List of rivers that have reversed direction
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File:ReversingFalls inbound.jpg of Saint John River]]
A number of rivers are known to have reversed the direction of their flow, either permanently or temporarily, in response to geological activity, weather events, climate change, tides, or direct human intervention.
Permanent reversals
=Natural=
| class="wikitable" style="text-align:center"
! River !! Original outlet !! Current outlet !! Continent !! Date of reversal !! Cause of reversal !! References | ||||||
| Amazon River | Pacific Ocean | Atlantic Ocean | South America | data-sort-value="1 Jan -145000000" | Cretaceous period | Formation of Andes Mountains | |
| Wisconsin River | Great Lakes Basin | Mississippi River | North America | Pleistocene Epoch | Pre-Illinoian glaciers | {{Cite web|url=https://www.wiscontext.org/when-wisconsin-river-flowed-east|title = When the Wisconsin River Flowed East|date = 11 September 2018}} |
=Artificial=
| class="wikitable" style="text-align:center"
! River !! Original outlet !! Current outlet !! Continent !! Date of reversal !! Cause of reversal !! References | ||||||
| Chicago River | Lake Michigan | Mississippi River | North America | 1900 | Construction of Chicago Sanitary and Ship Canal |
Temporary reversals
=Daily=
All tidal sections of rivers reverse their flow with the tide about twice a day (or semidiurnally), by definition. The following are notable examples.
| class="wikitable" style="text-align:center"
! River !! Outlet !! Continent !! References | |||
| Hudson River | Upper New York Bay | North America | |
| Saint John River (Reversing Falls) | Bay of Fundy | North America | |
| Salmon River | Bay of Fundy | North America | |
| Channel of Vivari | Straits of Corfu | Europe | [https://intarch.ac.uk/journal/issue62/2/ia.62.2.pdf Butrint National Park - Combining Natural Park with Cultural Heritage] Retrieved 8 May 2024. |
=Annual=
| class="wikitable" style="text-align:center"
! River !! Outlet !! Continent !! Cause of reversal !! References | ||||
| Krupa River | Neretva River | Europe | High water levels of the Neretva River | [https://medwetmanagers.net/hutovo-blato-between-the-past-the-present-and-the-future/ Krupa River] Retrieved 30 August 2022. |
| Petexbatún River | Pasión River | Central America | Winter rain flooding of the Pasión River | [https://prensacomunitar.medium.com/riesgo-de-desastre-ecol%C3%B3gico-irreversible-se-est%C3%A1-secando-la-laguna-de-petexbat%C3%BAn-e000e5e8905 The Petexbatún eco-system] (in Spanish) Retrieved 30 January 2021. |
| Qiantang River | Hangzhou Bay | Asia | Tidal bore in Hangzhou Bay | [https://www.theatlantic.com/photo/2016/09/the-bore-tides-of-the-qiantang-river/500843/ The Bore Tides of the Qiantang River] Retrieved 30 January 2021. |
| Tonlé Sap River | Mekong River | Asia | Monsoon flooding of the Mekong River |
=Intermittent=
Hurricane storm surges often cause temporary reversals of coastal rivers.
| class="wikitable" style="text-align:center"
! River !! Outlet !! Continent !! Date of reversal !! Cause of reversal !!References | |||||
| Chicago River{{efn|group=intermittent|These reversals represent a return to the Chicago River's original natural outlet in Lake Michigan.}} | Mississippi River | North America | 2017 and others{{efn|group=regular|Reversals of the Chicago River have been increasing in frequency in association with global warming, and may soon occur at least once each year.}} | Storm surge | |
| rowspan="4" | Mississippi River | rowspan="4" | Gulf of Mexico | rowspan="4" | North America
| 1812 | Tectonic uplift caused by New Madrid earthquakes | ||
| 2005 | Storm surge from Hurricane Katrina | ||||
| 2012 | Storm surge from Hurricane Isaac | ||||
| 2021
|Storm surge from Hurricane Ida |
{{Notelist|group=intermittent}}
See also
- Stream capture, in which a stream or river is diverted from its own bed, and flows instead down a neighboring channel
References
{{reflist|refs=
{{cite news |last1=Jennings |first1=Ken |title=Why the Tonle Sap River Is Unlike Any Other River in the World |url=https://www.cntraveler.com/stories/2015-02-02/maphead-ken-jennings-cambodia-tonle-sap-river |accessdate=18 March 2019 |work=Condé Nast Traveler |date=February 2, 2015}}
{{cite web |title=The Hudson Estuary: A River That Flows Two Ways |url=https://www.dec.ny.gov/lands/4923.html |publisher=New York State Department of Environmental Conservation |accessdate=19 March 2019}}
{{cite web |title=How Climate Change Is Making This River Run Backwards |url=https://www.ecowatch.com/chicago-river-run-backwards-2429212108.html |website=EcoWatch |publisher=Natural Resources Defense Council |accessdate=19 March 2019 |date=June 4, 2017}}
{{cite news |title=Mississippi River Flows Backwards Due to Isaac |url=https://archive.usgs.gov/archive/sites/www.usgs.gov/newsroom/article.asp-ID=3387.html |accessdate=19 March 2019 |work=USGS Newsroom |publisher=United States Geological Survey |date=August 29, 2012}}
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{{rivers, streams and springs}}
{{river morphology}}