Diamantina River
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The Diamantina River is a river in Queensland, Australia. Rising north-west of Longreach, it flows in a south-westerly direction through central Queensland to form the Warburton River, which, in extremely wet years, flows as far as Lake Eyre.
Most of the basin of the Diamantina is very flat: even the highets points in the northeast do not reach 500 metres (1600 feet) above sea level and Lake Eyre itself is sixteen metres below sea level. Apart from a few streams near Winton (the largest town in the basin) almost all rivers in the basin flow southwestwards towards Birdsville. The major feature of the river's sluggish course is Diamantina National Park about halfway between Winton and Birdsville. Apart from the national park, almost all land in the basin is used from grazing cattle and sheep; though numbers fluctuate greatly and considerable skill is required on the part of graziers.
The climate of the basin is hot and arid. In January, temperatures throughout the basin average around 37°C (98°F) during the day and decline only to about 24°C (75°F) at night. In winter, they typically range from 25°C (77°F) during the day to 11°C (52°F) at night. On occasions, however, frost has been reported in all areas of the basin: Winton has recorded minima as low as -1.8°C (29°F).
Rainfall is heavily concentrated between December and March: averages for these four months range from 310mm (12 inches) at Winton and Kynuna to around 90mm (3.5 inches) at Birdsville. In the rest of the year rainfall is very scanty and only on the rarest occasions are significant falls reported: throughout most of the basin the average rainfall between May and September totals around 40mm (1.5 inches). However, the rainfall of the basin, as with all of the Lake Eyre Basin, is exceedingly erratic and catastropic droughts and floods tend to be the normal state of affairs throughout this region. In the northern part of the basin, annual rainfalls as high as 1,100 millimetres (43 inches) were reported in 1894, 1950, 1974 and 2000, whilst even in Birdsville annual totals as high as 550 millimetres (22 inches) have been reported. In dry years such as 1902, 1905, 1928, 1961, 1965 and 2002, almost the whole basin reported totals under 100mm (4 inches). There can also be significant variation from station to station over small areas: although the annual averages and variability at Winton and Kynuna are almost alike, the actual totals at the two stations can differ by as much as 200mm (8 inches) in some years due to isolated very heavy rainfalls.
The soils in the region are mainly grey and brown Vertisols, with some Fluvents in the drier areas. Although they do not have high phosphate contents, they have adequate levels of most other nutrients: consequently when rainfall is abundant the grasses within the basin are extremely nutritious, especially in the lower reaches of the river around Birdsville, which is a primary region for cattle fattening in years when rainfall further north is adequate to flood the region.
The river was named by William Landsborough in 1866 for Diamantina Roma, wife of Sir George Ferguson Bowen, the first Governor of Queensland.
