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<span>Function</span> </div> </a> <button aria-controls="toc-Function-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> <span class="vector-icon mw-ui-icon-wikimedia-expand"></span> <span>Toggle Function subsection</span> </button> <ul id="toc-Function-sublist" class="vector-toc-list"> <li id="toc-Flow_measurement" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Flow_measurement"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.1</span> <span>Flow measurement</span> </div> </a> <ul id="toc-Flow_measurement-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Flow_over_a_V-notch_weir" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Flow_over_a_V-notch_weir"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.2</span> <span>Flow over a V-notch weir</span> </div> </a> <ul id="toc-Flow_over_a_V-notch_weir-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Control_of_invasive_species" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Control_of_invasive_species"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.3</span> <span>Control of invasive species</span> </div> </a> <ul id="toc-Control_of_invasive_species-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Watermills" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Watermills"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.4</span> <span>Watermills</span> </div> </a> <ul id="toc-Watermills-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Flood_control_and_altering_river_conditions" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Flood_control_and_altering_river_conditions"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.5</span> <span>Flood control and altering river conditions</span> </div> </a> <ul id="toc-Flood_control_and_altering_river_conditions-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Issues" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Issues"> <div class="vector-toc-text"> <span class="vector-toc-numb">3</span> <span>Issues</span> </div> </a> <button aria-controls="toc-Issues-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> <span class="vector-icon mw-ui-icon-wikimedia-expand"></span> <span>Toggle Issues subsection</span> </button> <ul id="toc-Issues-sublist" class="vector-toc-list"> <li id="toc-Ecology" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Ecology"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.1</span> <span>Ecology</span> </div> </a> <ul id="toc-Ecology-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Fish_migration" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Fish_migration"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.2</span> <span>Fish migration</span> </div> </a> <ul id="toc-Fish_migration-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Safety" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Safety"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.3</span> <span>Safety</span> </div> </a> <ul id="toc-Safety-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Common_types" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Common_types"> <div class="vector-toc-text"> <span class="vector-toc-numb">4</span> <span>Common types</span> </div> </a> <button aria-controls="toc-Common_types-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> <span class="vector-icon mw-ui-icon-wikimedia-expand"></span> <span>Toggle Common types subsection</span> </button> <ul id="toc-Common_types-sublist" class="vector-toc-list"> <li id="toc-Broad-crested" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Broad-crested"> <div class="vector-toc-text"> <span class="vector-toc-numb">4.1</span> <span>Broad-crested</span> </div> </a> <ul id="toc-Broad-crested-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Compound" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Compound"> <div class="vector-toc-text"> <span class="vector-toc-numb">4.2</span> <span>Compound</span> </div> </a> <ul id="toc-Compound-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-V-notch" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#V-notch"> <div class="vector-toc-text"> <span class="vector-toc-numb">4.3</span> <span>V-notch</span> </div> </a> <ul id="toc-V-notch-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Polynomial" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Polynomial"> <div class="vector-toc-text"> <span class="vector-toc-numb">4.4</span> <span>Polynomial</span> </div> </a> <ul id="toc-Polynomial-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-See_also" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#See_also"> <div class="vector-toc-text"> <span class="vector-toc-numb">5</span> <span>See also</span> </div> </a> <ul id="toc-See_also-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-References" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#References"> <div class="vector-toc-text"> <span class="vector-toc-numb">6</span> <span>References</span> </div> </a> <button aria-controls="toc-References-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> <span class="vector-icon mw-ui-icon-wikimedia-expand"></span> <span>Toggle References subsection</span> </button> <ul id="toc-References-sublist" class="vector-toc-list"> <li id="toc-Citations" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Citations"> <div class="vector-toc-text"> <span class="vector-toc-numb">6.1</span> <span>Citations</span> </div> </a> <ul id="toc-Citations-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Works_cited" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Works_cited"> <div class="vector-toc-text"> <span class="vector-toc-numb">6.2</span> <span>Works cited</span> </div> </a> <ul id="toc-Works_cited-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Further_reading" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Further_reading"> <div class="vector-toc-text"> <span class="vector-toc-numb">7</span> <span>Further reading</span> </div> </a> <ul id="toc-Further_reading-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-External_links" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#External_links"> <div class="vector-toc-text"> <span class="vector-toc-numb">8</span> <span>External links</span> </div> </a> <ul id="toc-External_links-sublist" class="vector-toc-list"> </ul> </li> </ul> </div> </div> </nav> </div> </div> <div class="mw-content-container"> <main id="content" class="mw-body"> <header class="mw-body-header vector-page-titlebar"> <nav aria-label="Contents" class="vector-toc-landmark"> <div id="vector-page-titlebar-toc" class="vector-dropdown vector-page-titlebar-toc vector-button-flush-left" title="Table of Contents" > <input type="checkbox" id="vector-page-titlebar-toc-checkbox" role="button" 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Available in 32 languages" > <label id="p-lang-btn-label" for="p-lang-btn-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--action-progressive mw-portlet-lang-heading-32" aria-hidden="true" ><span class="vector-icon mw-ui-icon-language-progressive mw-ui-icon-wikimedia-language-progressive"></span> <span class="vector-dropdown-label-text">32 languages</span> </label> <div class="vector-dropdown-content"> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li class="interlanguage-link interwiki-als mw-list-item"><a href="https://als.wikipedia.org/wiki/Wehr_(Wasserbau)" title="Wehr (Wasserbau) – Alemannic" lang="gsw" hreflang="gsw" data-title="Wehr (Wasserbau)" data-language-autonym="Alemannisch" data-language-local-name="Alemannic" class="interlanguage-link-target"><span>Alemannisch</span></a></li><li class="interlanguage-link interwiki-ar mw-list-item"><a href="https://ar.wikipedia.org/wiki/%D9%87%D8%AF%D8%A7%D8%B1" title="هدار – Arabic" lang="ar" hreflang="ar" data-title="هدار" data-language-autonym="العربية" data-language-local-name="Arabic" class="interlanguage-link-target"><span>العربية</span></a></li><li class="interlanguage-link interwiki-az mw-list-item"><a href="https://az.wikipedia.org/wiki/Sua%C5%9F%C4%B1ran" title="Suaşıran – Azerbaijani" lang="az" hreflang="az" data-title="Suaşıran" data-language-autonym="Azərbaycanca" data-language-local-name="Azerbaijani" class="interlanguage-link-target"><span>Azərbaycanca</span></a></li><li class="interlanguage-link interwiki-ca mw-list-item"><a href="https://ca.wikipedia.org/wiki/Sobreeixidor" title="Sobreeixidor – Catalan" lang="ca" hreflang="ca" data-title="Sobreeixidor" data-language-autonym="Català" data-language-local-name="Catalan" class="interlanguage-link-target"><span>Català</span></a></li><li class="interlanguage-link interwiki-cs mw-list-item"><a href="https://cs.wikipedia.org/wiki/Jez" title="Jez – Czech" lang="cs" hreflang="cs" data-title="Jez" data-language-autonym="Čeština" data-language-local-name="Czech" class="interlanguage-link-target"><span>Čeština</span></a></li><li class="interlanguage-link interwiki-cy mw-list-item"><a href="https://cy.wikipedia.org/wiki/Cored" title="Cored – Welsh" lang="cy" hreflang="cy" data-title="Cored" data-language-autonym="Cymraeg" data-language-local-name="Welsh" class="interlanguage-link-target"><span>Cymraeg</span></a></li><li class="interlanguage-link interwiki-da mw-list-item"><a href="https://da.wikipedia.org/wiki/Stemmev%C3%A6rk" title="Stemmeværk – Danish" lang="da" hreflang="da" data-title="Stemmeværk" data-language-autonym="Dansk" data-language-local-name="Danish" class="interlanguage-link-target"><span>Dansk</span></a></li><li class="interlanguage-link interwiki-de mw-list-item"><a href="https://de.wikipedia.org/wiki/Wehr_(Wasserbau)" title="Wehr (Wasserbau) – German" lang="de" hreflang="de" data-title="Wehr (Wasserbau)" data-language-autonym="Deutsch" data-language-local-name="German" class="interlanguage-link-target"><span>Deutsch</span></a></li><li class="interlanguage-link interwiki-et mw-list-item"><a href="https://et.wikipedia.org/wiki/%C3%9Clevoolupais" title="Ülevoolupais – Estonian" lang="et" hreflang="et" data-title="Ülevoolupais" data-language-autonym="Eesti" data-language-local-name="Estonian" class="interlanguage-link-target"><span>Eesti</span></a></li><li class="interlanguage-link interwiki-es mw-list-item"><a href="https://es.wikipedia.org/wiki/Vertedero_hidr%C3%A1ulico" title="Vertedero hidráulico – Spanish" lang="es" hreflang="es" data-title="Vertedero hidráulico" data-language-autonym="Español" data-language-local-name="Spanish" class="interlanguage-link-target"><span>Español</span></a></li><li class="interlanguage-link interwiki-eo mw-list-item"><a href="https://eo.wikipedia.org/wiki/Vejro" title="Vejro – Esperanto" lang="eo" hreflang="eo" data-title="Vejro" data-language-autonym="Esperanto" data-language-local-name="Esperanto" class="interlanguage-link-target"><span>Esperanto</span></a></li><li class="interlanguage-link interwiki-fa mw-list-item"><a href="https://fa.wikipedia.org/wiki/%D8%B3%D8%B1%D8%B1%DB%8C%D8%B2" title="سرریز – Persian" lang="fa" hreflang="fa" data-title="سرریز" data-language-autonym="فارسی" data-language-local-name="Persian" class="interlanguage-link-target"><span>فارسی</span></a></li><li class="interlanguage-link interwiki-fr mw-list-item"><a href="https://fr.wikipedia.org/wiki/Seuil_(barrage)" title="Seuil (barrage) – French" lang="fr" hreflang="fr" data-title="Seuil (barrage)" data-language-autonym="Français" data-language-local-name="French" class="interlanguage-link-target"><span>Français</span></a></li><li class="interlanguage-link interwiki-fy mw-list-item"><a href="https://fy.wikipedia.org/wiki/Keardaam" title="Keardaam – Western Frisian" lang="fy" hreflang="fy" data-title="Keardaam" data-language-autonym="Frysk" data-language-local-name="Western Frisian" class="interlanguage-link-target"><span>Frysk</span></a></li><li class="interlanguage-link interwiki-ko mw-list-item"><a href="https://ko.wikipedia.org/wiki/%EB%B3%B4_(%EC%88%98%EB%A6%AC_%EC%8B%9C%EC%84%A4)" title="보 (수리 시설) – Korean" lang="ko" hreflang="ko" data-title="보 (수리 시설)" data-language-autonym="한국어" data-language-local-name="Korean" class="interlanguage-link-target"><span>한국어</span></a></li><li class="interlanguage-link interwiki-hi mw-list-item"><a href="https://hi.wikipedia.org/wiki/%E0%A4%AC%E0%A4%82%E0%A4%A7%E0%A4%BF%E0%A4%95%E0%A4%BE" title="बंधिका – Hindi" lang="hi" hreflang="hi" data-title="बंधिका" data-language-autonym="हिन्दी" data-language-local-name="Hindi" class="interlanguage-link-target"><span>हिन्दी</span></a></li><li class="interlanguage-link interwiki-id mw-list-item"><a href="https://id.wikipedia.org/wiki/Bendung" title="Bendung – Indonesian" lang="id" hreflang="id" data-title="Bendung" data-language-autonym="Bahasa Indonesia" data-language-local-name="Indonesian" class="interlanguage-link-target"><span>Bahasa Indonesia</span></a></li><li class="interlanguage-link interwiki-is mw-list-item"><a href="https://is.wikipedia.org/wiki/St%C3%ADflugar%C3%B0ur" title="Stíflugarður – Icelandic" lang="is" hreflang="is" data-title="Stíflugarður" data-language-autonym="Íslenska" data-language-local-name="Icelandic" class="interlanguage-link-target"><span>Íslenska</span></a></li><li class="interlanguage-link interwiki-it mw-list-item"><a href="https://it.wikipedia.org/wiki/Briglia_(opera_idraulica)" title="Briglia (opera idraulica) – Italian" lang="it" hreflang="it" data-title="Briglia (opera idraulica)" data-language-autonym="Italiano" data-language-local-name="Italian" class="interlanguage-link-target"><span>Italiano</span></a></li><li class="interlanguage-link interwiki-jv mw-list-item"><a href="https://jv.wikipedia.org/wiki/Bendung" title="Bendung – Javanese" lang="jv" hreflang="jv" data-title="Bendung" data-language-autonym="Jawa" data-language-local-name="Javanese" class="interlanguage-link-target"><span>Jawa</span></a></li><li class="interlanguage-link interwiki-ms mw-list-item"><a href="https://ms.wikipedia.org/wiki/Bendung" title="Bendung – Malay" lang="ms" hreflang="ms" data-title="Bendung" data-language-autonym="Bahasa Melayu" data-language-local-name="Malay" class="interlanguage-link-target"><span>Bahasa Melayu</span></a></li><li class="interlanguage-link interwiki-nl mw-list-item"><a href="https://nl.wikipedia.org/wiki/Stuw" title="Stuw – Dutch" lang="nl" hreflang="nl" data-title="Stuw" data-language-autonym="Nederlands" data-language-local-name="Dutch" class="interlanguage-link-target"><span>Nederlands</span></a></li><li class="interlanguage-link interwiki-ja mw-list-item"><a href="https://ja.wikipedia.org/wiki/%E5%A0%B0" title="堰 – Japanese" lang="ja" hreflang="ja" data-title="堰" data-language-autonym="日本語" data-language-local-name="Japanese" class="interlanguage-link-target"><span>日本語</span></a></li><li class="interlanguage-link interwiki-pl mw-list-item"><a href="https://pl.wikipedia.org/wiki/Jaz" title="Jaz – Polish" lang="pl" hreflang="pl" data-title="Jaz" data-language-autonym="Polski" data-language-local-name="Polish" class="interlanguage-link-target"><span>Polski</span></a></li><li class="interlanguage-link interwiki-ru mw-list-item"><a href="https://ru.wikipedia.org/wiki/%D0%92%D0%BE%D0%B4%D0%BE%D1%81%D0%BB%D0%B8%D0%B2" title="Водослив – Russian" lang="ru" hreflang="ru" data-title="Водослив" data-language-autonym="Русский" data-language-local-name="Russian" class="interlanguage-link-target"><span>Русский</span></a></li><li class="interlanguage-link interwiki-simple mw-list-item"><a href="https://simple.wikipedia.org/wiki/Weir" title="Weir – Simple English" lang="en-simple" hreflang="en-simple" data-title="Weir" data-language-autonym="Simple English" data-language-local-name="Simple English" class="interlanguage-link-target"><span>Simple English</span></a></li><li class="interlanguage-link interwiki-sv mw-list-item"><a href="https://sv.wikipedia.org/wiki/%C3%96verfallsv%C3%A4rn" title="Överfallsvärn – Swedish" lang="sv" hreflang="sv" data-title="Överfallsvärn" data-language-autonym="Svenska" data-language-local-name="Swedish" class="interlanguage-link-target"><span>Svenska</span></a></li><li class="interlanguage-link interwiki-ta mw-list-item"><a href="https://ta.wikipedia.org/wiki/%E0%AE%95%E0%AE%B2%E0%AE%BF%E0%AE%99%E0%AF%8D%E0%AE%95%E0%AF%81" title="கலிங்கு – Tamil" lang="ta" hreflang="ta" data-title="கலிங்கு" data-language-autonym="தமிழ்" data-language-local-name="Tamil" class="interlanguage-link-target"><span>தமிழ்</span></a></li><li class="interlanguage-link interwiki-th mw-list-item"><a href="https://th.wikipedia.org/wiki/%E0%B8%9D%E0%B8%B2%E0%B8%A2" title="ฝาย – Thai" lang="th" hreflang="th" data-title="ฝาย" data-language-autonym="ไทย" data-language-local-name="Thai" class="interlanguage-link-target"><span>ไทย</span></a></li><li class="interlanguage-link interwiki-tr mw-list-item"><a href="https://tr.wikipedia.org/wiki/Su_bendi" title="Su bendi – Turkish" lang="tr" hreflang="tr" data-title="Su bendi" data-language-autonym="Türkçe" data-language-local-name="Turkish" class="interlanguage-link-target"><span>Türkçe</span></a></li><li class="interlanguage-link interwiki-uk mw-list-item"><a href="https://uk.wikipedia.org/wiki/%D0%92%D0%BE%D0%B4%D0%BE%D0%B7%D0%BB%D0%B8%D0%B2" title="Водозлив – Ukrainian" lang="uk" hreflang="uk" data-title="Водозлив" data-language-autonym="Українська" data-language-local-name="Ukrainian" class="interlanguage-link-target"><span>Українська</span></a></li><li class="interlanguage-link interwiki-zh mw-list-item"><a href="https://zh.wikipedia.org/wiki/%E5%A0%B0" title="堰 – Chinese" lang="zh" hreflang="zh" data-title="堰" data-language-autonym="中文" data-language-local-name="Chinese" class="interlanguage-link-target"><span>中文</span></a></li> </ul> <div class="after-portlet after-portlet-lang"><span class="wb-langlinks-edit wb-langlinks-link"><a href="https://www.wikidata.org/wiki/Special:EntityPage/Q1066997#sitelinks-wikipedia" title="Edit interlanguage links" class="wbc-editpage">Edit links</a></span></div> </div> </div> </div> </header> <div class="vector-page-toolbar"> <div class="vector-page-toolbar-container"> <div id="left-navigation"> <nav aria-label="Namespaces"> <div id="p-associated-pages" class="vector-menu vector-menu-tabs mw-portlet mw-portlet-associated-pages" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="ca-nstab-main" class="selected vector-tab-noicon mw-list-item"><a href="/wiki/Weir" title="View the content page [c]" accesskey="c"><span>Article</span></a></li><li id="ca-talk" class="vector-tab-noicon mw-list-item"><a href="/wiki/Talk:Weir" rel="discussion" title="Discuss 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searchaux" style="display:none">Artificial river barrier</div> <style data-mw-deduplicate="TemplateStyles:r1236090951">.mw-parser-output .hatnote{font-style:italic}.mw-parser-output div.hatnote{padding-left:1.6em;margin-bottom:0.5em}.mw-parser-output .hatnote i{font-style:normal}.mw-parser-output .hatnote+link+.hatnote{margin-top:-0.5em}@media print{body.ns-0 .mw-parser-output .hatnote{display:none!important}}</style><div role="note" class="hatnote navigation-not-searchable">For other uses, see <a href="/wiki/Weir_(disambiguation)" class="mw-disambig" title="Weir (disambiguation)">Weir (disambiguation)</a>.</div> <figure class="mw-default-size mw-halign-right" typeof="mw:File/Thumb"><a href="/wiki/File:Humber_Weir.JPG" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/en/thumb/6/63/Humber_Weir.JPG/220px-Humber_Weir.JPG" decoding="async" width="220" height="146" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/6/63/Humber_Weir.JPG/330px-Humber_Weir.JPG 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/6/63/Humber_Weir.JPG/440px-Humber_Weir.JPG 2x" data-file-width="4288" data-file-height="2848" /></a><figcaption>A weir on the Humber River near <a href="/wiki/Raymore_Park" class="mw-redirect" title="Raymore Park">Raymore Park</a> in Toronto, Ontario, Canada</figcaption></figure> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Culverts_under_yass_river_walkway_weir.JPG" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/e/e4/Culverts_under_yass_river_walkway_weir.JPG/220px-Culverts_under_yass_river_walkway_weir.JPG" decoding="async" width="220" height="165" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/e/e4/Culverts_under_yass_river_walkway_weir.JPG/330px-Culverts_under_yass_river_walkway_weir.JPG 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/e/e4/Culverts_under_yass_river_walkway_weir.JPG/440px-Culverts_under_yass_river_walkway_weir.JPG 2x" data-file-width="4608" data-file-height="3456" /></a><figcaption>A weir on the <a href="/wiki/Yass_River" title="Yass River">Yass River</a>, New South Wales, Australia, directly upstream from a shared pedestrian-bicycle <a href="/wiki/Low_water_crossing" class="mw-redirect" title="Low water crossing">river crossing</a></figcaption></figure> <figure class="mw-default-size mw-halign-right" typeof="mw:File/Thumb"><a href="/wiki/File:Tikkurilankoski_in_April.