Lake Carnegie (Western Australia)

Lake Carnegie is a large ephemeral lake in the Shire of Wiluna in the Goldfields-Esperance region of Western Australia. The lake is named after David Carnegie, who explored much of inland Western Australia in the 1890s. A similar lake lies to its south east - Lake Wells.

Geography
Lake Carnegie is predominantly surrounded by desert environments. It lies east of Wiluna, at the southern edge of the Little Sandy Desert, and at the southwestern border of the Gibson Desert. It is northeast of Leonora and northwest of the Great Central Road and the Great Victoria Desert. Lake Carnegie is north of the main region of gold fields in Western Australia.

The lake is approximately 100 km in length and approximately 30 km at its widest part. It has a total area of approximately 5714 km2, making it one of the largest lakes in Australia. The surface elevation is 439 m above mean sea-level.

Lake Carnegie fills with water only during very rare periods of significant rainfall, such as during the huge 1900 floods, and in numerous recent tropical wet seasons when climate change has moved the monsoon and tropical cyclones south. In dry years, it is reduced to a muddy marsh.

In 1973 Tropical Cyclone Kerry crossed the northwest coast and moved southwest as far as the northern gold fields. Over a four-day period, nearby pastoral leases such as Windidda Station received falls of 310 mm, while Prenti Downs received 209 mm. The runoff was enormous, causing widespread flooding, with the lake overflowing and leaving the area between Carnegie and Wiluna "one huge lake".

Water entering the lake, unlike in more easterly playas of the Australian arid zone, does not come from well-defined river channels. The soils of the region are so weathered – lacking tectonic or glacial activity since the Carboniferous ice ages – that sediment is completely absent; the terrain is so flat that only the rocks most impervious to weathering remain on the surface. Well-defined river channels cannot form, especially since the extreme age of the soils and consequent high rooting density of native flora limit runoff to an extreme degree.

Climate
Lake Carnegie has a hot desert climate (Köppen): BWh; with very hot summers and mild winters. Precipitation is low and erratic year-round, with a strong summer peak.

Pastoral leases
The lake area is bounded by Windidda, Yelma, Wongawel, Niminga, Carnegie and Prenti Downs pastoral leases, otherwise known in Western Australia as stations.