in the upper reaches of the King River gorge where the river breaks through the West Coast Range. It captures the high rainfall in the catchment of the King River and allows diversion of water through a tunnel to the John Butters Power Station downstream of the dam.

The concrete-faced rock-filled dam wall is 83 metres (272 ft) high and 245 metres (804 ft) long. When full, Lake Burbury has capacity of 1,081,420 megalitres (876,720 acre⋅ft) and covers 53,250 hectares (131,600 acres), draw from a catchment area of 559 square kilometres (216 sq mi). The single controlled and uncontrolled spillway is capable of discharging 435 cubic metres per second (15,400 cu ft/s).[1]

Spillway

The spillway is located on the embankment, rather than on one of the rock abutments. This unique spillway approach had never been successfully attempted before in the design of dams of any significant height, due to problems in making allowance for embankment settlements. In the case of the Crotty Dam, the embankment was partly composed of well graded gravels, and thus a very high modulus of embankment deformation was achieved. The high modulus limits embankment settlements. Additionally, the spillway was designed to articulate in order to accommodate any settlement that did occur and to allow sufficient time for a large jet flow valve located in the diversion tunnel to be opened so that larger floods can be safely handled.

The spillway designers, Sergio Giudici, also the chief engineer on the Gordon Dam, Frank Kinstler, Steven Li, Tony Morse and Graeme Maher were acknowledged within the engineering community because the spillway was the first known to provide for articulation of the spillway structure so that movements in its foundations could occur without damage to the overlying structure.[7] In 2001, Engineers Australia selected Crotty Dam as one of the 25 dams with the greatest Australian heritage value and it was awarded a Historic Engineering Marker as part of the Engineering Heritage Recognition Program.[8]

Reservoir

Looking north across the reservoir, from Bradshaw Bridge

Named in honour of Stanley Burbury, a former Governor of Tasmania,[5] Lake Burbury is fed mainly by rivers from the north, including the upper King, Nelson, Princess, and Eldon rivers that drain the West Coast Range and include the Linda Valley.[9] A natural lake, known as Lake Beatrice, lies just north of the reservoir's northern shore which is below the eastern end of Mount Sedgwick. Part of the reservoir is crossed by the Bradshaw Bridge[a] to connect with the Lyell Highway.

When it was impounded, the historical sites of Crotty and Darwin were flooded, the bridge of the North Mount Lyell Railway over the King River was not salvaged, and significant portions of the Kelly Basin Road were inundated. The dam and its reservoir were identified as "indicative places" on the (now defunct) Register of the National Estate.[10]

Recreation

A regulation sign at the reservoir

The reservoir is popular for fishing and anglers should be aware that the area is susceptible to extreme weather. A webcam is located on the south east shore of the lake which looks across to where the Lyell Highway emerges from the Linda Valley and moves south around the eastern base of Mount Owen and vision of fishing conditions may be viewed remotely.[11]

The reservoir lies to the west of the Franklin-Gordon Wild Rivers National Park and has a series of buffer zone conservation areas; the Princess River Conservation Area and the Crotty Conservation Area on the east shore, and the West Coast Range Regional Reserve on the west. Access to the reservoir's shore is limited below 242 metres (794 ft) AHD, which is above the full supply level of 235 metres (771 ft) AHD. Access is also restricted on the island created by the impoundment.[9][12]

Hydroelectric power station

The John Butters Power Station was commissioned by the Hydro Electric Commission (TAS) in 1992 as part of the King – Yolande River Power Scheme that comprises three hydroelectric power stations. Located 8 kilometres (5.0 mi) below the dam wall, near the King River confluence with the Queen River,[13][14][15] the power station is fed by water from Lake Burbury, and to the south by Darwin Dam. Water flow to the station is via a long headrace tunnel from the Crotty Dam via a 6.5-kilometre-long (4.0 mi) unlined headrace tunnel that runs through Mount Jukes, and a 500-metre-long (1,600 ft) steel lined power tunnel.[16]

Built by the HEC, it was one of the last power stations constructed before its disaggregation and transformation to Hydro Tasmania.[15][17]: 327–347  The station has one Fuji Francis turbines with a generating capacity of 144 megawatts (193,000 hp) of electricity. Within the station building, the turbine has a half embedded spiral casing controlled via a spherical rotary inlet valve and a vertical lift, gravity closed intake gate designed to cut off full flow. The station output, estimated to be 576 gigawatt-hours (2,070 TJ) annually,[1] is fed to TasNetworks' transmission grid via a 13.8 kV/220 kV three-phase Fuji generator transformer to the outdoor switchyard.[16]

The station is remotely controlled from the Sheffield Control Centre.[13]

Etymology

The power station was named in honour of John Butters, the first general manager and chief engineer of Hydro Tasmania.[6]: 16–17 [17]: 34–49  When the King power scheme was approved by the Tasmanian Government the name on hydro plans for the proposed power station at that time was the Newall Power station.[18][19][20]

See also

Notes

  1. ^ Named after the family that owned and operated the sawmill that was inundated at Princess River.

