Sanggan River is the upper reaches of Yongding River (under Lugou Bridge) and belongs to Haihe River system. According to legend, every year when the mulberries mature, the river will dry up, hence the name. Sanggan River flows out of Shanxi Province in Weijiabao Village, Nanxuzhuang, Yanggao County, Datong. In Huailai County, Hebei Province, Zhuguantun meets Yanghe River, which is called Yongding River. Then it flows through Hebei Province and Beijing, and flows into Haihe River and Bohai Sea in Tianjin.
The origin of sanggan river
Sanggan River originates from the northern foot of Guancen Mountain in Shaanxi Plateau, flows through Datong Basin, Huangnashui River, Hunhe River, Yu He River and Erdao River in the northeast, flows into Hebei Province, flows into Liuhu River in Qianjiashawa, Hua Shao Township, Yangyuan County, flows through Xuanhua County and Zhuolu County in the northeast, flows into Yanghe River at the junction of Zhuolu County and Huailai County, and enters Guanting Reservoir. Out of Guanting Reservoir, it is called Yongding.