Editing Dam (section)

===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>