Erlongshan Reservoir in Heilongjiang Province

Erlongshan Reservoir

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Erlongshan Reservoir is located in Erlongshan village, Xinli Township, 6 kilometers southwest of Binxian County, on Feiketu River, a small tributary on the right bank of Songhua River, with a drainage area of 275.5 square kilometers. The designed total storage capacity is 108 million cubic meters, and the actual total storage capacity is 91 million cubic meters. It is a multi-year regulation and comprehensive utilization reservoir mainly for irrigation and flood control, combined with fish culture and power generation.

location of a reservoir

Erlongshan Reservoir is located in Erlongshan village, Xinli Township, 6 km southwest of Binxian County, on Feiketu River, a small tributary on the right bank of Songhua River.
　　

Reservoir hub

The reservoir project consists of three parts: dam, spillway and water conveyance tunnel. (1) the dam is a sand shell dam with clay core, with a total length of 800m, an average height of 18m, a maximum height of 22m and a crest width of 6m. Both the upstream slope and the downstream slope are provided with 2m wide raceway. The slope ratio below the raceway of the upstream slope is 1:4, and that above the raceway is 1:2.75; that below the raceway of the downstream slope is 1:3.5, and that above the raceway is 1:2.5. Both the upstream slope and the downstream slope are protected by dry block stone, and riprap is used below 4m of the raceway on the upstream slope. (2) the spillway is located at the saddle of the mountain at the left end of the dam, which is open on the river bank. The net width of the weir crest is 20 meters. There are two spillways, each with a net width of 10 meters, controlled by a 10 × 6 meter radial steel gate, with a maximum discharge of 660 cubic meters per second. The upstream approach channel section of the spillway is 150 meters long, the middle part of the gate chamber is 42.5 meters long, the downstream adopts the form of flip bucket energy dissipation, and the tailrace channel is 800 meters long. (3) the water conveyance tunnel is located at the right end of the dam, with a length of 106m and a reinforced concrete structure. The inlet is a 2-hole square pipe with a cross section of 3 × 1.4m; the middle is a circular pipe with a diameter of 1.4m; the outlet is a 4-hole circular pipe with a diameter of 1m, and the maximum water delivery capacity is 25m3 / s. (see the attached figure) there are two mountains called DALONGSHAN and Xiaolongshan at both ends of Erlongshan Reservoir dam. Between the "dragon heads" of the two mountains, there is a circular island called "Pearl Island". The myth of "two dragons playing with pearls" has been spread among the people, and the local villages and reservoirs are named for it.

Reservoir construction

Longshan reservoir was built in December 1971 after two times of design and construction. The first time was in September 1958 when the ground was broken and designed by Binxian shuilike. 7000 people and 500 carriages were sent to participate in the construction. In May 1959, the dam was closed for the first time. In late August, due to continuous rainfall in the upper reaches, the temporary spillway at the right end of the dam was destroyed. In October, the dam was closed for the second time, and the construction was stopped in autumn 1960. The second construction was carried out in December 1966. It was designed by the Provincial Water Conservancy Survey and Design Institute. The people's Committee of Binxian county organized four beneficiary communes, including Juren, Binxi, Yonghe and Tangfang, and dispatched 1100 militia to participate in the construction. It was completed in December 1971, with a total amount of 1.557 million cubic meters. The state invested 7.824 million yuan. In August 1974, an appraisal and acceptance working group composed of water conservancy, construction commission, finance and banking departments of the province, Songhuajiang region and Binxian county carried out inspection and acceptance. After the completion and acceptance, the uplift part of the dam upstream slope was renovated in 1976. In 1980, the subsidence part of the dam slope was treated. In 1985, the left side slope protection of spillway entrance section was renovated.

Reservoir benefit

After the completion of Erlongshan Reservoir, the water storage in the reservoir was only about 40 million cubic meters until 1980 due to the low annual precipitation. After 1981, the water storage in the reservoir increased, meeting the design requirements. In 1984, the reservoir water was used to irrigate 20000 mu of paddy fields, which increased to 30000 mu in 1985, reaching the designed irrigation benefit area. The reservoir supplies 3 million cubic meters of water to the residents of the town (county) and the sugar factory of Pennsylvania every year. In terms of flood control, in August 1981, there were two rainstorms in the upper reaches of the reservoir, the frequency of which was equivalent to the standard of flood with a return period of 10 years. The reservoir has successively impounded 42 million cubic meters of flood, reducing the threat to the downstream. The reservoir has 11820 mu of water surface for fish culture and 261 mu of fish ponds. The catch was 80000 kg in 1984 and 112000 kg in 1985. There are 3000 mu of suitable forest area in the reservoir area, and 2000 mu of economic forest has been planted. After 1982, thinning has been carried out three times, and the income is 65000 yuan. As the reservoir is only 58 kilometers away from Harbin, the provincial capital, and near Harbin (erbin) Tongjiang highway, it has become a prosperous tourist area with convenient transportation. Since 1982, it has received an average of 500000 visitors every summer. After 1983, the reservoir management funds were self-sufficient with a slight surplus. From 1983 to 1985, the reservoir management office was awarded the title of advanced unit of reservoir management by Songliao water conservancy commission of Ministry of water resources and electric power. In 1985, it was also rated as the advanced collective of water conservancy management in Heilongjiang Province.

Primary productivity and related indicators

Heilongjiang water system, Erlongshan Reservoir water system, water area, primary yield daily 0.534 g oxygen / m2. Daily, primary yield annual 225 kcal / m2. Annual, fish yield 2.66 kcal / m2. Annual, f / p1.18, biomass 7.8 g / m2, daily P / b0.44, total nitrogen 2.1 mg / L, inorganic nitrogen 0.705 mg / L, total phosphorus 0.17 mg / L, phosphate 0.13 mg / L, organic oxygen consumption 5.79 mg / L The transparency is 33 cm. plankton (mg / L) floating plant yield 0.534, floating plant standing stock 1.482, floating dominant species dinoflagellate, green algae, zooplankton 3.340. seasonal variation of phytoplankton biomass and Dominant Algae (mg / L) in 1981, the spring biomass was 2.05, the spring biomass was 1.39, the summer biomass was 1.22, and the autumn biomass was 1.39. The phytoplankton biomass (mg / L) and its composition of the reservoir floating biomass 1.480, diatom 3.1%, green algae 11.4%, Chrysophyta 2.1%, dinoflagellate 83.1%, Euglenophyta 0.0%, Cyanophyta 0.3%. Biomass and seasonal variation of zooplankton in reservoir (mg / L) primary biomass 0.01, rotifer biomass 0.01, Cladocera biomass 1.75, copepod biomass 1.57, total biomass 3.34, spring biomass 2.45, summer biomass 4.21, autumn biomass 3.36