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/3/37/Tikkurilankoski_in_April.jpg/220px-Tikkurilankoski_in_April.jpg" decoding="async" width="220" height="164" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/3/37/Tikkurilankoski_in_April.jpg/330px-Tikkurilankoski_in_April.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/3/37/Tikkurilankoski_in_April.jpg/440px-Tikkurilankoski_in_April.jpg 2x" data-file-width="3556" data-file-height="2644" /></a><figcaption>A weir on the Tikkurilankoski rapids in <a href="/wiki/Vantaa" title="Vantaa">Vantaa</a>, Finland</figcaption></figure> <figure class="mw-default-size" typeof="mw:File/Thumb"><span><video id="mwe_player_0" poster="//upload.wikimedia.org/wikipedia/commons/thumb/2/20/Tilting_weir_installation_-_Gwent_Levels.webm/220px--Tilting_weir_installation_-_Gwent_Levels.webm.jpg" controls="" preload="none" data-mw-tmh="" class="mw-file-element" width="220" height="124" data-durationhint="45" data-mwtitle="Tilting_weir_installation_-_Gwent_Levels.webm" data-mwprovider="wikimediacommons" resource="/wiki/File:Tilting_weir_installation_-_Gwent_Levels.webm"><source src="//upload.wikimedia.org/wikipedia/commons/2/20/Tilting_weir_installation_-_Gwent_Levels.webm" type="video/webm; codecs="vp8, vorbis"" data-width="640" data-height="360" /><source src="//upload.wikimedia.org/wikipedia/commons/transcoded/2/20/Tilting_weir_installation_-_Gwent_Levels.webm/Tilting_weir_installation_-_Gwent_Levels.webm.360p.vp9.webm" type="video/webm; codecs="vp9, opus"" data-transcodekey="360p.vp9.webm" data-width="640" data-height="360" /><source src="//upload.wikimedia.org/wikipedia/commons/transcoded/2/20/Tilting_weir_installation_-_Gwent_Levels.webm/Tilting_weir_installation_-_Gwent_Levels.webm.360p.webm" type="video/webm; codecs="vp8, vorbis"" data-transcodekey="360p.webm" data-width="640" data-height="360" /><source src="//upload.wikimedia.org/wikipedia/commons/transcoded/2/20/Tilting_weir_installation_-_Gwent_Levels.webm/Tilting_weir_installation_-_Gwent_Levels.webm.240p.vp9.webm" type="video/webm; codecs="vp9, opus"" data-transcodekey="240p.vp9.webm" data-width="426" data-height="240" /></video></span><figcaption>Time-lapse video of a new tilting weir being installed in the <a href="/wiki/Caldicot_and_Wentloog_Levels" title="Caldicot and Wentloog Levels">Caldicot and Wentloog Levels</a></figcaption></figure> <p>A <b>weir</b> <span class="rt-commentedText nowrap"><span class="IPA nopopups noexcerpt" lang="en-fonipa"><a href="/wiki/Help:IPA/English" title="Help:IPA/English">/<span style="border-bottom:1px dotted"><span title="'w' in 'wind'">w</span><span title="/ɪər/: 'ear' in 'near'">ɪər</span></span>/</a></span></span> or <b>low-head dam</b> is a barrier across the width of a river that alters the flow characteristics of water and usually results in a change in the height of the <a href="/wiki/Water_level" title="Water level">water level</a>. Weirs are also used to control the flow of water for outlets of lakes, ponds, and reservoirs. There are many weir designs, but commonly water flows freely over the top of the weir crest before cascading down to a lower level. There is no single definition as to what constitutes a weir. </p><p><i>Weir</i> can also refer to the skimmer found in most in-ground swimming pools, which controls the flow of water pulled into the filtering system. </p> <meta property="mw:PageProp/toc" /> <div class="mw-heading mw-heading2"><h2 id="Etymology">Etymology</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Weir&action=edit&section=1" title="Edit section: Etymology"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The word likely originated from Middle English <i>were</i>, Old English <i>wer</i>, a derivative of the root of the verb <i>werian,</i> meaning "to defend, dam".<sup id="cite_ref-1" class="reference"><a href="#cite_note-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-2" class="reference"><a href="#cite_note-2"><span class="cite-bracket">[</span>2<span class="cite-bracket">]</span></a></sup> The German cognate is <i>Wehr</i>, which means the same as English weir. </p> <div class="mw-heading mw-heading2"><h2 id="Function">Function</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Weir&action=edit&section=2" title="Edit section: Function"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Thorp_Gristmill_Weir.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/d/df/Thorp_Gristmill_Weir.jpg/250px-Thorp_Gristmill_Weir.jpg" decoding="async" width="220" height="308" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/d/df/Thorp_Gristmill_Weir.jpg/330px-Thorp_Gristmill_Weir.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/d/df/Thorp_Gristmill_Weir.jpg/500px-Thorp_Gristmill_Weir.jpg 2x" data-file-width="2000" data-file-height="2800" /></a><figcaption>The broad crested weir at the Thorp grist mill in <a href="/wiki/Thorp,_Washington" title="Thorp, Washington">Thorp, Washington</a>, US</figcaption></figure> <p>Commonly, weirs are used to prevent <a href="/wiki/Flooding" class="mw-redirect" title="Flooding">flooding</a>, measure water discharge, and help render rivers more <a href="/wiki/Navigability" title="Navigability">navigable</a> by boat. In some locations, the terms <a href="/wiki/Dam" title="Dam">dam</a> and weir are synonymous, but normally there is a clear distinction made between the structures. Usually, a dam is designed specifically to impound water behind a wall, whilst a weir is designed to alter the river flow characteristics. </p><p>A common distinction between dams and weirs is that water flows over the top (crest) of a weir or underneath it for at least some of its length. Accordingly, the crest of an overflow <a href="/wiki/Spillway" title="Spillway">spillway</a> on a large dam may therefore be referred to as a weir. Weirs can vary in size both horizontally and vertically, with the smallest being only a few centimetres in height whilst the largest may be many metres tall and hundreds of metres long. Some common weir purposes are outlined below. </p> <div class="mw-heading mw-heading3"><h3 id="Flow_measurement">Flow measurement</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Weir&action=edit&section=3" title="Edit section: Flow measurement"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Weirs allow <a href="/wiki/Hydrology" title="Hydrology">hydrologists</a> and engineers a simple method of measuring the <a href="/wiki/Volumetric_flow_rate" title="Volumetric flow rate">volumetric flow rate</a> in small to medium-sized streams/rivers or in industrial discharge locations. Since the geometry of the top of the weir is known and all water flows over the weir, the depth of water behind the weir can be converted to a rate of flow. However, this can only be achieved in locations where all water flows over the top of the weir crest (as opposed to around the sides or through conduits or sluices) and at locations where the water that flows over the crest is carried away from the structure. If these conditions are not met, it can make flow measurement complicated, inaccurate, or even impossible. </p><p>The discharge calculation can be summarised as </p> <dl><dd><span class="texhtml"><var style="padding-right: 1px;">Q</var> = <var style="padding-right: 1px;">C</var><var style="padding-right: 1px;">L</var><var style="padding-right: 1px;">H</var><sup><var style="padding-right: 1px;">n</var></sup></span></dd></dl> <p>where </p> <dl><dd><span class="texhtml"><var style="padding-right: 1px;">Q</var></span> is the <a href="/wiki/Volumetric_flow_rate" title="Volumetric flow rate">volumetric flow rate</a> of fluid (the <a href="/wiki/Discharge_(hydrology)" title="Discharge (hydrology)">discharge</a>),</dd> <dd><span class="texhtml"><var style="padding-right: 1px;">C</var></span> is the <a href="/wiki/Flow_coefficient" title="Flow coefficient">flow coefficient</a> for the structure (on average a figure of 3.33),</dd> <dd><span class="texhtml"><var style="padding-right: 1px;">L</var></span> is the width of the <a href="/wiki/Crest_(hydrology)" title="Crest (hydrology)">crest</a>,</dd> <dd><span class="texhtml"><var style="padding-right: 1px;">H</var></span> is the height of <a href="/wiki/Hydraulic_head" title="Hydraulic head">head</a> of water over the crest,</dd> <dd><span class="texhtml"><var style="padding-right: 1px;">n</var></span> varies with structure (e.g., <style data-mw-deduplicate="TemplateStyles:r1154941027">.mw-parser-output .frac{white-space:nowrap}.mw-parser-output .frac .num,.mw-parser-output .frac .den{font-size:80%;line-height:0;vertical-align:super}.mw-parser-output .frac .den{vertical-align:sub}.mw-parser-output .sr-only{border:0;clip:rect(0,0,0,0);clip-path:polygon(0px 0px,0px 0px,0px 0px);height:1px;margin:-1px;overflow:hidden;padding:0;position:absolute;width:1px}</style><span class="frac"><span class="num">3</span>⁄<span class="den">2</span></span> for horizontal weir, <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027" /><span class="frac"><span class="num">5</span>⁄<span class="den">2</span></span> for V-notch weir).</dd></dl> <p>However, this calculation is a generic relationship and specific calculations are available for the many different types of weir. Flow measurement weirs must be well maintained if they are to remain accurate.