Editing Murray River (section)

== Water storage and irrigation ==
[[File:Murray howlong.jpg|left|thumb|A branch of the Murray in its middle reaches, near [[Howlong]]]]
Small-scale pumping plants began drawing water from the Murray in the 1850s and the first high-volume plant was constructed at Mildura in 1887. The introduction of pumping stations along the river promoted an expansion of farming and led ultimately to the development of [[irrigation]] areas (including the [[Murrumbidgee Irrigation Area]]).<ref>{{cite web|url=https://www.mdba.gov.au/topic/irrigation|title=Irrigation|website=www.mdba.gov.au|access-date=2017-08-15|archive-date=15 August 2017|archive-url=https://web.archive.org/web/20170815111205/https://www.mdba.gov.au/topic/irrigation|url-status=dead}}</ref>

In 1915, the three Murray states – New South Wales, Victoria, and South Australia – signed the River Murray Agreement which proposed the construction of storage reservoirs in the river's headwaters as well as at [[Lake Victoria, New South Wales|Lake Victoria]] near the South Australian border. Along the intervening stretch of the river a series of [[canal lock|lock]]s and [[weir]]s were built. These were originally proposed to support navigation even in times of low water, but riverborne transport was already declining due to improved highway and railway systems.

The disruption of the river's natural flow, run-off from agriculture, and the introduction of pest species such as the [[European carp]] has led to serious environmental damage along the river's length. There are widespread concerns that the river will be unusably salty in the medium to long term – a serious problem given that the Murray supplies 40&nbsp;per cent of the water supply for [[Adelaide]]. Efforts to alleviate the problems have proceeded but disagreement between various groups has hampered progress.{{When|date=December 2011}}

Introduced fish species such as [[common carp|carp]], ''[[gambusia]]'', [[Misgurnus|weather loach]], [[European perch|redfin perch]], [[brown trout]], and [[rainbow trout]] have also had serious negative effects on native fish. The most pernicious are carp, which have contributed to environmental degradation of the Murray and its tributaries by destroying aquatic plants and permanently raising [[turbidity]]. Carp is the most common species, and can be found in all segments of the river.<ref>{{cite web | url=https://vfa.vic.gov.au/recreational-fishing/fishing-locations/inland-angling-guide/special-articles/the-murray-river | title=The Murray River | date=23 December 2013 }}</ref>

===Reservoirs===
Four large reservoirs were built along the Murray. In addition to Lake Victoria (completed late 1920s), these are [[Lake Hume]] near [[Albury-Wodonga]] (completed 1936), [[Lake Mulwala]] at [[Yarrawonga]] (completed 1939), and [[Lake Dartmouth]], which is actually on the [[Mitta Mitta River]] upstream of Lake Hume (completed 1979). The Murray also receives water from the complex dam and pipeline system of the [[Snowy Mountains Scheme]]. An additional reservoir was proposed in the 1960s at [[Chowilla Dam]], which was to have been built in South Australia and would have flooded land mostly in Victoria and New South Wales. It was cancelled in favour of building Dartmouth Dam due to costs and concerns relating to increased salinity.

===Barrages===
[[File:Map -- location of barrages at the mouth of the River Murray.tif|thumb|Locations of the barrages at the mouth of the Murray]]
[[File:Goolwa Barrage.JPG|thumb|[[Goolwa Barrages|Goolwa Barrage]] viewed from the freshwater side]]

From 1935 to 1940 a series of [[Barrage (dam)|barrages]] was built near the Murray Mouth to stop seawater entering the lower part of the river during low flow periods. They are the Goolwa Barrage, with a length of {{convert|632|m}}; Mundoo Channel Barragel {{convert|800|m}}; Boundary Creek Barragel {{convert|243|m}}; Ewe Island Barrage, {{convert|853|m}}; and Tauwitchere Barrage, {{convert|3.6|km}}.

[[File:Dead and dying River Red Gums on the Murray River near Berri, South Australia.jpg|right|thumb|Dead and dying [[Eucalyptus|River Red Gum]]s on the lower Murray near [[Berri, South Australia]]]]
These dams inverted the patterns of the river's natural flow from the original winter-spring flood and summer-autumn dry to the present low level through winter and higher during summer. These changes ensured the availability of water for irrigation and made the Murray Valley Australia's most productive agricultural region, but have seriously disrupted the life cycles of many ecosystems both inside and outside the river, and the irrigation has led to [[Salinity in Australia|dryland salinity]] that now threatens the agricultural industries.

In 2006, the [[Government of South Australia]] released a plan to investigate the construction of controversial [[Wellington Weir]].{{Update inline|date=February 2021}}

===Locks===
Lock 1 was completed near [[Blanchetown]] in 1922. [[Torrumbarry weir]] downstream of [[Echuca]] began operating in December 1923. Of the several locks that were proposed, only thirteen were completed; Locks 1 to 11 on the stretch downstream of [[Mildura]], Lock 15 at [[Euston, New South Wales|Euston]] and Lock 26 at [[Torrumbarry]]. Construction of the remaining weirs purely for navigation purposes was abandoned in 1934. The last lock to be completed was Lock 15, in 1937.<ref name="Locks"/> Lock 11, just downstream of Mildura, creates a {{convert|100|km|mi|adj=on}} long lock pool that aided irrigation pumping from Mildura and [[Red Cliffs, Victoria|Red Cliffs]].

