The Derwent River, in Tasmania, Australia, starts from Lake St. Clair in the Central Highlands of the island State and flows approximately 240 km (about 150 miles) south-east to its outfall into Storm Bay. It is tidal up-river as far as about New Norfolk, about 50 km from the mouth. Where the estuary widens is the state capital, Hobart, which occupies both banks, especially the western, for a number of kilometres. At the Port of Hobart, the largest liners can be docked at wharves only a few hundred metres from the Central Business District. (Over the years the U.S. Navy has frequently used the port as an R and R stop-over.)
The lower Derwent Valley is prime agricultural land, first visited by Bass and Flinders in 1798 and with settlement beginning within a year or two of the founding of Hobart in 1803/4. Hops, apples, pears, dairy cattle, fishing, and tourism are the mainstays of the area. In 1941 a paper mill began operating at Boyer, downstream from New Norfolk. Further up, in the Highlands, the river is used as part of Tasmania’s extensive Hydro-Electric system.
In Hobart itself, a major zinc processing plant has added to pollution already evident from agricultural run-off and the timber industry upstream. Modern pollution minimisation schemes are taking effect.
The estuary was first sighted by Abel Tasman in 1642 but strong winds prevented him exploring further, (hence “Storm Bay.” ) The Frenchman, Bruny d’Entrecasteaux poked around there in 1793 and named it “Rivière du Nord.” Its present name was given, only about 2 months later, by an English East India Company captain, John Hayes, in honour of the River Derwent in Cumbria, England. Aboriginal names include Raagapyarranne and Nibbalin.
A ferry service began in 1814, a toll bridge at New Norfolk opened in 1841. For many years a vehicular pontoon bridge spanned the river in Hobart before the multi-lane Tasman Bridge was opened in 1964. In 1975 a bulk ore carrier, the “Lake Illawarra” collided with one of the pylons and part of the bridge collapsed, killing 12 and causing major disruption to access to the Eastern Shore. A replacement bridge was completed two years later and a “supplementary” bridge some 2 km up river was completed shortly after.
Since 1945, the Derwent near “Constitution Dock” in central Hobart has seen the finish of the annual Sydney to Hobart yacht race, one of the longest and most difficult bluewater races in the world. A little upriver the Hobart Regatta is held; the oldest event of its type in the Southern Hemisphere. Apart from 1967, when the south of the state was being devastated by bushfires, it has occurred every year since 1838.
Part of the river, between Hobart and New Norfolk, at a point where the road and rail links to the north of the state cross the river. at the appropriately named Bridgewater, is the natural habitat of a rare colony of black swans.