Longhekou reservoir

Longhekou reservoir

Longhekou reservoir is built in the upper reaches of Hangbu River, a tributary of Chaohu river system in Shucheng County, Anhui Province. The reservoir area is 1111 square kilometers, accounting for 56.4% of the total area of 1970 square kilometers above datanwan in Hangbu River Basin. The total storage capacity is 820 million cubic meters, and the bottom storage capacity is 53 million cubic meters. It was started in November 1958, and was mainly operated by the county office in the initial stage. The project was suspended in April 1961 and resumed in October 1965. It was included in the infrastructure project and completed in October 1969.

The reservoir dam, known as the world's first artificial earth rock dam, was praised as "a very remarkable project" by Mr. Lanxi, former chairman of the United Nations Commission on dams.

Hekou reservoir is not only the water source project of hangbuhe irrigation area, but also the headwork project. The flood protection area is 530000 mu. After the construction of the reservoir, the flood burden of Hangbu river was greatly reduced. It irrigated 1.55 million mu of farmland in Shucheng, Lujiang and Lu'an counties.

Longhekou reservoir area is an important part of China's Dabieshan Geopark. At the beginning of the 21st century, Wanfo Lake Town, Shucheng County, where the reservoir is located, began to use the natural resources of the reservoir area to develop tourism projects, and named "Wanfo Lake". Selected as a national 4A tourist area, it has been identified as one of the key tourist attractions in Anhui World Expo. In 2016, it successfully established a national 5A scenic spot and became the 11th 5A scenic spot in Anhui Province.

Reservoir characteristics

Longhekou reservoir is built in the upper reaches of Hangbu River in Shucheng County, Anhui Province. The reservoir area is 1111 square kilometers, accounting for 56.4% of the total area of 1970 square kilometers above datanwan in Hangbu River Basin. The total storage capacity is 820 million cubic meters, and the bottom storage capacity is 53 million cubic meters.

Main works

The reservoir complex is composed of main dam, auxiliary dam, spillway, temporary extraordinary spillway and Meiling and Niujiaochong intake gates.

Library part

The main dam is divided into east dam and west dam. There is a hill between the two dams. It is located at the Longhekou of Hangbu River between Castanopsis mountain and Niutoushan mountain in Shucheng County, with a total length of 600 meters. Both of them are sand shell dams with clay core. The crest elevation has changed many times. In 1958, it was designed for 50 years and checked for 200 years. The dam crest elevation is 71m (taking Wusongkou as the zero point, the same below). In 1960, it was designed according to 100 years and checked in 1000 years, and the crest elevation was 75 meters; in 1965, it was rebuilt to 74.4 meters; in 1975, it accepted the lesson of linzhuang, Henan Province, and in 1976, it increased the crest elevation to 75.4 meters and the crest width to 5 meters, and built a wave wall with the crest elevation of 76.5 meters. The length of the East and West dams are 320m and 280m respectively, and the maximum dam height is 33.4m and 32.4m respectively. From east to west, there are eight auxiliary dams, including duxiaodian, matigang, niujiaolao, Guankou, sichong, luohuachong, mosongchong and datanggeng, with a total length of 998m, the highest dam height of 9.5m and the crest elevation of about 75m. The spillway is located at doulichong, one kilometer east of the east dam. It is open and has a maximum discharge of 3820 m3 / s. Fenghuangchong and menkanshi temporary extraordinary spillways, the maximum discharge is 3910 m3 / s.

Irrigation area

Longhekou reservoir is not only the water source project of hangbuhe irrigation area, but also the canal head project. The water is diverted from Niujiaochong and Meiling intake gates of the reservoir respectively. According to the original plan, the main canal of hangbei main canal is connected with the main canal of pihang through Jiangjunshan aqueduct and Dashan aqueduct, and the South-to-North Water Diversion Project will connect the irrigation area of hangbuhe river with that of Pihe River. In 1981, the water resources and irrigated area of Pihe irrigation district and hangbuhe irrigation district were analyzed and balanced again. It was considered that the water quantity was insufficient to meet the agricultural water demand of this irrigation district. Therefore, the actual benefit of the communication project in hangpi irrigation area is not great.

The headwork is composed of two intake gates, Niujiaochong and Meiling, of Longhekou reservoir. Niujiaochong sluice is the head of Shulu main canal, with two inlets, 2.3m wide and 6m high, and one outlet, 4.6m wide and 6m high, and 62m long. The sluice body is a reinforced concrete drainage culvert structure, which is located under the earth rock mixed dam. The designed irrigation flow is 55 cubic meters per second, and the flood discharge is 100 cubic meters per second. Meiling intake sluice is the head of the main canal in North Hangzhou. It is located under the 58 meter long masonry gravity dam, with four gate shaped diversion culverts. The single hole is 2 meters wide and 3.6 meters high. The designed irrigation flow is 50 cubic meters per second, and the flood discharge is 100 cubic meters per second.

Meiling intake sluice is located in the north of dameishan, Niujiaochong intake sluice is located in the east of the spillway of the reservoir, which are hangbei main canal, Shulu main canal and canal head respectively. The flood discharge is 100 m3 / s, the irrigation flow is 50 m3 / s in Meiling, and 55 m3 / s in Niujiaochong.

Construction and maintenance

It was started in November 1958, and was mainly operated by the county office in the initial stage. The project was suspended in April 1961 and resumed in October 1965. It was included in the infrastructure project and completed in October 1969.

