Cao E Jiang

Cao E Jiang

Cao'e River, the largest tributary of Qiantang River, which flows into the East China Sea alone, is named after Cao'e, a girl of the Eastern Han Dynasty, who went to save her father. The area near Shengzhou is also called Shanxi, Shangyu is also called Shangyu River, the area near Baiguan is called Shunjiang in ancient times, and the downstream section is called dongxiaojiang in ancient times.

Cao'e River originates from Changwu of Dapan mountains in Wangcun village, Shanghu Town, Pan'an County. It flows from south to north through Xinchang County, Shengzhou City, Shangyu district and Keqiao district. It flows into Hangzhou Bay through Cao'e River Sluice at the downstream of new Sanjiang sluice below Sanjiang estuary in Shaoxing. The total length of the main stream is 193 km (197.2 km)

）The drainage area is 5099.15 square kilometers (6080 square kilometers)

）The upper reaches are above Shengzhou Chengguan, the middle reaches are from Shengzhou Chengguan to Shangyu Baiguan, and the lower reaches are from Shengzhou Chengguan to Shangyu Baiguan. The upstream section is a mountain stream River, and the tidal section below Shangpu sluice in the middle reaches is affected by the tide of Hangzhou Bay.

Cao'e River is the last important tributary flowing into Qiantang River. Most of the rivers are important industrial and agricultural water sources in coastal areas, with Shangpu sluice and other diversion projects. The downstream shipping capacity is strong, and Cao'e port is an important port. The estuary is greatly affected by sea tide, and the famous Caoejiang sluice project is built to prevent (flood) and control waterlogging.

General situation of main stream

River course

Cao'e River, ancient hydrology said: Shan River (that is, the middle reaches of Cao'e River) four sources: chengtan River, Xinchang River, huangze River and Changle river. Chengtan river is the source of modern hydrology, so the main stream of Cao'e River from the source to the estuary is Jiaxi (the source of chengtan River), chengtan River and Cao'e River.

Jiaxi section

In Pan'an County, the upper reaches of chengtan River, the main stream of Cao'e River, is called Jiaxi. It originates from jiangongling (870 meters above sea level) of Changwu, Shanghu Town, Pan'an County, and is initially called Teng river. It flows through Shanghu and wancang and flows into wuzhangyan reservoir, which is called Jiaxi. Then it flows into Shimen Reservoir of Xinchang County through Jianshan town, wulongxia scenic area, shibawo Scenic Area, underwater hole scenic area and huzhaixiang. In Xinchang, it is called Chengtan river. The main stream is 33km long and the drainage area is 179.1 square meters Km.

Chengtan river section

In Xinchang County, Chengtan river flows into Shengzhou City from jingling, chengtan, Meizhu and other towns from south to north, and flows into Shengzhou City from Baidu River, with a total length of 91 km. Xinchang is 44.1km long, with a drainage area of 388.63km2, accounting for 3l.8% of the total area of the county. The upstream and downstream river widths are about 80-140m respectively. More than 60% of the county's arable land and more than 70% of its population are concentrated on both sides of the Strait. After the founding of the people's Republic of China, Shimen Reservoir and Menxi reservoir were built in the upper reaches of Xinchang County, which provided guarantee for controlling and alleviating flood disasters along the river.

Cao'e River Section

In Shengzhou City, the main stream of Cao'e River is chengtan River, its tributaries are Changle River, Xinchang River, huangze River, etc., which successively converge in taojiu, Nanjin bridge, wannianting and other places near Chengguan town. After the confluence of the tributaries, the amount of water increased sharply. The section from the confluence of chengtan River and Changle River to the third boundary is called Shanxi River, which is called Cao'e River. The main stream is 32.2 km long in the city. Near Chengguan Town, it is about 7 km from sanjutan, Xianyan town to ma'aohong, Sanjie town. In the river valley, below ma'ao, the river becomes wider. It flows northward into Shangyu. The annual average flow of Cao'e River in Shengzhou City is 1.66 billion cubic meters, the annual average flow is 52.6 cubic meters per second, and the annual average flow of the driest month is 23.0 cubic meters per second. The maximum discharge was 447 cubic meters per second (1962), and the minimum discharge was 0 cubic meters per second (1971). However, with the completion of Changzao reservoir at the source of Xinchang River in the upper reaches of Cao'e River (1980), the water flow of Cao'e River has been greatly regulated. According to the actual measurement of Shengzhou hydrological station since 1980, the minimum flow in dry season is not less than 4.14 cubic meters per second, and the flow at 90% guarantee rate is 8.796 cubic meters per second. Cao'e River is a perennial river. Near Shengzhou City, the river course is curved and silted up. Below Shangpu sluice, there is a tidal reach with a general drop of about 40cm and a maximum tidal range of 60cm.

