River Derwent (Tasmania)

{{Short description|River in south east Tasmania, Australia}} {{Use dmy dates|date=January 2022}} {{Use Australian English|date=July 2015}} {{Infobox river | name = Derwent | name_native = {{native name|mis|timtumili minanya|paren=omit}} (Mouheneenner language) | name_native_lang = | name_other = | name_etymology = River Derwent, Cumbria  | image = Runrise over derwent river.jpg | image_size = 240 | image_caption = Sunrise over the River Derwent | map = | map_size = 240 | map_caption = | pushpin_map = Australia Tasmania | pushpin_map_size = 280 | pushpin_map_caption= Location of the river mouth in Tasmania | mapframe = yes  | subdivision_type1 = Country | subdivision_name1 = Australia | subdivision_type2 = State | subdivision_name2 = Tasmania | subdivision_type3 = | subdivision_name3 = | subdivision_type4 = | subdivision_name4 = | subdivision_type5 = Cities | subdivision_name5 = Derwent Bridge, New Norfolk, Hobart  | length = {{convert|239|km|mi|abbr=on}} | width_min = | width_avg = | width_max = | depth_min = | depth_avg = | depth_max = | discharge1_location= Storm Bay | discharge1_min = {{convert|50|m3/s|cuft/s|abbr=on}} | discharge1_avg = {{convert|90|m3/s|cuft/s|abbr=on}} | discharge1_max = {{convert|140|m3/s|cuft/s|abbr=on}}  | source1 = Lake St Clair | source1_location = Central Highlands | source1_coordinates= | source1_elevation = | source_confluence = {{unbulleted list|Narcissus River|Cuvier River}} | source_confluence_location = Cradle Mountain-Lake St Clair National Park | source_confluence_coordinates= {{coord|42|7|12|S|146|12|37|E|display=inline}} | source_confluence_elevation = {{convert|738|m|abbr=on}} | mouth = Storm Bay | mouth_location = Hobart | mouth_coordinates = {{coord|43|3|3|S|147|22|38|E|display=inline,title}} | mouth_elevation = {{convert|0|m|abbr=on}} | progression = | bridges = {{hlist||Derwent|Wayatinah|Lake Repulse Road|Upper Meadowbank|Bushy Park|Blair Street|Bridgewater|Bowen|Tasman}} | waterbodies = {{hlist|Saint Clair Lagoon|Lake St Clair}} | waterfalls = | river_system = | basin_size = {{convert|9832|km2|abbr=on}} | tributaries_left = {{hlist|Nive|Dee|Ouse|Clyde|Jordan}} | tributaries_right = {{hlist|Repulse|Tyenna|Styx|Plenty|Lachlan}} | custom_label = Dams | custom_data = {{hlist|Clark|Wayatinah|Catagunya|Repulse|Cluny|Meadowbank|King William}} | extra = <ref name=bonzle>{{cite web |url=http://www.bonzle.com.au/c/a?a=p&p=209362&cmd=sp |title=Map of River Derwent, TAS |work=Bonzle Digital Atlas of Australia |date=2015 |access-date=3 July 2015 |url-status=live |archive-url=https://web.archive.org/web/20150923193628/http://www.bonzle.com.au/c/a?a=p&p=209362&cmd=sp |archive-date=23 September 2015 }}</ref><ref name=doe>{{cite web |url=http://www.environment.gov.au/water/quality/improvement/hotspots/tas/derwent-estuary |title=Derwent Estuary and its catchment |work=Department of the Environment |date=June 2009 |publisher=Australian Government |access-date=3 July 2015 |url-status=live |archive-url=https://web.archive.org/web/20150703054836/http://www.environment.gov.au/water/quality/improvement/hotspots/tas/derwent-estuary |archive-date=3 July 2015 }}</ref> }} {{River Derwent routemap}}

The '''River Derwent''' (palawa kani: '''''timtumili minanya'''''<ref>{{Cite web|url=https://tacinc.com.au/nipaluna/|title=Tasmanian Aboriginal Centre – nipaluna|website=tacinc.com.au|language=en-AU|access-date=2018-09-27}}</ref>) is a significant perennial river and tidal estuary in Tasmania, Australia. It begins its journey as a freshwater river in the Central Highlands at Lake St Clair, descending over {{convert|700|m}} across a distance of more than {{convert|200|km}}. At the settlement of New Norfolk in the Derwent Valley its waters become brackish, flowing through Hobart, the capital city of Tasmania, its seawater estuary eventually empties into Storm Bay and the Tasman Sea.