In the construction of the reservoir project, the masses of Shucheng County worked 10 million working days, and the state invested 23.39 million yuan, with a total of 1.37 million cubic meters of earthwork, 400000 cubic meters of stonework, and 22400 cubic meters of concrete. During the construction, Shucheng County mobilized more than 50000 workers. In June 1959, Zeng Xisheng, the first Secretary of the CPC Anhui Provincial Committee, inspected the construction site and immediately allocated 1000 flatbed trucks. Later, governor Huang Yan allocated 500 rubber tyred unicycles to improve work efficiency. In the first ten days of February 1960, at the critical moment of Helong of dongdaba, more than 500 male and female Communist Party members and members of the Communist Youth League, including Xu Fanghua, Xie Dayong and Wang Chengying, took the lead in diving into the water and formed three human walls, which made the Helong of dongdaba successful. When the spillway was blasted on March 15 of the same year, Zhao Xuexue, deputy director of Shucheng County Water Conservancy and Power Bureau, and Wang Conggao, a migrant worker, unfortunately died in order to protect the migrant workers in the warning area. In May 1963, the original diversion channel of the west dam caused a small gush of water after a rain, and then reduced to a seepage shape, and appeared many times. In 1966, two vertical shafts were excavated in the clay core walls of the East and West Main dams. Through trench inspection, it was found that there were two attack joints in the core walls, which were roughly parallel to the dam axis. After clay curtain grouting and anti-seepage reinforcement, it ended in 1971. The spillway gate was completed in 1969. The flood discharge in the flood season of that year exceeded 1500 m3 / s, the river channel under the gate backflowed, the earth dam on the right bank landslide, and cracks appeared in the four corners of the spillway gate wall. In 1970, the reinforcing plate was used to reinforce the spillway gate. In 1973, the channel 30 meters downstream of the sluice was partially scoured to a depth of 5 meters, and the clay blanket in the upstream of the sluice was also damaged. After reinforcement in 1974, erdaoba energy dissipation project was built in 1976, but the hidden dangers of the reservoir project were not completely eliminated, the flood control standard and storage capacity were low, the flood discharge was frequent, the dam leakage and termite damage occurred.

In 2002, the Longhekou reservoir was reinforced, and the flood control standard of the reservoir was raised to once in ten thousand years.

Reservoir benefit

The flood protection area is 530000 mu. On June 24, 1954, before the construction of the reservoir, the daily rainfall was 118mm, the discharge of the Longhekou of the Hangbu river was 2120m3 / s, and the polder was broken, causing a disaster of 70000 mu. On July 14, 1969, after the construction of the reservoir, the daily rainfall was 216.5 mm, and the peak discharge of the reservoir reached 10320 m3 / s, only 2150 m3 / s was discharged, greatly reducing the flood burden of the Hangbu river. The reservoir is designed to irrigate 1.55 million mu of farmland in Shucheng, Lujiang and Lu'an counties. In the 1990s, 1.23 million mu of farmland was actually irrigated, including 617000 mu in Lujiang County, 643000 mu in Shucheng county and 106000 mu in Lu'an City (formerly Lu'an county)

. In 1978, there was a severe drought, with 578 million cubic meters of water supplied by the reservoir and 1.059 million mu of farmland harvested. The fish culture area is 45000 mu, with an average catch of 96000 kg. There are 6 channels in the reservoir, with a total length of 30 km and 15 transport ships.

Main water sources

Hangbu River, called Longshu River in ancient times, is also called Nanxi because it is in the southeast of Shucheng County, and Qianhe river is named in Shucheng county annals by Guangxu of Qing Dynasty. After the founding of the people's Republic of China, Hangbu river was renamed as Hangbu river because it passed through Hucheng county. Ancient books and records are said to have originated from Jingyuan (gujingyuan) in Yuexi County, but actually from maoerjian in Shiguan on the west side of Tongan village in Yuexi County. After flowing through Yuexi County, Shucheng county and Lujiang County, Sanhe Town of Feixi County in Hefei City converges with fengle River, it flows into Chaohu Lake. In Shucheng County gravel beach into the Longhekou reservoir. The total length is 145 km, of which 86 km is in the territory, with a drainage area of 3064 square kilometers. The main tributaries are Xihe River, chashui River, Shuanghe River, Shizao River, Jiumu River, shanqili River, Huashui River, Hepeng River (Wusha River), Jiujing River, Longtan River, Nangang River and fengle river. The peak discharge of Longhekou reaches 6400 m3 / S (1914). The inflow of Longhekou reservoir was as high as 10320 m3 / s.

Xiaotianhe, formerly the upper reaches of Hangbu River, is called yaojiahe in Yuexi County. Xiaotianhe, known as xiaotianhe in Shucheng County, originates from Lingtou, the southern boundary of Yuexi County. Since the completion of Longhekou reservoir in 1958, it was cut off from Hangbu river. From hongshizui, the river enters Nanyue village, Dahe Township, the county, passes Hezhu River (originated from xiaojianchong) in Xiaotian Town, and reaches the river along hetiancangshui. Through Xiaohekou township to Shuanggui Village gravel beach of shanqihe Town, it flows into Longhekou reservoir. The width of the river is about 200 meters, which is 20 kilometers in the county. The whole basin covers an area of 588.9 square kilometers, with the maximum flow of 34

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