Editing Dam (section)

==History==
===Ancient dams===
[[File:Dujiang Weir (cropped).jpg|thumb|The [[Dujiangyan]] irrigation system was initially constructed during the [[Qin dynasty]], around 256 BC.]]
Early dam building took place in [[Mesopotamia]] and the [[Middle East]]. Dams were used to control water levels, for Mesopotamia's weather affected the [[Tigris]] and [[Euphrates]] Rivers.

The earliest known dam is the [[Jawa Dam (Jordan)|Jawa Dam]] in [[Jordan]], {{convert|100|km}} northeast of the capital [[Amman]]. This gravity dam featured an originally {{convert|9|m|ft|adj=mid|-high}} and {{convert|1|m|ft|adj=mid|-wide|abbr=on}} stone wall, supported by a {{convert|50|m|ft|adj=mid|-wide|abbr=on}} earthen rampart. The structure is dated to 3000 BC.<ref>Günther Garbrecht: "Wasserspeicher (Talsperren) in der Antike", ''Antike Welt'', 2nd special edition: ''Antiker Wasserbau'' (1986), pp.51–64 (52)</ref><ref>S.W. Helms: "Jawa Excavations 1975. Third Preliminary Report", Levant 1977</ref> However, the oldest continuously operational dam is [[Lake Homs Dam]], built in [[Syria]] between 1319-1304 BC.<ref>{{Cite web |title=The world's oldest dams still in use |url=https://www.water-technology.net/features/feature-the-worlds-oldest-dams-still-in-use/ |access-date=2023-12-18 |website=www.water-technology.net}}</ref>

The [[Ancient Egypt]]ian [[Sadd-el-Kafara Dam]] at Wadi Al-Garawi, about {{convert|25|km|abbr=on}} south of [[Cairo]], was {{convert|102|m|abbr=on}} long at its base and {{convert|87|m|abbr=on}} wide. The structure was built around 2800<ref name="Günther Garbrecht 52f.">Günther Garbrecht: "Wasserspeicher (Talsperren) in der Antike", ''Antike Welt'', 2nd special edition: ''Antiker Wasserbau'' (1986), pp.51–64 (52f.)</ref> or 2600 BC<ref name="Bazzasowr">{{cite web|url=http://www.fao.org/world/Regional/RNE/morelinks/Publications/English/HYSTORY-OF-WATER-RESOURCES.pdf |title=overview of the hystory &#91;sic&#93; of water resources and irrigation management in the near east region |access-date=1 August 2007 |author=Mohamed Bazza |date=28–30 October 2006 |publisher=Food and Agriculture Organization of the United Nations |url-status=dead |archive-url=https://web.archive.org/web/20070808082928/http://www.fao.org/world/Regional/RNE/morelinks/Publications/English/HYSTORY-OF-WATER-RESOURCES.pdf |archive-date=8 August 2007 }}http://www.fao.org/docrep/005/y4357e/y4357e14.htm</ref> as a [[diversion dam]] for flood control, but was destroyed by heavy rain during construction or shortly afterwards.<ref name="Günther Garbrecht 52f." /><ref name="Bazzasowr" /> During the [[Twelfth Dynasty of Egypt|Twelfth Dynasty]] in the 19th century BC, the Pharaohs Senosert III, [[Amenemhat III]], and [[Amenemhat IV]] dug a canal {{convert|16|km|abbr=on}} long linking the [[Fayum Depression]] to the [[Nile]] in Middle Egypt. Two dams called Ha-Uar running east–west were built to retain water during the annual flood and then release it to surrounding lands. The lake called ''Mer-wer'' or [[Lake Moeris]] covered {{convert|1700|sqkm|sqmi|abbr=on}} and is known today as Birket Qarun.<ref>{{Cite web|url=https://www.brown.edu/Departments/Joukowsky_Institute/courses/afterpharaohs2010/13390.html|title=Lake Moeris|publisher=Brown University |access-date=2018-08-14}}</ref>

