The water of the North River is now running westerly to the West River and, therefore, the water from the West River cannot flow into Guangzhou through the small stream, Sixianjiao.

• 由于北江正干的淤积、西江正干刷深，使古代（唐代以前）西江合北江同流向东流人番禺（广州）的形势大变，形成江水反向西流人西江，西江水不能过滘人广州。