Editing Tidal bore

{{Short description|A water wave traveling upstream a river or narrow bay because of an incoming tide}}
{{Use British English|date=April 2020}}
[[File:Tidal Bore - geograph.org.uk - 324581.jpg|thumbnail|A bore in [[Morecambe Bay]], in the [[United Kingdom]]|alt=]]
[[File:Arnside bore.ogv|thumb|Video of the [[Arnside Bore]], in the United Kingdom]]
[[File:Turnagain-bore.jpg|thumb|upright=1.35|The tidal bore in Upper [[Cook Inlet]], in [[Alaska]]]]

A '''tidal bore''',<ref>Sometimes also known as an '''aegir''', '''eagre''', or '''eygre''' in the context of specific instances in Britain.</ref> often simply given as '''bore''' in context, is a [[tide|tidal]] phenomenon in which the leading edge of the incoming tide forms a wave (or waves) of water that travels up a river or narrow bay, reversing the direction of the river or bay's current. It is a strong tide that pushes up the river, against the current.

=={{Anchor|Whelp}} Description== <!-- [[Whelp (tidal bore)]] redirects here -->
Bores occur in relatively few locations worldwide, usually in areas with a large tidal range (typically more than {{convert|6|m|ft|0|sp=us}} between high and low tide) and where incoming tides are funneled into a shallow, narrowing river or lake via a broad bay.<ref name="Chanson2011">{{cite book|author=Chanson, H. |title= Tidal Bores, Aegir, Eagre, Mascaret, Pororoca. Theory and Observations |url= https://www.worldscientific.com/worldscibooks/10.1142/8035 |publisher=World Scientific, Singapore |year=2011 |doi= 10.1142/8035 |isbn= 978-981-4335-41-6|author-link= Hubert Chanson }}</ref> The funnel-like shape not only increases the tidal range, but it can also decrease the duration of the [[flooding tide|flood tide]], down to a point where the flood appears as a sudden increase in the water level. A tidal bore takes place during the flood tide and never during the [[Slack water|ebb tide]].

[[File:Undular bore Araguari River-Brazil-USGS-bws00026.jpg|thumb|right|upright=1.35|[[Undular bore]] and whelps near the mouth of [[Araguari River (Amapá)|Araguari River]] in northeastern Brazil. The view is oblique towards the mouth from airplane at approximately {{convert|100|ft|m|abbr=on|order=flip}} altitude.<ref>Figure 5 in: {{citation| author1=Susan Bartsch-Winkler |author2=David K. Lynch |publisher=[[United States Geological Survey|U. S. Geological Survey]] |type=Circular 1022 |year=1988 |title=Catalog of worldwide tidal bore occurrences and characteristics |journal=USGS Report |series=Circular |page=12 |doi=10.3133/cir1022 |bibcode=1988usgs.rept...12B |url=https://pubs.er.usgs.gov/#search:advance/page=1/page_size=100/advance=undefined/series_cd=CIR/report_number=1022:0}}</ref>]]
A tidal bore may take on various forms, ranging from a single breaking wavefront with a {{nowrap|roller{{hsp}}{{mdash}}{{tsp}}}}somewhat like a [[hydraulic jump]]<ref name="Chanson_2012">{{cite journal|author=Chanson, H. |title= Momentum considerations in hydraulic jumps and bores |url= http://espace.library.uq.edu.au/view/UQ:273253 |journal=Journal of Irrigation and Drainage Engineering|publisher= ASCE|volume= 138 |issue= 4 |pages= 382–85 |year=2012 |issn= 0372-0187 |doi= 10.1061/(ASCE)IR.1943-4774.0000409|bibcode= 2012JIDE..138..382C |author-link= Hubert Chanson |url-access= subscription }}</ref><ref name="Chanson2009b">{{cite journal|author=Chanson, H. |title= Current Knowledge In Hydraulic Jumps And Related Phenomena. A Survey of Experimental Results |url= http://espace.library.uq.edu.au/view/UQ:162239 |journal=European Journal of Mechanics B |volume=28 |issue=2 |pages= 191–210 |doi= 10.1016/j.euromechflu.2008.06.004 |issn= 0997-7546 |year=2009 |bibcode = 2009EuJMB..28..191C |author-link= Hubert Chanson |url-access= subscription }}</ref>⁠{{mdash}}{{tsp}}to [[undular bore]]s, comprising a smooth wavefront followed by a train of secondary [[water waves|waves]] known as '''whelps'''.<ref name="Chanson2009">{{cite book|author=Chanson, H. |title= Environmental, Ecological and Cultural Impacts of Tidal Bores, Benaks, Bonos and Burros |url= http://espace.library.uq.edu.au/view/UQ:185349 |publisher=Proc. International Workshop on Environmental Hydraulics IWEH09, Theoretical, Experimental and Computational Solutions, Valencia, Spain, 29–30 October Editor P.A. Lopez-Jimenez et al., Invited keynote lecture, 20 pp. (CD-ROM) |year=2009 |author-link= Hubert Chanson }}</ref> Large bores can be particularly unsafe for shipping but also present opportunities for [[river surfing]].<ref name="Chanson2009"/>