<sup id="cite_ref-3" class="reference"><a href="#cite_note-3"><span class="cite-bracket">[</span>3<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-Factors_affecting_weir_flow_measurement_accuracy_4-0" class="reference"><a href="#cite_note-Factors_affecting_weir_flow_measurement_accuracy-4"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading3"><h3 id="Flow_over_a_V-notch_weir">Flow over a V-notch weir</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Weir&action=edit&section=4" title="Edit section: Flow over a V-notch weir"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The flow over a V-notch weir (in ft<sup>3</sup>/s) is given by the Kindsvater–Shen equation:<sup id="cite_ref-FOOTNOTEShen1981B31Equ_6_5-0" class="reference"><a href="#cite_note-FOOTNOTEShen1981B31Equ_6-5"><span class="cite-bracket">[</span>5<span class="cite-bracket">]</span></a></sup> </p> <dl><dd><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle Q={\frac {8}{15}}{\sqrt {2g}}\,C_{e}\tan {\frac {\theta }{2}}(h+k)^{\frac {5}{2}},}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>Q</mi> <mo>=</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mn>8</mn> <mn>15</mn> </mfrac> </mrow> <mrow class="MJX-TeXAtom-ORD"> <msqrt> <mn>2</mn> <mi>g</mi> </msqrt> </mrow> <mspace width="thinmathspace"></mspace> <msub> <mi>C</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>e</mi> </mrow> </msub> <mi>tan</mi> <mo>⁡</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mi>θ</mi> <mn>2</mn> </mfrac> </mrow> <mo stretchy="false">(</mo> <mi>h</mi> <mo>+</mo> <mi>k</mi> <msup> <mo stretchy="false">)</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mn>5</mn> <mn>2</mn> </mfrac> </mrow> </msup> <mo>,</mo> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle Q={\frac {8}{15}}{\sqrt {2g}}\,C_{e}\tan {\frac {\theta }{2}}(h+k)^{\frac {5}{2}},}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/1da2320a6517efcf4ecf943a373f4aa482d7a640" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -1.838ex; width:31.462ex; height:5.343ex;" alt="{\displaystyle Q={\frac {8}{15}}{\sqrt {2g}}\,C_{e}\tan {\frac {\theta }{2}}(h+k)^{\frac {5}{2}},}" /></span></dd></dl> <p>where </p> <dl><dd><i>Q</i> is the <a href="/wiki/Volumetric_flow_rate" title="Volumetric flow rate">volumetric flow rate</a> of fluid in ft<sup>3</sup>/s,</dd> <dd><i>g</i> is the acceleration due to gravity in ft/s<sup>2</sup>,</dd> <dd><i>C<sub>e</sub></i> is the flow correction factor given in <a href="#CITEREFShen1981">Shen 1981</a>, p. B29, Fig. 12,</dd> <dd><i>θ</i> is the angle of the V-notch weir,</dd> <dd><i>h</i> is the height of the fluid above the bottom of the V-notch,</dd> <dd><i>k</i> is the head correction factor given in <a href="#CITEREFShen1981">Shen 1981</a>, p. B20, Fig 4.</dd></dl> <div class="mw-heading mw-heading3"><h3 id="Control_of_invasive_species">Control of invasive species</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Weir&action=edit&section=5" title="Edit section: Control of invasive species"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>As weirs are a physical barrier, they can impede the longitudinal movement of fish and other animals up and down a river. This can have a negative effect on fish species that migrate as part of their breeding cycle (e.g., <a href="/wiki/Salmonids" class="mw-redirect" title="Salmonids">salmonids</a>), but it also can be useful as a method of preventing <a href="/wiki/Invasive_species" title="Invasive species">invasive species</a> moving upstream. For example, weirs in the <a href="/wiki/Great_Lakes" title="Great Lakes">Great Lakes</a> region have helped to prevent invasive <a href="/wiki/Sea_lamprey" title="Sea lamprey">sea lamprey</a> from colonising farther upstream. </p> <div class="mw-heading mw-heading3"><h3 id="Watermills">Watermills</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Weir&action=edit&section=6" title="Edit section: Watermills"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p><a href="/wiki/Mill_pond" title="Mill pond">Mill ponds</a> are created by a weir that impounds water that then flows over the structure. The energy created by the change in height of the water can then be used to power waterwheels and power sawmills, grinding wheels, and other equipment. </p> <div class="mw-heading mw-heading3"><h3 id="Flood_control_and_altering_river_conditions">Flood control and altering river conditions</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Weir&action=edit&section=7" title="Edit section: Flood control and altering river conditions"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951" /><div role="note" class="hatnote navigation-not-searchable">See also: <a href="/wiki/Floodgate" title="Floodgate">Floodgate</a></div> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Weir_at_Bray_Lock,_May_2018.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/6/68/Weir_at_Bray_Lock%2C_May_2018.jpg/220px-Weir_at_Bray_Lock%2C_May_2018.jpg" decoding="async" width="220" height="165" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/6/68/Weir_at_Bray_Lock%2C_May_2018.jpg/330px-Weir_at_Bray_Lock%2C_May_2018.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/6/68/Weir_at_Bray_Lock%2C_May_2018.jpg/440px-Weir_at_Bray_Lock%2C_May_2018.jpg 2x" data-file-width="3264" data-file-height="2448" /></a><figcaption>A sluice gate-based weir at <a href="/wiki/Bray_Lock" title="Bray Lock">Bray Lock</a> on the <a href="/wiki/River_Thames" title="River Thames">River Thames</a>, facing downstream. In the background is the smaller secondary "overspill" weir. Two small boats are also visible held against the overspill weir, having been washed against it during a particularly high discharge as a result of meltwater and subsequent rainfall following the <a href="/wiki/2018_Great_Britain_and_Ireland_cold_wave" class="mw-redirect" title="2018 Great Britain and Ireland cold wave">2018 winter cold wave.</a></figcaption></figure> <p>Weirs are commonly used to control the flow rates of rivers during periods of high discharge. <a href="/wiki/Sluice_gates" class="mw-redirect" title="Sluice gates">Sluice gates</a> (or in some cases the height of the weir crest) can be altered to increase or decrease the volume of water flowing downstream. Weirs for this purpose are commonly found upstream of towns and villages and can either be automated or manually operated. By slowing the rate at which water moves downstream even slightly, a disproportionate effect can be had on the likelihood of flooding. On larger rivers, a weir can also alter the flow characteristics of the waterway to the point that vessels are able to navigate areas previously inaccessible due to extreme <a href="/wiki/Current_(fluid)" title="Current (fluid)">currents</a> or <a href="/wiki/Eddies" class="mw-redirect" title="Eddies">eddies</a>. Many larger weirs will have construction features that allow boats and river users to "shoot the weir" and navigate by passing up or down stream without having to exit the river. Weirs constructed for this purpose are especially common on the <a href="/wiki/River_Thames" title="River Thames">River Thames</a>, and most are situated near each of the river's 45 <a href="/wiki/Locks_and_weirs_on_the_River_Thames" title="Locks and weirs on the River Thames">locks</a>. </p> <div class="mw-heading mw-heading2"><h2 id="Issues">Issues</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Weir&action=edit&section=8" title="Edit section: Issues"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Grial%C3%ABces_cuecenes.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/b/bc/Grial%C3%ABces_cuecenes.jpg/220px-Grial%C3%ABces_cuecenes.jpg" decoding="async" width="220" height="147" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/b/bc/Grial%C3%ABces_cuecenes.jpg/330px-Grial%C3%ABces_cuecenes.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/b/bc/Grial%C3%ABces_cuecenes.jpg/440px-Grial%C3%ABces_cuecenes.jpg 2x" data-file-width="7360" data-file-height="4912" /></a><figcaption>During periods of high river flow, this nineteenth century weir of porphyry stone on a creek in the Alps would have significantly more water flowing over it.</figcaption></figure> <div class="mw-heading mw-heading3"><h3 id="Ecology">Ecology</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Weir&action=edit&section=9" title="Edit section: Ecology"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Because a weir impounds water behind it and alters the flow regime of the river, it can have an effect on the local <a href="/wiki/Ecology" title="Ecology">ecology</a>. Typically, the reduced river velocity upstream can lead to increased <a href="/wiki/Siltation" title="Siltation">siltation</a> (deposition of fine particles of <a href="/wiki/Silt" title="Silt">silt</a> and clay on the river bottom) that reduces the <a href="/wiki/Water_oxygenation" class="mw-redirect" title="Water oxygenation">water oxygen content</a> and smothers invertebrate habitat and fish <a href="/wiki/Spawning" title="Spawning">spawning</a> sites. The oxygen content typically returns to normal once water has passed over the weir crest (although it can be hyper-oxygenated), although increased river velocity can scour the river bed causing erosion and habitat loss. </p> <div class="mw-heading mw-heading3"><h3 id="Fish_migration">Fish migration</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Weir&action=edit&section=10" title="Edit section: Fish migration"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Weirs can have a significant effect on <a href="/wiki/Fish_migration" title="Fish migration">fish migration</a>.