Lake George (New South Wales)

Lake George

A panorama image of Lake George, taken from a rest stop on the Federal Highway (M23).
Location New South Wales
Coordinates 35°10′S 149°25′E / 35.167°S 149.417°ECoordinates: 35°10′S 149°25′E / 35.167°S 149.417°E
Lake type Intermittent
Primary outflows evaporation
Basin countries Australia
Max. length 25 km (16 mi)
Max. width 10 km (6.2 mi)
Average depth 1 metre (3 ft 3 in)
Max. depth 7.5 m (25 ft)

Lake George (or Weereewa in the indigenous language) is a lake in south-eastern New South Wales, Australia. It is about 40 kilometres north-east of Canberra along the Federal Highway en route to Sydney.

Geography / Geology

Lake George is an Endorheic lake, as it has no outflow of water to rivers and oceans.

The lake is 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.[1] Lake George has in previous Ice Ages been much larger and deeper.

The thickness of sediment beneath the lake exceeds 250 metres (820 ft), according to a Bureau of Mineral Resources Canberra drilling programme 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 stratigraphy.

At 25 km (16 mi) long and 10 km (6.2 mi) 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 1.5–4.5 metres (4 ft 11 in–14 ft 9 in); however in many areas it is only around 0.8–1.0 metre (2 ft 7 in–3 ft 3 in) deep. Its deepest point has been measured as 7.5 metres (25 ft). When full, the lake holds about 500,000,000 cubic metres (1.8×1010 cu ft) of water. Between the late 1980s and mid-1990s, the lake lapped the Federal Highway on its western edge.

Activities

Zebra herd, where it was first installed in 2010

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 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.

Public art

In 2010, Canberra artists Alan and Julie Aston installed a herd of zebras on the lake adjacent to the highway stop commemorating Kevin "Dasher" Wheatley VC, used as a "Driver Reviver" site. They were named Stopper, Reviver, Survivor, and Dasher. They were a sensation, but the Government of New South Wales ordered that they be removed, following a complaint from the leaseholder of the land.[2] They reappeared at Floriade, Canberra in September 2010, along with a baby, George.

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.[3] It was first discovered by Joseph Wild on 19 August 1820.[4] In the local indigenous language, its name was Werriwa (originally spelled Weereewa in the journals of the explorers who noted the name), which means "bad water"; even when full, the lake is one of the saltiest bodies of water in inland NSW, almost as saline as seawater.[5]

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; they bred rapidly and from the 1850s to the 1890s Lake George abounded with Murray cod. A small fishing trawler trawled the lake for the cod. The Federation Drought commenced in the mid-1890s, and by 1902 the lake dried out completely. In their search for water to survive in, the Murray cod flocked into the few small creek mouths feeding the lake and were killed by the thousands. The original billabong has long since been drained.

One of the original 75 electoral divisions of the Australian House of Representatives was named "Werriwa" in 1901. By 1913, the electorate no longer covered the lake and it presently covers some South-Western suburbs of Sydney.

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 (19 mi) 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.

On 8 July 1956 five cadets from the Royal Military College, Duntroon drowned in a yachting accident.

Looking east over a dry lake bed

Due to the ongoing drought in Australia, Lake George dried out completely in November 2002 and remained so until February 2010 when it started filling. The last time the lake dried out completely was during a severe drought in the 1940s,[6] although it was partially dry in 1986, leaving large pools of water. When the lake is empty it is used by farmers to graze sheep and cattle.

The unusual fluctuations in the lake's levels have given rise to fanciful urban myths that the lake is somehow connected to lakes in Peru or South Africa, although NSW government ecologist Justin Nancarrow theorises that the lake may indeed be connected to the nearby Yass River by subterranean aquifers which pass under the surrounding escarpment, and that this connection may explain the salinity of the river.[6]

Capital Wind Farm

The 140 megawatt Capital Wind Farm completed in 2009 is located along the south-eastern side of Lake George.

Capital Wind Farm near Lake George

Images

References

  1. ↑ Cartwright, Sarah; Gary Jones (2002). "By George, It Really Is a Lake!" (PDF (SEE PAGES 9 - 10)). Watershed, Issue No. 27 - August 2002. Co-operative Research Centre for Freshwater Ecology. Retrieved 2007-10-23. 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.
  2. ↑ Goodbye Stopper, Reviver and Survivor, Natasha Rudra, Canberra Times, 16 July 2010, accessed 4 October 2010
  3. ↑ Official Year Book of the Commonwealth of Australia, 1931 (ABS cat. no. 1301.0)
  4. ↑ Canberra's Engineering Heritage, William Charles Andrews, Institution of Engineers, Canberra, 1990 p2
  5. ↑ James Woodford, "Getting to the bottom of the Lake George mystery", Sydney Morning Herald, 30 November 2002
  6. ↑ 6.0 6.1 James Woodford, "Getting to the bottom of the Lake George mystery", Sydney Morning Herald, 30 November 2002

External links