Deua River

The Deua River, being the main perennial river of the Moruya River catchment, is located in the South Coast region of New South Wales, Australia.

The Deua River rises about 5 kilometres (3.1 mi) southeast of Bendethera Mountain, on the eastern slopes of the Badja Range, part of the Great Dividing Range, within Deua National Park, in rugged and thickly forested ranges south of Braidwood. The river flows generally south, west, north, northeast, south southeast and east, making almost a complete circle, and is joined by fourteen minor tributaries, before becoming the Moruya River near Kiora.[1] The river descends 634 metres (2,080 ft) over its 139 kilometres (86 mi) course.[2]

The lower reaches of the river are estuarine by nature and are called the Moruya River,[1] while the freshwater reaches are called the Deua River. The upper catchment of the Deua River is suspected to be in a rain shadow, so the Deua River is on the whole a small river, and naturally experiences periods of very low flow. Heavy use of groundwater and riverwater however, for summer irrigation of fruit crop in the tributary Araluen Valley and the main river locality Merricumbene, greatly exacerbate summer low flows.

The village of Araluen lies in the valley of Araluen Creek, that joins the Deua River at roughly the midpoint in its course. The name ‘Araluen’ means ‘water lily’ or ‘place of the water lilies’ in the local aboriginal dialect.[3] At the time of European settlement Araluen was described as a broad alluvial valley with one or more large natural billabongs covered with water lilies. No such billabongs exist in the Araluen valley today. As with most river and creek valleys in south-eastern Australia, the natural landscape and landforms of Araluen Creek and its valley were destroyed by rampant and destructive gold mining in the latter half of the 19th century. This has mobilised hundreds of thousands of tons of coarse granitic sand and has led to serious sand-slugging or sand siltation of the lower half of the Deua River below the Araluen Creek confluence. New gold mines in the headwaters of the river remain controversial and have attracted considerable public attention for their proposed use of cyanide and breaches of environmental standards.

Despite the sand-slugging the Deua River is bio-diverse and supports an extremely important population of the endangered fish the Australian grayling (Prototroctes maraena)[4]—possibly the best in the state of New South Wales—as well as thriving populations of several other native freshwater fish species including Cox’s gudgeon (Gobiomorphus coxii), congolli (Pseudaphritis urvillii), Australian smelt (Retropinna semoni) and Galaxiids (Galaxias sp.). The river also supports healthy populations of platypus, azure kingfishers and eastern water dragons.