{{short description|River in Armenia}} {{Infobox river | name = Hrazdan | image = Hrazdan river - panoramio.jpg | image_caption = The river in [[Yerevan]] | source1_location = [[Lake Sevan]] | mouth = [[Aras (river)|Aras]] | mouth_coordinates = {{coord|39|59|25|N|44|27|10|E|region:AM_type:waterbody_source:kolossus-etwiki|display=it}} | subdivision_type1 = Country | subdivision_name1 = [[Armenia]] | length_km = 141 | source1_elevation = {{convert|1904|m|ft|abbr=on}} | mouth_elevation = {{convert|826|m|ft|abbr=on}} | discharge1_avg = {{convert|17.9|m3/s|cuft/s|abbr=on}} | basin_size_km2 = 2560 | progression = {{RAras}} | tributaries_left = [[Getar]] | tributaries_right = }} The '''Hrazdan''' ({{langx|hy|Հրազդան}}, {{lang|hy-Latn|Hrazdan}}) is a major river and the second largest in [[Armenia]]. It originates at the northwest extremity of [[Lake Sevan]] and flows south through the [[Kotayk Province]] and Armenia's capital, [[Yerevan]]; the lake in turn is fed by several streams.<ref name="Brit">{{Cite web|url=http://www.britannica.com/place/Armenia#ref481291|title= Armenia|access-date=1 November 2015|publisher=Encyclopædia Britannica}}</ref><ref name=Effluent>{{Cite web|url=http://ace.aua.am/monitoring-dissolved-oxygen-in-the-hrazdan-river/|title=Monitoring Dissolved Oxygen in the Hrazdan River|access-date=18 November 2015|publisher=Acopian Centre for Environment}}</ref> In the [[Ararat plain]] it joins the [[Aras (river)|Aras river]] along the border with [[Turkey]]. It joins as a left tributary the [[Kura (South Caucasus river)|Kura river]], which then flows into the Caspian Sea.
A series of [[hydro-electric]] projects have been constructed on the Hrazdan. Its waters are in demand to [[irrigate]] crops.<ref name= Gharabegian/><ref name=Resource>{{Cite web|url=http://www.fao.org/nr/water/aquastat/countries_regions/Profile_segments/ARM-WR_eng.stm|title=Armenia:Water resources |access-date=18 November 2015|publisher=[[FAO]] Organization}}</ref>
==Names== The river is called '''Ildaruni''' in [[Urartian language|Urartian]] inscriptions.<ref name="Hewsen 92">{{cite book|last1=Hewsen|first1=Robert H.|author-link1=Robert H. Hewsen|title=The Geography of Ananias of Širak: Ašxarhacʻoycʻ, the Long and the Short Recensions|date=1992|publisher=Reichert|isbn=9783882264852|page=192|quote=...the Turkish Zanga; (Urart: Ildaruni; Arm.: Hrazdan)...}}</ref><ref>{{cite book |last1=Maranci |first1=Christina |author1-link=Christina Maranci |title=The Art of Armenia: An Introduction |date=2018 |publisher=Oxford University Press |isbn=9780190269005 |page=[https://books.google.com/books?id=jzdtDwAAQBAJ&dq=Ildaruni+hrazdan&pg=PA13 13] |quote=The stele bears a text of forty-seven lines in Urartian cuneiform identifying King Rusa II (r. c. 680–639 BCE), son of Argishti II, and his building and irrigation works, including the construction of a canal from the Ildaruni (Hrazdan) River.}}</ref><ref>{{cite book|last=Lang|first=David Marshall|author-link=David Marshall Lang|title=Armenia: Cradle of Civilization|date=1970|location=London|publisher=[[Allen & Unwin]] |page= 98|quote="The canal from the Ildaruni (Razdan) river I built.' "}}</ref>
The name ''Hrazdan'' derives from a [[Middle Iranian]] form of [[Avestan]] {{Lang|ae-Latn|Frazdānu}}, which in [[Zoroastrianism|Zoroastrian]] mythology is the body of water by which [[Vishtaspa]] converted to Zoroastrianism.<ref>{{cite book |last= |first= |author-link= |url=https://books.google.com/books?id=9ZptAAAAMAAJ |title=Armenian Tsopk/Kharpert |publisher=Mazda Publishers |year=2002 |isbn=9781568591506 |editor-last=Hovannisian |editor-first=Richard G. |editor-link=Richard G. Hovannisian |location=Costa Mesa, California |page=174}}</ref> {{Lang|ae-Latn|Frazdānu}} is composed of the elements {{Lang|ae-Latn|fraz}} 'elevated, high' and {{Lang|ae-Latn|dānu}} 'river'. {{Lang|ae-Latn|Dānu}} derives from the same [[Iranian languages|Iranian]] root as a number of [[hydronym]]s in Europe, such as [[Don (river)|Don]], [[Dnieper]], [[Danube]] and [[Dniester]].