Two key features of a tidal bore are the intense turbulence and [[turbulent mixing]] generated during the bore propagation, as well as its rumbling noise. The visual observations of tidal bores highlight the turbulent nature of the surging waters. The tidal bore induces a strong turbulent mixing in the estuarine zone, and the effects may be felt along considerable distances. The velocity observations indicate a rapid deceleration of the flow associated with the passage of the bore as well as large velocity fluctuations.<ref name="KochChanson2008">{{cite journal|author=Koch, C. and [[Hubert Chanson|Chanson, H.]] |title= Turbulent Mixing beneath an Undular Bore Front |url= http://espace.library.uq.edu.au/view/UQ:151916 |journal=Journal of Coastal Research|volume=24|issue=4|pages= 999–1007 |doi= 10.2112/06-0688.1 |year=2008 |s2cid= 130530635 |url-access=subscription }}</ref><ref name="KochChanson2009">{{cite journal|author=Koch, C. and [[Hubert Chanson|Chanson, H.]] |title= Turbulence Measurements in Positive Surges and Bores |url= http://espace.library.uq.edu.au/view/UQ:164015 |journal=Journal of Hydraulic Research |volume=47|issue= 1|pages= 29–40 |doi= 10.3826/jhr.2009.2954 |year=2009 |bibcode= 2009JHydR..47...29K |s2cid= 124743367 |url-access= subscription }}</ref> A tidal bore creates a powerful roar that combines the sounds caused by the turbulence in the bore front and whelps, entrained air bubbles in the bore roller, sediment erosion beneath the bore front and of the banks, scouring of shoals and bars, and impacts on obstacles. The bore rumble is heard far away because its low frequencies can travel over long distances. The low-frequency sound is a characteristic feature of the advancing roller in which the air bubbles entrapped in the large-scale eddies are acoustically active and play the dominant role in the rumble-sound generation.<ref name="Chanson2009c">{{cite journal|author=Chanson, H. |title= The Rumble Sound Generated by a Tidal Bore Event in the Baie du Mont Saint Michel |url= http://espace.library.uq.edu.au/view/UQ:178445 |journal=[[Journal of the Acoustical Society of America]]|volume= 125|issue= 6|pages= 3561–68 |doi= 10.1121/1.3124781|pmid= 19507938 |year=2009 |bibcode = 2009ASAJ..125.3561C |author-link= Hubert Chanson |url-access= subscription }}</ref>

==Etymology==
The word ''bore'' derives through [[Old English language|Old English]] from the [[Old Norse language|Old Norse]] word ''bára'', meaning "wave" or "swell."

==Effects==
Tidal bores can be dangerous. Certain rivers such as the [[Seine]] in [[France]], the [[Petitcodiac River]] in [[Canada]], and the [[Colorado River]] in [[Mexico]] to name a few, have had a sinister reputation in association with tidal bores. In China, despite warning signs erected along the banks of the [[Qiantang River]], a number of fatalities occur each year by people who take too much risk with the bore.<ref name="Chanson2011" /> The tidal bores affect the shipping and navigation in the estuarine zone, for example, in [[Papua New Guinea]] (in the [[Fly River|Fly]] and [[Bamu River]]s), [[Malaysia]] (the Benak in the [[Lupar River|Batang Lupar]]), and [[India]] (the [[Hooghly River]] bore).