References

  1. ^ a b c "Register of Large Dams Australia-2015" (Excel. Requires download. Row 135). ANCOLD. January 2022. Retrieved 5 March 2026.
  2. ^ King River Power Development Hydro-Electric Commission December 1983
  3. ^ "Anthony and King Power Developments approved". Cross Currents (70). Hydro-Electric Commission. 1983. ISSN 0811-4803.
  4. ^ Blainey, Geoffrey (2000). The Peaks of Lyell (6th ed.). Hobart: St. David's Park Publishing. p. 253. ISBN 978-0-7246-2265-8. The early survey of Huntley Clarke at the King near the confluence with the Tofft River, and also at the head of the King river gorge between Mount Owen and Mount Huxley.
  5. ^ a b Whitham, Charles (2003). Western Tasmania – A land of riches and beauty (Reprint 2003 ed.). Queenstown: Municipality of Queenstown.
  6. ^ a b Felton, Heather (2007). Tickleberry Tales and Other Stories from the People of the Hydro. Tasmania, Australia: Hydro Tasmania. ISBN 978-0-646-47724-4.
  7. ^ "Crotty Dam, Tasmania" (PDF). Submission for historic engineering marker. Engineers Australia. September 2000.
  8. ^ "Crotty Dam, King River, 1991-". Engineers Australia. 2001. Retrieved 27 April 2020.
  9. ^ a b "Franklin: Sheet 8013" (Map). Tasmania. 1:100,000. 1997. The smaller rivers on the eastern shore include the Princess River, Nelson River; to the west the Comstock Creek flows in from the valley between Mount Lyell and Mount Sedgwick.
  10. ^ "Crotty Dam and Lake Burbury, Lyell Hwy, Gormanston, TAS, Australia (Place ID 101584)". Australian Heritage Database. Australian Government. Retrieved 24 May 2018.
  11. ^ "Lake Burbury webcam". Anglers Alliance Tasmania.
  12. ^ Owen: 3833 (Map) (2 ed.). 1:25,000. Tasmap. 2001.
  13. ^ a b King River power development. Hydro-Electric Commission. 1992. pp. 10–13. Retrieved 9 June 2018 – via Trove. National Library of Australia.
  14. ^ "King - Yolande". Energy: Our power stations. Hydro Tasmania. Retrieved 21 June 2015.
  15. ^ a b "The Hydro after 100 Years" (PDF). EHA Magazine. March 2015. p. 19. Archived from the original (PDF) on 21 August 2022.
  16. ^ a b "John Butters Power Station: Technical fact sheet" (PDF). King - Yolande Catchment. Hydro Tasmania. Archived (PDF) from the original on 17 June 2023. Retrieved 18 June 2023.
  17. ^ a b Lupton, Roger (1999). Lifeblood: Tasmania's hydro power. Focus Publications. ISBN 978-1-875359-33-2.
  18. ^ Tasmania. Hydro-Electric Commission (1992). King River power development (Map). Hydro-Electric Commission. pp. 8–9. Retrieved 10 June 2018. Lake Burbury being an extract from TASMAP Franklin 1: 100 000: There is a Newall Spur off Mount Jukes, 3 km south east of the power station, as well as Newall Creek, and a former mining site Harris' Reward on Newall Creek.
  19. ^ How, Duncan (1992). Historic mines of Western Tasmania : a walking guide. Walk the West Publications. p. 40. ISBN 978-0-646-10651-9.
  20. ^ "Crotty Dam, Tasmania" (PDF). Submission for historic engineering marker. Engineers Australia. September 2000.

Further reading

  • Rae, Lou (2001). The Abt Railway and Railways of the Lyell region. Sandy Bay: Lou Rae. ISBN 978-0-9592098-7-7. ISBN 0-9592098-7-5.
  • Whitham, Lindsay (2002). Railways, Mines, Pubs and People and other historical research. Sandy Bay: Tasmanian Historical Research Association. ISBN 0-909479-21-6.
  • Wikimedia Commons logo Media related to Crotty Dam at Wikimedia Commons
  • "King Catchment". Hydro Tasmania. Archived from the original on 18 September 2006.
  • "Our power stations: King-Yolande". Hydro Tasmania.
This article is issued from Wikipedia. The text is available under Creative Commons Attribution-Share Alike 4.0 unless otherwise noted. Additional terms may apply for the media files.