By the mid-late third millennium BC, an intricate water-management system in [[Dholavira]] in modern-day [[India]] was built. The system included 16 reservoirs, dams and various channels for collecting water and storing it.<ref>{{cite web|url=http://himalmag.com/component/content/article/44/1062-The-reservoirs-of-Dholavira.html|title=The reservoirs of Dholavira|date=December 2008|publisher=The Southasia Trust|access-date=27 February 2011|url-status=dead|archive-url=https://web.archive.org/web/20110711170319/http://himalmag.com/component/content/article/44/1062-The-reservoirs-of-Dholavira.html|archive-date=11 July 2011|df=dmy}}http://old.himalmag.com/component/content/article/1062-the-reservoirs-of-dholavira.html {{Webarchive|url=https://web.archive.org/web/20160821053324/http://old.himalmag.com/component/content/article/1062-the-reservoirs-of-dholavira.html |date=21 August 2016 }}</ref>

One of the engineering wonders of the ancient world was the [[Marib Dam|Great Dam of Marib]] in [[Yemen]]. Initiated sometime between 1750 and 1700 BC, it was made of packed earth – triangular in cross-section, {{convert|580|m|abbr=on}} in length and originally {{convert|4|m|abbr=on}} high – running between two groups of rocks on either side, to which it was linked by substantial stonework. Repairs were carried out during various periods, most importantly around 750 BC, and 250 years later the dam height was increased to {{convert|7|m|abbr=on}}. After the end of the [[Sabaeans|Kingdom of Saba]], the dam fell under the control of the [[Himyarite Kingdom|Ḥimyarites]] (c. 115 BC) who undertook further improvements, creating a structure {{convert|14|m|abbr=on}} high, with five spillways, two masonry-reinforced sluices, a settling pond, and a {{convert|1000|m|abbr=on|adj=on}} canal to a distribution tank. These works were not finished until 325 AD when the dam permitted the irrigation of {{Convert|25000|acre|sqkm}}.

[[Eflatun Pınar]] is a [[Hittites|Hittite]] dam and spring temple near [[Konya]], Turkey. It is thought to date from the Hittite empire between the 15th and 13th centuries BC.

The [[Kallanai]] is constructed of unhewn stone, over {{convert|300|m|abbr=on}} long, {{convert|4.5|m|abbr=on}} high and {{convert|20|m|abbr=on}} wide, across the main stream of the [[Kaveri]] River in [[Tamil Nadu]], [[South India]]. The basic structure dates to the 2nd century AD<ref>{{cite web|url=http://lawlibrary.unm.edu/nrj/48/3/03_agoramoorthy_indian.pdf |title=The Check-Dam Route to Mitigate India's Water Shortages |author1=Govindasamy Agoramoorthy |author2=Sunitha Chaudhary |author3=Minna J. Hsu |publisher=Law library&nbsp;– University of New Mexico |access-date=8 November 2011 |url-status=dead |archive-url=https://web.archive.org/web/20130720143611/http://lawlibrary.unm.edu/nrj/48/3/03_agoramoorthy_indian.pdf |archive-date=20 July 2013 }}</ref> and is considered one of the oldest water diversion or water regulating structures still in use.<ref name="kallanai_oldest">{{cite web|last=Kalyanaraman|first=S |url=http://www.hindunet.org/saraswati/traditionwater.pdf |title=Water management: Historical maritime, riverine tradition of Bharat|date=18 March 2003|access-date=23 January 2021|archive-url=https://web.archive.org/web/20070206130842/http://www.hindunet.org/saraswati/traditionwater.pdf |archive-date=6 February 2007 |url-status=dead |df=dmy }}</ref> The purpose of the dam was to divert the waters of the Kaveri across the fertile delta region for irrigation via canals.<ref name="kallanai_googlebook">{{cite book |last=Singh |first=Vijay P. |author2=Ram Narayan Yadava |title=Water Resources System Operation: Proceedings of the International Conference on Water and Environment |publisher=Allied Publishers |year=2003 |url=https://books.google.com/books?id=Bge-0XX6ip8C&q=kallanai&pg=PA508 |isbn=978-81-7764-548-4 |page=508 |access-date=2015-11-09}}</ref>

