Lake Pedder

Lake Pedder, once a glacial outwash lake, is an artificial reservoir and diversion lake located in South West Tasmania, Australia. In addition to its natural catchment from the Frankland Range, the lake was formed by the 1972 damming of the Serpentine and Huon Rivers by the Hydro-Electric Commission (TAS) (HEC) for the purpose of generating hydroelectricity at the Gordon Power Station.

The original Lake Pedder was renowned for its beauty, and community opposition to its flooding led to the first environmentalism based political party in the world, the United Tasmania Group, with one of its candidates going on to found the Tasmanian Greens. It also marked the end of unopposed damming of wild rivers in Tasmania by the HEC, with the next attempted dam drawing national and international condemnation until the project was abandoned.

The new Lake Pedder reservoir has had a surface area approximately 24,133 hectares (59,630 acres), making it Tasmania's second-largest lake^{[1][2][3]: 242}, and its waters are used to generate about 500GWh of electricity for Tasmania per year. It is a popular trout fishing location.

The original Lake Pedder was a glacial outwash lake, formed from sediment runoff from the Frankland Range, and located in the upper Serpentine river valley. Sitting at an altitude of 300m, its size ranged from ~10km² in the winter, but retracted in the drier Tasmanian summers exposing a wide beach with mega-ripples along its length - described as spectacular by researchers,^[4] activists^[5] and the Scenic board (National Parks precursor organisation).^[6] In the context of protests against its inundation, Roy Fagan, the deputy premier called it "...a very charming lake, and it is a pity it has to be flooded".^[7]

It was a shallow lake, with a depth of ~3m, and drained into the Serpentine River. The surrounding Frankland Range is made of Precambrian quartzites, while the valley is phyllites and schist, with some carbonate rock.^[4] Immediately to the east of Lake Pedder there was a group of small lakes and swamps called the Maria Lakes which seasonally drained into Pedder.^[4]

A fault line with clear scarp landforms runs 11km SE of the original lake, including two scarp ponds called Lake Edgar (now flooded).^[4]

The Serpentine River itself was meandering in its upper reaches with numerous oxbow lakes and peat bogs, but as it approached the Gordon River formed into a steep gorge (now flooded).^[4]

Lake Pedder had the highest number of endemic species for any lake in Australia, with numerous invertebrates only found on its shores,^[8]: 87 and several species of freshwater fish. The swamp galaxias is endemic to Lake Pedder and its tributaries,^[9] as was the Pedder Galaxias, now extinct in its native range.^[10]

The vegetation of the valleys around Lake Pedder varied from wetlands and buttongrass moorlands to eucalypt forests and rainforests.^[11]

Aboriginal people have lived in Tasmania for approximately 35,000 years, crossing over the Bassian Plain from the mainland.^[12] Early Aboriginal heritage sites indicate that they occupied SW Tasmania from that time, until early European colonisation, however, there are no known heritage sites within the Lake Pedder reservoir.^[13] Aboriginal Tasmanians used fire to clear vegetation and control the movement of macropods, which may have contributed to the extent of the buttongrass plains around the Serpentine valley and wider SW.^[14]

European surveyors found Lake Pedder during a trigonometric survey^[13] in 1835, with surveyor John Wedge naming it after the first chief justice of Van Diemen's Land, John Pedder.^[8]: 87 The area was further explored by piners and later miners during the mineral rush of the early 1900s. As bushwalking and recreation became more popular throughout the 1900s, old mining huts were repurposed and old tracks saw new use.^[13]

In 1954 the Hobart Walking Club approached the Scenery Preservation Board proposing to make the area surrounding Lake Pedder a national park due to both its beauty, and that there was no potential for mining or forestry development in the surrounds.^[15] However, noting that the HEC might be interested in damming the Serpentine river and lower Serpentine valley, they limited the national park to the upper reaches of the valley around Lake Pedder.^[15]

They were successful, and in 1955, Lake Pedder, and the surrounding 59,000 acres was declared a scenic reserve (the precursor to a national park) called Lake Pedder National Park due to the beauty of the pink-white sands of the beach, ring of mountains and definable location.^[6]

In 1963 the HEC received a grant to build an explorative road towards the Gordon and Serpentine rivers to examine placing a new dam in the area, however, this was not well known outside of government as the Premier was reluctant to release information.

