{{Short description|Dam and power station in Tasmania, Australia}} {{Use Australian English|date=July 2015}} {{Use dmy dates|date=May 2026}} {{Infobox dam | name = Cethana Dam | name_official = | image = Cethana Dam, Tasmania (32422396502).jpg | image_size = 240 | image_caption = The dam wall, in 2017 | image_alt = | location_map = Australia Tasmania | location_map_size = 240 | location_map_caption = Location of the dam in [[Tasmania]] | location_map_alt = | mapframe = yes | coordinates = {{coord|41|28|47|S|146|8|1|E|type:landmark_region:AU-TAS|display=inline,title}} | country = Australia | location = [[North West Tasmania|Northern]] [[Tasmania]] | purpose = P | status = O | construction_began = {{start date|1967}} | opening = {{start date|1971}} | demolished = | cost = | owner = [[Hydro Tasmania]] | operator = | dam_type = H | dam_crosses = [[Forth River (Tasmania)|Forth River]] | dam_height = {{cvt|113|m}} | dam_height_foundation= | dam_height_thalweg = | dam_length = {{cvt|213|m}} | dam_elevation_crest = | dam_width_crest = | dam_width_base = | dam_volume = {{cvt|1407|e3m3}} | spillway_count = 1 | spillway_type = [[Spillway#Types|Uncontrolled]] | spillway_capacity = {{cvt|1980|m3/s}} | res_name = [[Sheffield, Tasmania#Lake Cethana|Lake Cethana]] | res_capacity_total = {{cvt|112.21|GL|acre.ft}} | res_capacity_active = | res_capacity_inactive= | res_catchment = {{cvt|610|km2}} | res_surface = {{cvt|41.4|ha}} | res_max_length = | res_max_width = | res_max_depth = | res_elevation = | res_tidal_range = | plant_name = Cethana Power Station | plant_coordinates = | plant_operator = [[Hydro Tasmania]] | plant_commission = {{start date|1971}} | plant_decommission = | plant_type = R | plant_hydraulic_head = {{cvt|98|m}} | plant_turbines = 1 x {{cvt|100|MW}}<br />[[Fuji Heavy Industries|Fuji]] [[Francis turbine|Francis-type]] | plant_capacity = {{cvt|100|MW}} | plant_capacity_factor= 0.85 | plant_annual_gen = {{cvt|434|GWh}} | website = {{URL|hydro.com.au/clean-energy/our-power-stations/mersey-forth|hydro.com.au}} | extra = <ref name=ANCOLD/> }}

The '''Cethana Dam''' is a concrete-faced rockfill [[embankment dam]] across the [[Forth River (Tasmania)|Forth River]], located near {{TAScity|Sheffield}} in [[North West Tasmania|northern]] [[Tasmania]], Australia. Completed in 1971, the resultant [[reservoir]], [[Sheffield, Tasmania#Lake Cethana|Lake Cethana]], was established for the purpose of generating [[hydro-electricity|hydro-electric power]] via the '''Cethana Power Station''', a [[Run-of-the-river hydroelectricity|run-of-the-river]] hydroelectric [[power station]].

The dam, its reservoir, and the power station are owned and operated by [[Hydro Tasmania]].

== Dam and reservoir overview == Built between 1967 and 1971,<ref>{{cite web |url=https://northwesttasmania.com.au/things-to-do/lake-cethana/ |title=Lake Cethana |work=North West Tasmania |publisher=West X North West |date=n.d. |access-date=2026-04-23 }}</ref> the concrete-faced [[rock-filled dam]] wall is {{convert|113|m}} high and {{convert|213|m}} long. When full, Lake Cethana has capacity of {{convert|112.21|GL|acre.ft|lk=on}} and covers {{convert|414|ha}}, drawn from a [[drainage basin|catchment area]] of {{convert|612|km2}}. The single [[spillway#Types|uncontrolled spillway]] is capable of discharging {{convert|1980|m3/s}}.<ref name=ANCOLD>{{cite web |title=Register of Large Dams Australia-2015 |date=January 2022 |access-date=2026-03-05 |url=https://ancold.org.au/information-resources/dams-information/ |work=[[ANCOLD]] |format=[[Microsoft Excel|Excel]]. Requires download. Row 98}}</ref>

The Cethana Dam is listed as a National Engineering Landmark by [[Engineers Australia]] as part of its [[Engineers Australia#Engineering Heritage Recognition Program|Engineering Heritage Recognition Program]].<ref>{{cite web|url=https://portal.engineersaustralia.org.au/heritage/cethana-dam-forth-river-1971|title=Cethana Dam, Forth River, 1971-|publisher=Engineers Australia|access-date=2020-04-27}}</ref>