Historically, the banks of the Derwent were covered by forests and frequented by Aboriginal Tasmanians. With the arrival of European settlers, the area saw agricultural development and the construction of dams for hydroelectricity generation during the 20th century.

Today, the Derwent's catchment area is characterised by agriculture, forestry, and hydropower generation. It serves as a vital source of water for irrigation and urban supply, notably providing a significant portion of Hobart's water needs.<ref>{{cite web |url=http://www.derwentestuary.org.au/catchment/ |title=Catchment and flow |work=Derwent Estuary Program |date=16 October 2014 |access-date=2 July 2015 |url-status=live |archive-url=https://web.archive.org/web/20150703083316/http://www.derwentestuary.org.au/catchment/ |archive-date=3 July 2015 }}</ref> The river is also crucial for recreation, supporting activities such as boating, fishing, and leisure along its banks. Additionally, it facilitates marine transportation and various industrial activities, playing a central role in Tasmania's economy and lifestyle.<ref name=doe/>

==Etymology== The upper part of the river 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".<ref>{{cite web |url=http://web.ukonline.co.uk/sw.rae/rivers.htm |title=Names of Rivers |archive-url=https://web.archive.org/web/20060718190141/http://web.ukonline.co.uk/sw.rae/rivers.htm |archive-date=18 July 2006 |work=web.ukonline.co.uk |date= |access-date= }}</ref><ref>{{cite web |url=http://www.yorksj.ac.uk/dialect/celtpn.htm |title=Celtic Place Names |archive-url=https://web.archive.org/web/20071206051120/http://www.yorksj.ac.uk/dialect/celtpn.htm |archive-date=6 December 2007 |work=www.yorksj.ac.uk |date= |access-date= }}</ref> Matthew Flinders placed the name "Derwent River" on all of the river.<ref>{{cite book |title=Observations on the coasts of Van Diemen's Land, on Bass's Strait and its islands, and on parts of the coasts of New South Wales; intended to accompany the charts of the late discoveries in those countries |author=Flinders, Matthew |author-link=Matthew Flinders |author2=(Second lieutenant of His Majesty's Ship Reliance) |publisher=John Nichols |year=1801 |page=5 }}</ref> The name "River Derwent" was officially endorsed on 20 May 1959.<ref>{{cite web |url=https://www.placenames.tas.gov.au |work=Nomenclature Board of Tasmania |title=River Derwent: Nomenclature number 470L |date=1959-05-20 |access-date= }}</ref>

==History== The River Derwent valley was inhabited by the Muwinina people for at least 8,000 years before British settlement.<ref>{{cite web |url=http://www.parliament.tas.gov.au/ha/So&Sessionals.pdf |work=Parliament of Tasmania |title=House of Assembly Standing Orders |date= |access-date= |archive-url=https://web.archive.org/web/20090604173725/http://www.parliament.tas.gov.au/ha/So%26Sessionals.pdf |archive-date=4 June 2009 |quote="We acknowledge the traditional people of the land upon which we meet today, the Mouheneener people." }}</ref> Evidence of their occupation is found in many middens along the banks of the river.{{citation needed|date=October 2011}} The first European to chart the river was Bruni d'Entrecasteaux, who named it the ''Rivière du Nord'' in 1793.<ref>{{cite web |title=River Derwent |url=https://www.utas.edu.au/library/companion_to_tasmanian_history/R/River%20Derwent.htm |website=The Companion to Tasmanian History |publisher=Centre for Tasmanian Historical Studies {{!}} University of Tasmania |date= |access-date=17 October 2021}}</ref> Later that same year, John Hayes explored the river and named it after the River Derwent, which runs past his birthplace of Bridekirk, Cumberland.<ref name=adb>{{Australian Dictionary of Biography |last=Roe |first=Margriet |year=1966 |id=A010487b |title=Hayes, Sir John (1768–1831) |access-date=20 August 2009}}</ref>