In Shangyu District, it flows through Xinchang County and Shengzhou from south to north, enters Pingyuan village, Qingtan Township, Shangyu District, passes 18 townships (towns) including Longpu, binjian, Zhangzhen, Lianjiang, Shangpu, haoba, Jiangshan, Lianghu, Baiguan, ejiang, Zhongtang, Huazhen, Daoxu, DuPu, Xiaojin, Sanlian, Lidong, Sanhui, etc., and connects Ma'an town (formerly Keqiao District) in kesiqiao District of Shaoxing City with bayiqiu Lihai town in Shangyu District flows into Qiantang River Estuary through Cao'e River sluice, with a total length of 193 km and a total drainage area of 6046 square km, 69 km and 649 square km in Shangyu. Cao'e River, also known as Shunjiang River in ancient times, is also known as Shanxi River and Shangyu river. In the second year of Han'an in the Eastern Han Dynasty (143), the story of Cao'e, a Shangyu man, who went to seek his father in the river, was changed to its present name after it was spread. Now the upper reaches of chengtan River, in Shengzhou huangze river below the beginning of Cao'e River. The tributaries in the area are Fanyang River, Yintan River, Xiaguan River and Xiaoshun river.

Channel characteristics

Chengtan river is the upstream section of the main stream of Cao'e River, from its source to Chengguan town of Shengzhou, with a length of 85 km and a drainage area of 854 square km. The main tributaries are Changle River, Xinchang River and huangze River, which successively converge near Chengguan Town, showing a typical fan-shaped water system. There are two large reservoirs in Changzhao and Nanshan, and four medium-sized reservoirs in Bantou, liaowan, Shanyuan and Qiaoying, which have played a certain role in alleviating flood, drought and other disasters in the middle and lower reaches. Restricted by Qingfeng gorge, the section from Xianyan to Yipu in the middle reaches is close to the Bank of the river with narrow river surface, blocking water and detention. Below Xipu, the river flows into the flat Zhangzhen basin, with gentle water potential. From the south to the north, the middle reaches are divided into Yintan River, Xiaguan River, Fanyang River, Xiaoshun River and other tributaries. The downstream river is widened and the water depth is increased, which is affected by the tide. Along both sides of the river, there are dikes and ponds, Baili seawall in the East and Xiaoshao seawall in the West.

hydrographic features

Cao'e River is a perennial River, the upstream is a mountain stream River, and the downstream is a tidal channel. The river bed is 100-600 meters wide, the average water depth in the middle reaches is 4-5 meters, and the water depth in the lower reaches is 1-2 meters.

Shangyu dongshabu hydrological station measured that the maximum runoff was 6420 M / s, the highest water level was 13.42 m (September 6, 1962), and the lowest water level was Hegan (dongshabu hydrological station) on August 19, 1967. Over the years, Shangyu has exported 3.105 billion cubic meters of water annually. The upper reaches of Cao'e River are characterized by large gradient, rapid flow and stream like characteristics. After entering Shangyu, the river is open, the current is gentle, and affected by the tide, the tide goes up to Shangpu sluice. The river water flow is affected by seasonal rainfall distribution, and the river water rises and falls sharply. Generally, the difference between the annual maximum water level and the annual minimum water level is more than 9 meters.

From 1972 to 1990, the average annual discharge of Shengzhou station was 55.7 cubic meters per second. In 1973, the annual average discharge was 84.1 cubic meters per second, and the annual runoff was 2.651 billion cubic meters; in 1979, the annual average discharge was 28.4 cubic meters per second, and the annual runoff was only 896 million cubic meters. The highest water level over the years measured by Shengzhou station on Cao'e River is 22.63 meters (1962), the lowest value of the highest water level over the years is 16.90 meters (1976), and the average value of the highest water level over the years is 19.89 meters.

Cao'e River is a tributary of the lower Qiantang River near the estuary, which is greatly affected by the tide of Hangzhou Bay. The tide jacking will not only cause the river flow to stagnate and flood discharge to be impeded, which will affect the drainage of the Neijiang River, but also cause sediment deposition, increase the riverbed and aggravate the flood disaster. The influence of tides is not conducive to irrigation. For example, above Shangpu of Cao'e River, the influence of tides is very slight or not affected, so they are all fresh water and can be used for irrigation; below Shangpu, the influence of tides is great and the salinity of river water increases, so they cannot be used for irrigation. Cao'e River is the last important tributary flowing into Qiantang River, so it is greatly affected by the tide. When the water level is low, the tide can go up to between zhangjiabu and Sanjie; the surge into the river mouth is as high as 0.9-1.2 meters, and a vertical surge of 0.6 meters has been observed in Baiguan. According to the observation in 1923, the tide level records of xinbutou (may 10-july 13), Baiguan (may 10-july 13), Shangpu (may 20-July 13) and zhangjiabu (may 22-July 13) are as follows. The characteristics of tidal level are tidal range, the highest and lowest tidal levels, and the duration of rising and falling tides. The highest tide level measured at Shangpu station over the years is 12.85 m (September 7, 1962), and the lowest tide level measured at Shangpu station is 2.37 m (December 29, 1990). The maximum tidal range is 4.50 meters at sangpendian station (Mashan, Shaoxing) on July 28, 1968, generally less than 3 meters. Generally, the duration of high tide is about 2 hours and that of low tide is about 10 hours. In recent years, a large amount of sediment has been excavated in the river, which leads to the decrease of the river bed and the increase of the tide influence. For example, the tide influence of Cao'e River has only reached dongshabu for a long time, but it has reached Qingfeng gorge in Shengzhou in 1990.

The Cao'e River Basin is one of the rivers with the largest amount of sand and serious flood in Zhejiang Province. The annual erosion modulus of the upper reaches of the river reaches 400 tons / square kilometer

Chinese PinYin : Cao E Jiang