On the other hand, tidal bore-affected [[estuaries]] are rich feeding zones and breeding grounds of several forms of wildlife.<ref name="Chanson2011" /> The estuarine zones are the spawning and breeding grounds of several native [[fish]] species, while the [[aeration]] induced by the tidal bore contributes to the abundant growth of many species of fish and [[shrimp]] (for example in the [[Rokan River]], [[Indonesia]]). The tidal bores also provide opportunity for recreational inland [[surfing]], such as the Seven Ghosts bore on the [[Kampar River]], [[Indonesia]] or the [[Severn bore|Severn Bore]] on the [[River Severn]], [[England]].

===Scientific studies===
Scientific studies have been carried out at the [[River Dee, Wales|River Dee]]<ref name="Simpson_etal2004">{{cite journal|author=Simpson, J.H., Fisher, N.R., and Wiles, P.  |title= Reynolds Stress and TKE Production in an Estuary with a Tidal Bore   |journal=[[Estuarine, Coastal and Shelf Science]]|volume= 60|issue=4|pages= 619–27 |year=2004 |doi=10.1016/j.ecss.2004.03.006|quote = during this […] deployment, the [ADCP] instrument was repeatedly buried in sediment after the 1st tidal cycle and had to be dug out of the sediment, with considerable difficulty, at the time of recovery.|bibcode = 2004ECSS...60..619S }}</ref> in Wales in the United Kingdom, the [[Garonne]]<ref name="Chanson_etal2010">{{cite book|author=[[Hubert Chanson|Chanson, H.]], Lubin, P., Simon, B., and Reungoat, D. |title= Turbulence and Sediment Processes in the Tidal Bore of the Garonne River: First Observations |url= http://espace.library.uq.edu.au/view/UQ:219711 |publisher=Hydraulic Model Report No. CH79/10, School of Civil Engineering, The University of Queensland, Brisbane, Australia, 97 pp.|year=2010 |isbn= 978-1-74272-010-4}}</ref><ref name="Simon_et_al2011">{{cite book|author=Simon, B., Lubin, P., Reungoat, D., [[Hubert Chanson|Chanson, H.]] |title= Turbulence Measurements in the Garonne River Tidal Bore: First Observations |url= http://espace.library.uq.edu.au/view/UQ:243200 |publisher=Proc. 34th IAHR World Congress, Brisbane, Australia, 26 June–1 July, Engineers Australia Publication, Eric Valentine, Colin Apelt, James Ball, [[Hubert Chanson]], Ron Cox, Rob Ettema, George Kuczera, Martin Lambert, Bruce Melville and Jane Sargison Editors, pp. 1141–48 |year=2011 |isbn= 978-0-85825-868-6}}</ref><ref name="Chanson_etal2012">{{cite journal|author=[[Hubert Chanson|Chanson, H.]], Reungoat, D., Simon, B., Lubin, P. |title= High-Frequency Turbulence and Suspended Sediment Concentration Measurements in the Garonne River Tidal Bore |journal=Estuarine, Coastal and Shelf Science |doi= 10.1016/j.ecss.2011.09.012 |year=2012 |issn= 0272-7714|bibcode = 2011ECSS...95..298C |url=http://espace.library.uq.edu.au/view/UQ:261649 |volume=95 |issue= 2–3 |pages=298–306|citeseerx= 10.1.1.692.2537 }}</ref><ref name="Reungoat_etal2014a">{{cite journal|author=Reungoat, D., [[Hubert Chanson|Chanson, H.]], Caplain, C. |title= Sediment Processes and Flow Reversal in the Undular Tidal Bore of the Garonne River (France) |journal=[[Environmental Fluid Mechanics]] |doi= 10.1007/s10652-013-9319-y |year=2014 |issn= 1567-7419 |url=http://espace.library.uq.edu.au/view/UQ:330273 |volume=14 |number=3 |pages=591–616|bibcode= 2014EFM....14..591R |s2cid= 14357850 |url-access=subscription }}</ref><ref name="Reungoat_etal2014b">{{cite book|author=Reungoat, D., [[Hubert Chanson|Chanson, H.]], Keevil, C. |title= Turbulence, Sedimentary Processes and Tidal Bore