<sup id="cite_ref-FOOTNOTETummersWinterSilvaO’Brien2016183–194_6-0" class="reference"><a href="#cite_note-FOOTNOTETummersWinterSilvaO’Brien2016183–194-6"><span class="cite-bracket">[</span>6<span class="cite-bracket">]</span></a></sup> Any weir that exceeds either the maximum height a species can jump or creates flow conditions that cannot be bypassed (e.g., due to excessive water velocity) effectively limits the maximum point upstream that fish can migrate. In some cases this can mean that huge lengths of breeding habitat are lost, and over time this can have a significant impact on fish populations. </p><p>In many countries, it is now a legal requirement to build <a href="/wiki/Fish_ladder" title="Fish ladder">fish ladders</a> into the design of a weir that ensure that fish can bypass the barriers and access upstream habitats. Unlike dams, weirs do not usually prevent downstream fish migration (as water flows over the top and allows fish to bypass the structure in that water), although they can create flow conditions that injure juvenile fish. Recent studies suggest that navigation locks have also potential to provide increased access for a range of <a href="/wiki/Biota_(biology)" class="mw-redirect" title="Biota (biology)">biota</a>, including poor swimmers.<sup id="cite_ref-FOOTNOTESilvaLowryMacaya-SolisByatt2017291–302_7-0" class="reference"><a href="#cite_note-FOOTNOTESilvaLowryMacaya-SolisByatt2017291–302-7"><span class="cite-bracket">[</span>7<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading3"><h3 id="Safety">Safety</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Weir&action=edit&section=11" title="Edit section: Safety"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <figure class="mw-default-size" typeof="mw:File/Thumb"><span><video id="mwe_player_1" poster="//upload.wikimedia.org/wikipedia/commons/thumb/2/2c/Creature_Craft_rescue_boats_demonstration_for_low_head_dam_rescue_and_recovery.webm/220px--Creature_Craft_rescue_boats_demonstration_for_low_head_dam_rescue_and_recovery.webm.jpg" controls="" preload="none" data-mw-tmh="" class="mw-file-element" width="220" height="124" data-durationhint="593" data-mwtitle="Creature_Craft_rescue_boats_demonstration_for_low_head_dam_rescue_and_recovery.webm" data-mwprovider="wikimediacommons" resource="/wiki/File:Creature_Craft_rescue_boats_demonstration_for_low_head_dam_rescue_and_recovery.webm"><source src="//upload.wikimedia.org/wikipedia/commons/transcoded/2/2c/Creature_Craft_rescue_boats_demonstration_for_low_head_dam_rescue_and_recovery.webm/Creature_Craft_rescue_boats_demonstration_for_low_head_dam_rescue_and_recovery.webm.480p.vp9.webm" type="video/webm; codecs="vp9, opus"" data-transcodekey="480p.vp9.webm" data-width="854" data-height="480" /><source src="//upload.wikimedia.org/wikipedia/commons/transcoded/2/2c/Creature_Craft_rescue_boats_demonstration_for_low_head_dam_rescue_and_recovery.webm/Creature_Craft_rescue_boats_demonstration_for_low_head_dam_rescue_and_recovery.webm.720p.vp9.webm" type="video/webm; codecs="vp9, opus"" data-transcodekey="720p.vp9.webm" data-width="1280" data-height="720" /><source src="//upload.wikimedia.org/wikipedia/commons/2/2c/Creature_Craft_rescue_boats_demonstration_for_low_head_dam_rescue_and_recovery.webm" type="video/webm; codecs="vp9, opus"" data-width="1920" data-height="1080" /><source src="//upload.wikimedia.org/wikipedia/commons/transcoded/2/2c/Creature_Craft_rescue_boats_demonstration_for_low_head_dam_rescue_and_recovery.webm/Creature_Craft_rescue_boats_demonstration_for_low_head_dam_rescue_and_recovery.webm.1080p.vp9.webm" type="video/webm; codecs="vp9, opus"" data-transcodekey="1080p.vp9.webm" data-width="1920" data-height="1080" /><source src="//upload.wikimedia.org/wikipedia/commons/transcoded/2/2c/Creature_Craft_rescue_boats_demonstration_for_low_head_dam_rescue_and_recovery.webm/Creature_Craft_rescue_boats_demonstration_for_low_head_dam_rescue_and_recovery.webm.144p.mjpeg.mov" type="video/quicktime" data-transcodekey="144p.mjpeg.mov" data-width="256" data-height="144" /><source src="//upload.wikimedia.org/wikipedia/commons/transcoded/2/2c/Creature_Craft_rescue_boats_demonstration_for_low_head_dam_rescue_and_recovery.webm/Creature_Craft_rescue_boats_demonstration_for_low_head_dam_rescue_and_recovery.webm.240p.vp9.webm" type="video/webm; codecs="vp9, opus"" data-transcodekey="240p.vp9.webm" data-width="426" data-height="240" /><source src="//upload.wikimedia.org/wikipedia/commons/transcoded/2/2c/Creature_Craft_rescue_boats_demonstration_for_low_head_dam_rescue_and_recovery.webm/Creature_Craft_rescue_boats_demonstration_for_low_head_dam_rescue_and_recovery.webm.360p.vp9.webm" type="video/webm; codecs="vp9, opus"" data-transcodekey="360p.vp9.webm" data-width="640" data-height="360" /><source src="//upload.wikimedia.org/wikipedia/commons/transcoded/2/2c/Creature_Craft_rescue_boats_demonstration_for_low_head_dam_rescue_and_recovery.webm/Creature_Craft_rescue_boats_demonstration_for_low_head_dam_rescue_and_recovery.webm.360p.webm" type="video/webm; codecs="vp8, vorbis"" data-transcodekey="360p.webm" data-width="640" data-height="360" /></video></span><figcaption>Rescue boats designed for rescue and recovery from low head dams.</figcaption></figure> <p>Even though the water around weirs can often appear relatively calm, they can be extremely dangerous places to boat, swim, or wade, as the circulation patterns on the downstream side—typically called a <a href="/wiki/Hydraulic_jump" title="Hydraulic jump">hydraulic jump</a>—can submerge a person indefinitely. This phenomenon is so well known to canoeists, kayakers, and others who spend time on rivers that they even have a rueful name for weirs: "drowning machines".<sup id="cite_ref-8" class="reference"><a href="#cite_note-8"><span class="cite-bracket">[</span>8<span class="cite-bracket">]</span></a></sup> The Ohio DNR recommends that a victim should "tuck the chin down, draw the knees up to the chest with arms wrapped around them. Hopefully, conditions will be such that the current will push the victim along the bed of the river until swept beyond the boil line and released by the hydraulic."<sup id="cite_ref-9" class="reference"><a href="#cite_note-9"><span class="cite-bracket">[</span>9<span class="cite-bracket">]</span></a></sup> The Pennsylvania State Police also recommends to victims, "curl up, dive to the bottom, and swim or crawl downstream".<sup id="cite_ref-10" class="reference"><a href="#cite_note-10"><span class="cite-bracket">[</span>10<span class="cite-bracket">]</span></a></sup> As the hydraulic jump <a href="/wiki/Water_aeration" title="Water aeration">entrains air</a>, the buoyancy of the water between the dam and boil line will be reduced by upward of 30%, and if a victim is unable to float, escape at the base of the dam may be the only option for survival. </p> <div class="mw-heading mw-heading2"><h2 id="Common_types">Common types</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Weir&action=edit&section=12" title="Edit section: Common types"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>There are many different types of weirs and they can vary from a simple stone structure that is barely noticeable, to elaborate and very large structures that require extensive management and maintenance. </p> <ul class="gallery mw-gallery-traditional"> <li class="gallerybox" style="width: 235px"> <div class="thumb" style="width: 230px; height: 230px;"><span typeof="mw:File"><a href="/wiki/File:Dorset_sn_weir_01.jpg" class="mw-file-description" title="The bridge and weir mechanism at Sturminster Newton on the River Stour, Dorset, UK"><img alt="The bridge and weir mechanism at Sturminster Newton on the River Stour, Dorset, UK" src="//upload.wikimedia.org/wikipedia/commons/thumb/e/e0/Dorset_sn_weir_01.jpg/150px-Dorset_sn_weir_01.jpg" decoding="async" width="150" height="200" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/e/e0/Dorset_sn_weir_01.jpg/225px-Dorset_sn_weir_01.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/e/e0/Dorset_sn_weir_01.jpg/300px-Dorset_sn_weir_01.jpg 2x" data-file-width="600" data-file-height="800" /></a></span></div> <div class="gallerytext">The bridge and weir mechanism at <a href="/wiki/Sturminster_Newton" title="Sturminster Newton">Sturminster Newton</a> on the <a href="/wiki/River_Stour,_Dorset" title="River Stour, Dorset">River Stour</a>, <a href="/wiki/Dorset" title="Dorset">Dorset</a>, UK</div> </li> <li class="gallerybox" style="width: 235px"> <div class="thumb" style="width: 230px; height: 230px;"><span typeof="mw:File"><a href="/wiki/File:Weir_on_the_river_wear.png" class="mw-file-description" title="Two weirs on the River Wear in Durham, UK: the lower weir is a compound weir that also has fish ladders to allow fish such as salmon to navigate the weir"><img alt="Two weirs on the River Wear in Durham, UK: the lower weir is a compound weir that also has fish ladders to allow fish such as salmon to navigate the weir" src="//upload.wikimedia.org/wikipedia/commons/thumb/2/20/Weir_on_the_river_wear.png/200px-Weir_on_the_river_wear.png" decoding="async" width="200" height="67" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/2/20/Weir_on_the_river_wear.png/300px-Weir_on_the_river_wear.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/2/20/Weir_on_the_river_wear.png/400px-Weir_on_the_river_wear.png 2x" data-file-width="1543" data-file-height="519" /></a></span></div> <div class="gallerytext">Two weirs on the <a href="/wiki/River_Wear" title="River Wear">River Wear</a> in <a href="/wiki/Durham,_England" title="Durham, England">Durham</a>, UK: the lower weir is a compound weir that also has <a href="/wiki/Fish_ladders" class="mw-redirect" title="Fish ladders">fish ladders</a> to allow fish such as salmon to navigate the weir</div> </li> <li class="gallerybox" style="width: 235px"> <div class="thumb" style="width: 230px; height: 230px;"><span typeof="mw:File"><a href="/wiki/File:HambleLock02.JPG" class="mw-file-description" title="The weir at Hambleden Lock on the River Thames at Hambleden, Buckinghamshire. A broad-crest weir, the public has right of way to cross the river using its walkway."