Lake Pedder
Lake in South West Tasmania, Australia
From Wikipedia, the free encyclopedia
Lake Pedder, once a glacial outwash lake, is a man-made 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) for the purpose of generating hydroelectricity at the Gordon Power Station.
| Lake Pedder | |
|---|---|
 Lake Pedder, c. 2014 | |
  Lake Pedder Location of the lake in Tasmania | |
 Map showing Lake Pedder in Tasmania | |
| Location | South West Tasmania |
| Coordinates | 42°56′S 146°08′E |
| Type | |
| Etymology | Sir John Pedder |
| Part of | Upper Gordon River hydroelectric generation scheme |
| Frankland Range | |
River sources | |
| |
| 734 km2 (283 sq mi) | |
| Basin countries | Australia |
Construction engineer | Hydro Tasmania |
First flooded | 1972 |
Surface area | 24,133 ha (59,630 acres) |
Average depth | 13–16 m (43–52 ft) (as a reservoir) |
| Max. depth |
|
Water volume | 2,937.93 GL (2,381,820 acre⋅ft) |
Surface elevation | 300 m (980 ft) AHD |
| Islands |
|
| References | [1] |
As a result, since 1972 the flooded Lake Pedder has had a surface area approximately 24,133 hectares (59,630 acres), making it Tasmania's second-largest lake.[1][2][3]
The original and modified lake
The original lake was named, in the early part of the 20th century, in honour of Sir John Pedder, the first chief justice of Tasmania. Following its flooding in 1972, the impoundment retained the name of the original lake. Although the new Lake Pedder incorporated the original lake, it does not resemble it in size, appearance, or ecology.[citation needed]
Since 1972, the lake has been fed by releases from 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 dams were designed and constructed by Tasmania's Hydro Electric Commission (HEC) as part of the Upper Gordon River hydroelectric generation scheme. 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 secondary industry[citation needed] to the state with the incentive of cheap,[citation needed] renewable energy. 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.[a][4][5][6] After use in the Gordon Power Station, water from Lake Gordon then exits through the Gordon Dam and into the Gordon River.[7] Together, as of June 2015[update], the Pedder and Gordon lakes formed the biggest water catchment and storage system in Australia.[4]
Damming
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, in place since 1955. The HEC was perceived as a surrogate wing[weasel words] of the Tasmanian government[citation needed] when political or social dissent against the HEC's power over the Tasmanian environment seemed impregnable.[citation needed] Tasmania's Premier Eric Reece, and Allan Knight, the HEC commissioner, were seen as the leading proponents of the damming of Tasmania against any[citation needed] 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.[8]
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".[9] 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".[10] Reece retrospectively commented:[11]
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.[12]
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.[citation needed] 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.[13]
The protests included the United Tasmania Group, which were the precursor to the Tasmanian Greens, recognised as the world's first green party.[citation needed] The group that preceded the Tasmanian Wilderness Society – the South West Tasmania 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. 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.[9]: 280–281
Hesba Fay Brinsmead, an Australian children's author and environmentalist, wrote two books about the damming of Lake Pedder.[citation needed]
Concerns over the construction of the dam revolved around the loss of the distinctive pink quartzite beach of the original lake,[citation needed] and an increased understanding of the unique nature of the wilderness quality to the south west of Tasmania.[citation needed] This[clarification needed] developed further with the Franklin Dam issue.