Collision in the Arcins Channel, Garonne River (October 2013) |journal=Hydraulic Model Report No. CH94/14, School of Civil Engineering, the University of Queensland, Brisbane, Australia, 145 Pp. |year=2014 |isbn= 9781742721033 |url=http://espace.library.uq.edu.au/view/UQ:331049}}</ref> and [[Sélune]]<ref name="Mouaze_et_al2010">{{cite book|author=Mouazé, D., [[Hubert Chanson|Chanson, H.]], and Simon, B. |title= Field Measurements in the Tidal Bore of the Sélune River in the Bay of Mont Saint Michel (September 2010) |url= http://espace.library.uq.edu.au/view/UQ:226153  |publisher=Hydraulic Model Report No. CH81/10, School of Civil Engineering, The University of Queensland, Brisbane, Australia, 72 pp. |year=2010 |isbn= 978-1-74272-021-0|quote = the field study experienced a number of problems and failures. About 40 s after the passage of the bore, the metallic frame started to move. The ADV support failed completely 10 minutes after the tidal bore.}}</ref> in France, the [[Daly River (Northern Territory)|Daly River]]<ref name="Wolanski_etal2004">{{cite journal|author=Wolanski, E., Williams, D., Spagnol, S., and [[Hubert Chanson|Chanson, H.]]  |title= Undular Tidal Bore Dynamics in the Daly Estuary, Northern Australia |url= http://espace.library.uq.edu.au/view/UQ:74059  |journal=Estuarine, Coastal and Shelf Science|volume= 60|issue=4|pages= 629–36 |doi= 10.1016/j.ecss.2004.03.001 |year=2004 |bibcode = 2004ECSS...60..629W |quote = About 20 min after the passage of the bore the two aluminium frames at site C were toppled. […] A 3-min-duration patch of macroturbulence was observed. […] This unsteady motion was sufficiently energetic to topple moorings that had survived much higher, quasi-steady currents of 1.8 m/s.|url-access= subscription}}</ref> in Australia, and the [[Qiantang River]] estuary<ref name="qiantang 2019">{{cite journal |last1=Li |first1=Ying |last2=Pan |first2=Dong-Zi |last3=Chanson |first3=Hubert |last4=Pan |first4=Cun-Hong |title=Real-time characteristics of tidal bore propagation in the Qiantang River Estuary, China, recorded by marine radar |journal=Continental Shelf Research |date=July 2019 |volume=180 |pages=48–58 |doi=10.1016/j.csr.2019.04.012 |publisher=Elsevier |bibcode=2019CSR...180...48L |s2cid=155917795 |url=https://espace.library.uq.edu.au/view/UQ:be98433/UQbe98433_OA.pdf |quote=The Qiantang River tidal bore was recorded at two different geographical locations. Characteristic flow patterns were derived and analysed, including temporal changes over a relatively large-scale area. The experimental results showed that the radar-derived celerity and calculated height of the tidal bore were consistent with visual observations in this estuarine zone.}}</ref> in China. The force of the tidal bore flow often poses a challenge to scientific measurements, as evidenced by a number of field work incidents in the River Dee,<ref name="Simpson_etal2004" /> Rio Mearim, Daly River,<ref name="Wolanski_etal2004" /> and Sélune River.<ref name="Mouaze_et_al2010" />

==Rivers and bays with tidal bores==
Rivers and bays that have been known to exhibit bores include those listed below.<ref name="Chanson2011" /><ref name="Chanson">{{cite book|author=Chanson, H.  |title= Photographic Observations of Tidal Bores (Mascarets) in France   |url= http://espace.library.uq.edu.au/eserv/UQ:158867  |publisher=Hydraulic Model Report No. CH71/08, Univ. of Queensland, Australia, 104 pp.  |year=2008 |isbn=978-1-86499-930-3 |author-link= Hubert Chanson }}</ref>