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.<ref name="DEP"/>

There was a thriving whaling industry until the 1840s when the industry rapidly declined due to over-exploitation.<ref>{{cite web |url=http://www.parks.tas.gov.au/historic/swhaling/history.html |title=A History of Shore-Based Whaling |publisher=Parks.tas.gov.au |date=25 July 2008 |access-date=6 January 2013 |url-status=live |archive-url=https://web.archive.org/web/20080612184148/http://www.parks.tas.gov.au/historic/swhaling/history.html |archive-date=12 June 2008 }}</ref> [[Image:Flock of Little Pied Cormorants.jpg|thumb|Little pied cormorants on the River Derwent]]

==Geography== Formed by the confluence of the Narcissus and Cuvier rivers within Lake St Clair, the Derwent flows generally southeast over a distance of {{convert|187|km}} to New Norfolk and the estuary portion extends a further {{convert|52|km}} out to the Tasman Sea. Flows average in range from {{convert|50|to|140|m3/s}} and the mean annual flow is {{convert|90|m3/s}}.<ref name="DEP"/>

The large estuary forms the Port of the City of Hobart – the deepest sheltered harbour in the Southern Hemisphere.<ref>{{cite web |url=https://tasmania.com/points-of-interest/river-derwent |work=Tasmania.com |title=River Derwent Length and Geography |date= |access-date= }}</ref> Some past guests of the port include {{HMS|Beagle||6}} in February 1836, carrying Charles Darwin; the {{USS|Enterprise|CVN-65|6}}; {{USS|John C. Stennis|CVN-74|6}} and {{USS|Missouri|BB-63|6}}. The largest vessel to ever travel the Derwent is the {{convert|113000|t|LT|adj=on}}, {{convert|61|m|adj=on}} high, ocean liner ''Diamond Princess'', which made her first visit in January 2006.<ref>{{cite web |url=http://www.tasports.com.au/port_services/hobart.html |title=Shipping Movements List for Hobart |access-date=3 October 2017 |location=Australia |work=TasPorts |url-status=live |archive-url=https://web.archive.org/web/20160327051954/http://www.tasports.com.au/port_services/hobart.html |archive-date=27 March 2016 }}</ref>

At points in its lower reaches the river is nearly {{convert|3|km}} wide, and as such is the widest river in Tasmania.{{citation needed|date=July 2015}}

The Derwent estuary contains dozens of white sandy beaches, many of which are staples of local activity within Hobart suburbs and include Bellerive Beach, Blackmans Bay Beach, Howrah Beach, Nutgrove Beach, Lords Beach, Long Beach, Taroona Beach, Hinsby Beach, Kingston Beach and Windermere Beach.

===Hydro schemes=== Until the construction of several dams between 1934 and 1968, the river was prone to flooding.{{citation needed|date=July 2015}} Now there are more than twenty dams and reservoirs used for the generation of hydroelectricity on the Derwent and its tributaries, including the Clyde, Dee, Jordan, Nive, Ouse, Plenty and Styx rivers. Seven lakes have been formed by damming the Derwent and the Nive rivers for hydroelectric purposes and include the Meadowbank, Cluny, Repulse, Catagunya, Wayatinah, Liapootah and King William lakes or lagoons.

