The Trent Aegir 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 (up to five feet (1.5m) high). It takes its name from Ægir, the Norse god of the ocean.[1]
The aegir occurs when a high spring tide meets the downstream flow of the river.[1] 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.
The aegir can be seen at Gainsborough, Morton, East Stockwith, West Stockwith and Owston Ferry. The Environment Agency publishes predictions for the occurrence of the bore.[2]
It is alleged that King Cnut (Canute) performed his purposely unsuccessful attempt to turn the tide back in the River Trent at Gainsborough. If this is the case, it is highly probable that Cnut was attempting to turn the aegir tide.