Yin Hua River, the largest tributary in the upper reaches of Danjiang River, has two sources. Nanyuan is an east-west gully, which originates from the residual vein on the east side of Guling-Banban at an altitude of 1468.4m; The north source is the North River, which originates from the foot of the slope at the southern foot of Liu Ling, and the two sources meet the high dam, and the flow direction is east-west. It has successively accepted major tributaries such as Nanjiageng River, Damiaogou, Luoyu River, Shang Lu River, Gulu River and Shicaogou, and paid attention to Danjiang River in Zhu Lin.
Wuguan River is a large tributary of the upper reaches of Danjiang River, which originates from the south side of Mangling Mountain at an altitude of 1.744 meters, flows into Gengjiahe River in the southeast, and is called Wuguan River only after reaching Shimen. It turns north and south in Luanzhuang and flows into Danjiang River through Wuguan, Mao Ping and Yujiawan. There are many tributaries of Wuguan River, among which Xiahe, Taoping River, Zhaochuan River and Baiyangguan River are the largest. The tributaries on both sides are symmetrically distributed, with an average width of 7.7 kilometers, which is an obvious dendritic water system.
Qin Nan, also known as inlet and outlet, is a first-class tributary of Danjiang River. It originates from Jiguanling, Dongyuemiao Township in the west of Shangzhou City, flows from west to east, with a total length of 48 kilometers, and joins Danjiang River in Liuwan Township. The basin covers an area of 575.9 square kilometers, with an altitude of 702 ~ 1577.6 meters, a total drop of 875.6 meters and an average slope of 0.83%. The main tributaries are Lincha River, Shidaoyu, Chishui Valley, Shilongwan River, Jinling Temple River and Liuyuhe. The average annual runoff in Qin Nan is10.60 billion cubic meters, the runoff modulus is 7.93 cubic meters per second, the average flow is 3.53 cubic meters per second, and the measured maximum flow is 44 1 cubic meter per second.
The annual distribution of runoff is more in summer and autumn and less in winter and spring. The average sediment concentration is 4.44 kg/m3, the average sediment transport rate is 18.4kg/sec, the average annual sediment transport is 634,000 tons, the erosion modulus is 1302 tons /km2, and the measured maximum erosion modulus is 2,750 tons /km2.
Danjiang River, a tributary of the Han River and the Yangtze River system, flows into the Han River in danjiangkou city, hence the name Danshui Yu Yao. Named after the legend that Dan fish was once produced. Legend has it that Yu's grandson used to control water here. In memory of him, it was later called Danshui and Danjiang. Danjiang River was called Danhe River and Danshui River in ancient times, also known as Danyuan, Chishui and Fenqing River. In Shaanxi, also known as Zhouhe, Xichuan County, Henan Province, danjiangkou city Section, Hubei Province, formerly known as Shui Jun.
Danjiang River originates from the southern foot of Qinling Mountain in the northwest of Shangluo area, Shaanxi Province, flows through Shaanxi Province, Henan Province and Hubei Province, joins the Hanjiang River in danjiangkou city, Hubei Province, and flows into Danjiangkou Reservoir. With a total length of 390 kilometers, the main stream is the longest tributary of the Han River, with a drainage area of 1.73 million square kilometers, accounting for 10% of the total drainage area of the Han River. The average annual flow is 174 m3/s, and the natural drop is 140 1 m ... In history, Danjiang shipping was developed, and the Ming and Qing Dynasties were the golden age of Danjiang shipping.
Danjiang River has the characteristics of small runoff, great interannual variation, serious and frequent floods and high sediment concentration. The water conservancy project in the basin is a famous ancient river project connecting Danjiang and Bashui. After 1950s, water conservancy and hydropower projects such as Erlongshan and Longtan were built along the Yangtze River, which played a role in water storage and irrigation, power generation and flood regulation.