<ref>{{Cite journal |last=Nalbandian |first=G. M. |date=1983 |title=К этимологии армянского հրաժեշտ (= hražešt = прощание) и гидронима Հրազդան (= hrazdan = раздан) |trans-title=On the etymology of Armenian հրաժեշտ (= hražešt = farewell) and the hydronym Հրազդան (= Hrazdan) |url=https://tert.nla.am/archive/NLA%20AMSAGIR/Banber%20Yerevani%20Hamalsarani/1983(2).pdf |journal=Banber Erevani Hamalsarani |language=ru |volume=2 |issue=50 |pages=246–248 |via=[[National Library of Armenia]]}}</ref> The change of word-initial {{Lang|ira-Latn|fr-}} to {{Lang|xcl-Latn|hr-}} can be seen in a number of Iranian borrowings into Armenian.<ref>{{Cite thesis |last=Russell |first=James R. |title=Zoroastrianism in Armenia |date=1982 |access-date=14 April 2024 |degree=PhD |publisher=University of London, School of Oriental and African Studies |url=https://www.proquest.com/docview/1977402868 |page=81|id={{ProQuest|1977402868}}|url-access=subscription|author-link=James R. Russell}}</ref> The Hrazdan is mentioned in [[Movses Khorenatsi|Movses Khorenatsi's]] history. In the history attributed to [[Sebeos]], the form {{Lang|xcl-Latn|Hurazdan}} is used, while some later Armenian historians use the form {{Lang|xcl-Latn|Hurastan}}.<ref>{{Cite book |last=Hübschmann |first=Heinrich |author-link=Heinrich Hübschmann |url=https://archive.org/details/diealtarmenisch00hbgoog |title=Die altarmenische Ortsnamen |publisher=Verlag von Karl J. Trübner |year=1904 |location=Strasbourg |pages=446 |language=de |trans-title=The old Armenian place names}}</ref>
Its name in [[Turkic languages]] is '''Zangu''',<ref>{{cite book|last1=Chalabian|first1=Antranig|author-link1=Antranig Chalabian|title=Armenia after the coming of Islam|date=1999|page=450|quote=He also increased the water capacity of the Hrazdan (Zangu) River, which flows from Lake Sevan to the Araratian plain...}}</ref> '''Zanga''',<ref name="Hewsen 92" /><ref>{{cite web|last1=Hewsen|first1=R. H.|author-link1=Robert H. Hewsen|title=Ayrarat|url=http://www.iranicaonline.org/articles/ayrarat|website=[[Encyclopædia Iranica]]|date=15 December 1987|quote=...the upper course of the Hrazdan river (Turkish Zanga) which flows from Lake Sevan to the Araxes.}}</ref><ref>{{cite book|last1=Nansen|first1=Fridtjof|author-link1=Fridtjof Nansen|title=Reports and Papers on the Work for the Refugees|date=1922|publisher=[[League of Nations]]|page=19|quote=...surrounding Erivan, on both sides of the Zanga River, by the waters of that river...}}</ref> '''Zangi''',<ref>{{cite book|author-link=Brady Kiesling|last=Kiesling|first=Brady|title=Aediscovering Armenia: An Archaeological/touristic Gazetteer And Map Set For The Historical Monuments Of Armenia|year=1999|location=Yerevan|url=https://archive.org/details/RediscoveringArmenia|page=32|quote=The flow of the Hrazdan (formerly Zangi) river from Lake Sevan past Yerevan to the Arax River...}}</ref> or '''Zengy'''.<ref>{{cite book|last1=Conder|first1=Josiah|author-link1=Josiah Conder (editor and author)|title=A Dictionary of Geography, ancient and modern, etc|url=https://archive.org/details/adictionarygeog00condgoog|date=1834|publisher=Thomas Tegg & Son|location=London|page=210|quote=ERIVAN. A city of Armenia, situated on the river Zengy...}}</ref><ref>{{cite book|last1=Perkins|first1=Justin|title=A Residence of Eight Years in Persia, Among the Nestorian Christians: With Notices of the Muhammedans|url=https://archive.org/details/residenceofeight00perk|date=1843|publisher=Allen, Morrill & Wardwell|page=[https://archive.org/details/residenceofeight00perk/page/n160 129]|quote=There is an imposing citadel, on a hill of moderate elevation about a quarter of a mile south of the town, bordering also on the river Zengy...}}</ref> It was called Zanga in [[Russian Empire|Tsarist Russian]] nomenclature.<ref>{{cite book |author=[[:ru:Владислав Иванович Масальский|Masalsky, Vladislav Ivanovich]] |title=[[Brockhaus and Efron Encyclopedic Dictionary|Small Brockhaus and Efron Encyclopedic Dictionary]] Vol. XII |contribution=[[:s:ru:ЭСБЕ/Занга, река|Занга, река]] (Zanga, river)|language=ru |date=1894 }}</ref>
