Editing Dam (section)

===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>