Yuxi River Yuxi River was called Ruxushui in ancient times and connected with the water of Chaohu Lake system. The ancient ruxu water is the earliest Tongjiang river course in Chaohu Lake, which was formed in the Western Han Dynasty (206 BC-25 AD) and started at the mouth of ruxu. Ruxukou is located between Ruxushan and Qibaoshan. Ruxushan is located in Dongguan Township, hanshan county, which was called Dongguan in ancient times. Qibaoshan is in Huanghua Township, Wuwei County today, called Xiguan. The confrontation between the two mountains, surrounded by dangers, is the exit of the ancient Chaohu Lake, which was once the ancient battlefield of Wu and Wei. Ruxu water flows southward from Huangluo River mouth, passes through Cangtou Town to Makou Gate, enters Makou between the ninth William and the ninth William, and enters the Yangtze River at Shentang River mouth. The earliest estuary is the gate port downstream of Shentangkou, which has collapsed into the river. Later, the section between Shentangkou and the gate port also collapsed into the river, and the ruxu River retreated to Shentangkou.

By the Southern Song Dynasty (1 127 ~ 1279), the Tongjiang River from Chaohu to yuxikou was gradually formed. From Chaohu Lake to Dongguan, the section along the north dike of Yangliuwei to Sanchahe Town is called Houhe River, and it enters the river in the east. Starting from Xiekou, go straight through Huangluo River, reach Nahou River of Sanchahe River, reach Yongzheng, which is called River, and enter the river in the northeast. At this point, the Tongjiang River in Chaohu Lake has become two, namely, the ruxu River flowing south and the Yuxi River flowing east. In the 12th year of Tongzhi in Qing Dynasty (1873), the Shentang River mouth was blocked, and Yuxi River became the only channel for Chaohu Lake to enter the river, and Xihe River became the main tributary of Yuxi River. The upper reaches of Gurusu River from Dongguan to Huangluo Estuary have become a part of Yuxi River, and swimming from Huangluo Estuary to Makouzha has become the middle and lower reaches of Xihe River. From Song Dynasty to Ming and Qing Dynasties, the section from Chaohu to Dongguan of Yuxi River was called Tianhe, also known as Caohe, commonly known as Maweigou; The section from Dongguan to HuangLuohe Town is called Tiemao River; The reach from Huangluo Town to Cao Yun Town is called Caoyun River; Cao Yun Town, hereinafter referred to as Yuxi River, flows northeast into the Yangtze River through Yong Town (namely ruxu Town).

Yuxi River Basin covers 1 1 cities and counties such as Juchao District, Hefei, Feidong, Feixi, Lu 'an, Yuexi, Shucheng, Lujiang, Wuwei, Hanshan and Hexian. Watershed scope: bounded by Jianghuai watershed and Huaihe River basin in the west and north, adjacent to Caizi Lake, Baidang Lake and Sabrina Lake system in the south, adjacent to Chuhe River, Desheng River and Niutun River system in the northeast, and adjacent to the Yangtze River in the southeast. The total basin area above yuxikou is 12938 square kilometers, including 3386 square kilometers in mountainous areas and 6070 square kilometers in hills.

The polder in the middle of the lake covers an area of 2,479 square kilometers, and the lake surface 1003 square kilometers (including 783 square kilometers in Chaohu Lake). Yuxi River receives Chaohu Lake water, and the main rivers flowing into Chaohu Lake are: Zhaohe River, with a catchment area of 536 square kilometers, of which Huangpi Lake 1 138 square kilometers, with a river length of 34 kilometers; Baishi Tianhe, with a catchment area of 6 19 square kilometers and a river length of 35.5 kilometers; Hangbu River, with a drainage area of 4 150 square kilometers (including 2080 square kilometers of Fengle River) and a river length of 145.5 kilometers; Fengle River, a tributary of Hangbu River, has a drainage area of 2,080 square kilometers and a river length of 1 17.5 kilometers. Shangpai River has a catchment area of 584 square kilometers and a river length of 60 kilometers. Nanfeihe River, with a drainage area of 1446 square kilometers and a river length of 70 kilometers; The Gao Zhe River basin covers an area of 507 square kilometers, and the length of its main stream is 24.4 kilometers.

Yuxi River starts from Chaohu Gate, flows southeast, passes through the county seat of North Korea to Lijiadun, and reaches Qingxi River in Zuo Na. When I arrived at Lintou, the river in Zuonalintou came; Through Diaoyutai and Dongguan to Wachu Village, there are two streams: Laoyuxi River in the north, which has merged into the flood diversion channel of Niutun River, flows eastward to Taozui, and is connected with Niutun River through Tongcheng Gate; Yuxi Nanxi flows south to Huangluo River, and right Naxi comes to water; The river below the Huangluo River flows in a straight direction to the southeast, passing through Cao Yun Town to Sancha River, and a waterway on the left bank communicates with Niutun River through Tongchengmen. After passing through Huang Du to Yongjia Town, it turns north and flows east. After passing through Yuxi Gate in Yuxi Town, it turns east and joins the Yangtze River at Yuxi Mouth. The total length of the river is 60.4 kilometers, including 56.5 kilometers from Chaohu Gate to Yuxi Gate and 3.9 kilometers from Yuxi Gate to Hekou. The river bottom elevation is 4.2m from Chaohu Gate to Diaoyutai Gate and 5.0m from Diaoyutai Gate to Yuxi Gate. River width 125 ~ 145 m, river bottom width 100 ~ 120 m, slope1/34000; The safe discharge is 600 ~ 800 m3/s, once every 20 years, 1 170 m3/s and once every 0/00 years. See Table 3-3 for the historical maximum and minimum discharge and maximum and minimum water level of Yuxi River.

1969 The suspended sediment under Chaohu sluice is the largest in history, with an annual average sediment concentration of 0.170kg per cubic meter, an annual average sediment transport rate of 42. 1 kg per second and an annual sediment transport of 0/330,000 tons. 1968 is the lowest in history, with an annual average sediment concentration of 0.083kg/m3, an annual average sediment transport rate of -0.66 1 kg/s and an annual sediment transport of-20,900 tons.