===River health=== The Upper Derwent is affected by agricultural run-off, particularly from land clearing and forestry. The Lower Derwent suffers from high levels of toxic heavy metal contamination in sediments. The Tasmanian Government-backed ''Derwent Estuary Program'' has commented that the levels of mercury, lead, zinc and cadmium in the river exceed national guidelines. In 2015 the program recommended against consuming shellfish and cautioned against consuming fish in general. Nutrient levels in the Derwent between 2010 and 2015 increased in the upper estuary (between Bridgewater and New Norfolk) where there had been algal blooms.<ref name="DEP">{{cite news |url=http://www.abc.net.au/news/2015-04-23/state-of-the-derwent-heavy-metals-down-effluent-up/6416182 |date=23 April 2015 |author=Shannon, Lucy |title=River Derwent: Heavy metal contamination decreases, effluent increases, report finds |publisher=ABC News|location=Australia |access-date=3 July 2015 |url-status=live |archive-url=https://web.archive.org/web/20150704234728/http://www.abc.net.au/news/2015-04-23/state-of-the-derwent-heavy-metals-down-effluent-up/6416182 |archive-date=4 July 2015 }}</ref>

====Industrial pollution==== {{See also|Risdon Zinc Works#Pollution}} A large proportion of toxic heavy metal contamination stems from legacy pollution caused by major industries that discharge into the river including the Risdon Zinc Works, a historic smelter establish at Lutana in 1916,<ref>{{cite web|url=http://www.historycooperative.org/proceedings/asslh/barton.html|title=Communal life, common interests and healthy conditions|author=Ruth Barton|url-status=dead|archive-url=https://web.archive.org/web/20120214093823/http://www.historycooperative.org/proceedings/asslh/barton.html|archive-date=14 February 2012}}</ref> and the Boyer Mill at Boyer which opened in 1941.<ref>{{Citation | author1=Environmental Geochemistry Services | author2=Tasmania. Dept. of Environment and Planning | author3=Menzies Centre for Population Health Research | author4=John Miedecke and Partners | title=Investigation of heavy metals in soil and vegetation around the Pasminco Metals-EZ refinery, Hobart : stage 1 | publication-date=1991 | publisher=Dept. of Environment and Planning | url=http://trove.nla.gov.au/work/34468748 | access-date=12 June 2015 }}</ref><ref>{{Citation | author1=Environmental Geochemistry International | author2=Tasmania. Dept. of Environment and Planning | author3=John Miedecke and Partners | title=Heavy metals in soil and vegetation in the vicinity of the Pasminco Metals-EZ refinery, Hobart | publication-date=1992 | publisher=Dept. of Environment and Planning | url=http://trove.nla.gov.au/work/34469127 | access-date=12 June 2015 }}</ref><ref>{{Citation | author1=TASUNI Research. Aquahealth Division | author2=Jeffries, Maria | author3=Tasmania. Department of Primary Industry and Fisheries | author4=Australian Government Analytical Laboratories | author5=Tasmania. Department of Environment and Land Management | author6=Lutana Soil Contamination Working Group (Tas.) | title=Investigation of heavy metals in indoor dust, soils and home-grown vegetables : investigations in the vicinity of the Pasminco Metals-EZ refinery, Hobart | publication-date=1995 | publisher=Dept. of Environment and Land Management | url=http://trove.nla.gov.au/work/14888080 | access-date=12 June 2015 }}</ref><ref>{{Citation | author1=Dames & Moore | author2=Pasminco Metals – EZ | author3=Pasminco Australia Limited | title=Development proposal & environmental management plan : a proposal to implement the paragoethite co-treatment process at Pasminco Metals-EZ | publication-date=1995 | publisher=Pasminco | url=http://trove.nla.gov.au/work/21481760 | access-date=12 June 2015 }}</ref>

The Derwent adjoins or flows through the Pittwater–Orielton Lagoon, Interlaken Lakeside Reserve and Goulds Lagoon, all wetlands of significance protected under the Ramsar Convention.<ref name=doe/>

