Cochrane Dam (New South Wales)

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Not to be confused with Cochrane Dam.
Cochrane Dam
Cochrane Dam (New South Wales) is located in New South Wales
Cochrane Dam (New South Wales)
Location of the Cochrane Dam
in New South Wales
Country Australia
Location South Coast, New South Wales
Coordinates 36°33′54″S 149°27′04″E / 36.56500°S 149.45111°E / -36.56500; 149.45111Coordinates: 36°33′54″S 149°27′04″E / 36.56500°S 149.45111°E / -36.56500; 149.45111
Purpose Hydro-power, irrigation
Status Operational
Opening date 1958
Dam and spillways
Type of dam Embankment dam
Impounds Georges Creek
Height 29 metres (95 ft)
Length 199 metres (653 ft)
Dam volume 116 metres (381 ft)
Spillway capacity 424 cubic metres per second (15,000 cu ft/s)
Reservoir
Creates Cochrane Lake
Total capacity 385 megalitres (13.6×10^6 cu ft)
Catchment area 34.7 square kilometres (13.4 sq mi)
Power station
Commission date 1943
Type Conventional
Turbines 2
Installed capacity 4.95 megawatts (6,640 hp)

Cochrane Dam is a minor earthfill embankment dam with concrete spillway across Georges Creek, located in the South Coast region of New South Wales, Australia. The main purpose of the dam is to supply water for hydro-power at the downstream Brown Mountain Power Station and for irrigation purposes. The impounded reservoir is called Cochrane Lake.

Location and features[edit]

Completed in 1958, the Cochrane Dam is a minor ungated dam, located approximately 13 kilometres (8.1 mi) north-west of the village of Bemboka. The dam was built by Thiess Bros Pty Limited on behalf of Pacific Power[1] as water storage to assist the control of water flows to the Brown Mountain Power Station, and to supply water for irrigation in the Bega Valley.

The dam wall constructed with 116 cubic metres (4,100 cu ft) of earth fill is 29 metres (95 ft) high and 199 metres (653 ft) long. At 100% capacity the dam wall holds back 385 megalitres (13.6×10^6 cu ft) of water. The catchment area of Cochrane Lake is 37.7 square kilometres (14.6 sq mi). The uncontrolled concrete spillway is capable of discharging 424 cubic metres per second (15,000 cu ft/s).[1]

Power generation[edit]

A run-of-the-river and now, conventional hydro-electric power station, called Brown Mountain Power Station, is located on the eastern escarpment of the Great Dividing Range inland from Bega and downstream from the dam wall, on the Bemboka River. The power station commenced generating electricity in 1943 and was originally owned and operated by the Bega Valley County Council (since merged). Brown Mountain Power Station was initially commissioned with five high pressure turbo generators, with a generating capacity of 4.5 megawatts (6,000 hp) of electricity, generated from the run-of-the-river of Bemboka River.[2] Later, the creation of the Cochrane Dam, regulated flows of water on the Rutherford Creek to the Brown Mountain Power Station and to meet the irrigation requirements of the Bega Valley catchment.

In 2006 an A$6 million upgrade of facilities at the power station was completed[3] with the installation of a new 4.2 megawatts (5,600 hp) generating unit, supplied with water from Cochrane Dam. Unit 3[4] was upgraded with automatic controls; and water supplied from Rutherford Creek for power generation. Units 1, 2, 4 & 5 were decommissioned. Following completion of the project, the station has a total generating capacity of 4.95 megawatts (6,640 hp).[2][4]

Brown Mountain Power Station is connected to the 66 kV transmission line running between Cooma and Bega substations.[2][4]

See also[edit]

References[edit]

  1. ^ a b "Register of Large Dams in Australia" (Excel (requires download)). Dams information. The Australian National Committee on Large Dams Incorporated. 2010. Retrieved 22 April 2013. 
  2. ^ a b c Dugan, Des (31 May 2006). "Nothing new in NSW budget". Electrical World. Retrieved 4 May 2013. 
  3. ^ "Govt opens $6m hydro-electric power plant upgrade". ABC News (Australia). 14 December 2006. Retrieved 4 May 2013. 
  4. ^ a b c "Brown Mountain". Generation Portfolio: Hydro Power Stations. Eraring Energy. 2 May 2013. Retrieved 4 May 2013.