In the sixth year of the Republic of China (19 17), "Jiangyan Town, Jiangyan City, was called Sanshui in ancient times, where rivers, Huai and lakes all gather, and its water reaches Wanzikou in the west, and it is called Luotang in the east and north." Chongzhen's "Taizhou Zhi" contains: "Jiangyan, in front of Tianmu Mountain, is forty-five miles east of the state, and the flowing water flows north to Xixi Yunyan River and reaches Shanghe River. In the second year of Jiayou (1057), Wang moved to the weir near the Zhuang side of the Southern Song Dynasty, and in the second year of Xuanhe (1 120), he moved to Luotang Port near the mouth of the canal. " According to legend, from the Northern Song Dynasty to Renzong, Taizhou businessman Jiang bought land near Zhouzhi to Tianmu Mountain. At that time, there was sea water in the east, river water in the south and Huai water in the north, which was often a disaster. Jiang and Jiang Hua's father and son contributed money twice, led the people to build dikes and fight floods twice, and finally moved the weir (dam) to Luotang Port near the mouth of the canal. The upper dam and the lower dam were probably formed at this time.