The South Esk River is the longest river in Tasmania. It starts in the mountains near Fingal flowing through Avoca, Longford, Hadspan and finally Launceston. The river is dammed at Trevallyn, Launceston and used for the cities Hydro Electricity scheme. Although most of the water is dammed at Lake Trevallyn, some flows on into the Cataract Gorge where it becomes a tributary to the Tamar River. The river is constantly subject to flooding and overflows at Lake Trevallyn cause a scenic display of rapids gushing through the Gorge. Motto: Ubertas et Fidelitas (Fertility and Faithfulness) Nickname: The Apple Isle Other Australian states and territories Capital Hobart Government Governor Premier Const. ... Longford is a town in the north-east of Tasmania, Australia. ... Launceston City Council, Coat of Arms Launceston City Council, Tasmania Launceston is a small city in the north of Tasmania, Australia, population of approximately 98,000, located at the juncture of the North Esk, South Esk, and Tamar rivers. ... Hydroelectricity is a form of hydropower used to produce electricity. ... Picture of Cataract Gorge taken from the suspension bridge The Cataract Gorge Reserve is one of Launceston and northern Tasmanias premier tourist attractions. ... The Tamar River in northern Tasmania is formed by the merging of the North Esk River and South Esk Rivers in Launceston. ... Picture of Cataract Gorge taken from the suspension bridge The Cataract Gorge Reserve is one of Launceston and northern Tasmanias premier tourist attractions. ...