The aim of this scheme was to increase Tasmania's capacity to generate hydroelectricity in accordance with the Tasmanian government's policy of attempting to attract manufacturing industry to the state with the incentive of cheap hydroelectricity.^[6]

There were protests at the decision to flood the original lake that were held in Tasmania and mainland Australia, before, during, and after construction of the dams. Protests began in 1967 when the Tasmanian government revoked the protection status of the Lake Pedder National Park. The HEC dam recommendations were rarely examined by the Tasmanian Government before being enacted, and the full context of damming (loss of wilderness, cost-benefit analysis) wasn't within their remit. Additionally, there was a culture of not informing the public on the status and goals of projects under development.^[6] Tasmania's Premier Eric Reece, and Allan Knight, the HEC commissioner, were seen as the leading proponents of the damming of Tasmania against any opinion to the contrary, and were not averse to taking their opinions to statewide and national advertising campaigns asserting their right to dam the lake.^[16]

Reece was well known for his staunch support of the HEC and its renewable energy development schemes on the Gordon River, which earned him the epithet "Electric Eric".^[17] In 1972, Reece approved the flooding of Lake Pedder, which proceeded despite a determined protest movement and a blank cheque offer from his Labor colleague, Prime Minister Gough Whitlam, to preserve the Lake Pedder area. Reece refused Whitlam's offer, stating that he would "not have the federal government interfering with the sovereign rights of Tasmania".^[18] Reece retrospectively commented:^[19]

There was a National Park out there, but I can't remember exactly where it was ... at least, it wasn't of substantial significance in the scheme of things. The thing that was significant was that we had to double the output of power in this state in 10 years in order [to] supply the demands of industry and the community. And this was the scheme that looked as though it could do a greater part of [the] job for us.

A series of photographs in the 1976 Tasmanian Year book illustrated the process of flooding of the Lake Pedder area.^[20]

Opposition to the flooding of Lake Pedder extended well beyond Tasmania and spread throughout Australia and internationally. The focus on the South West Tasmania Wilderness area as an environmental battleground increased interest in the area, and many travelled to Lake Pedder before it was flooded to see what the issues were about. In 1971, a large number of people travelled to Pedder to see the lake before it was to be inundated, and a particular weekend in March of that year became known as the Pedder Pilgrimage.^[21]

The protests included the United Tasmania Group, which were the precursor to the Tasmanian Greens, recognised as the world's first green party.^[22] The group that preceded the Tasmanian Wilderness Society – the South West Tasmania Action Committee (itself preceded by the Lake Pedder Action Committee)^[23] - continued after the flooding, with the knowledge that surveying and appraising other catchments in the south west and west of Tasmania was well underway by the HEC. Although increasingly sophisticated economic, environmental, and engineering arguments were raised by the opponents of the dam, but until the Franklin scheme, neither the HEC nor its defenders even considered the critiques. In 1972, Christian activist Brenda Hean perished with pilot Max Price in a Tiger Moth aircraft they were flying from Tasmania to Canberra to protest the damming of Lake Pedder; allegedly, pro-dam campaigners had entered the plane's hangar and placed sugar in one of its fuel tanks.^{[17]: 280–281}

Hesba Fay Brinsmead, an Australian children's author and environmentalist, wrote two books about the damming of Lake Pedder in the 1970s and 1980s.^[24]

