Editing Seine (section)

==Navigation==
The Seine is dredged and ocean-going vessels can dock at [[Rouen]], {{convert|120|km|mi}} from the sea. Commercial craft (barges and push-tows) can use the river beginning at [[Marcilly-sur-Seine]], {{convert|516|km|mi}} to its mouth.<ref>{{Cite book|title=Inland Waterways of France|last=Edwards-May|first=David|publisher=Imray|year=2010|isbn=978-1-846230-14-1|location=St Ives, Cambs., UK|pages=90–94}}</ref>

At Paris, there are 37 bridges.<ref>{{Cite web |last=Sciolino |first=Elaine |date=November 4, 2019 |title=Knowing Paris by Its Bridges |url=https://www.nytimes.com/2019/11/04/travel/paris-bridges-seine.html |access-date=October 24, 2024 |website=[[The New York Times]]}}</ref> The river is only {{convert|24|m|ft}} above sea level {{convert|446|km|mi}} from its mouth, making it slow flowing and thus easily navigable.<ref>{{Cite web |date=2024-10-15 |title=Seine River {{!}} Paris, France, History & Facts {{!}} Britannica |url=https://www.britannica.com/place/Seine-River |access-date=2024-10-24 |website=www.britannica.com |language=en}}</ref>

The Seine Maritime, {{convert|123|km|mi}} from the English Channel at [[Le Havre]] to Rouen, is the only portion of the Seine used by ocean-going craft.<ref name="Fluvi2">[http://www.fluviacarte.com/fr/voies-navigables/region-bassin-de-la-seine-5/voie-seine-maritime-85 Fluviacarte] {{Webarchive|url=https://web.archive.org/web/20180925145715/http://www.fluviacarte.com/fr/voies-navigables/region-bassin-de-la-seine-5/voie-seine-maritime-85 |date=25 September 2018 }}, Seine maritime</ref> The tidal section of the Seine Maritime is followed by a canalized section (''Basse Seine'') with four large multiple locks until the mouth of the [[Oise (river)|Oise]] at [[Conflans-Sainte-Honorine]] ({{cvt|170|km|disp=sqbr}}). Smaller locks at [[Bougival]] and at [[Suresnes]] lift the vessels to the level of the river in Paris, where the junction with the [[Canal Saint-Martin]] is located. The distance from the mouth of the Oise is {{cvt|72|km}}.<ref>[http://www.fluviacarte.com/fr/voies-navigables/region-r-5/voie--84 Fluviacarte] {{Webarchive|url=https://web.archive.org/web/20180925142627/http://www.fluviacarte.com/fr/voies-navigables/region-r-5/voie--84 |date=25 September 2018 }}, Basse Seine</ref>

The ''Haute Seine'', from Paris to [[Montereau-Fault-Yonne]], is {{cvt|98|km}} long and has 8 locks.<ref>[http://www.fluviacarte.com/fr/voies-navigables/region-r-5/voie--83 Fluviacarte] {{Webarchive|url=https://web.archive.org/web/20180925142530/http://www.fluviacarte.com/fr/voies-navigables/region-r-5/voie--83 |date=25 September 2018 }}, Haute Seine</ref> At [[Charenton-le-Pont]] is the mouth of the [[Marne (river)|Marne]]. Upstream from Paris seven locks ensure navigation to [[Saint Mammès]], where the [[Loing]] mouth is situated. Through an eighth lock the river [[Yonne (river)|Yonne]] is reached at Montereau-Fault-Yonne. From the mouth of the Yonne, larger ships can continue upstream to [[Nogent-sur-Seine]] ({{cvt|48|km|disp=sqbr}}, 7 locks).<ref>[http://www.fluviacarte.com/fr/voies-navigables/region-r-5/voie--82 Fluviacarte] {{Webarchive|url=https://web.archive.org/web/20180925145711/http://www.fluviacarte.com/fr/voies-navigables/region-r-5/voie--82 |date=25 September 2018 }}, Petite Seine (aval)</ref> From there on, the river is navigable only by small craft to [[Marcilly-sur-Seine]] ({{cvt|19|km|disp=sqbr}}, 4 locks).<ref name="Fluvi1">[http://www.fluviacarte.com/fr/voies-navigables/region-r-5/voie--81 Fluviacarte] {{Webarchive|url=https://web.archive.org/web/20180925142411/http://www.fluviacarte.com/fr/voies-navigables/region-r-5/voie--81 |date=25 September 2018 }}, Petite Seine (amont)</ref> At Marcilly-sur-Seine the 19th century [[Canal de la Haute-Seine]] used to allow vessels to continue all the way to [[Troyes]]. This canal has been abandoned since 1957.<ref>{{cite web|url=http://www.aube.fr/include/viewFile.php?idtf=1687&path=28%2F1687_1321867581_histoire-construction.pdf|title=La construction du canal de la Haute-Seine|access-date=25 September 2018|archive-date=25 September 2018|archive-url=https://web.archive.org/web/20180925142053/http://www.aube.fr/include/viewFile.php?idtf=1687&path=28%2F1687_1321867581_histoire-construction.pdf|url-status=live}}</ref>

The Seine's average depth in Paris today is approximately 9.5 meters (31 feet). Until locks were installed to raise the level in the 1800s, the river was much shallower within the city, and consisted of a small channel of continuous flow bordered by sandy banks (depicted in many illustrations of the period). Today the depth is tightly controlled and the entire width of the river between the built-up banks on either side is normally filled with water. The average flow of the river is very low, only a few cubic metres per second, but much higher flows are possible during periods of heavy runoff.

=== Dredging ===
{{Unreferenced section|date=June 2024}}
[[Dredging]] in the 1960s mostly eliminated [[tidal bore]]s on the lower river, known in French as ''"le mascaret."''