Derwent River (Tasmania)

Derwent
River
Sunrise over the Derwent River
Country	Australia
State	Tasmania
Tributaries
- left	Nive River, Dee River, River Ouse, Clyde River, Jordan River
- right	Repulse River, Tyenna River, Styx River, Plenty River, Lachlan River
Cities	Derwent Bridge, New Norfolk, Bridgewater, Hobart
Source	Lake St Clair
Source confluence	Narcissus River Cuvier River
- location	Cradle Mountain-Lake St Clair National Park
- elevation	738 m (2,421 ft)
- coordinates	42°7′12″S 146°12′37″E / 42.12000°S 146.21028°E / -42.12000; 146.21028
Mouth	Storm Bay
- location	Hobart
- elevation	0 m (0 ft)
- coordinates	43°3′3″S 147°22′38″E / 43.05083°S 147.37722°E / -43.05083; 147.37722Coordinates: 43°3′3″S 147°22′38″E / 43.05083°S 147.37722°E / -43.05083; 147.37722
Length	239 km (149 mi)
Basin	9,832 km2 (3,796 sq mi)
Discharge	for Storm Bay
- average	90 m3/s (3,178 cu ft/s)
- max	140 m3/s (4,944 cu ft/s)
- min	50 m3/s (1,766 cu ft/s)
Natural lakes	Saint Clair Lagoon; Lake Saint Clair
Reservoirs	Catagunya; Cluny; (Echo;) King William; Liapootah; Meadowbank; Repulse; (Tungatinah;) Wayatinah
National park	Cradle Mountain-Lake St Clair
Dams	Catagunya; Clark; Cluny; Meadowbank; Repulse; Wayatinah
Power stations	Butlers Gorge; Catagunya; Cluny; (Lake Echo;) Liapootah; Meadowbank; Repulse; Tarraleah; (Tungatinah;) Wayatinah
Location of the river mouth in Tasmania

The Derwent is a river in Tasmania, Australia. The river rises in the state's Central Highlands and descends more than 700 metres (2,300 ft) over 200 kilometres (120 mi), flowing through Hobart, the state's capital city, before emptying into Storm Bay and flowing into the Tasman Sea. The banks of the Derwent were once covered by forests and occupied by Tasmanian Aborigines. European settlers farmed the area and during the 20th century many dams were built on its tributaries for the generation of hydro-electricity.

Agriculture, forestry, hydropower generation and fish hatcheries dominate catchment land use. The Derwent is also an important source of water for irrigation and water supply. Most of Hobart's water supply is taken from the lower Derwent River. Nearly 40% of Tasmania's population lives around the estuary's margins and the Derwent is widely used for recreation, boating, recreational fishing, marine transportation and industry.

It was named after the River Derwent, Cumbria, by British Commodore John Hayes who explored it in 1793. The name is Brythonic Celtic for "valley thick with oaks". John Hayes placed the name "Derwent River" only in the upper part of the river. Matthew Flinders placed the name on all of the river.

The Derwent River valley was inhabited by the Mouheneener people for at least 8,000 years before British settlement. Evidence of their occupation is found in many middens along the banks of the river. In 1793, John Hayes named it after the River Derwent, which runs past his birthplace of Bridekirk, Cumberland.

When first explored by Europeans, the lower parts of the valley were clad in thick she-oak forests, remnants of which remain in various parts of the lower foreshore.