Cuiping Lake

Cuiping Lake

Cuiping lake, also known as Yuqiao reservoir, is named after Cuiping mountain in the south. Yuqiao reservoir, located in the east of Jizhou District, Tianjin, is one of the key large reservoirs in China. The dam site of the reservoir is located at the exit of Zhouhe River, the left branch of Jizhou canal.

Cuiping lake is located in the east of Jizhou District, Tianjin, 4 kilometers away from the county seat. It is one of the main projects to harness the Jizhou canal. Cuiping lake has a wide water surface, 35 kilometers long from east to west. Looking down on Cuiping mountain, you can see the vast sea and the same color of water and sky; boating on the lake, the gulls float up and down, and the fish play with things. On the South Bank of Cuiping, there are grape branches, flowers and fruits all over the garden; on the West Bank, the levee lies horizontally, green trees edge the levee, and the distant mountains are like Dai. Cuiping lake is rich in fish and shrimp, especially golden winged carp.

essential information

Yuqiao reservoir is located 4 km to the east of Jizhou District, Tianjin city, at the mountain pass of Zhouhe River, belonging to the Zhouhe reach of Jizhou canal basin. The controlled drainage area is 2 060 km2 and the total storage capacity is 1.559 billion m3. The main inflow rivers in the upper reaches are Linhe River, Shahe River and Lihe River, with an average annual runoff of 506 million m3. After the completion of Luanhe Tianjin Water Diversion Project in 1983, Yuqiao reservoir was officially incorporated into the management of Luanhe Tianjin Water Diversion Project and became the only water source in Tianjin. Its main functions are flood control, urban water supply, irrigation and power generation.

Yuqiao reservoir, located in the north of Tianjin, is listed as an important drinking water source by the Ministry of water resources. It is another national protected urban water source after Panjiakou Daheiting reservoir.

According to the notice on publishing the list of drinking water sources (the second batch) recently issued by the Ministry of water resources, there are 59 drinking water sources in China in the second batch, including rivers, lakes, reservoirs, groundwater and other types of water sources, with a water supply population of more than 200000.

Yuqiao reservoir was built in 1959, with a total capacity of 1.559 billion cubic meters, a normal water level of 21.16 meters and a Xingli reservoir capacity of 421 million cubic meters. The main buildings include barrage, spillway tunnel (also used as power tunnel), spillway and power station. The total length of the dam is 2222 meters, and the maximum dam height is 24 meters. At the same time, it has many functions such as flood control, urban water supply, agricultural irrigation and power generation.

According to the relevant person in charge of Tianjin Water Conservancy Department, Yuqiao reservoir has become an important regulating and storage reservoir since the water diversion project from Luan River to Tianjin was opened on September 11, 1983, and has been listed as an important urban water source in Tianjin along with Panjiakou Reservoir and Daheiting reservoir. In the past 25 years, Yuqiao reservoir has supplied 17.972 billion cubic meters of safe water to Tianjin city, which not only ensures the drinking water safety of urban people, but also greatly improves the investment environment and ecological environment of Tianjin city, making important contributions to the healthy and coordinated development of Tianjin's economy and society.

Tianjin Water Conservancy Department said that the water conservancy department will further strengthen the protection of urban water sources, strictly implement the protection measures of urban water sources in combination with the supervision and management of water function areas, improve the water environment early warning system of Yuqiao reservoir, restore the reservoir ecosystem, and ensure the safety of urban water supply and water source ecological security in Tianjin.

Establishment time

The reservoir was built in 1959, and the first phase of the project (barrage and spillway tunnel) was completed in July 1960. In 1965, the excavation of spillway was continued (the actual excavation was only to the elevation of 23.0m).

Engineering structure

There are barrage, drainage tunnel, spillway and hydropower station in the reservoir project. The dam is a homogeneous earth dam with a total length of 2222m, a maximum dam height of 24m and a crest elevation of 28.72m. The diameter of the water discharge tunnel (also used as the power generation tunnel) is 5 m. There are four tubular units in Bahou hydropower station, with a total installed capacity of 5000 kW. The spillway is an open weir gate with eight gates, with a net width of 80m and a maximum discharge capacity of 4138 m3 / s.

Hydrological characteristics

Yuqiao reservoir is located in the upper reaches of Zhouhe River, 4km to the east of Jizhou District, Tianjin city. It is a valley type reservoir, mainly receiving the confluence of Shahe River, Lihe River and Linhe river. The average annual precipitation is 750mm, the annual runoff is 506 million m3, the controlled drainage area is 2060km2, the maximum storage capacity is 1559 million m3, the normal water level is 21.16m, the corresponding storage capacity is 385 million m3, the maximum water depth is 12.16m, and the average water depth is 4.74m.

