Trent Aegir

The Trent Aegir, also known as the Eagre, is a tidal bore on the River Trent in England. At certain times of the year, the lower tidal reaches of the Trent experience a moderately large bore high). It is said to take its name from Ægir, the Norse god of the ocean, although this is disputed. A more likely derivation is from Old English ēagor .
The Aegir occurs when a high spring tide meets the downstream flow of the river. The funnel shape of the river mouth exaggerates this effect, causing a large wave to travel upstream as far as Gainsborough, Lincolnshire, and sometimes beyond. The Aegir cannot travel much beyond Gainsborough as the shape of the river reduces the Aegir to little more than a ripple, and weirs north of Newark-on-Trent, Nottinghamshire stop its path completely.

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