Location in Western Australia
|Primary inflows||Ord River, Bow River|
|Primary outflows||Ord River|
|Catchment area||46,100 km2 (17,800 sq mi)|
|Surface area||703 km2 (271 sq mi)|
|Water volume||10,763 gigalitres (3.801×1011 cu ft)|
Lake Argyle is Western Australia's largest and Australia's second largest freshwater man-made reservoir by volume. The reservoir is part of the Ord River Irrigation Scheme and is located near the East Kimberley town of Kununurra. The lake flooded large parts of the Shire of Wyndham-East Kimberley on the Kimberley Plateau about 80 kilometres (50 mi) inland from the Joseph Bonaparte Gulf, close to the border with the Northern Territory.
The primary inflow is the Ord River, while the Bow River and many other smaller creeks also flow into the dam. The lake is a DIWA-listed wetland. as it is the largest lake in northern Australia and an excellent example of a man-made lake. Additionally Lake Argyle, along with Lake Kununurra, are recognised as a Ramsar protected wetlands and were listed in 1990 as Australian Site Number 32.
History and construction
The construction of the Ord River Dam was completed in 1971 by the American Dravo Corporation. The dam was officially opened the following year. The dam wall is 335 metres (1,099 ft) long, and 98 metres (322 ft) high. The earth-fill only dam wall at Lake Argyle is the most efficient dam in Australia in terms of the ratio of the size of the dam wall to the amount of water stored. The lake was named after the property it partly submerged, Argyle Downs.
In 1996, the spillway wall was raised by 6 metres (20 ft), which doubled the dam's capacity. Sediment flowing into the dam caused concerns in the mid-1990s that the dam's capacity could be dramatically reduced. By 2006 continual regeneration of the upper Ord catchment appeared to have reduced the amount of sediment inflow.
Lake Argyle normally has a surface area of about 1,000 square kilometres (390 sq mi). The storage capacity, to the top of the spillway is 10,763 gigalitres (3.801×1011 cu ft). The lake filled to capacity in 1973, and the spillway flowed until 1984. Lake Argyle's usual storage volume is 5,797 gigalitres (2.047×1011 cu ft), making it the largest reservoir in Australia. The combined Lake Gordon/Lake Pedder system in Tasmania is larger but is two dams connected by a canal. At maximum flood level, the lake would hold 35,000 gigalitres (1.2×1012 cu ft) of water and cover a surface area of 2,072 square kilometres (800 sq mi).
Lake Argyle, together with Lake Kununurra, is part of the Ord River Irrigation Scheme. There are currently some 150 square kilometres (58 sq mi) of farmland under irrigation in the East Kimberly region. The original plan was for dam water to irrigate rice crop for export to China. However these plans were scuttled as waterfowl, particularly magpie geese ate rice shoots quicker than they could be planted. Other crops are now grown, but Lake Argyle still remains Australia's most under-utilized lake.
Flora and fauna
The damming of the Ord River has caused major changes to the environment. Flows to the Ord River have been severely reduced. Within Lake Argyle itself a thriving new eco-system has developed. The lake is recognised as an important wetland area under the Ramsar Convention; with Lake Kununurra it forms the Lakes Argyle and Kununurra Ramsar Site.
The lake is now home to 26 species of native fish and a population of freshwater crocodiles currently estimated at some 25,000. Fish species that are present in Lake Argyle include barramundi, southern saratoga, archer fish, forktail cat fish, mouth almighty, long tom, bony bream and sleepy cod. While the official website states that only incidentally a saltwater crocodile is found, other experts disagree.
The lake, with its surrounding mudflats and grasslands, has been identified by BirdLife International as an Important Bird Area (IBA) because it supports about 150,000 waterbirds. Birds for which the lake has global importance include magpie geese, wandering whistling-ducks, green pygmy-geese, Pacific black ducks, hardheads, black-necked storks, Australian bustards, white-headed stilts, red-capped plovers, Oriental plovers, black-fronted dotterels, long-toed stints and sharp-tailed sandpipers.
- WA - Water Corporation
- "Largest Waterbodies". Geoscience Australia. Retrieved 15 March 2015.
- "Search for a Nationally Important Wetland". 2010. Retrieved 6 June 2010.
- "Australian Ramsar Sites - Lake Argyle and Kununurra". 2010. Retrieved 6 June 2010.
- Harrison, Rod; Ernie James; Chris Sully; Bill Classon; Joy Eckermann (2008). Queensland Dams. Bayswater, Victoria: Australian Fishing Network. pp. 60—61. ISBN 978-1-86513-134-4.
- Willacy, Marck (12 November 2006). "Fears for second stage of Ord Irrigation Scheme". Landline. Australian Broadcasting Corporation. Retrieved 15 May 2009.
- "Dept hopes sediment flow into Lake Argyle will decrease". ABC News online. Australian Broadcasting Corporation. 11 December 2006. Retrieved 15 May 2009.
- Australian Govt. Pub. Service Ord River Irrigation Area review. a joint Commonwealth and Western Australian review. 1979
- Narelle Towie (11 May 2009). "Cane toads thrive in Lake Argyle". PerthNow. The Sunday Times. Retrieved 15 May 2009.
- Claudia Bertorello-Kell (3 June 2007). "Argyle racers shrug off crocs". PerthNow. The Sunday Times. Retrieved 15 May 2009.
- "Freshwater Crocodiles (Crocodyllus Johnstoni)". Lake Argyle. Retrieved 31 March 2010.
- Bennett, Michael (27 March 2010). "Fatal crocodile attack 'inevitable'". The West Australian. Retrieved 31 March 2010.
- "IBA: Lake Argyle". Birdata. Birds Australia. Retrieved 2011-07-18.