1384.6 - Statistics - Tasmania, 2008  
ARCHIVED ISSUE Released at 11:30 AM (CANBERRA TIME) 13/09/2002  Ceased
   Page tools: Print Print Page Print all pages in this productPrint All  
Contents >> Environment >> Water >> Estuaries

An estuary is a semi-enclosed or periodically closed coastal body of water in which the aquatic environment is affected by both freshwater and marine systems. There are five general types of estuaries recognised in Tasmania:

  • coastal inlets (e.g. West Inlet, East Inlet)
  • drowned river valleys (e.g. Tamar Estuary, Derwent Estuary, Huon Estuary)
  • barrier (or bar) estuaries (e.g. Anson's Bay, Browns River)
  • river estuaries (e.g. Don River, Pieman River)
  • coastal lagoons (e.g. Grants Lagoon, Cameron Inlet).

A recent study of Tasmanian estuaries recognised approximately 111 medium to large estuaries on the Tasmanian mainland and Bass Strait islands (Edgar et al 1999).

Estuaries are important because they act as a filter and a channelling conduit between land and sea, and are thus sensitive to change. The sheltered tidal waters also support unique communities of plants and animals and provide many species of fish with sheltered waters for spawning and a safe habitat for juveniles to develop.

Each estuary possesses a unique environment due to its shape, size, depth, degree of tidal variation and catchment characteristics such as rainfall and run-off and vegetation cover. Human activities such as agriculture, forestry and urban development can all affect water quality within the estuary.

Nine potential threats to Tasmanian estuaries have been identified:
  • increased siltation resulting from land clearance and urban and rural run-off
  • increased nutrient loads resulting from sewage and agricultural use of fertilisers
  • urban effluent
  • foreshore development and dredging
  • marine farms
  • modification to water flow through dams and weirs
  • acidification of rivers and heavy metal pollution from mines
  • the spread of introduced pest species
  • long term climate change.

(Source: Edgar et al 1999, Tasmanian Aquaculture and Fisheries Institute and Department of Primary Industries, Water and Environment.)

Further information on water quality in Tasmania can be found on the Department of Primary Industries, Water and Environment web site at http://www.dpiwe.tas.gov.au/inter.nsf/ThemeNodes/DREN-4VH8C4?open



Previous PageNext Page