The river channel of the North Branch of Changj iang Estuary has been narrowed and its bed has been silted for recent years because of natural processes and artificial actions, which are the main causes of increased bore frequency and strength.

• 北支在自然和人为的影响下,河槽不断束狭、河床逐渐淤浅是近年来涌潮发生次数增多、潮头增大的原因。