Lachlan River

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Lachlan River
The Lachlan River at Cowra
Origin	east of Gunning
Mouth	confluence with the Murrumbidgee River near Oxley
Basin countries	Australia
Length	1450 km (901 mi)
Avg. discharge	averages 40m³/sec but extremely erratic
Basin area	84,700 km²

The Lachlan River is a significant river in central New South Wales, Australia. It rises in the central highland of New South Wales, part of the Great Dividing Range, 13km east of Gunning. Its major headwaters, the Carcoar River, the Belubula River and the Abercrombie River converge near the town of Cowra. Minor tributaries include the Morongla Creek.

Wyangala Dam was built near Cowra to regulate the flow of the river. However, the Lachlan, unlike the Murrumbidgee River and the Murray River further south, does not have its source in the snowfields and does not enjoy the large and reliable spring flow from the melting snow from which those rivers benefit. Indeed, the annual flow of the Lachlan is too erratic for really reliable dams to be possible. Annual flows have ranged from less than 1,000 megalitres (810 acre-feet) in 1944 to as much as 10,900,000 megalitres (8.8 million acre feet) in 1950. In dry years, the Lachlan can have periods of zero flow of over a year (April 1944 to April 1945), which is a complete contrast to the Murray and Murrumbidgee which have not been known to cease to flow since European settlement.

The Lachlan River flows west and then south, terminating in the Great Cumbung swamp near Oxley (between Hay and Balranald). The 500 km² swamp, a floodplain for the Lachlan, joins the Murrumbidgee River to the south. There is some irrigation in the middle reaches of the Lachlan.

[edit] History

The European discoverer of the Lachlan River in 1815 was Acting-Surveyor George William Evans, who named the river after Lachlan Macquarie, the Governor of the colony of New South Wales. The Lachlan River was substantially explored by John Oxley in 1817.^[1]

In the early days of the colony of New South Wales, the southern part of the Lachlan was known as Fish River. It was only after further exploration that it was realised that these two rivers were the same river and the name Fish River was dropped.