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Tidal bore of the Sélune river, Baie du Mont Saint Michel, France on 7 April 2004 (3)


When a river mouth has a flat, converging shape and when the tidal range exceeds 6 to 9 m, the river may experience a tidal bore ([1,2,3]). A tidal  bore is basically a series of waves propagating upstream as the tidal flow turns to rising. Hubert Chanson observed the tidal bore of the Sélune river, in the South-East of the Baie du Mont Saint Michel, France on 7 April 2004 when the tidal range exceeded 13 m [4,5]. The bore was first seen at Roche-Torin around 7:50 to 8:13am (Videos 1 and 2), and later at Pont Aubaud around 8:59am to 9:03 (Video 3).

This series of videos shows the Baie du Mont Saint Michel at sunrise before the arrival of the bore (Video 1), then the tidal bore at Roche-Torin, and at Pont Aubaud about 50 minutes later. The videos are associated with some technical details published in [4] and [5], and a series of photographs published in [6, 7, 8]. Two further websites on tidal bores are [7] and [8].


Hubert Chanson


Hubert Chanson


[1] CHANSON, H. (2001). "Flow Field in a Tidal Bore : a Physical Model." Proc. 29th IAHR Congress, Beijing, China, Theme E, Tsinghua University Press, Beijing, G. LI Ed., pp. 365-373 (ISBN 7-302-04676-X/TV). (CD-ROM, Tsinghua University Press, ISBN 7-900637-10-9.) {}

[2] CHANSON, H. (2005). "Physical Modelling of the Flow Field in an Undular Tidal Bore." Jl of Hyd. Res., IAHR, Vol. 43, No. 3, pp. 234-244 (ISSN 0022-1686). {}

[3] CHANSON, H. (2004). "Environmental Hydraulics of Open Channel Flows." Elsevier Butterworth-Heinemann, Oxford, UK, 483 pages (ISBN 0 7506 6165 8). {}

[4] CHANSON, Hubert (2004) Coastal Observations: The Tidal Bore of the Selune River, Mont Saint Michel Bay, France. Shore & Beach 72(4):14-16.  {}

[5] CHANSON, Hubert (2005) Tidal Bore Processes in the Baie du Mont Saint Michel (France): Field Observations and Discussion. In Jun, B. H. and Lee, S. I. and Seo, I. W. and Coi, G. W., Eds. 31st IAHR Biennial Congress, 11-17 September, 2005, pages 4037-4046, Seoul, Korea. {}

[6] KOCH, Christian and CHANSON, Hubert (2005) An Experimental Study of Tidal Bores and Positive Surges: Hydrodynamics and Turbulence of the Bore Front CH65/05, Department of Civil Engineering, The University of Queensland. {}

[7] CHANSON, H. (2004). "Tidal bores, Mascaret, Pororoca. Myths, Fables and Reality !!!" Internet resource. (Internet address :

[8] CHANSON, H. (2000). "The tidal bore of the Seine river, France. Le Mascaret de la Seine." Internet resource. (Internet address :

See also