Editing Small hydro (section)

== History ==
Wood [[Water wheel|water wheels]] along riversides may be considered the first examples of "small hydro".<ref>{{Cite book |last1=Jahren |first1=Per |url=https://books.google.com/books?id=7teSDQAAQBAJ&dq=water+wheel+china+history&pg=PA139 |title=How Water Influences Our Lives |last2=Sui |first2=Tongbo |date=2016-11-22 |publisher=Springer |isbn=978-981-10-1938-8 |language=en}}</ref> Up to the 17th century the efficiency of water wheels neared 70%. However, as the need for power generation increased small hydropower projects were phased out in favor of the large scale dams using newly designed turbines. <ref name=":03">{{Cite journal |last=Paish |first=Oliver |date=2002-12-01 |title=Small hydro power: technology and current status |url=https://www.sciencedirect.com/science/article/pii/S1364032102000060 |journal=Renewable and Sustainable Energy Reviews |volume=6 |issue=6 |pages=537–556 |doi=10.1016/S1364-0321(02)00006-0 |bibcode=2002RSERv...6..537P |issn=1364-0321|url-access=subscription }}</ref>

Post 20th century environmental doctrine is moving away from large-scale hydropower construction due to increased awareness of ecological problems associated with dams. Examples of previous dam deconstruction projects include the [[Restoration of the Elwha River]] and [[Un-Dam the Klamath]] river movement in the United States. Both of these projects deconstructed dams with generation capacities less than 30 MW.