The length of rivers with water in Beijing has increased by more than 500 kilometers, and the urban ＂water network＂ has become more and more dense.

　　After ecological replenishment, the Chaobai River is full of water and restores its natural beauty. Beijing Daily reporter Pan Zhiwang photo

　　Beijing Daily reporter Wang Tianqi

　　In early winter, the river in the upper reaches of Xiaozhong River in Shunyi District did not decrease, but gradually increased. The clear river flows slowly, adding a touch of agility to winter.

　　With the full start of ecological water replenishment in autumn of 2024 in Beijing, Miyun Reservoir and Huairou Reservoir began to recharge the downstream rivers, and Xiaozhonghe, a river that runs through the west of Shunyi, is expected to have water all along.

　　In recent years, in Beijing, more and more rivers that have been dry and cut off have resumed their flow. This is inseparable from Beijing’s continuous cross-basin multi-source ecological water replenishment action. After ten years in Beijing, "South Water" has gradually become the main source of urban water, replacing the local surface water that was originally responsible for water supply. Large and medium-sized reservoirs such as Miyun and Huairou have been able to make ecological water replenishment and recharge underground for some rivers and lakes.

　　Since the "South Water" entered Beijing in 2014, Beijing water department has made full use of water resources for scientific and fine dispatching. There are 26 rivers with water in Beijing, and the length of rivers with water has increased by more than 500 kilometers.

　　The five major rivers have penetrated into the sea for four consecutive years.

　　In November, along the Beijing section of Yongding River, the "Five Lakes and One Line" was damaged and repaired by water, and many post-disaster recovery and reconstruction projects such as Guanting Gorge Section, Lusan Section and Luliang Section were still under intense construction to seize the "golden period". In the "23.7" catastrophic flood of Haihe River last year, the Yongding River in Beijing was seriously affected. The construction of these reconstruction projects has its own emphasis, but almost all of them have the same link-diverting the Yongding River by building cofferdams or pipelines. This is to ensure that the upstream and downstream rivers are connected.

　　Yongding River is the mother river of Beijing, but it has been cut off because of years of drought and excessive water consumption in urban development. Since 2019, under the unified dispatch of the Ministry of Water Resources, Beijing has coordinated the deployment of multiple water sources to implement the ecological water replenishment of Yongding River. The Yellow River water from Wanjiazhai Reservoir at the junction of Shanxi and Inner Mongolia, the water from Cetian Reservoir in Datong, the water from Guanting Reservoir in Beijing and some reclaimed water are all merged into Yongding River. In 2019, 108 kilometers of the Yongding River Guanting Gorge section flowed across the whole line; In 2020, the Beijing section of Yongding River will be connected; In 2021, after 26 years of cut-off, Yongding River realized the first time that more than 800 kilometers of river course was flooded and merged into the sea. In 2023, the Yongding River was flooded for the first time in the whole year after it was cut off, and it is expected to be flooded for two consecutive years this year.

　　With the successful experience of ecological water replenishment in Yongding River, Beijing began to try to make overall arrangements for external water transfer, surface water, groundwater, rain and flood, and reclaimed water, so as to promote the synchronous management of the main stream and tributaries of the city and the coordinated restoration of the surface and underground. In 2021, the Chaobai River, the largest river in eastern Beijing, was once again flooded after 22 years of interruption.

　　So far, the five major rivers in Beijing have all reappeared as "flowing rivers" and penetrated into the sea. This year is the fourth consecutive year.

　　The "water network" of rivers and lakes is filling up day by day.

　　Li Shu, chief of the dispatching management section of Beijing Water Resources Dispatching Management Affairs Center, has a satellite image in his hand, which can clearly see the changes of Chaobai River in the past ten years.

　　In 2015, the Chaobai River was only a short section upstream of the confluence of Chaohe River and Baihe River and Niulanshan Rubber Dam, as well as some river sections in Tongzhou, and most of the rest were dry. However, since 2018, there have been more and more rivers with water in the Chaohe River and Baihe River after Miyun Reservoir’s discharge. By 2021-2022, the whole Chaobai River has turned blue, and even some capillary tributaries around it can be clearly seen in the image.

　　In Li Shu’s view, after the middle route of South-to-North Water Transfer Project was flooded, the water source structure and water supply pattern in Beijing changed, and the water resources allocation strategy was adjusted scientifically and finely with the development of water resources situation and the changes of key security targets in different periods. "Ecological water replenishment in Chaobai River is a microcosm of strategy adjustment."