Each lock has a navigable passage next to it through the weir, which is opened during periods of high river flow, when there is too much water for the lock. The weirs can be completely removed, and the locks completely covered by water during flood conditions. Lock 11 is unique in that the lock was built inside a bend of the river, with the weir in the bend itself. A channel was dug to the lock, creating an island between it and the weir. The weir is also of a different design, being dragged out of the river during high flow, rather than lifted out.

{| class="wikitable sortable floatleft mw-collapsible" border= "1" style="width:50%; font-size: 86%; float:left; margin-left:1em; margin-right:3em; margin-bottom:2em"
|+{{big|Lock distances and elevations}}<ref name="Locks">{{cite web |url=https://www.mdba.gov.au/river-information/running-river-murray/weirs-locks |title=Weirs and locks |date=28 October 2015 |publisher=[[Murray–Darling Basin Authority]] |access-date=17 June 2017 |archive-date=14 July 2017 |archive-url=https://web.archive.org/web/20170714162412/https://www.mdba.gov.au/river-information/running-river-murray/weirs-locks |url-status=dead }}</ref>
! Name !!No. !! River&nbsp;distance{{big|<nowiki>*</nowiki>}} !! Elevation{{big|<nowiki>**</nowiki>}} !! Com-<br />pleted
|-
|Blanchetown || 1 ||{{convert|274|km|mi|sigfig=3|abbr=on}}||{{convert|3.3|m|ft|sigfig=3|abbr=on}}||1922
|-
|Waikerie || 2||{{convert|362|km|mi|sigfig=3|abbr=on}}||{{convert|6.1|m|ft|sigfig=3|abbr=on}}||1928
|-
|Overland Corner ||3||{{convert|431|km|mi|sigfig=3|abbr=on}}||{{convert|9.8|m|ft|sigfig=3|abbr=on}}||1925
|-
|Bookpurnong ||4||{{convert|516|km|mi|sigfig=3|abbr=on}}||{{convert|13.2|m|ft|sigfig=3|abbr=on}}||1929
|-
|Renmark||5||{{convert|562|km|mi|sigfig=3|abbr=on}}||{{convert|16.3|m|ft|sigfig=3|abbr=on}}||1927
|-
|Murtho||6||{{convert|620|km|mi|sigfig=3|abbr=on}}||{{convert|19.2|m|ft|sigfig=3|abbr=on}}||1930
|-
|Rufus River||7||{{convert|697|km|mi|sigfig=3|abbr=on}}||{{convert|22.1|m|ft|sigfig=3|abbr=on}}||1934
|-
|Wangumma||8||{{convert|726|km|mi|sigfig=3|abbr=on}}||{{convert|24.6|m|ft|sigfig=3|abbr=on}}||1935
|-
|Kulnine||9||{{convert|765|km|mi|sigfig=3 |abbr=on}}||{{convert|27.4|m|ft|sigfig=3|abbr=on}}||1926
|-
|Wentworth||10||{{convert|825|km|mi|sigfig=3|abbr=on}}||{{convert|30.8|m|ft|sigfig=3|abbr=on}}||1929
|-
|Mildura||11||{{convert|878|km|mi|sigfig=3 |abbr=on}}||{{convert|34.4|m|ft|sigfig=3|abbr=on}}||1927
|-
|Euston||15||{{convert|1110|km|mi|sigfig=3 |abbr=on|comma=off }}||{{convert|47.6|m|ft|sigfig=3|abbr=on|comma=off }}||1937
|-
<!--Next two rows are formatted differently to force the column to widen-->
|Torrumbarry||26||1638&nbsp;km&nbsp;(1020&nbsp;mi) ||86.05&nbsp;m&nbsp;(280&nbsp;ft) ||1924
|-
|Yarrawonga Weir||n/a||1992&nbsp;km&nbsp;(1238&nbsp;mi) ||124.9&nbsp;m&nbsp;(410&nbsp;ft)||1939
|-
| colspan="5"|{{big|<nowiki>*</nowiki>}} Distance is from the Murray Mouth.<br />{{big|<nowiki>**</nowiki>}} Elevation is above sea level, at full supply level (i.e., maximum capacity).
|-
|}

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|[[Image: Lock 1 and weir at Blanchetown.JPG |border|800x260px |none]]
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|[[Image: Lock Five Renmark River Murray(GN05819) (cropped).jpg |border|800x260px |none]]
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|width="100"| Lock 1 and weir at [[Blanchetown]] 
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|width="100"| Lock 5 at [[Renmark, South Australia|Renmark]], about 1935 
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|[[Image: Lock11Mildura.jpg |border|800x260px |none]]
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|width="100"| Lock 11, [[Mildura]]
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