==Flora and fauna== thumb|The critically endangered spotted handfishIn recent years, southern right whales finally started making appearance in the river during months in winter and spring when their migration takes place. Some females even started using calm waters of the river as a safe ground for giving birth to their calves and would stay over following weeks after disappearance of almost 200 years due to being wiped out by intense whaling activities. In the winter months of 2014, humpback whales and a minke whale (being the first confirmed record of this species in the river) have been recorded feeding in the River Derwent for the first time since the whaling days of the 1800s.<ref>{{Cite web |title=It's mighty mouth: Whales feeding in River Derwent |work=Mercury |access-date=25 August 2014 |url= http://m.themercury.com.au/news/tasmania/its-mighty-mouth-whales-feeding-in-river-derwent/story-fnj4f7k1-1227002076373 |url-status=live |archive-url=https://web.archive.org/web/20140826120203/http://m.themercury.com.au/news/tasmania/its-mighty-mouth-whales-feeding-in-river-derwent/story-fnj4f7k1-1227002076373 |archive-date=26 August 2014 }}</ref>

The rare spotted handfish (''Brachionichthys hirsutus''), whose only habitat is in the Derwent estuary and surrounds,<ref name=fishbase/> was the first marine fish to be listed as critically endangered in the IUCN Red List, in 1996.<ref>{{Cite journal|title=Smooth Handfish Extinction Marks a Sad Milestone|url=https://www.scientificamerican.com/article/smooth-handfish-extinction-marks-a-sad-milestone/|volume=323|issue= 1|pages= 14 |date=July 2020|author=Shiffman, David|journal= Scientific American |doi=10.1038/scientificamerican0720-14a |pmid=39014622 |url-access=subscription}}</ref><ref>Edgar, G., Stuart-Smith, R. & Last, P.R. (2020). ''Brachionichthys hirsutus''. The IUCN Red List of Threatened Species. {{doi|10.2305/IUCN.UK.2020-1.RLTS.T2958A121210485.en}}</ref> The fish is threatened by the Northern Pacific seastar's invasion into southern Australian waters. The Northern Pacific seastar (''Asterias amurensis''), now firmly established in the Derwent,<ref name=gisd/><ref name=nimpis>{{cite web | title=Species - Asterias amurensis | website=National Introduced Marine Pest Information System| publisher= Australian Government | date=5 November 2020 | url=https://nimpis.marinepests.gov.au/species/species/105 | access-date=20 February 2021}}</ref> preys on not only the fish eggs,<ref name=fishbase>{{cite web| url= https://www.fishbase.de/summary/Brachionichthys-hirsutus.html |website= Fishbase|title=Brachionichtys-hirsutus}}</ref> but also on the sea squirts (ascidians)<ref name=gisd>{{cite web | title=Asterias amurensis| website=Global invasive species database|publisher=Invasive Species Specialist Group (ISSG)| date=10 March 2010 | url=http://www.iucngisd.org/gisd/speciesname/Asterias+amurensis | access-date=20 February 2021}}</ref> that help to form the substrate that the fish spawn on.<ref name=abc2021>{{cite web | last=MacDonald | first=Lucy | title=Volunteers hope efforts to remove invasive northern Pacific seastar will make a difference | website=ABC News| publisher= Australian Broadcasting Corporation | date=20 February 2021 | url=https://www.abc.net.au/news/2021-02-20/tas-invasive-northern-pacific-seastar-removal-efforts/13164004 | access-date=20 February 2021}}</ref>

==Bridges== Several bridges connect the western shore (the more heavily populated side of the river) to the eastern shore of Hobart – in the greater Hobart area, these include the five lane Tasman Bridge, near the CBD, just north of the port; the four lane Bowen Bridge; and the four lane Bridgewater Bridge. Until 1964 the Derwent was crossed by the unique Hobart Bridge, a floating concrete structure just upstream from where the Tasman Bridge now stands.<ref>{{cite web |url=http://www.parliament.tas.gov.au/history/hobartbr.htm |title=Parliament of Tasmania History site – Hobart to Tasman Bridge |publisher=Parliament.tas.gov.au |date=5 January 1975 |access-date=6 January 2013 |url-status=live |archive-url=https://web.archive.org/web/20130421004808/http://www.parliament.tas.gov.au/history/hobartbr.htm |archive-date=21 April 2013 }}</ref>