><img alt="The weir at Hambleden Lock on the River Thames at Hambleden, Buckinghamshire. A broad-crest weir, the public has right of way to cross the river using its walkway." src="//upload.wikimedia.org/wikipedia/commons/thumb/2/2d/HambleLock02.JPG/200px-HambleLock02.JPG" decoding="async" width="200" height="150" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/2/2d/HambleLock02.JPG/300px-HambleLock02.JPG 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/2/2d/HambleLock02.JPG/400px-HambleLock02.JPG 2x" data-file-width="2048" data-file-height="1536" /></a></span></div> <div class="gallerytext">The weir at <a href="/wiki/Hambleden_Lock" title="Hambleden Lock">Hambleden Lock</a> on the <a href="/wiki/River_Thames" title="River Thames">River Thames</a> at <a href="/wiki/Hambleden" title="Hambleden">Hambleden</a>, <a href="/wiki/Buckinghamshire" title="Buckinghamshire">Buckinghamshire</a>. A broad-crest weir, the public has <a href="/wiki/Right_of_way_(transit)" class="mw-redirect" title="Right of way (transit)">right of way</a> to cross the river using its walkway.</div> </li> <li class="gallerybox" style="width: 235px"> <div class="thumb" style="width: 230px; height: 230px;"><span typeof="mw:File"><a href="/wiki/File:Revin_Meuse_weir_20041230-_024.jpg" class="mw-file-description" title="A manually operated needle dam-type weir near Revin on the River Meuse, France"><img alt="A manually operated needle dam-type weir near Revin on the River Meuse, France" src="//upload.wikimedia.org/wikipedia/commons/thumb/7/72/Revin_Meuse_weir_20041230-_024.jpg/200px-Revin_Meuse_weir_20041230-_024.jpg" decoding="async" width="200" height="150" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/7/72/Revin_Meuse_weir_20041230-_024.jpg/300px-Revin_Meuse_weir_20041230-_024.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/7/72/Revin_Meuse_weir_20041230-_024.jpg/400px-Revin_Meuse_weir_20041230-_024.jpg 2x" data-file-width="1024" data-file-height="768" /></a></span></div> <div class="gallerytext">A manually operated <a href="/wiki/Needle_dam" title="Needle dam">needle dam</a>-type weir near Revin on the <a href="/wiki/Meuse_(river)" class="mw-redirect" title="Meuse (river)">River Meuse</a>, France</div> </li> <li class="gallerybox" style="width: 235px"> <div class="thumb" style="width: 230px; height: 230px;"><span typeof="mw:File"><a href="/wiki/File:WarkworthweirSeuilNewZealand.jpg" class="mw-file-description" title="A broad-crest weir in Warkworth, New Zealand"><img alt="A broad-crest weir in Warkworth, New Zealand" src="//upload.wikimedia.org/wikipedia/commons/thumb/2/2d/WarkworthweirSeuilNewZealand.jpg/250px-WarkworthweirSeuilNewZealand.jpg" decoding="async" width="150" height="200" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/2/2d/WarkworthweirSeuilNewZealand.jpg/330px-WarkworthweirSeuilNewZealand.jpg 2x" data-file-width="1728" data-file-height="2304" /></a></span></div> <div class="gallerytext">A broad-crest weir in <a href="/wiki/Warkworth,_New_Zealand" title="Warkworth, New Zealand">Warkworth</a>, New Zealand</div> </li> <li class="gallerybox" style="width: 235px"> <div class="thumb" style="width: 230px; height: 230px;"><span typeof="mw:File"><a href="/wiki/File:Dobbsweirvdropsjan2006.jpg" class="mw-file-description" title="A complicated series of broad-crest and V-notch weirs at Dobbs Weir in Hertfordshire, UK"><img alt="A complicated series of broad-crest and V-notch weirs at Dobbs Weir in Hertfordshire, UK" src="//upload.wikimedia.org/wikipedia/commons/thumb/1/1d/Dobbsweirvdropsjan2006.jpg/250px-Dobbsweirvdropsjan2006.jpg" decoding="async" width="200" height="113" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/1/1d/Dobbsweirvdropsjan2006.jpg/330px-Dobbsweirvdropsjan2006.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/1/1d/Dobbsweirvdropsjan2006.jpg/500px-Dobbsweirvdropsjan2006.jpg 2x" data-file-width="3072" data-file-height="1728" /></a></span></div> <div class="gallerytext">A complicated series of broad-crest and V-notch weirs at <a href="/wiki/Dobbs_Weir" title="Dobbs Weir">Dobbs Weir</a> in <a href="/wiki/Hertfordshire" title="Hertfordshire">Hertfordshire</a>, UK</div> </li> </ul> <div class="mw-heading mw-heading3"><h3 id="Broad-crested">Broad-crested</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Weir&action=edit&section=13" title="Edit section: Broad-crested"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>A broad-crested weir is a flat-crested structure, where the water passes over a crest that covers much or all of the channel width. This is one of the most common types of weir found worldwide. </p> <div class="mw-heading mw-heading3"><h3 id="Compound">Compound</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Weir&action=edit&section=14" title="Edit section: Compound"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>A compound weir is any weir that comprises several different designs into one structure. They are commonly seen in locations where a river has multiple users who may need to bypass the structure. A common design would be one where a weir is broad-crested for much of its length, but has a section where the weir stops or is 'open' so that small boats and fish can traverse the structure. </p> <div class="mw-heading mw-heading3"><h3 id="V-notch">V-notch</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Weir&action=edit&section=15" title="Edit section: V-notch"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>A notch weir is any weir where the physical barrier is significantly higher than the water level except for a specific <a href="/wiki/Notch_(engineering)" title="Notch (engineering)">notch</a> (often V-shaped) cut into the panel. At times of normal flow all the water must pass through the notch, simplifying flow volume calculations, and at times of flood the water level can rise and submerge the weir without any alterations made to the structure. </p> <div class="mw-heading mw-heading3"><h3 id="Polynomial">Polynomial</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Weir&action=edit&section=16" title="Edit section: Polynomial"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>A polynomial weir is a weir that has a geometry defined by a <a href="/wiki/Polynomial_equation" class="mw-redirect" title="Polynomial equation">polynomial equation</a> of any order <i>n</i>.<sup id="cite_ref-FOOTNOTEBaddour2008260–262_11-0" class="reference"><a href="#cite_note-FOOTNOTEBaddour2008260–262-11"><span class="cite-bracket">[</span>11<span class="cite-bracket">]</span></a></sup> In practice, most weirs are low-order polynomial weirs. The standard rectangular weir is, for example, a polynomial weir of order zero. The triangular (V-notch) and <a href="/wiki/Trapezoid" title="Trapezoid">trapezoidal</a> weirs are of order one. High-order polynomial weirs are providing wider range of Head-Discharge relationships, and hence better control of the flow at outlets of lakes, ponds, and reservoirs. </p> <div class="mw-heading mw-heading2"><h2 id="See_also">See also</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Weir&action=edit&section=17" title="Edit section: See also"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li><a href="/wiki/Crump_weir" class="mw-redirect" title="Crump weir">Crump weir</a></li> <li><a href="/wiki/Drop_structure" title="Drop structure">Drop structure</a></li> <li><a href="/wiki/Fishing_weir" title="Fishing weir">Fishing weir</a></li> <li><a href="/wiki/Fixed-crest_dam" class="mw-redirect" title="Fixed-crest dam">Fixed-crest dam</a></li> <li><a href="/wiki/Flume" title="Flume">Flume</a></li> <li><a href="/wiki/International_Control_Dam" title="International Control Dam">International Control Dam</a></li></ul> <div class="mw-heading mw-heading2"><h2 id="References">References</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Weir&action=edit&section=18" title="Edit section: References"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <div class="mw-heading mw-heading3"><h3 id="Citations">Citations</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Weir&action=edit&section=19" title="Edit section: Citations"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1239543626">.mw-parser-output .reflist{margin-bottom:0.5em;list-style-type:decimal}@media screen{.mw-parser-output .reflist{font-size:90%}}.mw-parser-output .reflist .references{font-size:100%;margin-bottom:0;list-style-type:inherit}.mw-parser-output .reflist-columns-2{column-width:30em}.mw-parser-output .reflist-columns-3{column-width:25em}.mw-parser-output .reflist-columns{margin-top:0.3em}.mw-parser-output .reflist-columns ol{margin-top:0}.mw-parser-output .reflist-columns li{page-break-inside:avoid;break-inside:avoid-column}.mw-parser-output .reflist-upper-alpha{list-style-type:upper-alpha}.mw-parser-output .reflist-upper-roman{list-style-type:upper-roman}.mw-parser-output .reflist-lower-alpha{list-style-type:lower-alpha}.mw-parser-output .reflist-lower-greek{list-style-type:lower-greek}.mw-parser-output .reflist-lower-roman{list-style-type:lower-roman}</style><div class="reflist"> <div class="mw-references-wrap mw-references-columns"><ol class="references"> <li id="cite_note-1"><span class="mw-cite-backlink"><b><a href="#cite_ref-1">^</a></b></span> <span class="reference-text"><style data-mw-deduplicate="TemplateStyles:r1238218222">.mw-parser-output cite.citation{font-style:inherit;word-wrap:break-word}.mw-parser-output .citation q{quotes:"\"""\"""'""'"}.mw-parser-output .citation:target{background-color:rgba(0,127,255,0.133)}.mw-parser-output .id-lock-free.id-lock-free a{background:url("//upload.wikimedia.org/wikipedia/commons/6/65/Lock-green.