The total storage capacity is 1.559 billion cubic meters, the normal water level is 21.16 meters (Dagu), the flood limit water level is 19.87 meters, and the dead water level is 15 meters. The lower reaches of the reservoir directly affect the low-lying areas of Jixian, Baodi, Ninghe, Yutian, Hangu and other counties (districts), with a population of nearly one million and cultivated land of more than 3 million mu.

After the Luanhe Water Diversion Project was put into operation in 1983, Yuqiao reservoir has become an important regulating and storing reservoir in the Luanhe Tianjin water diversion project. It is the only drinking water source in Tianjin. It undertakes the important task of regulating and storing Luanhe Water Diversion Project and supplying water to Tianjin. It is also located in the hinterland of Beijing, Tianjin and Tang Dynasty, and has a very important social and economic status.

There are three inflow rivers in the reservoir, Shahe, Lihe and Linhe. Among them, Shahe has a drainage area of 887km2, a river length of 70km and an average annual inflow of 1.355 × 108m3. Linhe river is one of the three inflow rivers, with a drainage area of 252km2, a river length of only 47km and an average annual inflow of 0.28 × 108m3.

The Lihe River basin covers an area of 488km2 and has a length of 55.5km. The water inflow of Lihe River includes the water inflow from Luanhe River and its own water production. The average annual water production of Lihe River is 0.71 × 108m3, and the average annual water diversion from Luanhe River is 5.58 × 108m3.

Control measures

1、 As the source of drinking water in Tianjin, the water quality of Yuqiao reservoir directly affects the economic development and social stability of Tianjin. In order to improve the ability of Luanhe Water Diversion Project to deal with public health safety and public emergency, prevent and reduce the public emergency and its damage to the greatest extent, and ensure the public drinking water safety, this paper makes statistical analysis on the measured data of pH value and hydrological data of Yuqiao Reservoir in recent 6 years (taking Yuqiao Reservoir center as an example). As shown in Table 1, 2 and figure 1.

1. Influence of water diversion period on pH value after water diversion every year, the pH value has a rising period. The hydrodynamic effect of large inflow flow on the formation of sediment in qiaoreservoir area accelerates the dissociation reaction of water body. The results showed that the nutrients absorbed by aquatic plants were accelerated, and the water flow also accelerated the water quality

The speed of hydrolysis reaction accelerates the rise of pH value.

2. When the water storage of Yuqiao reservoir is less, the pH value is relatively high, especially when the water storage of Yuqiao reservoir is less than 150 million m3.

3. The influence of temperature on pH value is great. Before and after May Day, the temperature in Yuqiao reservoir area rose rapidly and the sunlight was sufficient. In May, the pH value of Yuqiao Reservoir increased significantly.

Table 2 Statistics of storage and water diversion of Yuqiao reservoir from 2000 to 2005

4. The influence of aquatic plant growth on pH value enters may every year, and the aquatic plants in Yuqiao reservoir area begin to grow rapidly. The rapid growth of aquatic plants consumes nutrients and absorbs a lot of CO2, which accelerates the hydrolysis reaction of water body and precipitates some metal ions, resulting in the obvious increase of pH value. Second, the feasible measures to control the pH value of Yuqiao reservoir temperature is the factor of pH value rise, there is no force to adjust the climate conditions of local waters through artificial measures, only through the containment of aquatic plants and the adjustment of water conveyance operation to control the pH value rise. As the control of water plants requires a lot of manpower and financial resources, it is a feasible means to consider the use of water conveyance dispatching for effective regulation and control. 1. The establishment of a pre reservoir in the upstream of the reservoir can greatly reduce the direct inflow of water diversion from Luanhe River and river flood pollution load. According to the analysis of pollutant concentration and pollution load of Yuqiao reservoir from 1983 to 2002, the river pollution load accounts for 90% of the total river pollution load of Yuqiao reservoir. The phenomenon of high pollution load water head exists in flood season and water diversion from Luanhe River. The direct storage of pollution load can be greatly reduced by introducing the high pollution water head into the front reservoir for aquatic plant purification Quantity. After entering the front reservoir, the flood with high pollutant concentration will be transferred to the reservoir after being purified by aquatic plants for 10-15 days, which will not only reduce the direct inflow of pollution load, but also not lose water resources.

Table 2 Statistics of storage and water diversion of Yuqiao reservoir from 2000 to 2005

2. The water quantity of Yuqiao reservoir should be controlled above 150 million m3 as far as possible. When the water quantity is lower than 150 million m3, the carrying capacity and self purification capacity of the reservoir water body are poor. In addition, due to the influence of temperature, water grass growth, water diversion quality and other factors, the water quality of the reservoir is likely to fall below class III water and is no longer suitable for drinking water. 3. Try to choose the right time for water diversion, and avoid may, June, July and August, so as to stagger the water diversion period with the growth period of aquatic plants and the period of high temperature. It is best to conduct water diversion twice a year: the first time is used from February to April before flood season, and the maximum water diversion is about 300 million m3

Chinese PinYin : Cui Ping Hu