Lake George (New South Wales)

Infobox_lake
lake_name = Lake George
image_lake = Lake George 2 7 07.jpg
caption_lake = July 2007, after heavy rain
image_bathymetry =
caption_bathymetry =
location = New South Wales
coords = coord|35|10|S|149|25|E|region:AU_type:waterbody|display=inline,title
type = Intermittent
inflow =
outflow = "evaporation"
catchment =
basin_countries = Australia
length = 25 km
width = 10 km
area =
depth = 1 m
max-depth = 2 m
volume =
shore =
elevation =
islands =
cities =

Lake George (or Weerewaa in the indigenous language) is a lake in south-eastern New South Wales, Australia about 30 minutes drive north-east of Canberra along the Federal Highway enroute to Sydney.

It is renowned for emptying and filling on a cyclical basis, and for the treachery of its waters when full (a number of people have drowned).cite news| last = Jones | first = Cheryl | | url= http://bulletin.ninemsn.com.au/article.aspx?id=128997 | title= Lake eerie | work= | publisher= The Bulletin |date=2001-08-22 | accessdate= 2007-07-31]

Geography / Geology

Lake George is an ancient lake, believed to be more than a million years old. Originally, small streams drained its catchment into the Yass River, but then the Lake George Escarpment rose due to major crustal movement along a strong fault line, blocking this drainage and forming the lake.cite web | last = Cartwright | first = Sarah | authorlink = | coauthors = Gary Jones | year = 2002 | url = http://freshwater.canberra.edu.au/publications.nsf/6bf76071ddee7e92ca256f1e0014ee1e/27b4c6b20aa3fa56ca256f1900153afc/$FILE/august02.pdf | title = By George, It Really Is a Lake! | format = pdf (see pages 9 - 10)| work = Watershed, Issue No. 27 - August 2002 | publisher = Co-operative Research Centre for Freshwater Ecology | accessdate = 2007-10-23 |quote = Lake George, one of the world's oldest lakes, is shallow and has a history of dramatically fluctuating water levels, despite being closed with no outlet. Originally there was no lake at all, and water drained from the Great Dividing Range west to the Yass River. That was before geological uplift, five million years ago, which formed the Lake George Range — a natural dam blocking the creeks.] Lake George has in previous Ice Ages been much larger and deeper.Fact|date=October 2007

The thickness of sediment beneath the lake exceeds 250 metres, according to a Bureau of Mineral Resources Canberra drilling program in the 1982/83 summer. The oldest sediments, which lie some distance above the bedrock, were dated at 3 - 5 million years using spore and pollen analysis and magnetic reversal stratigraphyFact|date=August 2007.

At 25 km long and 10 km wide, Lake George is long, largely flat and extremely shallow, with a very small catchment. Resultant evaporation rates as well as a tendency for strong winds to blow the water back on itself explain the mysterious filling and drying episodes on both short term (hours) and long term (years) time scales that have been observed.

The lake's depth when full can range from 1.5 to 4.5 metres; however in many areas it is only around 0.8–1.0 metre deep. Its deepest point has been measured as 7.5 metres. When full, the lake holds about 500 million cubic metres of water. Between the late 1980s and mid 1990s, the lake lapped the Federal Highway on its western edge.

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.

History

The Lake was named on 28 October 1820 for King George III by Governor Macquarie, who was touring the area as part of a Royal Commission to inquire into the condition of the Colony [Official Year Book of the Commonwealth of Australia, 1931 (ABS cat. no. 1301.0)] . It was first 'discovered' by Joseph Wild on 19 August 1820. [ "Canberra's Engineering Heritage", William Charles Andrews, Institution of Engineers, Canberra, 1990 p2 ] In the local indigenous language, its name was Werriwa (originally spelt "Weereewa" in the journals of the explorers who noted the name), which means "bad water".

A large and beautiful billabong existed at the swampy Bungendore end of the lake, and in the 1850s was stocked with Murray cod fished out of the Molonglo River. At some time the billabong overflowed and introduced Murray cod into the lake. The Murray cod bred rapidly, hence from the 1850s to the 1890s Lake George abounded with Murray cod. [cite web | last = Thornton | first = Mark | year = | url = http://www.weereewafestival.org/boatstory.htm | title = Mucking about, carefully, in sailing boats on Lake George | format = | work = Some stories about Lake George | publisher = Weereewa - A Festival of Lake George Inc | accessdate = 2007-10-23] A small fishing trawler even trawled the lake for the cod. Fact|date=October 2007 The Federation Drought commenced in the mid 1890s, and by 1902 the lake had dried out completely. In their search for water to survive in, the Murray cod flocked into the few small creek mouths feeding the lake but were killed in their thousands.Fact|date=October 2007. The original billabong has long since been drained.

In the early 1900s an area immediately to the east of the lake was surveyed as a possible site for the Capital city of Australia. Instead, the Australian Capital Territory and city of Canberra were established some 30 km 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.

In 1956, five cadets from the Royal Military College, Duntroon drowned on 8 July in a yachting accident. An unsuccessful rescue attempt lasted five and a half hours, the rescuers received the George Medal. [cite web | last = | first = | authorlink = | coauthors = | year =
url = http://www.defence.gov.au/ARMY/AHU/On_This_Day/July/8_July.htm | title = On this day - 8 July
format = | work = | publisher = Australian Department of Defence: Army History Unit | accessdate = 2007-07-31]

Due to the ongoing drought in Australia, Lake George dried in November 2002, and remained so as of May 2007. As at September 2007 there were large pools of water in the lake. The last time the lake was as dry was in the 1940s, although it did partially dry in 1986, leaving large pools of water. When the lake is empty it is used by farmers to graze sheep and cattle.

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References