In 1994, a campaign group was launched called Pedder 2000.[14][15] They proposed, unsuccessfully, the draining and restoration of the lake to its original state. A low-key campaign is going on with the same goal by the group known as the Lake Pedder Action Committee, which remains active.[16]
Restoration campaign
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.[17] 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.[citation needed]
Environmental impact
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.[18]
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.[19] In 2012, the continued existence of the species was reported.[20]
The Pedder galaxias, an Australian freshwater fish, is considered extinct in its natural habitat of Lake Pedder and its tributaries, although it still exists in captivity and in two translocated populations, one at Lake Oberon in the Western Arthurs mountain range[21] and the other at a modified water-supply dam near Strathgordon.[22]
Name controversy
As is the case in many land-use, land-ownership, and territorial disputes,[citation needed] the name currently officially assigned to this body of water has considerable significance.[according to whom?] It is also important[according to whom?] in terms of understanding the technical status of the body of water as a component of a hydroelectric scheme.[citation needed]
From a technical, hydroelectric scheme point of view,[according to whom?] the current Lake Pedder can be correctly[weasel words] termed a lake or reservoir, as the water from Lake Pedder can flow into Lake Gordon via the McPartlan's Pass Canal and is thereby connected to the Gordon Power Station.[5] However, people opposed to the flooding of the original lake do not accept the legitimacy of the official, gazetted name of Lake Pedder for the body of water that drowned it in 1972.[citation needed] Instead, they prefer to refer to the lake as the Huon–Serpentine Impoundment, denoting the two major rivers dammed to create the lake, and describes the technical status of the lake as an element of a hydroelectric scheme more accurately.[23] Some bushwalkers informally refer to it as "Fake Pedder".[24][25]
Climate
Lake Pedder has an oceanic climate (Köppen: Cfb).
| Climate data for Lake Pedder (Scotts Peak Dam) (1992–2022) | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Month | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Year |
| Record high °C (°F) | 38.6 (101.5) |
35.9 (96.6) |
37.5 (99.5) |
29.1 (84.4) |
22.0 (71.6) |
15.7 (60.3) |
17.1 (62.8) |
22.5 (72.5) |
25.2 (77.4) |
30.6 (87.1) |
34.8 (94.6) |
36.3 (97.3) |
38.6 (101.5) |
| Mean daily maximum °C (°F) | 21.2 (70.2) |
21.2 (70.2) |
18.6 (65.5) |
14.9 (58.8) |
11.6 (52.9) |
9.8 (49.6) |
9.3 (48.7) |
10.4 (50.7) |
12.4 (54.3) |
14.9 (58.8) |
17.8 (64.0) |
19.0 (66.2) |
15.1 (59.2) |
| Mean daily minimum °C (°F) | 9.5 (49.1) |
9.4 (48.9) |
8.5 (47.3) |
6.9 (44.4) |
5.5 (41.9) |
4.0 (39.2) |
3.3 (37.9) |
3.4 (38.1) |
4.3 (39.7) |
5.2 (41.4) |
6.9 (44.4) |
8.0 (46.4) |
6.2 (43.2) |
| Record low °C (°F) | 2.6 (36.7) |
3.3 (37.9) |
1.3 (34.3) |
−0.4 (31.3) |
−1.1 (30.0) |
−1 (30) |
−2.3 (27.9) |
−2.1 (28.2) |
−1.6 (29.1) |
−1 (30) |
−0.5 (31.1) |
1.5 (34.7) |
−2.3 (27.9) |
| Average precipitation mm (inches) | 95.2 (3.75) |
81.9 (3.22) |
120.4 (4.74) |
132.6 (5.22) |
191.6 (7.54) |
181.4 (7.14) |
211.9 (8.34) |
229.7 (9.04) |
210.8 (8.30) |
165.8 (6.53) |
111.2 (4.38) |
143.2 (5.64) |
1,927.8 (75.90) |
| Average precipitation days (≥ 0.2 mm) | 17.4 | 15.8 | 19.3 | 21.8 | 25.8 | 25.8 | 27.1 | 26.4 | 25.5 | 24.5 | 19.7 | 20.2 | 269.3 |
| Average afternoon relative humidity (%) | 58 | 59 | 66 | 74 | 82 | 86 | 85 | 81 | 76 | 69 | 62 | 63 | 72 |
| Source: Bureau of Meteorology[26] | |||||||||||||
Gallery
Shores of Lake Pedder, c. 1970.
Photograph of Lake Pedder Beach, March 1966.
See also
Notes
- The canal is located at 42°50′51″S 146°11′45″E.
