| Clarence River | |
|---|---|
| Origin | in Border Ranges, near Tooloom National Park, New South Wales |
| Mouth | Pacific Ocean |
| Basin countries | Australia |
| Length | 394 km (245 mi) |
| Source elevation | 1100m (3600 ft) at source |
| Avg. discharge | 160 m³/s but can vary from less than 1 to over 20,000 m³/s |
| Basin area | 22,850 km2 (8,820 sq mi) |
The Clarence River is situated in northeastern New South Wales, Australia. The river originates on the watershed that marks the Queensland border. After flowing south and northeast for 394 km it then empties into the Pacific Ocean at Iluka/Yamba. On its journey it passes through the towns of Grafton, Ulmarra, Cowper/Brushgrove, Maclean and Harwood. Its chief tributaries are the Mann River, Nymboida River, and Orara River. The river features many large river islands, including Woodford Island, Chatsworth Island, and Harwood Island. The river supports a large prawn trawling and fishing industry.
The Clarence River system is an extensive East Coast drainage with many tributaries of differing size. Apart from the Murray River, it is the largest river in mainland Australia south of the Tropic of Capricorn, though its flow for comparison is only half that of the Potomac. Its basin is, together with the very similarly-sized Hawkesbury, Australia's largest Pacific watershed south of Bundaberg. The extremely intense rainfalls that typify the North Coast mean, however, that major floods can temporarily raise the flow of the Clarence to levels equivalent to some of the largest rivers in the world.
The climate of most of the basin is subtropical (Köppen Cfa), though the highest areas with cooler weather are of the temperate Cfb type. Annual rainfall ranges from 1,600 millimetres (63 in) on the coast at Yamba down to 960 millimetres (38 in) in the shielded valley at Grafton. At higher altitudes, rainfall may reach 2,000 millimetres (79 in) on exposed slopes but data are very poor. Most of the high areas actually receive no more rain than Grafton though variability from year to year is less. Temperatures are generally very warm, with maxima in lower area ranging from 27 °C (81 °F) in January to 19 °C (66 °F) in July. In the highlands, however, temperatures are much cooler and in July range from lows of around 2 °C (36 °F) to maxima around 13 °C (55 °F) - though in January days remain very warm at around 25 °C (77 °F). Rainfall per month on the coast typically ranges from around 220 millimetres (8.7 in) in February and March to around 70 millimetres (2.8 in) in September; it can average as low as 40 millimetres (1.6 in) between May and September inland, where exposed areas sometimes suffer bushfires after droughts, as occurred in 1915 and 2000.
Most of the Clarence basin is heavily forested, with important areas of remnant subtropical and temperate rainforest occurring all along the course. Only in alluvial areas where soils are less leached is there major agricultural development: in these areas the chief industries are cattle rearing and the growing of sugar cane in lower-lying areas.
Of particular interest is the small island town of Harwood, where a Sperry New Holland factory and a quaint Bush Pub overlook the Clarence Delta. Harwood is also the location of the local sugar Mill, the Harwood Sugar Mill built in 1873 and is the oldest Australian mill still operational. The sugar mill is situated on the river due to its importance in transporting sugar cane from farms in the surrounding area in previous times. Harwood is just after the Yamba Bridge on part of Australia's National Highway from Sydney, Port Macquarie, Coffs Harbour to Brisbane.
The freshwater reaches of the Clarence River support important populations of native freshwater fish including Eastern freshwater cod, an endangered fish species unique to the Clarence River system, and Australian bass.
The lower half of the river valley is part of the Local Government Area of the Clarence Valley.
The Aboriginal people of the lower reaches call the river there Breimba or Berrinbah.[1]