Lake Corangamite
Encyclopedia
Lake Corangamite is Victoria’s largest natural lake
, located near Colac
in south-west Victoria
, Australia
in the Lakes and Craters region of the Victorian Volcanic Plains. The lake is hypersaline, and salinity levels have increased dramatically as the lake level has dropped in recent decades. It is Australia's largest permanent saline lake, covering approximately 230 km2 with a circumference of about 150 km. It forms part of the Ramsar-listed
Western District Lakes
wetland site.
crater complex overlooks the south west shore. The Mount Warrion flows caused the lake to form by blocking drainage to the east.
As is typical of lakes in the area, the eastern flanks of the lake consist of lunettes formed by wind borne sediments blown from the lake during periods with dry climates.
Flow into the lake is extremely variable and negligible in the driest years. Currently it is endorheic
(there is no outflow) but during the wet decade of the 1950s the lake flooded and became connected via a series of wetlands and lakes to Lake Murdeduke and the Barwon River
. It has never been completely dry since European settlement, and there it is evidence it was an open lake
for centuries prior to the when 1840s rainfall and runoff were similar to those of the 1950s.
The main inflows are from Pirron Yaloak Creek flowing from the Otway plains to the south, the Woady Yaloak River flowing from the flanks of the Victorian midlands to the north, and Salt Creek flowing from the plains to the north-west. The Pirron Yaloak has high nutrient loads due to dairy farming in its catchment.
In response to the floods of the 1950s, the Woady Yalloak was diverted away from Lake Corangamite and into the Barwon River. The diversion is managed on the basis of a trigger level for the lake, above which the diversion is enacted. This has not occurred in recent years. Levels have been dropping for decades and it is possible that it will dry completely. In 1980 the salinity was approximately that of seawater and has since risen at least 4x that of seawater.
, Common Galaxias
, Flat-headed Gudgeon and Small-mouth Hardyhead. These may still survive in refuges such as Pirron Yaloak creek and various freshwater springs flowing from the stony rises on the south west side of the lake. Springs on the south east side have dried - possibly due to over exploitation of the Warrion Aquifer for irrigation. More recently the fauna included brine shrimp
and a species of isopod.
s. The lake was previously an important breeding site for waterbirds. Most recently Pelican
colonies occurred at Wool Wool rocks and Vaughn Island. However, as water levels have dropped, prey have disappeared and fox
es have gained access to the colonies, which have now been abandoned. After receiving substantial grants from the government to undertake conservation works, the owner of Vaugn Island used earth moving equipment to remove habitat such as rocks and remnant vegetation. The lake forms part of the Lake Corangamite Complex Important Bird Area
, so identified by BirdLife International
because it sometimes supports globally important numbers of waterbirds.
This plane is believed to be an RAAF Wirraway Serial No. A20-405 that is recorded as having crashed into Lake Corangamite, 400 metres from shore on 17 March 1943. There were at least 355 military aircraft crashes recorded in Victoria during World War II, most of them the result of training incidents.
Wirraways were the first aircraft to be mass manufactured in Australia, and this eighteen years before the first mass manufactured Australian car. Between 1939 and 1946 the Commonwealth Aircraft Corporation
(CAC) produced 755 Wirraways for use as a general purpose trainer, though they saw action in the desperate defence of Malaya
and Papua New Guinea
where they were lost at an appalling rate to superior Japanese Mitsubishi
A6M Zero
fighters. Only eight Wirraways are still in existence as restored or partly restored historic aircraft.
Lake
A lake is a body of relatively still fresh or salt water of considerable size, localized in a basin, that is surrounded by land. Lakes are inland and not part of the ocean and therefore are distinct from lagoons, and are larger and deeper than ponds. Lakes can be contrasted with rivers or streams,...
, located near Colac
Colac, Victoria
Colac is a small city located in the Western District of Victoria, Australia, situated approximately 150 kilometres south-west of Melbourne on the southern shore of Lake Colac and the surrounding volcanic plains, approximately 40 km inland from Bass Strait. Colac is the largest city in and...
in south-west Victoria
Victoria (Australia)
Victoria is the second most populous state in Australia. Geographically the smallest mainland state, Victoria is bordered by New South Wales, South Australia, and Tasmania on Boundary Islet to the north, west and south respectively....
, Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
in the Lakes and Craters region of the Victorian Volcanic Plains. The lake is hypersaline, and salinity levels have increased dramatically as the lake level has dropped in recent decades. It is Australia's largest permanent saline lake, covering approximately 230 km2 with a circumference of about 150 km. It forms part of the Ramsar-listed
Ramsar Convention
The Ramsar Convention is an international treaty for the conservation and sustainable utilization of wetlands, i.e., to stem the progressive encroachment on and loss of wetlands now and in the future, recognizing the fundamental ecological functions of wetlands and their economic, cultural,...
Western District Lakes
Western District Lakes
The Western District Lakes of Victoria, in the Western District of Victoria, south-eastern Australia, were recognised on 15 December 1982 as wetlands of international importance by listing under the Ramsar Convention, as Ramsar site no.268.-Description:...
wetland site.
Physical features and hydrology
The waterbody is surrounded to the south and east by rocky outcrops (known locally as the stony rises) which were formed by lava flows from Mount Porndon to the south-west and Mount Warrion to the east. The spectacular 'Red Rocks' maarMaar
A maar is a broad, low-relief volcanic crater that is caused by a phreatomagmatic eruption, an explosion caused by groundwater coming into contact with hot lava or magma. A maar characteristically fills with water to form a relatively shallow crater lake. The name comes from the local Moselle...
crater complex overlooks the south west shore. The Mount Warrion flows caused the lake to form by blocking drainage to the east.
As is typical of lakes in the area, the eastern flanks of the lake consist of lunettes formed by wind borne sediments blown from the lake during periods with dry climates.
Flow into the lake is extremely variable and negligible in the driest years. Currently it is endorheic
Endorheic
An endorheic basin is a closed drainage basin that retains water and allows no outflow to other bodies of water such as rivers or oceans...
(there is no outflow) but during the wet decade of the 1950s the lake flooded and became connected via a series of wetlands and lakes to Lake Murdeduke and the Barwon River
Barwon River (Victoria)
The Barwon River rises in the Otway Ranges of Victoria, Australia, runs through Winchelsea and the city of Geelong, where it is joined by the Moorabool River, and enters the sea at Barwon Heads after passing through Lake Connewarre on the Bellarine Peninsula...
. It has never been completely dry since European settlement, and there it is evidence it was an open lake
Open and closed lakes
Open and closed lakes refer to the major subdivisions of lakes - bodies of water surrounded by land.An open lake is a lake where water constantly flows out under almost all climatic circumstances. Because water does not remain in an open lake for any length of time, open lakes are always fresh...
for centuries prior to the when 1840s rainfall and runoff were similar to those of the 1950s.
The main inflows are from Pirron Yaloak Creek flowing from the Otway plains to the south, the Woady Yaloak River flowing from the flanks of the Victorian midlands to the north, and Salt Creek flowing from the plains to the north-west. The Pirron Yaloak has high nutrient loads due to dairy farming in its catchment.
In response to the floods of the 1950s, the Woady Yalloak was diverted away from Lake Corangamite and into the Barwon River. The diversion is managed on the basis of a trigger level for the lake, above which the diversion is enacted. This has not occurred in recent years. Levels have been dropping for decades and it is possible that it will dry completely. In 1980 the salinity was approximately that of seawater and has since risen at least 4x that of seawater.
Fish
Aquatic fauna once included fish species such as Short-finned EelShort-finned eel
The short-finned eel, Anguilla australis, is one of the 15 species of eel in the family Anguillidae. It is native to the lakes, dams and coastal rivers of south-eastern Australia, New Zealand, and much of the South Pacific, including New Caledonia, Norfolk Island, Lord Howe Island, Tahiti, and...
, Common Galaxias
Common galaxias
The common galaxias or the inanga , is a species of fish from the galaxiid family that is very widespread in the southern hemisphere. It is a slim narrow fish with a forked tail and as an adult it lives in freshwater rivers and lakes. Common galaxias grows to a length of 40 to 120 mm, but can grow...
, Flat-headed Gudgeon and Small-mouth Hardyhead. These may still survive in refuges such as Pirron Yaloak creek and various freshwater springs flowing from the stony rises on the south west side of the lake. Springs on the south east side have dried - possibly due to over exploitation of the Warrion Aquifer for irrigation. More recently the fauna included brine shrimp
Brine shrimp
Artemia is a genus of aquatic crustaceans known as brine shrimp. Artemia, the only genus in the family Artemiidae, has changed little externally since the Triassic period...
and a species of isopod.
