Lake George (New South Wales)
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| Lake George, NSW, Australia | |
|---|---|
 |
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| Coordinates | |
| Lake type | Intermittent |
| Primary outflows | Evaporation |
| Max-length | 25km |
| Max-width | 10km |
| Surface area | |
| Average depth | 1m |
| Max-depth | 2m |
| Water volume | |
| Shore length1 | |
| Surface elevation | |
| 1 Shore length is an imprecise measure which may not be standardized for this article. | |
Lake George is a lake in south-eastern New South Wales, Australia and is about 30 minutes drive north-east of Canberra along the Federal Highway enroute to Sydney, state capital of New South Wales. The basin of the lake is 25km long and 10km wide.
It is renowned for emptying and filling on a cyclical basis, for the treachery of its waters when full (a number of people have drowned), and for a mirage which makes it appear full when it is in fact empty.[citation needed]
[edit] Geography / Geology
Lake George is an ancient lake, believed to be more than a million years old. Originally small streams drained the Lake George catchment into the Yass River, but then the Lake George Escarpment rose due to major crustal movement along a strong faultline, and blocked this drainage forming the lake. Lake George has in previous Ice Ages been much larger and deeper, however there is no evidence that Lake George has ever flowed over the escarpment into the Yass River.
Sediment coring has revealed there are 30 metres of lacustrine sediment below the current bed surface of Lake George, which have been deposited over the lakes long existence.
Lake George is a long shallow lake with a very small catchment. Resultant evaporation rates and an ability for strong winds to blow the water back on itself fully explain the mysterious filling and drying episodes on both short term (hours) and long term (years) time scales that people have observed over the years.
The lake can achieve a depth of over 2 metres in some areas, however, the mean depth is nearer 1 metre. Between the late 1980s and mid 1990s, the lake lapped the Federal Highway on its western edge.
The lake dried in November 2002. Before that it dried in 1986, but then the lake still had several large pools of water. It was utterly dry, as it is now, in the 1940s.
[edit] Activities
Lake George is the site of an experimental scientific wave behaviour platform established by researchers from the Civil Engineering department of the Australian Defence Force Academy in Canberra.
Lake George has been a popular fishery at times, after high water levels and stockings of fish.
Hang gliders are flown from the escarpment when easterly winds form standing waves. Pilots can then fly along the twenty-five kilometre length of the lake. Unpowered model aircraft are also flown from this area, and powered models are flown from the lake floor.
Wine grapes are grown along the western edge of the lake, on the escarpment. Sheep are grazed on the lake when it is dry or nearly so.
The thickness of sediment beneath the Lake in fact exceeds 250 metres (the Bureau of Mineral Resources Canberra instituted a drilling program in the 1982/83 summer). The oldest dated sediments, which lie some distance above the bedrock beneath the lake, are dated at 3 - 5 million years, using both spores and pollen and magnetic reversal stratigraphy.
[edit] History
The Lake was named for King George III by European explorers. In the local indigenous language, its name was Werriwa, originally spelt Weereewa in the journals of the explorers who noted the name, and means "bad water".
An area immediately to the east of the lake was surveyed in the early 1900s as a possible site for the Capital city of Australia. Instead, the Australian Capital Territory and city of Canberra was established some 30km south-west of the lake.
During World War II, a wooden 'dummy' ship was floated on the lake and used for bombing practice by the Royal Australian Air Force. It is possible that there is still unexploded ordnance settled into the lake bed.