===Asia===
* [[Ganges]]–[[Brahmaputra]], [[India]] and [[Bangladesh]]
* [[Indus River]], [[India]] and [[Pakistan]]
* [[Sittaung River]], [[Burma]]
* [[Qiantang River]], [[China]], which has the world's largest bore,<ref name="Chanson2011" /><ref name="qiantang 2019" /> up to {{convert|9|m|ft|0|sp=us|abbr=on}} high, traveling at up to {{convert|40|km/h||0|sp=us|abbr=on}}
* Batang Lupar or Lupar River, near [[Simanggang|Sri Aman]], [[Malaysia]]. The tidal bore is locally known as ''benak''.<ref name="Chanson2009" />
* Batang Sadong or Sadong River, Sarawak, Malaysia.
* Bono, [[Kampar River]], at Meranti Bay, Pelalawan, [[Indonesia]]. The phenomenon is feared by the locals to sink ships.{{citation needed|date=May 2020}} It is reported to break up to {{convert|130|km|sp=us|abbr=on}} inland, but usually up to {{convert|40| km|abbr=on}} with {{convert|6|m|ft|abbr=on}}  height.<ref>{{cite web |url=https://en.tempo.co/read/news/2017/02/03/199842849/Riau-to-Introduce-Bono-Wave-to-International-Tourism |title=Riau to Introduce Bono Wave to International Tourism |author=Ryan Novitra |date=February 3, 2017}}</ref>

===Oceania===
====Australia====
* [[Styx River (Queensland)|Styx River]], [[Queensland]]
* [[Daly River (Northern Territory)|Daly River]], [[Northern Territory]]

====New Zealand====
*[[Wairoa River (Northland)|Wairoa River]], [[Northland Region]]<ref>{{cite news |title=Wairoa Tidal Bore |url=https://paperspast.natlib.govt.nz/newspapers/NZH19140318.2.99 |access-date=25 November 2024 |work=New Zealand Herald |issue=15560 |date=18 March 1914}}</ref>

====Papua New Guinea====
* [[Fly River]]<ref>p. 159, Barrie R. Bolton. 2009. ''The Fly River, Papua New Guinea: Environmental Studies in an Impacted Tropical River System.'' Elsevier Science. {{ISBN|978-0444529640}}.</ref>
* [[Turama River]]

===Europe===
====Ireland====
* [[River Shannon]], up the [[Shannon Estuary]] to Limerick, Ireland: 21 September 2013

====United Kingdom====
[[File:Trent Aegir 2.JPG|thumb|The Trent Aegir seen from West Stockwith, [[Nottinghamshire]], 20 September 2005]]
[[File:Trent Aegir 3.JPG|thumb|The Trent Aegir at [[Gainsborough, Lincolnshire]], 20 September 2005]]
* [[River Dee, Wales|River Dee]], [[Wales]] and [[England]]
* [[River Mersey]]. The second highest tidal bore after the Severn bore, up to {{convert|1.7|m|ft|0|sp=us}} high. The bore tends to form around the [[Manchester Ship Canal]].
* The [[Severn bore]] on the [[River Severn]], Wales and England, up to {{convert|2|m|ft|0|sp=us}} high
* The [[Trent Aegir]] on the [[River Trent]], England, up to {{convert|1.5|m|ft|0|sp=us}} high. Also other tributaries of the [[Humber|Humber Estuary]].
* [[River Parrett]]
* [[River Welland]]
* The [[Arnside Bore]] on the [[River Kent]]
* [[River Great Ouse]]
* [[River Ouse, Yorkshire]]. Like the Trent bore, this is also known as "the Aegir".
* [[River Eden, Cumbria|River Eden]]
* [[River Esk, Dumfriesshire|River Esk]]
* [[River Nene]]. This was also known as the Eagre.
* [[River Nith]]
* [[River Lune]], Lancashire
* [[River Ribble]], Lancashire
* [[River Yealm]], [[Devon]]
* [[River Leven, Cumbria]]
[[File:River Ribble bore.jpg|thumb|alt=A tidal bore wave moves along the River Ribble between the entrances to the Rivers Douglas and Preston.|Tidal bore on the [[River Ribble]]]]