Concerns over the construction of the dam revolved around the loss of the distinctive pink quartzite beach of the original lake,^[25] and an increased understanding of the unique nature of the wilderness quality to the south west of Tasmania.^[26] Although the early environmental activists failed to save Lake Pedder, the raised awareness of the HEC's dam building in the Tasmanian wilderness was rechanneled into opposing the proposed Franklin Dam, which was successful.^[27]

The Lake Pedder earthworm (Hypolimnus pedderensis) is only known by the type specimen collected from a beach on Lake Pedder, Tasmania, in 1971. After the flooding of the lake, the invertebrate has not been seen. A 1996 survey that sought to determine whether the species still existed in the area failed to find any examples. Since 2003, the Lake Pedder earthworm has been listed as extinct on the IUCN Red List of Threatened Species.^[28]

An extinction claimed to have occurred after the flooding is that of the Lake Pedder planarian (Romankenkius pedderensis), an endemic flatworm. Since 1996, this invertebrate was listed as extinct on the IUCN Red List of Threatened Species.^[29] In 2012, the continued existence of the species was reported.^[30]

Following the impoundment 35,000 brown trout, an invasive species, were released into the new reservoir.^[31] This made the new lake a popular trout fishing location,^[32] but scientists believe that predation by the brown trout is the main cause of the local extinction of the Pedder galaxias, a native freshwater fish, which used to be endemic to Lake Pedder and its tributaries.^[10] The Pedder galaxias still exists in captivity and in two translocated populations, one at Lake Oberon in the Western Arthurs mountain range^[33] and the other at a modified water-supply dam near Strathgordon.^[34]

The Lake Pedder reservoir is impounded by three dams:^[1]

• Serpentine Dam – a 38-metre-high (125 ft) rock-fill embankment with a concrete upstream face on the Serpentine River
• Scotts Peak Dam – a 43-metre-high (141 ft) rock-fill embankment with a bitumen upstream face on the upper reaches of the Huon River near Scotts Peak
• Edgar Dam – a 17-metre-high (56 ft) saddle embankment at Lake Edgar near Scotts Peak

The water in Lake Pedder provides around 40% of the water used in the Gordon Power Station. Water in Lake Pedder is diverted to Lake Gordon (formed by the Gordon Dam) via the McPartlan Pass Canal and then into the Gordon Power Station.^{[a][35][36][37]} As a result, although the lake is 14m deep and covers 242km² only the top 1.5m is used.^[38][39] This was considered desirable for aesthetic reasons, as it means there's never large sections of exposed mud flats.^{[36]: 12 [40]} Additionally, trees that would have died from the inundation were cleared to make the lake more picturesque from common viewing points.^[36]: 12

A 1995 enquiry found that the Pedder reservoir contributed 65MW (570GWh per year) of electricity to the grid.^[3]: 48 A 2019 consultancy report estimated that water from the Pedder reservoir contributed to about 5.7% of Tasmania's electricity demand in the previous year, or approximately 624GWh.^[41] In 2022 The Restore Lake Pedder Campaign found that over the last decade the waters of Lake Pedder contributed 57MW on average (500GWh per year),^[42] a figure also stated by the Greens in 2024.^[43]

During the 2016 Tasmanian energy crisis, Hydro Tasmania considered drawing down Lake Pedder, but it was considered impractical.^[44]

The Lake Pedder reservoir has been a popular brown trout fishing location since 1972, when the area was flooded and fish introduced.^[31][3] Immediately after damming, the average fish size was almost 5kg,^[10] a common phenomenon for artificial reservoirs as the rotting plant matter provides an excellent food source. Between 1975-1983 it was a world class trophy fishing location, popular with interstate and overseas visitors.^{[3]: 54–55} However, in the years since as the reservoir matured the fish sizes stabilised to 1kg,^[10] and angling activity declined, but is still well regarded.^{[3]: 54–55}

In the 2015-2016 financial year 25,710 interstate and international visitors went to Lake Pedder,^[45] comparable to the 28,100 who visited from 2002-2003, making up 4.3% of visitors to Tasmania.^[46]