==Geography== Lake Sevan (with 30 rivers contributing to its storage), the largest located in the central part of the country and the Hrazdan River which originates from it, together form the "Sevan-Hrazdan Management Area", which is one of the five sub-basins of the 14 sub-basins of Kura and Araks basins of Armenia. The river originates from the lake at an elevation of {{Convert|1900| m}}.<ref name=Resource/> The river which flows from the lake in a southern direction passes through a deep gorge as it enters on the western side of the Yerevan city, and then debauchees into the Aras River on the southern side of the city.{{Sfn|Holding|2014|p=109}} The geological formations along the river course are made up of lava flows (existing as basalts) generated from three volcanoes in the [[Gegham mountains|Gegham]] range. The lava surfaces represent environments that existed in the form of "lakes, river channels and floodplains". The chronology of landscape of the upper most layer of basalts indicates an age of 200,000 years.<ref>{{Cite web|url=http://www.winchester.ac.uk/academicdepartments/archaeology/Research/Pages/HrazdanGorgePalaeolithicProjectGeoarchaeology.aspx|archive-url=https://web.archive.org/web/20151119102219/http://www.winchester.ac.uk/academicdepartments/archaeology/Research/Pages/HrazdanGorgePalaeolithicProjectGeoarchaeology.aspx|url-status=dead|archive-date=19 November 2015|title=Hrazdan Gorge Palaeolithic Project: the Geoarchaeology|access-date=18 November 2015|publisher=University of Winchester}}</ref>
The river drains a total catchment area of {{Convert|2566|km2}}. Precipitation volume is 1572 million cubic metre<ref name=Resource/> from an annual rainfall of {{Convert|257| mm}} with a maximum of {{Convert|43| mm}} in May and a minimum of {{Convert|8| mm}} during August. The average temperature recorded in the basin varies from {{Convert|-3|C}} in January to {{Convert|26|C}} in July with diurnal variation with the lowest night temperature of {{Convert|-15|C}} in January and highest day temperature of {{Convert|44|C}} in July.{{Sfn|Holding|2014|p=109}} The total flow in the river is 733 million cubic meter. The regulated outflow into the river, which forms the Ararat Valley, is utilized for irrigation and hydro-power benefits.<ref name=Resource/>
<gallery mode="packed" heights="200px"> File:Davtashen panorama.jpg|A panorama of the Hrazdan River gorge and [[Davtashen]] from [[Arabkir (district)|Arabkir]], Yerevan </gallery>
===Fauna=== The fauna reported from the river includes 33 species of [[Chironomidae|chironomids]] and 23 species of [[Black fly|blackflies]]. The chironomids belong to five subfamilies of [[Tanypodinae]], [[Diamesinae]], [[Prodiamesinae]], [[Orthocladiinae]], and [[Chironominae]].<ref>{{Cite journal|title= The fauna of chironomids and blackflies (Diptera: Chironomidae, Simuliidae) and hydrochemical characteristics of the Hrazdan River (Armenia)|date= February 2007|doi=10.1134/S0013873807010071|volume=87|journal=Entomological Review|pages=73–81 | last1 = Kachvoryan | first1 = E. A.|issue= 1|bibcode= 2007EntRv..87...73K|s2cid= 34675406}}</ref> 25 species of invertebrates comprising two species of [[rotifers]], 13 species of [[cladocerans]] and 10 species of [[copepods]] have been recorded in the river.<ref>{{Cite web|url=http://watchemec.ru/en/article/24868/|title=Zooplankton changes in the long profile of Hrazdan river, Armenia|year=2012|access-date=18 November 2015|publisher=Scientific Journal of Chemistry and ecology}}</ref>
While the fish species contained in the lake consist of the [[Sevan trout]] (''Salmo ischchan'') or "Prince Fish," siga, crucian, carp, crayfish, bojak (''Salmo ischchan danilewskii'') and winter bakhtak (''Salmo ischchan ischchan'') and summer bakhtak (''Salmo ischchan aestivalis''), the river is reported to have species of [[crayfish]] as well as karas in abundance.<ref>{{Cite web|url=http://fishing-center.com/fishing-in-armenia|title=Fishing in Armenia|access-date=18 November 2015|publisher=Fishing Centre}}</ref>
