The Cethana Dam is a concrete-faced rockfill embankment dam across the Forth River, located near Sheffield in northern Tasmania, Australia. Completed in 1971, the resultant reservoir, Lake Cethana, was established for the purpose of generating hydro-electric power via the Cethana Power Station, a run-of-the-river hydroelectric power station.
| Cethana Dam | |
|---|---|
.jpg) The dam wall, in 2017 | |
  Cethana Dam Location of the dam in Tasmania | |
 Interactive map of Cethana Dam | |
| Country | Australia |
| Location | Northern Tasmania |
| Coordinates | 41°28′47″S 146°8′1″E / 41.47972°S 146.13361°E |
| Purpose | Power |
| Status | Operational |
| Construction began | 1967 |
| Opening date | 1971 |
| Owner | Hydro Tasmania |
| Dam and spillways | |
| Type of dam | Rock-fill dam |
| Impounds | Forth River |
| Height | 113 m (371 ft) |
| Length | 213 m (699 ft) |
| Dam volume | 1,407×103 m3 (49.7×106 cu ft) |
| Spillways | 1 |
| Spillway type | Uncontrolled |
| Spillway capacity | 1,980 m3/s (70,000 cu ft/s) |
| Reservoir | |
| Creates | Lake Cethana |
| Total capacity | 112.21 GL (90,970 acre⋅ft) |
| Catchment area | 610 km2 (240 sq mi) |
| Surface area | 41.4 ha (102 acres) |
| Cethana Power Station | |
| Operator | Hydro Tasmania |
| Commission date | 1971 |
| Type | Run-of-the-river |
| Hydraulic head | 98 m (322 ft) |
| Turbines | 1 x 100 MW (130,000 hp) Fuji Francis-type |
| Installed capacity | 100 MW (130,000 hp) |
| Capacity factor | 0.85 |
| Annual generation | 434 GWh (1,560 TJ) |
| Website hydro.com.au | |
| [1] | |
The dam, its reservoir, and the power station are owned and operated by Hydro Tasmania.
Dam and reservoir overview
editBuilt between 1967 and 1971,[2] the concrete-faced rock-filled dam wall is 113 metres (371 ft) high and 213 metres (699 ft) long. When full, Lake Cethana has capacity of 112.21 gigalitres (90,970 acre⋅ft) and covers 414 hectares (1,020 acres), drawn from a catchment area of 612 square kilometres (236 sq mi). The single uncontrolled spillway is capable of discharging 1,980 cubic metres per second (70,000 cu ft/s).[1]
The Cethana Dam is listed as a National Engineering Landmark by Engineers Australia as part of its Engineering Heritage Recognition Program.[3]
Hydroelectric power station
edit
The Cethana Power Station is part of the Mersey–Forth scheme that comprises seven run-of-the-river hydroelectric power stations and one mini-hydro power station. The sixth station in the scheme, the Cethana Power Station is located underground and is supplied with water from Lake Cethana, from the Wilmot Power Station located below Lake Gairdner, and uncontrolled flow from the Forth River. Water from the Cethana power station is returned to the Forth River through a tailrace tunnel which has a tailrace gate structure at the outlet portal.[4]
The power station was commissioned in 1971 by the Hydro Electric Corporation (TAS) and the station has one Fuji Francis-type turbine, with a generating capacity of 100 megawatts (130,000 hp) of electricity. The station output, estimated to be 434 gigawatt-hours (1,560 TJ) annually,[1] is fed to the outdoor switchyard via a three single-phase 13.8 kV/220 kV Fuji generator transformer.[5]
Proposed pumped-storage station
editIn 2023, under the Environment Protection and Biodiversity Conservation Act 1999 (Cth), Hydro Tasmania, as part of their Battery of the Nation initiative,[6] submitted to the Australian Government approval of a proposed 750-megawatt (1,010×103 hp) underground pumped-storage hydroelectric plant. It was proposed that the plant use the existing Lake Cethana as a lower storage reservoir and that it be connected, via underground tunnels and a new underground power station, to a new off-stream embankment dam with capacity of 12.4 gigalitres (10,100 acre⋅ft) covering approximately 100 hectares (250 acres), located above the western side of the existing reservoir. Additional transmission lines and a switchyard were also proposed.[7] In April 2025, Hydro Tasmania decided to cancel the project.[8]
See also
edit
References
edit- 1 2 3 "Register of Large Dams Australia-2015" (Excel. Requires download. Row 98). ANCOLD. January 2022. Retrieved 5 March 2026.
- ↑ "Lake Cethana". North West Tasmania. West X North West. n.d. Retrieved 23 April 2026.
- ↑ "Cethana Dam, Forth River, 1971-". Engineers Australia. Retrieved 27 April 2020.
- ↑ "Mersey - Forth | Energy". Hydro Tasmania. Retrieved 3 July 2015.
- ↑ "Cethana Power Station: Technical fact sheet" (PDF). Mersey-Forth Catchment. Hydro Tasmania. Archived (PDF) from the original on 18 June 2023. Retrieved 18 June 2023.
- ↑ "Battery of the Nation – A Concept Study of Tasmanian Pumped Hydro Options". Australian Renewable Energy Agency. Australian Government. 31 January 2018. Retrieved 23 April 2026.
- ↑ "Cethana pumped hydro energy storage – Project Update" (PDF). Hydro Tasmania. July 2023. Retrieved 23 April 2026.
- ↑ "Cethana Pumped Hydro Energy Storage Project". EPBC Act Public Portal. Department of Climate Change, Energy, the Environment and Water. Australian Government. 22 April 2025. Retrieved 23 April 2026.