Simplify the following text for a Grade 6 native English-speaking person.
Original: 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 .
Simplified: 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 .