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 wild beauty, and community opposition to its flooding led to the formation of 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.
With a size of approximately 242 km2, the new Lake Pedder reservoir is Tasmania's second-largest lake and its waters are used to generate about 500GWh of electricity for Tasmania per year, or a bit under 6% of the state's requirements. It is a popular trout fishing location.
Geomorphology
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, it had a surface area of ~10 km2 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, activists and the Scenic board (National Parks precursor organisation).
A 1975 government enquiry described it as:
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".
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. 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.
There were unusual rocks found along the beach called Pedder Pennies.
A fault line with clear scarp landforms runs 11 km SE of the original lake, including two scarp ponds called Lake Edgar (now flooded).
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).
Ecology Lake Pedder had the highest number of endemic species for any lake in Australia, with numerous invertebrates only found on its shores, and several species of freshwater fish. The swamp galaxias is endemic to Lake Pedder and its tributaries, as was the Pedder Galaxias, now extinct in its native range.
The vegetation of the valleys around Lake Pedder varied from wetlands and buttongrass moorlands to eucalypt forests and rainforests.
Early human history
Aboriginal people have lived in Tasmania for approximately 35,000 years, crossing over the Bassian Plain from the mainland. 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. 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.
European surveyors found Lake Pedder during a trigonometric survey in 1835, with surveyor John Wedge naming it after the first chief justice of Van Diemen's Land, John Pedder. The area was further explored by piners and later miners during the mineral rush of the early 1900s, however no significant deposits were found and the forests were remote and difficult to access. The landscape of the South West is extremely rugged, has poor soils and a difficult climate which made it unattractive for agriculture so it remained uninhabited.
As bushwalking and recreation became more popular throughout the 1900s, old mining huts and tracks were repurposed for recreation. Some of the same traits that made it unattractive for industry, remoteness, ruggedness and bad weather gave it, what McKenry of the Australian Conservation Foundation, described a "rugged natural beauty".
National park
In 1954 the Hobart Walking Club approached the Scenery Preservation Board proposing to make the area surrounding Lake Pedder a national park. Pedder had become more accessible as people became richer in the post-war years, and the Aero Club of Southern Tasmania was able to land on its wide beach to drop off people and supplies. It was nominated due to both its beauty, and that there was no potential for mining or forestry development in the surrounds. 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.
They were successful, and in 1955, Lake Pedder, and the surrounding 59,000 acres was declared a scenic reserve (the predecessor 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.
Internal HEC dam plans
In the 1950s60s the HEC was Tasmania's largest public corporation, employing approximately 4000 people, and was tasked with generating as much hydroelectricity as possible in accordance with the Tasmanian government's policy of attracting manufacturing industry to the state with the incentive of cheap power, known as hydro-industrialisation. It was successful as a hydroelectric dam building organisation and often pioneered new techniques in dam construction. The early dams were located in the more accessible parts of the state, including the Mersey River, Forth River and Central Highlands, but after those rivers were exhausted the HEC began to explore the more remote south west. It was not common for the public to be consulted on the HECs plans, it tended to "denigrate its opponents", and the full context of damming (loss of wilderness, cost-benefit analysis, flow of profit for cheap electricity) was not within their remit. Additionally, the government normally accepted the commission's recommendations without question. In contrast, the Snowy Mountains Hydro-electric Authority, which held a similar remit to build dams on the mainland, was more consultative.
As early as 1955, when the scenic board made Lake Pedder National Park, they were told by HEC Chief Commissioner Allan Knight that they had some designs to dam the Serpentine valley. However, it was a closed meeting so neither the wider public nor early environmentalists were aware.
By 1962 the HEC was actively planning to dam the Serpentine Valley, and, aware of the significance of Lake Pedder and the surrounding national park, was considering alternatives to drowning it. These included creating a lower Serpentine Dam and pumping water up to the Gordon, creating a tunnel to move water directly into the power station, routing water from the Huon around or through Lake Pedder, or abandoning the flow of the Huon. In 1963 the HEC received a $5 million commonwealth grant to build an explorative road towards the Gordon and Serpentine rivers to examine placing a new dam in the area. Although the grant details were not released to the public, the construction of the road was one of the few external indicators that they were planning to dam the area. B.W. Davis later noted that grant application noted that the roads "...somewhat circuitous route [would be] necessary to avoid areas which will subsequently be flooded by the Middle Gordon storages", indicating that the project layout was near finalised. In 1966 they formally decided to flood the entire Serpentine Valley, as it provided the most hydroelectric power at a minimum cost. However, these discussions were entirely internal, and a 1972 interim government enquiry concluded that the analyses of alternative dams were "inadequate on both technical and economic grounds".
Early conservationist reactions In early 1962, conservationists became aware that the south west was less inherently remote and self-protecting than it used to be and formed the South West Committee to coordinate conservation and development, balancing wilderness and recreation with the electric and forestry industries. Requests for information were treated with "extreme reticence" and it was castigated by the Premier for interfering in public affairs, however in 1965 the Premier said there would be "some modification of the Lake Pedder National Park".
Damming
In 1967 HEC publicly recommended damming the middle Gordon river, installing a power station, and adding extra dams around the Serpentine valley to increase the reservoir size. It asserted that the new Lake Pedder would be larger and more attractive than the old. The entire Gordon scheme was costed at about $90 million.
This decision to flood Pedder attracted protests across Australia, before, during, and after construction of the dams. 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.
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". 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". Reece retrospectively commented:
Community response 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. Concerns over the construction of the dam revolved around the loss of the distinctive pink quartzite beach of the original lake, and an increased understanding of the unique nature of the wilderness quality to the south west of Tasmania.
The protests included the United Tasmania Group, which were the precursor to the Tasmanian Greens, recognised as the world's first green party. The group that preceded the Tasmanian Wilderness Society – the South West Tasmania Action Committee (itself preceded by the Lake Pedder Action Committee) - 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.
Alternative dam proposals