Although the official name of the reservoir is Lake Pedder, activitists and academics sometimes refer to it as the Huon–Serpentine Impoundment, after the two major dammed rivers,^[13] and some bushwalkers informally refer to it as "Fake Pedder".^[47][48]

In 1982, during the Franklin Dam protests, South West Tasmania was listed as a world heritage site, the Tasmanian Wilderness World Heritage Area, due to its "outstanding value to humanity".^[49][50] The site excluded the Lake Gordon reservoir as it had a large drawdown, which left "desolate" areas below the high water, but included Lake Pedder because its more stable water level makes it more scenic, and because of the potential for the "long term restoration of the original lake".^[51]: 16

In 1994, a campaign group was launched called Pedder 2000.^[52][53] They proposed, unsuccessfully, the draining and restoration of the lake to its original state. Although a parliamentary inquiry found it was technically feasible and would increase the site's World Heritage value, it also found that it was not compelled to drain the lake under international law, the project would be costly, and it was unlikely to succeed given it was not supported by either major Tasmanian political party.^{[3]: 1 [5]} However, it also stated that it was "unlikely that such a project... would now be approved" and that since the original Lake Pedder was well preserved under the reservoir the decision could be made to drain it in the future as public opinion changed.^{[3]: 71–73}

To coincide with the United Nations Decade of Ecological Restoration, covering 2021–2030, the Lake Pedder Restoration Committee called, in 2019, to have the lake restored to its original state.^[54] The committee, convened by Christine Milne with support from Todd Dudley, Bob Brown, Paul Thomas, and Tabatha Badger, planned to have an ecological management plan to restore the original Lake Pedder and surrounding iconic ecosystems.^[55]

The restoration campaign faced a setback in 2024 when the federal government approved strengthening works on the Edgar Dam (found to be on an active fault line) without a full environmental impact report or considering draining the reservoir.^[56]

Lake Pedder has an oceanic climate (Köppen: Cfb).

• Shores of Lake Pedder, c. 1970.
• Lake Pedder Beach, March 1966.

• List of reservoirs and dams in Australia § Tasmania
• List of lakes of Australia § Tasmania
• Olegas (opera)
• The South West Book

• Brinsmead, H. F. (1972). Echo in the Wilderness.. (A children's novel set on Lake Pedder on the eve of its flooding).
• Brinsmead, H. F. (1983). I Will Not Say the Day Is Done.. (Her only nonfiction/adult book that described the struggle to save Lake Pedder.).
• Buckman, Greg (2008). Tasmania's Wilderness Battles A History. Allen & Unwin. ISBN 978-1-74176-487-1.
• Gee, Helen; Fenton, Janet, eds. (1978). The south west book: a Tasmanian wilderness. Australian Conservation Foundation. ISBN 978-0-85802-056-6.
• Green, Roger; Lea, G. (1984). Battle for the Franklin: conversations with the combatants in the struggle for south west Tasmania. Fontana/Australian Conservation Foundation. ISBN 978-0-00-636715-4.
• Lines, William J. (2006). Patriots: defending Australia's natural heritage. University of Queensland Press. ISBN 978-0-7022-3554-2.
• Neilson, David (1975). South West Tasmania: a land of the wild. Rigby. ISBN 978-0-85179-874-5.
• Thompson, Peter (1981). Power in Tasmania. Australian Conservation Foundation. ISBN 978-0-85802-067-2.

• "Gordon-Pedder". Our power stations. Hydro Tasmania. Retrieved 1 June 2018.
• Position in World Heritage Area – Tasmanian National Parks
• Panorama of new Lake Pedder – Photograph Archived 14 February 2004 at the Wayback Machine
• National Archives original documents relating to Lake Pedder Archived 14 March 2011 at the Wayback Machine
• "Inquiry into the Proposal to Drain and Restore Lake Pedder" (PDF). House of Representatives Standing Committee on Environment, Recreation and the Art. Parliament of Australia. June 1995.