[[Dujiangyan irrigation system|Du Jiang Yan]] is the oldest surviving [[irrigation]] system in China that included a dam that directed waterflow. It was finished in 251 BC. A large earthen dam, made by [[Sunshu Ao]], the [[prime minister]] of [[Chu (state)]], flooded a valley in modern-day northern [[Anhui]] Province that created an enormous irrigation reservoir ({{convert|62|mi|order=flip|abbr=on}} in circumference), a reservoir that is still present today.<ref name="needham volume 4 part 3 271">Needham, Joseph (1986). ''Science and Civilization in China: Volume 4, Part 3''. [[Taipei]]: Caves Books, Ltd.</ref>

===Roman engineering===
[[File:Roman Cornalvo dam, Extremadura, Spain. Pic 01.jpg|thumb|The [[Cornalvo Dam|Roman dam at Cornalvo]] in [[Spain]] has been in use for almost two millennia.]]

[[List of Roman dams and reservoirs|Roman dam]] construction was characterized by "the Romans' ability to plan and organize engineering construction on a grand scale."<ref name="Smith 1971, 49">{{harvnb|Smith|1971|p=49}}</ref> Roman planners introduced the then-novel concept of large [[reservoir]] dams which could secure a permanent [[water supply]] for urban settlements over the dry season.<ref>{{harvnb|Smith|1971|p=49}}; {{harvnb|Hodge|1992|pp=79f.}}</ref> Their pioneering use of water-proof hydraulic [[mortar (masonry)|mortar]] and particularly [[Roman concrete]] allowed for much larger dam structures than previously built,<ref name="Smith 1971, 49" /> such as the [[Lake Homs Dam]], possibly the largest water barrier to that date,<ref name="Smith 1971, 42">{{harvnb|Smith|1971|p=42}}</ref> and the [[Harbaqa Dam]], both in [[Syria (Roman province)|Roman Syria]]. The highest Roman dam was the [[Subiaco Dam]] near [[Rome]]; its record height of {{convert|50|m|abbr=on}} remained unsurpassed until its accidental destruction in 1305.<ref name="Hodge 1992, 87">{{harvnb|Hodge|1992|p=87}}</ref>

Roman engineers made routine use of ancient standard designs like embankment dams and masonry gravity dams.<ref>{{harvnb|Hodge|2000|pp=331f.}}</ref> Apart from that, they displayed a high degree of inventiveness, introducing most of the other basic dam designs which had been unknown until then. These include [[arch-gravity dam]]s,<ref>{{harvnb|Hodge|2000|p=332}}; {{harvnb|James|Chanson|2002}}</ref> [[arch dam]]s,<ref name="Earliest known arch dam">{{harvnb|Smith|1971|pp=33–35}}; {{harvnb|Schnitter|1978|pp=31f.}}; {{harvnb|Schnitter|1987a|p=12}}; {{harvnb|Schnitter|1987c|p=80}}; {{harvnb|Hodge|2000|p=332, fn. 2}}</ref> [[buttress dam]]s<ref>{{harvnb|Schnitter|1987b|pp=59–62}}</ref> and [[Arch dam#Variations|multiple arch buttress dams]],<ref name="Earliest known multiple arch buttress dam">{{harvnb|Schnitter|1978|p=29}}; {{harvnb|Schnitter|1987b|pp=60, table 1, 62}}; {{harvnb|James|Chanson|2002}}; {{harvnb|Arenillas|Castillo|2003}}</ref> all of which were known and employed by the 2nd century AD (see [[List of Roman dams]]). Roman workforces also were the first to build dam bridges, such as the [[Bridge of Valerian]] in Iran.<ref>{{harvnb|Vogel|1987|p=50}}</ref>

[[File:Sushtar Bridge.jpg|thumb|left|Remains of the [[Band-e Kaisar]] dam, built by the Romans in the 3rd century AD]]