==Development== {{main|Sevan–Hrazdan Cascade}} [[File:Hrazdan Gorge from Argel Village.webm|thumb|300x300px|Hrazdan Gorge from Argel Village]] The lake waters have been used for irrigation since the 19th century, and from early 20th century hydro-power development has also been implemented. The lake waters were planned to be used through the river for irrigating {{convert|100000|ha}} in the Ararat Valley out of which an irrigation of {{convert|80000|ha}} was created. The hydro-power development was planned on the river as the [[Sevan–Hrazdan Cascade]] involving seven schemes in a {{Convert|70|km}} stretch of the river with a total installed capacity of 560 MW with mean annual energy generation of around 500 million kilowatt hours; it is the largest hydro-power generating scheme in Armenia.<ref name= Gharabegian/> This scheme was implemented between 1930 and 1962. These are small- and medium-size projects built as run-of-the river power plants. The seven power stations are: Sevan HEP with installed capacity of 34.2 MW with two units completed in 1949; the Hrazdan HEP of 81.6 MW with two units commissioned in 1959; the Argel HEP with installed capacity of 224 MW completed in 1953; the Arzni HEP with capacity of 70.6 MW with installation of 3 units commissioned in 1956; the Kanaker HEP with installed capacity of 100 MW with 6 units completed in 1936; the Yerevan-1 HEP commissioned in 1962 with installation of 44 MW with 2 units; and the Yerevan-3 with capacity of 5 MW with one unit commissioned in 1960. However, priority of release of water from the lake is for irrigation and accordingly the power stations are operated.<ref name= Gharabegian>{{Cite web|last= Gharabegian |first= Areg |url=http://asbarez.com/123306/sevan-hrazdan-cascade-hydropower-system/|title=Sevan–Hrazdan Cascade Hydropower System|date=21 May 2014|access-date=18 November 2015|publisher=[[Asbarez]] News}}</ref>
The civil works involved construction of diversion works, open canals or tunnels and power house which over the years were in need of substantial rehabilitation as they were all built around the middle of the twentieth century.<ref name= Gharabegian/> In 2003, the International Energy Corporation", a Closed Joint Stock Company, acquired the projects from the Public Services Regulatory Commission of the country under a license No. 0108 for generation of electrical energy. Right from the time of acquisition they started rehabilitating the projects to maximize power generation. The works were completed during 2004.<ref>{{Cite web|url=http://www.minenergy.am/en/page/449|title=Sevan-Hrazdan Cascade|access-date=18 November 2015|publisher= Ministry Of Energy And Natural Resources Of The Republic Of Armenia}}</ref> The works were carried out under a US$25 million loan from the [[Asian Development Bank]].<ref>{{Cite web|url=http://www.hydroworld.com/articles/2013/05/adb-makes-loan-for-sevan-hrazdan-cascade-modernization-project.html|title=ADB makes loan for Sevan-Hrazdan cascade modernization project |date=21 May 2013|publisher= HydroWorld: Hydro News}}</ref>
==River pollution== The river water is polluted by effluent flows from agricultural, commercial, industrial, and residential development, but particularly by the untreated wastewater from Yerevan. This affects the water quality in the river with dissolved oxygen (DO) levels (less than 5% of the saturated dissolved oxygen level) remaining much lower than the permissible limits. A study carried out in 2008 indicates that a 16 km stretch of the river, from 2 km upstream of the Yerevan wastewater outfalls to 14 km below, is insufficiently aerated to provide a healthy environment for aquatic life.<ref name=Effluent/>
A study assessing the river's ecological state from 2016 to 2018 found a significant degradation in water quality as the river flows downstream, primarily due to the influx of untreated municipal, agricultural, and industrial wastewater.<ref>{{cite journal |last1=Kobelyan |first1=H. H. |last2=Ghukasyan |first2=E. Kh. |last3=Khosrovyan |first3=A. M. |title=Հրազդան գետի ներկա էկոլոգիական վիճակի գնահատականըАssessment of the current еcological state of the Hrazdan River |journal=Biological Journal of Armenia |date=2021 |volume=73 |issue=1 |url=https://arar.sci.am/dlibra/publication/293448/edition/269409/content |language=hy |issn=0366-5119}}</ref>
==See also== * [[List of rivers of Armenia]] * [[List of lakes of Armenia]] * [[Geography of Armenia]]
==References== {{reflist|30em}}
==Bibliography== * {{cite book|last= Holding |first=Deirdre |title=Armenia: with Nagorno Karabagh|url=https://books.google.com/books?id=Gbz-AwAAQBAJ&pg=PA109|year=2014|publisher=Bradt Travel Guides|isbn=978-1-84162-555-3}} {{Yerevan landmarks}}
{{Use dmy dates|date=April 2017}}
[[Category:Rivers of Armenia]] [[Category:Geography of Yerevan]] [[Category:Geography of Kotayk Province]]
{{Category Commons|Hrazdan River}}