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-limited.id-lock-limited a,.mw-parser-output .id-lock-registration.id-lock-registration a{background:url("//upload.wikimedia.org/wikipedia/commons/d/d6/Lock-gray-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-subscription.id-lock-subscription a{background:url("//upload.wikimedia.org/wikipedia/commons/a/aa/Lock-red-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .cs1-ws-icon a{background:url("//upload.wikimedia.org/wikipedia/commons/4/4c/Wikisource-logo.svg")right 0.1em center/12px no-repeat}body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-free a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-limited a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-registration a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-subscription a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .cs1-ws-icon a{background-size:contain;padding:0 1em 0 0}.mw-parser-output .cs1-code{color:inherit;background:inherit;border:none;padding:inherit}.mw-parser-output .cs1-hidden-error{display:none;color:var(--color-error,#d33)}.mw-parser-output .cs1-visible-error{color:var(--color-error,#d33)}.mw-parser-output .cs1-maint{display:none;color:#085;margin-left:0.3em}.mw-parser-output .cs1-kern-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right{padding-right:0.2em}.mw-parser-output .citation .mw-selflink{font-weight:inherit}@media screen{.mw-parser-output .cs1-format{font-size:95%}html.skin-theme-clientpref-night .mw-parser-output .cs1-maint{color:#18911f}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .cs1-maint{color:#18911f}}</style><cite class="citation web cs1"><a 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Retrieved <span class="nowrap">2017-03-03</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=Dictionary.com&rft.atitle=the+definition+of+weir&rft_id=http%3A%2F%2Fwww.dictionary.com%2Fbrowse%2Fweir&rfr_id=info%3Asid%2Fen.wikipedia.org%3AWeir" class="Z3988"></span></span> </li> <li id="cite_note-2"><span class="mw-cite-backlink"><b><a href="#cite_ref-2">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://www.etymonline.com/index.php?term=weir">"Weir"</a>. <i>www.etymonline.com</i>. Online Etymology Dictionary. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20170319204027/http://www.etymonline.com/index.php?term=weir">Archived</a> from the original on 19 March 2017<span class="reference-accessdate">. Retrieved <span class="nowrap">20 May</span> 2017</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=www.etymonline.com&rft.atitle=Weir&rft_id=http%3A%2F%2Fwww.etymonline.com%2Findex.php%3Fterm%3Dweir&rfr_id=info%3Asid%2Fen.wikipedia.org%3AWeir" class="Z3988"></span></span> </li> <li id="cite_note-3"><span class="mw-cite-backlink"><b><a href="#cite_ref-3">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://www.engineeringtoolbox.com/weirs-flow-rate-d_592.html">"Weirs – Flow Rate Measure"</a>. <i>www.engineeringtoolbox.com</i>. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20170304035718/http://www.engineeringtoolbox.com/weirs-flow-rate-d_592.html">Archived</a> from the original on 2017-03-04<span class="reference-accessdate">. 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Retrieved <span class="nowrap">2 May</span> 2018</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=openchannelflow.com&rft.atitle=Factors+affecting+weir+flow+measurement+accuracy&rft_id=http%3A%2F%2Fwww.openchannelflow.com%2Fproducts%2Fweirs%2Fflow-characteristics%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3AWeir" class="Z3988"></span></span> </li> <li id="cite_note-FOOTNOTEShen1981B31Equ_6-5"><span class="mw-cite-backlink"><b><a href="#cite_ref-FOOTNOTEShen1981B31Equ_6_5-0">^</a></b></span> <span class="reference-text"><a href="#CITEREFShen1981">Shen 1981</a>, p. B31, Equ 6.</span> </li> <li id="cite_note-FOOTNOTETummersWinterSilvaO’Brien2016183–194-6"><span class="mw-cite-backlink"><b><a href="#cite_ref-FOOTNOTETummersWinterSilvaO’Brien2016183–194_6-0">^</a></b></span> <span class="reference-text"><a href="#CITEREFTummersWinterSilvaO’Brien2016">Tummers et al. 2016</a>, pp. 183–194.</span> </li> <li id="cite_note-FOOTNOTESilvaLowryMacaya-SolisByatt2017291–302-7"><span class="mw-cite-backlink"><b><a href="#cite_ref-FOOTNOTESilvaLowryMacaya-SolisByatt2017291–302_7-0">^</a></b></span> <span class="reference-text"><a href="#CITEREFSilvaLowryMacaya-SolisByatt2017">Silva et al. 2017</a>, pp. 291–302.</span> </li> <li id="cite_note-8"><span class="mw-cite-backlink"><b><a href="#cite_ref-8">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite id="CITEREFMichael_RobinsonRobert_Houghtalen" class="citation news cs1">Michael Robinson; Robert Houghtalen. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20100812233126/http://www.ricka-flatwater.org/dams.htm">"Dangerous dams"</a>. <i>Rhode Island Canoe/Kayak Association</i>. Rhode Island. Archived from <a rel="nofollow" class="external text" href="http://www.ricka-flatwater.org/dams.htm">the original</a> on 2010-08-12<span class="reference-accessdate">. Retrieved <span class="nowrap">2011-06-26</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Rhode+Island+Canoe%2FKayak+Association&rft.atitle=Dangerous+dams&rft.au=Michael+Robinson&rft.au=Robert+Houghtalen&rft_id=http%3A%2F%2Fwww.ricka-flatwater.org%2Fdams.htm&rfr_id=info%3Asid%2Fen.wikipedia.org%3AWeir" class="Z3988"></span></span> </li> <li id="cite_note-9"><span class="mw-cite-backlink"><b><a href="#cite_ref-9">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite id="CITEREFOhio_DNR_Division_of_Parks_and_Watercraft_Boating" class="citation web cs1">Ohio DNR Division of Parks and Watercraft Boating. <a rel="nofollow" class="external text" href="http://watercraft.ohiodnr.gov/lowheaddams">"Lowhead Dam Safety"</a>. watercraft.ohiodnr.gov. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20161130105322/http://watercraft.ohiodnr.gov/lowheaddams">Archived</a> from the original on 30 November 2016<span class="reference-accessdate">. Retrieved <span class="nowrap">2 May</span> 2018</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Lowhead+Dam+Safety&rft.pub=watercraft.ohiodnr.gov&rft.au=Ohio+DNR+Division+of+Parks+and+Watercraft+Boating&rft_id=http%3A%2F%2Fwatercraft.ohiodnr.gov%2Flowheaddams&rfr_id=info%3Asid%2Fen.wikipedia.org%3AWeir" class="Z3988"></span></span> </li> <li id="cite_note-10"><span class="mw-cite-backlink"><b><a href="#cite_ref-10">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://www.post-gazette.com/.media/2/2017/05/23/27754452-e17c-469d-923e-cb4851d248db.jpg">"Archived copy"</a>. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20180502185106/http://www.post-gazette.com/.media/2/2017/05/23/27754452-e17c-469d-923e-cb4851d248db.jpg">Archived</a> from the original on 2018-05-02<span class="reference-accessdate">. Retrieved <span class="nowrap">2017-06-15</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Archived+copy&rft_id=http%3A%2F%2Fwww.post-gazette.com%2F.media%2F2%2F2017%2F05%2F23%2F27754452-e17c-469d-923e-cb4851d248db.jpg&rfr_id=info%3Asid%2Fen.wikipedia.org%3AWeir" class="Z3988"></span><span class="cs1-maint citation-comment"><code class="cs1-code">{{<a href="/wiki/Template:Cite_web" title="Template:Cite web">cite web</a>}}</code>: CS1 maint: archived copy as title (<a href="/wiki/Category:CS1_maint:_archived_copy_as_title" title="Category:CS1 maint: archived copy as title">link</a>)</span> Escaping a low-head dam</span> </li> <li id="cite_note-FOOTNOTEBaddour2008260–262-11"><span class="mw-cite-backlink"><b><a href="#cite_ref-FOOTNOTEBaddour2008260–262_11-0">^</a></b></span> <span class="reference-text"><a href="#CITEREFBaddour2008">Baddour 2008</a>, pp. 260–262.</span> </li> </ol></div></div> <div class="mw-heading mw-heading3"><h3 id="Works_cited">Works cited</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Weir&action=edit&section=20" title="Edit section: Works cited"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1239549316">.mw-parser-output .refbegin{margin-bottom:0.5em}.mw-parser-output .refbegin-hanging-indents>ul{margin-left:0}.mw-parser-output .refbegin-hanging-indents>ul>li{margin-left:0;padding-left:3.2em;text-indent:-3.2em}.mw-parser-output .refbegin-hanging-indents ul,.mw-parser-output .refbegin-hanging-indents ul li{list-style:none}@media(max-width:720px){.mw-parser-output .refbegin-hanging-indents>ul>li{padding-left:1.6em;text-indent:-1.6em}}.mw-parser-output .refbegin-columns{margin-top:0.3em}.mw-parser-output .refbegin-columns ul{margin-top:0}.mw-parser-output .refbegin-columns li{page-break-inside:avoid;break-inside:avoid-column}@media screen{.mw-parser-output .refbegin{font-size:90%}}</style><div class="refbegin refbegin-hanging-indents" style=""> <ul><li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite id="CITEREFAkers1978" class="citation book cs1">Akers, Peter (1978). <span class="id-lock-registration" title="Free registration required"><a rel="nofollow" class="external text" href="https://archive.org/details/weirsflumesforfl0000unse"><i>Weirs and Flumes for Flow Measurement</i></a></span>. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0471996378" title="Special:BookSources/978-0471996378"><bdi>978-0471996378</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Weirs+and+Flumes+for+Flow+Measurement&rft.date=1978&rft.isbn=978-0471996378&rft.aulast=Akers&rft.aufirst=Peter&rft_id=https%3A%2F%2Farchive.org%2Fdetails%2Fweirsflumesforfl0000unse&rfr_id=info%3Asid%2Fen.wikipedia.org%3AWeir" class="Z3988"></span></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite id="CITEREFBaddour2008" class="citation journal cs1">Baddour, Raouf E. (2008). "Head-Discharge Equation for Sharp-Crested Polynomial Weir". <i>Journal of Irrigation and Drainage Engineering</i>. <b>134</b> (2): <span class="nowrap">260–</span>262. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1061%2F%28ASCE%290733-9437%282008%29134%3A2%28260%29">10.1061/(ASCE)0733-9437(2008)134:2(260)</a>. <a href="/wiki/ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/0733-9437">0733-9437</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Journal+of+Irrigation+and+Drainage+Engineering&rft.atitle=Head-Discharge+Equation+for+Sharp-Crested+Polynomial+Weir&rft.volume=134&rft.issue=2&rft.pages=%3Cspan+class%3D%22nowrap%22%3E260-%3C%2Fspan%3E262&rft.date=2008&rft_id=info%3Adoi%2F10.1061%2F%28ASCE%290733-9437%282008%29134%3A2%28260%29&rft.issn=0733-9437&rft.aulast=Baddour&rft.aufirst=Raouf+E.