In [[Iran]], bridge dams such as the [[Band-e Kaisar]] were used to provide [[hydropower]] through [[water wheel]]s, which often powered water-raising mechanisms. One of the first was the Roman-built dam bridge in [[Dezful]],<ref>{{harvnb|Hartung|Kuros|1987|pp=232, 238, fig. 13; 249}}</ref> which could raise water 50 [[cubit]]s (c. 23 m) to supply the town. Also [[diversion dam]]s were known.<ref name="Hill-Engineering">[[Donald Routledge Hill]] (1996), "Engineering", p. 759, in {{cite book |last1=Rashed |first1=Roshdi |last2=Morelon  |first2=Régis |year=1996 |title=Encyclopedia of the History of Arabic Science |publisher=[[Routledge]] |isbn=978-0-415-12410-2 |pages=751–795 |title-link=Encyclopedia of the History of Arabic Science }}</ref> [[Mill (grinding)|Milling]] dams were introduced which the [[Muslim Agricultural Revolution|Muslim engineers]] called the ''Pul-i-Bulaiti''. The first was built at Shustar on the River [[Karun]], Iran, and many of these were later built in other parts of the [[Islamic world]].<ref name="Hill-Engineering" /> Water was conducted from the back of the dam through a large pipe to drive a water wheel and [[watermill]].<ref name="Lucas">Adam Lucas (2006), ''Wind, Water, Work: Ancient and Medieval Milling Technology'', p. 62. Brill, {{ISBN|90-04-14649-0}}.</ref> In the 10th century, [[Al-Muqaddasi]] described several dams in Persia. He reported that one in [[Ahvaz|Ahwaz]] was more than {{convert|3000|ft|order=flip|abbr=on}} long,<ref name="Hill-56-8" /> and that it had many water-wheels raising the water into [[aqueduct (water supply)|aqueducts]] through which it flowed into reservoirs of the city.<ref name="Hill-31">{{cite book |title=A history of engineering in classical and medieval times |author=Donald Routledge Hill |publisher=Routledge |year=1996 |isbn=978-0-415-15291-4 |page=31}}</ref> Another one, the Band-i-Amir Dam, provided irrigation for 300 villages.<ref name="Hill-56-8">{{cite book |title=A history of engineering in classical and medieval times |author=Donald Routledge Hill |publisher=[[Routledge]] |year=1996 |isbn=978-0-415-15291-4 |pages=56–8 |author-link=Donald Routledge Hill}}</ref>

===Middle Ages===
[[File:Shah Abbas Arch Dam.jpg|thumb|14th c. Shāh Abbās arch dam]]
Shāh Abbās Arch (Persian: طاق شاه عباس), also known as [[Kurit Dam]], is the thinnest arch dam in the world and one of the oldest arch dams in Asia. It was constructed some 700 years ago in [[Tabas County|Tabas county]], South [[Khorasan province|Khorasan Province]], [[Iran]]. It stands 60 meters tall, and in crest is a one meter width. Some historians believe the dam was built by Shāh Abbās I, whereas others believe that he repaired it.

In the [[Netherlands]], a low-lying country, dams were often built to block rivers to regulate the water level and to prevent the sea from entering the marshlands. Such dams often marked the beginning of a town or city because it was easy to cross the river at such a place, and often influenced Dutch place names. The present Dutch capital, [[Amsterdam]] (old name ''Amstelredam''), started with a dam on the river [[Amstel]] in the late 12th century, and [[Rotterdam]] began with a dam on the river [[Rotte (river)|Rotte]], a minor tributary of the [[Nieuwe Maas]]. The central square of Amsterdam, covering the original site of the 800-year-old dam, still carries the name ''[[Dam Square]]''.

===Industrial Revolution===
[[File:Engraving of Rideau Canal locks.jpg|thumb|upright|240x240px|An engraving of the [[Rideau Canal]] locks at [[Bytown]]]]
The Romans were the first to build [[arch dam]]s, where the [[reaction force]]s from the abutment stabilizes the structure from the external [[hydrostatic pressure]], but it was only in the 19th century that the engineering skills and construction materials available were capable of building the first large-scale arch dams.