Travelling further north from the Bridgewater crossing, the next crossing point is the Blair Street Bridge at New Norfolk, slightly north of the point where the Derwent reverts from seawater to fresh water, Bushy Park, Upper Meadowbank Lake, Lake Repulse Road, Wayatinah, and the most northerly crossing is at Derwent Bridge, before the river reaches its source of Lake St Clair. At the Derwent Bridge crossing, the flow of the river is generally narrow enough to be stepped across.

==Cultural references== The river is the subject of the multimedia performance "Falling Mountain" (2005 Mountain Festival), a reference to the mountain in the Cradle Mountain-Lake St Clair National Park from which the river rises.

The Derwent is mentioned in the song, ''Mt Wellington Reverie'' by Australian band, Augie March.<ref>{{cite web |url=http://www.augie-march.com/lyrics/home.do?catalogueNo=82876785592&affiliateId=0510&side=1&seq=10&lyricId=20291 |title=AUGIE MARCH - lyrics |access-date=2010-04-18 |url-status=live |archive-url=https://web.archive.org/web/20090914092734/http://www.augie-march.com/lyrics/home.do?catalogueNo=82876785592&affiliateId=0510&side=1&seq=10&lyricId=20291 |archive-date=14 September 2009 }} augie-march.com Retrieved 6 January 2013</ref> Hobart is located in the foothills of Mount Wellington.

==Panoramas== {{Wide image|Derwent River Tasmania panorama.jpg|1200 px|The River Derwent (facing south), at the Bridgewater causeway}} {{Wide image|Austins Ferry and Derwent River from Poimenna Reserve.jpg|1200 px|The River Derwent as seen from Poimenna Reserve, Austins Ferry}}

==See also== {{Portal|Australia|Water|Environment}} * Bridgewater Jerry * Ferries in Hobart * Hydro Tasmania * List of rivers of Tasmania * Whaling in Australia * List of deepest natural harbours

==References== {{Reflist}}

==External links== {{commons category|Derwent River}} * {{cite web |url=https://www.derwentestuary.org.au/ |title=Home page |work=Derwent Estuary Program |date= |access-date= }} * {{cite web |url=http://www.hydro.com.au/home/Energy/Tasmanian+Hydro+Electric+Schemes/Catchment+Areas/Derwent+Catchment/Overview+of+the+Derwent+Catchment.htm |title=Overview of the Derwent Catchment |work=Hydro Tasmania |date= |access-date= |archive-url=https://web.archive.org/web/20060919105102/http://www.hydro.com.au/home/Energy/Tasmanian+Hydro+Electric+Schemes/Catchment+Areas/Derwent+Catchment/Overview+of+the+Derwent+Catchment.htm |archive-date=19 September 2006 }} * {{cite map |url=http://epa.tas.gov.au/documents/upper_derwent_river_catchment_map.pdf |date=December 2000 |title=Upper Derwent Catchment: Land Tenure and Water Uses |work=Environment Protection Agency |publisher=Tasmanian Government }} * {{cite web |url=http://epa.tas.gov.au/documents/derwent_river_catchment_final_paper.pdf |date=April 2003 |title=Derwent River (''sic'') Catchment: Environmental Management Goals |work=Environment Protection Agency |publisher=Tasmanian Government |access-date= }}

{{River Derwent Dams|state=collapsed}} {{Rivers of Tasmania|state=autocollapse}} {{CentralHighlandsTasmania|state=autocollapse}} {{Southern Tasmania}} {{Authority control}}

Category:Geography of Hobart Category:Central Highlands (Tasmania) Category:South East coast of Tasmania Category:River Derwent (Tasmania) Category:Rivers of Hobart Category:Whaling in Australia Category:Whaling stations in Australia