Input (grade 7): At certain times of the year, the lower tidal reaches of the Trent experience a moderately large tidal bore (up to five feet (1.5 m) high), commonly known as the Trent Aegir.
Output (grade 4): At certain times of the year, the lower tidal reaches of the Trent experience a tidal bore which can be up to five feet (1.5 m) high.