　　Li Shu introduced that from 2015 to 2022, Beijing coordinated multiple water sources to replenish 1.97 billion cubic meters of water to Chaobai River, with the largest year of 1.05 billion cubic meters and the smallest year of 08 million cubic meters. The year-to-year variation of water replenishment is so great, because the water storage of Miyun Reservoir was very small at the beginning of the "South Water", so the main goal is to store more water and increase the strategic reserve of water resources. By 2021, the precipitation in Beijing is extremely abundant. After Miyun Reservoir began to operate with high reserves, the water department used local water and "South Water" to implement multi-path and large-scale water replenishment, and fully recovered the ecological environment of Chaobai River.

　　The ecological water replenishment of rivers and lakes in Beijing can not only meet the needs of the citizens for the ecological environment, but also make the groundwater source be replenished through the slow infiltration of rivers and "store" the water into the ground. In order to effectively guarantee the ecological water quantity of the river, and extend the length of the river with water as much as possible, the Municipal Water Resources Dispatching and Management Center will make careful calculations every year, formulate a scientific and comprehensive water transfer plan, and carefully select the water replenishment path to maximize the benefits of ecological water replenishment.

　　After ecological water supply, not only the main stream of Chaobai River, but also a number of dry and cut-off rivers such as Xiaozhonghe and Fangshi Canal have been "revived". Through Jingmi diversion canal, the northern water systems of Shagou River, Xiaocun River, Beishahe River and Nanshahe River have also been supplemented. Agricultural irrigation channels that have been abandoned for many years have also been utilized. Through ecological replenishment such as Chaohe main canal, East main canal and Middle main canal, the water system in the east of Shunyi has been connected, and the Tangzhishan Reservoir, which has been empty for more than 20 years, is once again picturesque.

　　The criss-crossing natural rivers and artificial water systems weave a "water network" of the city, and the ecological water supply makes this network more and more dense and increasingly full. Liu Bo, director of the Water Quality and Water Ecology Laboratory of Beijing Hydrological Station, told the reporter that since "Nanshui" entered Beijing in 2014, the number of rivers with water in Beijing has increased from 96 to 122, the length of rivers with water has increased from 2,352 km to 2,887 km, and the proportion of rivers with water has increased from 36.7% to 45%. Although there were some fluctuations during this period, it generally showed a good trend.

　　Rivers and lakes are moving from "sub-health" to "very healthy"

　　Hold your breath, hold your mobile phone steady, and with a click, a picture of an egret looking down for food by the river is fixed. For Wang Yan, who lives near Liangshui River in Yizhuang, patting the beautiful scenery by the river is his greatest enjoyment after each jog.

　　There should be not only water in the river, but also clear water and green shore. After "South Water" took over the heavy burden of urban water supply, pollution control and water environment management of rivers and lakes in Beijing are also accelerating. Liangshui River is the most typical one.

　　Liangshui River, located in the south of Beijing, was once named as "Milk River" because of serious pollution, and the river turned white and green. The old residents nearby called it "Smelly River", and even dared not open the windows in the summer when they lived close. With the continuous implementation of the "three-year pollution control action" by Beijing water department, the sewage outlets along Liangshui River have been closed, and sewage is prohibited from being discharged directly into the river. Dredge the river, repair the river bank and plant more aquatic plants to make the river look brand-new In several reclaimed water plants in the basin, high-quality reclaimed water is continuously replenished into the river every day, so that the water body can be replaced, and "flowing water does not rot".

　　According to the Beijing local standard "Technical Specification for Water Ecological Health Assessment", Liangshui River was still in an unhealthy state in 2016, turned into a sub-health state from 2017, and reached a healthy level in 2020. "This also fully illustrates the transformation of water quality and water ecological environment of Liangshui River." Liu Bo said.

　　According to the Report on Water Ecological Monitoring and Health Assessment in Beijing in 2023, among the major rivers, lakes, reservoirs and wetlands in the city, 83% are in health grade. In 2023, 402 species of phytoplankton, 444 species of zooplankton, 245 species of macroinvertebrate benthos, 85 species of aquatic plants and 73 species of fish were detected in the city. "Compared with the previous year, except for the slight decrease of phytoplankton species, the species of other biological categories have increased, and the aquatic biodiversity in the city is in a state of continuous stability and improvement." Liu Bo said.