Lake Argyle

From Wikipedia, the free encyclopedia

For the state park in Illinois, USA, see Argyle Lake State Park.

Lake Argyle from space, August 1985. The main channel of the Ord River (dark, meandering feature) north of the lake is visible as it drains northward, eventually emptying into the Joseph Bonaparte Gulf. The Ord and Bow Rivers that flow into the southern end of the lake are difficult to discern. Low, folded mountains can be identified east and west of this river valley.

Lake Argyle ( 16°19′S, 128°43′E) is Australia's second largest artificial lake (by area), part of the Ord River Scheme, near the East Kimberley (Western Australia) town of Kununurra, located on the Kimberley Plateau.

The construction of the dam was completed in 1972. The Ord River dam is 335 metres long, and 98 metres high. The earth-fill only dam wall at Lake Argyle is the most efficient dam in Australia in the ratio of the size of the dam wall to the amount of water stored.

Lake Argyle normally has a surface area of about 1,000 square kilometres. The storage capacity, to the top of the spillway, is 10,763,000 megalitres. The lake filled to capacity in 1973, and the spillway flowed until 1984. Since then, there has been insufficient wet season rainfall to bring the lake up to its designed capacity. Lake Argyle's usual storage volume is 5,797,000 megalitres, making it the second largest reservoir in Australia (the combined Lake Gordon/Lake Pedder in Tasmania is the largest.) At maximum flood level, the lake would hold 35 million megalitres of water and cover a surface area of 2,072 square kilometres.

Lake Argyle (together with Lake Kununurra) is part of the Ord River irrigation scheme. There are currently some 150 square kilometres of farmland under irrigation in the East Kimberly region.

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 now home to 26 species of native fish and a population of freshwater crocodiles currently estimated at some 25,000. The damming of the Ord River also turned a number of low lying ridges into islands. Crocodiles can sometimes be seen on these islands along with a number of birds.