Birds
In the past the lake has supported internationally-significant numbers of Banded StiltBanded Stilt
The Banded Stilt is a nomadic stilt from Australia. It belongs to the monotypical genus Cladorhynchus. It gets its name from the red-brown breast band found on breeding adults, but this is mottled or entirely absent in non-breeding adults and juveniles. Its remaining plumage is pied and the eyes...
s. The lake was previously an important breeding site for waterbirds. Most recently Pelican
Australian Pelican
The Australian Pelican is a large water bird, widespread on the inland and coastal waters of Australia and New Guinea, also in Fiji, parts of Indonesia and as a vagrant to New Zealand.-Taxonomy:...
colonies occurred at Wool Wool rocks and Vaughn Island. However, as water levels have dropped, prey have disappeared and fox
Fox
Fox is a common name for many species of omnivorous mammals belonging to the Canidae family. Foxes are small to medium-sized canids , characterized by possessing a long narrow snout, and a bushy tail .Members of about 37 species are referred to as foxes, of which only 12 species actually belong to...
es have gained access to the colonies, which have now been abandoned. After receiving substantial grants from the government to undertake conservation works, the owner of Vaugn Island used earth moving equipment to remove habitat such as rocks and remnant vegetation. The lake forms part of the Lake Corangamite Complex Important Bird Area
Important Bird Area
An Important Bird Area is an area recognized as being globally important habitat for the conservation of bird populations. Currently there are about 10,000 IBAs worldwide. The program was developed and sites are identified by BirdLife International...
, so identified by BirdLife International
BirdLife International
BirdLife International is a global Partnership of conservation organisations that strives to conserve birds, their habitats and global biodiversity, working with people towards sustainability in the use of natural resources...
because it sometimes supports globally important numbers of waterbirds.
World War II Aircraft
A crashed World War II RAAF Wirraway was discovered in early June 2005 in Lake Corangamite. Heritage Victoria protects all aircraft crash sites over 50 years old as historic archaeological sites, and the RAAF has been briefed on the find. The site was recently exposed by receding water levels in the Lake and reported by Parks Victoria officers to Heritage Victoria. The site appears intact and remains mostly submerged.This plane is believed to be an RAAF Wirraway Serial No. A20-405 that is recorded as having crashed into Lake Corangamite, 400 metres from shore on 17 March 1943. There were at least 355 military aircraft crashes recorded in Victoria during World War II, most of them the result of training incidents.
Wirraways were the first aircraft to be mass manufactured in Australia, and this eighteen years before the first mass manufactured Australian car. Between 1939 and 1946 the Commonwealth Aircraft Corporation
Commonwealth Aircraft Corporation
The Commonwealth Aircraft Corporation was an Australian aircraft manufacturer. The CAC was established in 1936, to provide Australia with the capability to produce military aircraft and engines.-History:...
(CAC) produced 755 Wirraways for use as a general purpose trainer, though they saw action in the desperate defence of Malaya
British Malaya
British Malaya loosely described a set of states on the Malay Peninsula and the Island of Singapore that were brought under British control between the 18th and the 20th centuries...
and Papua New Guinea
Papua New Guinea
Papua New Guinea , officially the Independent State of Papua New Guinea, is a country in Oceania, occupying the eastern half of the island of New Guinea and numerous offshore islands...
where they were lost at an appalling rate to superior Japanese Mitsubishi
Mitsubishi
The Mitsubishi Group , Mitsubishi Group of Companies, or Mitsubishi Companies is a Japanese multinational conglomerate company that consists of a range of autonomous businesses which share the Mitsubishi brand, trademark and legacy...
A6M Zero
A6M Zero
The Mitsubishi A6M Zero was a long-range fighter aircraft operated by the Imperial Japanese Navy Air Service from 1940 to 1945. The A6M was designated as the , and also designated as the Mitsubishi A6M Rei-sen and Mitsubishi Navy 12-shi Carrier Fighter. The A6M was usually referred to by the...
fighters. Only eight Wirraways are still in existence as restored or partly restored historic aircraft.