Three pioneering arch dams were built around the [[British Empire]] in the early 19th century. Henry Russel of the [[Royal Engineers]] oversaw the construction of the [[Mir Alam Tank|Mir Alam dam]] in 1804 to supply water to the city of [[Hyderabad]] (it is still in use today). It had a height of {{convert|12|m|abbr=on}} and consisted of 21 arches of variable span.<ref>{{cite web|url=http://www.simscience.org/cracks/advanced/butt_hist1.html |title=Key Developments in the History of Buttress Dams |url-status=dead |archive-url=https://web.archive.org/web/20120321190213/http://www.simscience.org/cracks/advanced/butt_hist1.html |archive-date=21 March 2012 |df=dmy }}</ref>

In the 1820s and 30s, Lieutenant-Colonel [[John By]] supervised the construction of the [[Rideau Canal]] in [[Canada]] near modern-day [[Ottawa]] and built a series of curved masonry dams as part of the waterway system. In particular, the [[Jones Falls Dam]], built by [[John Redpath]], was completed in 1832 as the largest dam in [[North America]] and an engineering marvel. In order to keep the water in control during construction, two [[sluice]]s, artificial channels for conducting water, were kept open in the dam. The first was near the base of the dam on its east side. A second sluice was put in on the west side of the dam, about {{convert|20|ft|abbr=on}} above the base. To make the switch from the lower to upper sluice, the outlet of Sand Lake was blocked off.<ref>{{cite web |url=http://www.mysteriesofcanada.com/Canada/john_redpath.htm |title=John Redpath, the Whispering Dam, and Sugar |date=2014-10-31}}</ref>

[[File:Lake Parramatta,New South Wales.jpg|left|thumb|Masonry arch wall, [[Parramatta]], [[New South Wales]], the first engineered dam built in Australia]]
Hunts Creek near the city of [[Parramatta]], [[Australia]], was dammed in the 1850s, to cater to the demand for water from the growing population of the city. The masonry [[arch dam]] wall was designed by Lieutenant Percy Simpson who was influenced by the advances in dam engineering techniques made by the [[Royal Engineers]] in [[British India|India]]. The dam cost £17,000 and was completed in 1856 as the first engineered dam built in Australia, and the second arch dam in the world built to mathematical specifications.<ref>{{cite web |url=http://www.traianvs.net/textos/archdams_en.htm |title=Historical Development of Arch Dams}}</ref>

The first such dam was opened two years earlier in [[France]]. It was the first French arch dam of the [[Industrial Revolution|industrial era]], and it was built by François Zola in the municipality of [[Aix-en-Provence]] to improve the supply of water after the [[Second cholera pandemic (1829–1851)|1832 cholera outbreak]] devastated the area. After [[Louis Philippe I|royal approval]] was granted in 1844, the dam was constructed over the following decade. Its construction was carried out on the basis of the mathematical results of scientific stress analysis.

The 75-miles dam near [[Warwick, Queensland|Warwick]], Australia, was possibly the world's first concrete arch dam. Designed by [[Henry Charles Stanley]] in 1880 with an overflow spillway and a special water outlet, it was eventually heightened to {{convert|10|m|abbr=on}}.

In the latter half of the nineteenth century, significant advances in the scientific theory of masonry dam design were made. This transformed dam design from an art based on empirical methodology to a profession based on a rigorously applied scientific theoretical framework. This new emphasis was centered around the engineering faculties of universities in France and in the United Kingdom. [[William John Macquorn Rankine]] at the [[University of Glasgow]] pioneered the theoretical understanding of dam structures in his 1857 paper ''On the Stability of Loose Earth''. [[Rankine theory]] provided a good understanding of the principles behind dam design.<ref>Rankine, W. (1857) "On the stability of loose earth". ''Philosophical Transactions of the Royal Society of London'', Vol. 147.</ref> In France, J. Augustin Tortene de Sazilly explained the mechanics of vertically faced masonry gravity dams, and Zola's dam was the first to be built on the basis of these principles.<ref>{{cite encyclopedia |url=https://www.britannica.com/EBchecked/topic/150337/dam/72085/The-19th-century |title=dam |encyclopedia=Encyclopædia Britannica|date=13 August 2023 }}</ref>

===Modern era===
[[File:Ansel Adams - National Archives 79-AAB-01.jpg|thumb|The [[Hoover Dam]] by [[Ansel Adams]], 1942]]