====Belgium====
* [[Durme]], [[Flanders]]

====France====
The phenomenon is generally named ''un mascaret'' in French.<ref>{{in lang|fr}} [http://www.cnrtl.fr/lexicographie/mascaret definition of mascaret]</ref> but some other local names are preferred.<ref name="Chanson" />
* [[Seine]] had a significant bore until the 1960s, locally named ''la barre''. Since then, it has been practically eliminated by [[dredging]] and [[Training (civil)|river training]].<ref name="Chanson" />
* Bay of [[Mont-Saint-Michel]] including [[Couesnon]], [[Sélune]], and [[Sée]]<ref name="Chanson" />
* [[Arguenon]]<ref name="Chanson" />
* {{ill|Frémur (baie de la Fresnaye)|fr}}<ref name="Chanson" />
* [[Vire]]<ref name="Chanson" />
*[[Sienne (river)|Sienne]]<ref name="Chanson" />
* [[Vilaine]], locally named ''le mascarin''
* [[Dordogne (river)|Dordogne]]<ref name="Chanson" />
* [[Garonne]]<ref name="Chanson" />

===North America===

====United States====
[[File:Tidal bore.jpg|thumb|Tidal bore on the [[Petitcodiac River]]]]
* The [[Turnagain Arm]] of [[Cook Inlet]], [[Alaska]]. Up to {{convert|2|m|ft|0|sp=us}} and {{convert|20|km/h|mph|0|abbr=on|sp=us}}.
* Historically, the [[Colorado River]] had a tidal bore up to 6 feet, that extended 47 miles up river.
* The [[Savannah River]] up to {{convert|10|mi|km|0|sp=us}} inland.{{Citation needed|reason=Source needed for the whole sentence|date=April 2021}}
* Small tidal bores, only a few inches in height, have been observed advancing up tidal bayous on the Mississippi Gulf Coast.
* The bay inlet of the Crissy Field Marsh, in San Francisco, California, can exhibit tidal bores near high tide.

====Canada====
With the [[Bay of Fundy]] having the highest [[tidal range]] in the world, most rivers draining into the upper bay between [[Nova Scotia]] and [[New Brunswick]] have significant tidal bores. They include:
* The [[Petitcodiac River]] formerly had the highest bore in North America at over {{convert|2|m|ft|1}} in height, but [[causeway]] construction between [[Moncton]] and [[Riverview, New Brunswick|Riverview]] in the 1960s led to subsequent extensive sedimentation which reduced the bore to little more than a ripple. After considerable political controversy, the causeway gates were opened on April 14, 2010, as part of the Petitcodiac River Restoration Project and the tidal bore began to grow again.<ref>[https://www.cbc.ca/news/canada/new-brunswick/petitcodiac-river-changing-faster-than-expected-1.944296 Petitcodiac River changing faster than expected]</ref> The restoration of the bore has been sufficient that in July 2013, professional surfers rode a {{convert|1|m|ft|1}}-high wave {{convert|29|km|mi|1}} up the Petitcodiac River from Belliveau Village to [[Moncton]] to establish a new North American record for continuous surfing.<ref>{{cite web |title=Surf's Up -- in Canada! Small New Brunswick Town Becomes International Surfing Hotspot |website=[[ABC News (United States)|ABC News]] |archive-url=https://web.archive.org/web/20230401213845/https://abcnews.go.com/Travel/surfs-canada-small-brunswick-town-international-surfing-hotspot/story?id=21450094 |archive-date=2023-04-01 |url-status=live |url=https://abcnews.go.com/Travel/surfs-canada-small-brunswick-town-international-surfing-hotspot/story?id=21450094}}</ref>
* The [[Shubenacadie River]] in Nova Scotia. When the tidal bore approaches, completely drained riverbeds are filled. It has caused the deaths of several tourists who were in the riverbeds when the bore came in.{{Citation needed|date=August 2008}} [[Tour boat]] operators offer rafting excursions in the summer.
* The bore is fastest and highest on some of the smaller rivers that connect to the bay including the [[River Hebert]] and [[Maccan River (Nova Scotia)|Maccan River]] on the [[Cumberland Basin (Canada)|Cumberland Basin]], the [[St. Croix River (Nova Scotia)|St. Croix]] and [[Kennetcook River|Kennetcook]] rivers in the [[Minas Basin]], and the [[Salmon River (Nova Scotia)|Salmon River]] in Truro.<ref>[http://ojs.library.dal.ca/NSM/article/view/3753 ''Natural History of Nova Scotia'' Vol. I, Chap. T "Ocean Currents", p. 109 ]</ref>