== Hydroelectric power station == [[File:It's underground - panoramio.jpg|thumb|left|Entrance to the underground Cethana Power Station]] The Cethana Power Station is part of the [[Mersey River (Tasmania)|Mersey]]{{endash}}[[Forth River (Tasmania)|Forth]] scheme that comprises seven [[Run-of-the-river hydroelectricity|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.<ref>{{cite web |url=https://www.hydro.com.au/energy/our-power-stations/mersey-forth |title=Mersey - Forth {{!}} Energy |work=[[Hydro Tasmania]] |access-date=3 July 2015}}</ref>

The power station was commissioned in 1971 by the [[Hydro Tasmania|Hydro Electric Corporation (TAS)]] and the station has one [[Fuji Heavy Industries|Fuji]] [[Francis turbine|Francis-type]] [[Water turbine|turbine]], with a generating capacity of {{convert|100|MW}} of electricity. The station output, estimated to be {{convert|434|GWh|TJ|lk=on}} annually,<ref name=ANCOLD/> is fed to the outdoor switchyard via a three single-phase 13.8&nbsp;k[[volt|V]]/220&nbsp;kV Fuji generator transformer.<ref>{{cite web|url=https://www.hydro.com.au/docs/default-source/clean-energy/our-power-stations/power-station-fact-sheets/cethana-power-station-fact-sheet.pdf?sfvrsn=2acd9b28_2|title=Cethana Power Station: Technical fact sheet|work=Mersey-Forth Catchment |publisher=[[Hydro Tasmania]]|accessdate=18 June 2023|archive-url=https://web.archive.org/web/20230618053505/https://www.hydro.com.au/docs/default-source/clean-energy/our-power-stations/power-station-fact-sheets/cethana-power-station-fact-sheet.pdf?sfvrsn=2acd9b28_2|archive-date=18 June 2023|url-status=live}}</ref>

=== Proposed pumped-storage station === In 2023, under the ''[[Environment Protection and Biodiversity Conservation Act 1999]]'' (Cth), Hydro Tasmania, as part of their ''Battery of the Nation'' initiative,<ref>{{cite web |url=https://arena.gov.au/projects/battery-of-the-nation/ |title=Battery of the Nation – A Concept Study of Tasmanian Pumped Hydro Options |work=[[Australian Renewable Energy Agency]] |publisher=[[Australian Government]] |date=2018-01-31 |access-date=2026-04-23 }}</ref> submitted to the Australian Government approval of a proposed {{convert|750|MW|e3hp|adj=on}} underground [[Pumped-storage hydroelectricity|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 {{convert|12.4|GL|acre.ft}} covering approximately {{convert|100|ha}}, located above the western side of the existing reservoir. Additional transmission lines and a switchyard were also proposed.<ref>{{cite web |url=https://ehq-production-australia.s3.ap-southeast-2.amazonaws.com/406656dec6af0608c977d3e77abfcb9e4e69a62c/original/1692052303/9744fab4619a0bc34fca1bf90ce6236d_230278_Hydro_Cethana_Community_Info_Sheet_spreads.pdf?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=AKIA4KKNQAKIII4DU7AG%2F20260423%2Fap-southeast-2%2Fs3%2Faws4_request&X-Amz-Date=20260423T024125Z&X-Amz-Expires=300&X-Amz-SignedHeaders=host&X-Amz-Signature=a35b31b927add7cc23a85701711be453de3749c7b97ff7808b6a2735f1bb07c8 |title=Cethana pumped hydro energy storage – Project Update |work=[[Hydro Tasmania]] |date=July 2023 |access-date=2026-04-23 }}</ref> In April 2025, Hydro Tasmania decided to cancel the project.<ref>{{cite web |url=https://epbcpublicportal.environment.gov.au/all-notices/project-decision/?id=3ed99c13-9d20-f011-998a-00224811099e |title=Cethana Pumped Hydro Energy Storage Project |work=EPBC Act Public Portal |publisher=Department of Climate Change, Energy, the Environment and Water. [[Australian Government]] |date=2025-04-22 |access-date=2026-04-23 }}</ref>

== See also == {{stack|{{Portal|Renewable energy|Australia|Water}}}} * [[List of power stations in Tasmania]] * [[List of reservoirs and dams in Australia#Tasmania|List of reservoirs and dams in Tasmania]] * [[List of run-of-the-river hydroelectric power stations]]

==References== {{Reflist}}

{{Dams in Tasmania|state=collapsed}} {{EnergyTasmania}}

[[Category:1971 establishments in Australia]] [[Category:Concrete-face rock-fill dams]] [[Category:Dams completed in 1971]] [[Category:Energy infrastructure completed in 1981]] [[Category:Hydroelectric power stations in Tasmania]] [[Category:Hydro Tasmania dams]] [[Category:Northern Tasmania]] [[Category:Recipients of Engineers Australia engineering heritage markers]] [[Category:Run-of-the-river power stations]]