Sand and mud brought down by the river gradually formed the upper and lower hamlets of Ch'i-wu-lan and Chou-tzu-wei, thus setting up the rivalry that underlies the nearly 200 year-old tradition of the Erh-lung dragon boat race.
河水帶來泥沙，因著時間推移形成了淇武蘭與洲仔尾上、下二莊，也寫下了二龍鬥舟近二百年的「二龍演義」。