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AWeir" class="Z3988"></span></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite id="CITEREFClemmens2010" class="citation book cs1">Clemmens, Albert (2010). <i>Water Measurement with Flumes and Weirs</i>. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-1887201544" title="Special:BookSources/978-1887201544"><bdi>978-1887201544</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Water+Measurement+with+Flumes+and+Weirs&rft.date=2010&rft.isbn=978-1887201544&rft.aulast=Clemmens&rft.aufirst=Albert&rfr_id=info%3Asid%2Fen.wikipedia.org%3AWeir" class="Z3988"></span></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite id="CITEREFShen1981" class="citation book cs1">Shen, John (1981). <a rel="nofollow" class="external text" href="https://pubs.usgs.gov/wsp/1617b/report.pdf"><i>Discharge Characteristics of Triangular-notch Thin-plate Weirs</i></a> <span class="cs1-format">(PDF)</span>. Washington: United States Government Printing Office.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Discharge+Characteristics+of+Triangular-notch+Thin-plate+Weirs&rft.place=Washington&rft.pub=United+States+Government+Printing+Office&rft.date=1981&rft.aulast=Shen&rft.aufirst=John&rft_id=https%3A%2F%2Fpubs.usgs.gov%2Fwsp%2F1617b%2Freport.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AWeir" class="Z3988"></span></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite id="CITEREFSilvaLowryMacaya-SolisByatt2017" class="citation journal cs1">Silva, Sergio; Lowry, Maran; Macaya-Solis, Consuelo; Byatt, Barry; Lucas, Martyn C. (2017). <a rel="nofollow" class="external text" href="https://doi.org/10.1016%2Fj.ecoleng.2017.02.027">"Can navigation locks be used to help migratory fishes with poor swimming performance pass tidal barrages? A test with lampreys"</a>. <i>Ecological Engineering</i>. <b>102</b>: <span class="nowrap">291–</span>302. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://doi.org/10.1016%2Fj.ecoleng.2017.02.027">10.1016/j.ecoleng.2017.02.027</a></span>. <a href="/wiki/ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/0925-8574">0925-8574</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Ecological+Engineering&rft.atitle=Can+navigation+locks+be+used+to+help+migratory+fishes+with+poor+swimming+performance+pass+tidal+barrages%3F+A+test+with+lampreys&rft.volume=102&rft.pages=%3Cspan+class%3D%22nowrap%22%3E291-%3C%2Fspan%3E302&rft.date=2017&rft_id=info%3Adoi%2F10.1016%2Fj.ecoleng.2017.02.027&rft.issn=0925-8574&rft.aulast=Silva&rft.aufirst=Sergio&rft.au=Lowry%2C+Maran&rft.au=Macaya-Solis%2C+Consuelo&rft.au=Byatt%2C+Barry&rft.au=Lucas%2C+Martyn+C.&rft_id=https%3A%2F%2Fdoi.org%2F10.1016%252Fj.ecoleng.2017.02.027&rfr_id=info%3Asid%2Fen.wikipedia.org%3AWeir" class="Z3988"></span></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite id="CITEREFTummersWinterSilvaO’Brien2016" class="citation journal cs1">Tummers, Jeroen S.; Winter, Emily; Silva, Sergio; O’Brien, Pat; Jang, Min-Ho; Lucas, Martyn C. (2016). <a rel="nofollow" class="external text" href="https://doi.org/10.1016%2Fj.ecoleng.2016.02.046">"Evaluating the effectiveness of a Larinier super active baffle fish pass for European river lamprey Lampetra fluviatilis before and after modification with wall-mounted studded tiles"</a>. <i>Ecological Engineering</i>. <b>91</b>: <span class="nowrap">183–</span>194. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://doi.org/10.1016%2Fj.ecoleng.2016.02.046">10.1016/j.ecoleng.2016.02.046</a></span>. <a href="/wiki/ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/0925-8574">0925-8574</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Ecological+Engineering&rft.atitle=Evaluating+the+effectiveness+of+a+Larinier+super+active+baffle+fish+pass+for+European+river+lamprey+Lampetra+fluviatilis+before+and+after+modification+with+wall-mounted+studded+tiles&rft.volume=91&rft.pages=%3Cspan+class%3D%22nowrap%22%3E183-%3C%2Fspan%3E194&rft.date=2016&rft_id=info%3Adoi%2F10.1016%2Fj.ecoleng.2016.02.046&rft.issn=0925-8574&rft.aulast=Tummers&rft.aufirst=Jeroen+S.&rft.au=Winter%2C+Emily&rft.au=Silva%2C+Sergio&rft.au=O%E2%80%99Brien%2C+Pat&rft.au=Jang%2C+Min-Ho&rft.au=Lucas%2C+Martyn+C.&rft_id=https%3A%2F%2Fdoi.org%2F10.1016%252Fj.ecoleng.2016.02.046&rfr_id=info%3Asid%2Fen.wikipedia.org%3AWeir" class="Z3988"></span></li></ul> </div> <div class="mw-heading mw-heading2"><h2 id="Further_reading">Further reading</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Weir&action=edit&section=21" title="Edit section: Further reading"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1239549316" /><div class="refbegin refbegin-hanging-indents" style=""> <ul><li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite id="CITEREFChanson2004" class="citation book cs1"><a href="/wiki/Hubert_Chanson" title="Hubert Chanson">Chanson, H.</a> (2004). <i>The Hydraulics of Open Channel Flow: An Introduction</i> (2nd ed.). Oxford: Butterworth-Heinemann. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-7506-5978-9" title="Special:BookSources/978-0-7506-5978-9"><bdi>978-0-7506-5978-9</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=The+Hydraulics+of+Open+Channel+Flow%3A+An+Introduction&rft.place=Oxford&rft.edition=2nd&rft.pub=Butterworth-Heinemann&rft.date=2004&rft.isbn=978-0-7506-5978-9&rft.aulast=Chanson&rft.aufirst=H.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AWeir" class="Z3988"></span></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite id="CITEREFChanson2007" class="citation journal cs1">Chanson, Hubert (2007). <a rel="nofollow" class="external text" href="https://espace.library.uq.edu.au/view/UQ:84668/UQ84668_OA.pdf">"Hydraulic Performances of Minimum Energy Loss Culverts in Australia"</a> <span class="cs1-format">(PDF)</span>. <i>Journal of Performance of Constructed Facilities</i>. <b>21</b> (4): <span class="nowrap">264–</span>272. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1061%2F%28ASCE%290887-3828%282007%2921%3A4%28264%29">10.1061/(ASCE)0887-3828(2007)21:4(264)</a>. <a href="/wiki/ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/0887-3828">0887-3828</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Journal+of+Performance+of+Constructed+Facilities&rft.atitle=Hydraulic+Performances+of+Minimum+Energy+Loss+Culverts+in+Australia&rft.volume=21&rft.issue=4&rft.pages=%3Cspan+class%3D%22nowrap%22%3E264-%3C%2Fspan%3E272&rft.date=2007&rft_id=info%3Adoi%2F10.1061%2F%28ASCE%290887-3828%282007%2921%3A4%28264%29&rft.issn=0887-3828&rft.aulast=Chanson&rft.aufirst=Hubert&rft_id=https%3A%2F%2Fespace.library.uq.edu.au%2Fview%2FUQ%3A84668%2FUQ84668_OA.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AWeir" class="Z3988"></span></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite id="CITEREFGonzalezChanson2007" class="citation journal cs1">Gonzalez, Carlos A.; Chanson, Hubert (2007). <a rel="nofollow" class="external text" href="http://espace.library.uq.edu.au/view/UQ:107673/fmi_07.pdf">"Experimental measurements of velocity and pressure distributions on a large broad-crested weir"</a> <span class="cs1-format">(PDF)</span>. <i>Flow Measurement and Instrumentation</i>. <b>18</b> (<span class="nowrap">3–</span>4): <span class="nowrap">107–</span>113. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1016%2Fj.flowmeasinst.2007.05.005">10.1016/j.flowmeasinst.2007.05.005</a>. <a href="/wiki/ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/0955-5986">0955-5986</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Flow+Measurement+and+Instrumentation&rft.atitle=Experimental+measurements+of+velocity+and+pressure+distributions+on+a+large+broad-crested+weir&rft.volume=18&rft.issue=%3Cspan+class%3D%22nowrap%22%3E3%E2%80%93%3C%2Fspan%3E4&rft.pages=%3Cspan+class%3D%22nowrap%22%3E107-%3C%2Fspan%3E113&rft.date=2007&rft_id=info%3Adoi%2F10.1016%2Fj.flowmeasinst.2007.05.005&rft.issn=0955-5986&rft.aulast=Gonzalez&rft.aufirst=Carlos+A.&rft.au=Chanson%2C+Hubert&rft_id=http%3A%2F%2Fespace.library.uq.edu.au%2Fview%2FUQ%3A107673%2Ffmi_07.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AWeir" class="Z3988"></span></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite id="CITEREFHenderson1996" class="citation cs2">Henderson, F.M. (1996), <i>Open Channel Flow</i>, New York: MacMillan Company</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Open+Channel+Flow&rft.place=New+York&rft.pub=MacMillan+Company&rft.date=1996&rft.aulast=Henderson&rft.aufirst=F.M.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AWeir" class="Z3988"></span></li> <li>McKay, G.R. (1971). "Design of Minimum Energy Culverts." Research Report, Dept of Civil Eng., Univ. of Queensland, Brisbane, Australia, 29 pages & 7 plates.</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite id="CITEREFSturm2010" class="citation book cs1">Sturm, Terry W. (2010). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=cOUiPwAACAAJ"><i>Open Channel Hydraulics</i></a>. McGraw-Hill. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-07-126793-9" title="Special:BookSources/978-0-07-126793-9"><bdi>978-0-07-126793-9</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Open+Channel+Hydraulics&rft.pub=McGraw-Hill&rft.date=2010&rft.isbn=978-0-07-126793-9&rft.aulast=Sturm&rft.aufirst=Terry+W.&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DcOUiPwAACAAJ&rfr_id=info%3Asid%2Fen.wikipedia.org%3AWeir" class="Z3988"></span></li></ul> </div> <div class="mw-heading mw-heading2"><h2 id="External_links">External links</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Weir&action=edit&section=22" title="Edit section: External links"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style 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Inc.","logo":{"@type":"ImageObject","url":"https:\/\/www.wikimedia.org\/static\/images\/wmf-hor-googpub.png"}},"datePublished":"2003-08-29T17:34:58Z","dateModified":"2025-03-23T04:47:10Z","image":"https:\/\/upload.wikimedia.org\/wikipedia\/en\/6\/63\/Humber_Weir.JPG","headline":"barrier across a river designed to alter its flow characteristics"}</script> </body> </html>