The era of large dams was initiated with the construction of the [[Aswan Low Dam]] in Egypt in 1902, a gravity [[masonry dam|masonry]] [[buttress dam]] on the [[Nile River]]. Following their 1882 [[Battle of Tel el-Kebir|invasion and occupation of Egypt]], the British began construction in 1898. The project was designed by Sir [[William Willcocks]] and involved several eminent engineers of the time, including Sir [[Benjamin Baker (engineer)|Benjamin Baker]] and Sir [[Sir John Aird, 1st Baronet|John Aird]], whose firm, [[John Aird & Co.]], was the main contractor.<ref>{{cite web|url=http://www.collectstocks.com/egyptbond.html |title=Egyptian Irrigation Bond 1898 – Aswan Dam on Nile River |work=Scripophily |access-date=9 November 2015 |url-status=dead |archive-url=https://web.archive.org/web/20050513224447/http://www.collectstocks.com/egyptbond.html |archive-date=13 May 2005 }}</ref><ref>{{Citation |last=Roberts |first=Chalmers |date=December 1902 |title=Subduing the Nile |url=https://books.google.com/books?id=DoDNAAAAMAAJ&pg=PA2861 |journal=[[World's Work|The World's Work: A History of Our Time]] |volume=V |pages=2861–2870 |access-date=2009-07-10}}</ref> Capital and financing were furnished by [[Ernest Cassel]].<ref>[http://jewishencyclopedia.com/view.jsp?artid=142&letter=F&search=Finance Finance], ''[[Jewish Encyclopedia]]'', c.1906</ref> When initially constructed between 1899 and 1902, nothing of its scale had ever before been attempted;<ref>Frederic Courtland Penfield, [[s:Century Magazine/Volume 57/Issue 4/Harnessing the Nile|"Harnessing the Nile"]], ''[[The Century Magazine]]'', Vol. 57, No. 4 (February 1899)</ref> on completion, it was the largest masonry dam in the world.<ref>{{cite web|title=The First Aswan Dam |url=http://www.umich.edu/~kelseydb/Exhibits/AncientNubia/PhotoIntro.html |archive-url=https://web.archive.org/web/19970615204902/http://www.umich.edu/~kelseydb/Exhibits/AncientNubia/PhotoIntro.html |url-status=dead |archive-date=15 June 1997 |publisher=University of Michigan |access-date=2 January 2011 }}</ref>

The [[Hoover Dam]] is a massive concrete [[arch-gravity dam]], constructed in the [[Black Canyon of the Colorado|Black Canyon]] of the [[Colorado River]], on the border between the US states of [[Arizona]] and [[Nevada]] between 1931 and 1936 during the [[Great Depression]]. In 1928, Congress authorized the project to build a dam that would control floods, provide irrigation water and produce [[hydroelectric power]]. The winning bid to build the dam was submitted by a consortium called [[Six Companies, Inc.]] Such a large concrete structure had never been built before, and some of the techniques were unproven. The torrid summer weather and the lack of facilities near the site also presented difficulties. Nevertheless, Six Companies turned over the dam to the federal government on 1 March 1936, more than two years ahead of schedule.<ref>{{cite book |last1=Interior |first1=United States Dept of the |title=The Hoover Dam Documents |date=1948 |publisher=U.S. Government Printing Office |page=79 |url=https://books.google.com/books?id=jTNAAAAAIAAJ&pg=PA79 |language=en}}</ref>

By 1997, there were an estimated 800,000 dams worldwide, some 40,000 of them over {{convert|15|m|abbr=on}} high.<ref>{{Cite journal |pmc=1470397 |last1=Joyce |first1=S. |title=Is it worth a dam? |date=October 1997 |journal=Environmental Health Perspectives |volume=105 |issue=10 |pages=1050–1055 |pmid=9349830 |doi=10.1289/ehp.971051050}}</ref> In 2014, scholars from the [[University of Oxford]] published a study of the cost of large dams – based on the largest existing dataset – documenting significant cost overruns for a majority of dams and questioning whether benefits typically offset costs for such dams.<ref>{{Cite journal |author1=Atif Ansar |author2=Bent Flyvbjerg |author3=Alexander Budzier |author4=Daniel Lunn |date=June 2014|title=Should we build more large dams? The actual costs of hydropower megaproject development|ssrn=2406852|journal=Energy Policy |volume=69 |pages=43–56|doi=10.1016/j.enpol.2013.10.069|arxiv=1409.0002 |bibcode=2014EnPol..69...43A |s2cid=55722535 }}</ref>