====Mexico====
Historically, there was a tidal bore on the [[Gulf of California]] in Mexico at the mouth of the [[Colorado River]]. It formed in the estuary about [[Montague Island (Mexico)|Montague Island]] and propagated upstream. It was once very strong, but diversions of the river for irrigation have weakened the flow of the river to the point the tidal bore has nearly disappeared.

===South America===

====Brazil====
* [[Amazon River]] in [[Brazil]], up to {{convert|4|m|ft|0|sp=us}} high, running at up to {{convert|13|mph|km/h|abbr=on}}. It is known locally as the ''[[pororoca]]''.<ref>{{in lang|en}} [http://fogonazos.blogspot.com/2007/03/pororoca-surfing-amazon.html "Pororoca: surfing the Amazon"] indicates that "The record that we could find for surfing the longest distance on the Pororoca was set by Picuruta Salazar, a Brazilian surfer who, in 2003, managed to ride the wave for 37 minutes and travel {{convert|12.5|km|mi|1|sp=us}}."</ref>
* [[Mearim River]] in Brazil
* [[Araguari River (Amapá)|Araguari River]] in Brazil. Very strong in the past, it is considered lost since 2015, due to buffaloes farming, irrigation, and dam construction along the river, leading to substantial loss of water flow.

====Venezuela====
* [[Orinoco River]] in [[Venezuela]]


====Chile====
* [[Southern Channels, ex. Canal de Castro, Chiloé Island (fjord of Castro)]] in [[Chile]]

==Lakes with tidal bores==
Lakes with an ocean [[inlet]] can also exhibit tidal bores.{{Citation needed|date=July 2010}}

===North America===
* [[Nitinat Lake]] on [[Vancouver Island]] has a sometimes dangerous tidal bore at Nitinat Narrows where the lake meets the Pacific Ocean. The lake is popular with windsurfers due to its consistent winds.

==See also==
{{Portal|United Kingdom|Transport}}
* [[1812 New Madrid earthquake]], a historic earthquake in the United States that caused the Mississippi River to flow backwards temporarily
* [[Tidal race]]
* [[Tsunami]]
* [[Tonlé Sap]], a lake and river system in Cambodia where monsoon flooding can cause the river to flow backwards temporarily albeit not as a tidal bore

==References==
{{Reflist|2}}

==External links==
{{Commons category|Tidal bores}}

{{Wiktionary|tidal bore|eagre}}
* [http://www.thesevernbore.co.uk Information about The Severn bore, UK]
* [https://www.youtube.com/watch?v=Cx89Dstc6v0 Amateur video of the "Wiggenhall Wave" tidal bore]
* [https://web.archive.org/web/20071119035703/http://www.pol.ac.uk/home/insight/riverbores.html link to Proudman Inst. page]
* [http://espace.library.uq.edu.au/view.php?pid=UQ:9447 Mascaret, Aegir, Pororoca, Tidal Bore. Quid ? Où? Quand? Comment? Pourquoi ?] in ''Journal La Houille Blanche'', No. 3, pp.&nbsp;103–14
* [http://espace.library.uq.edu.au/view/UQ:151916 Turbulent Mixing beneath an Undular Bore Front] in ''Journal of Coastal Research'', Vol. 24, No. 4, pp.&nbsp;999–1007 {{doi|10.2112/06-0688.1}}
* [http://staff.civil.uq.edu.au/h.chanson/reprints.html#YouTube ''Tidal bore research''] (2017) The University of Queensland.

{{Physical oceanography}}
{{Authority control}}

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