Play the ＂trump card＂ of reservoir to maximize the benefits of flood control and disaster reduction

　　From 18: 00 on August 8, the provincial water resources department adjusted the emergency response of flood and drought disaster prevention from level I to level II, which indicated that our province had made great progress in resisting torrential rains and floods.

　　In the face of this torrential rain disaster, the Provincial Water Resources Department carefully dispatched 20 large and medium-sized reservoirs. How do these reservoirs exert the benefits of flood control and disaster reduction?

　　"Reservoir dispatching is the trump card for flood control and fighting. In the face of serious floods, the Provincial Water Resources Department has continuously held consultations and comprehensive analysis to judge how to scientifically and finely dispatch water projects, play the’ trump card’ of reservoir flood control, timely stop floods and cut peaks, strive for multi-faceted initiative in time and space for downstream flood control, and maximize the benefits of flood control and disaster reduction. " On August 10th, Liu Zhengcai, Party Secretary of the Provincial Water Resources Department, said.

　　Since the flood season, strong convective weather has occurred frequently in our province, and local heavy rains and heavy rains have occurred from time to time. A total of 83 large and medium-sized reservoirs in the province have exceeded the flood limit water level. Five rivers, Qihe River, Dashahe River, Weihe River, Anyang River and Gonglianqu, have exceeded the flood limit, and four rivers, including Yinghe River, Honghe River, Qinhe River and Huiji River, have exceeded the police limit water level, and flash floods have occurred in some mountainous areas.

　　The Provincial Water Resources Department has organized more than 30 meetings in succession, and issued 63 orders to decisively dispatch Panshitou Reservoir, Baisha Reservoir, Baiguishan Reservoir and Yanshan Reservoir to reduce the discharge when the dikes in the lower reaches of Weihe River, Yinghe River and Shahe River are in danger. At the same time, pre-judging in advance, dispatching reservoirs for pre-discharging, finely dispatching 20 large and medium-sized reservoirs, such as Suya Lake and Chushandian, storing and discharging at the same time, and intercepting floods and cutting off peaks, all of which have effectively exerted the flood control benefits of reservoirs on the premise of ensuring the safety of the project.

　　Due to heavy rainfall, the water level of Baisha Reservoir, a large-scale reservoir built in 1953, rose sharply. In order to ensure the safe operation of the reservoir and the safety of life and property of the upstream and downstream people, according to the flood control dispatching instruction of the Provincial Water Resources Department, Baisha Reservoir opened its floodgates at 0: 00 on July 21. This is the first time that the spillway has been opened for flood discharge since it was built 68 years ago.

　　"Baisha Reservoir plays an important role in the flood control operation of Shaying River Basin. Below the reservoir, it belongs to the plain area, with fertile land, dense population and many enterprises on both sides of Yinghe River." Wang Hongwei, director of Baisha Reservoir Management Bureau, said that once the reservoir crashes, it will cause immeasurable losses to the lives and property of the people downstream. During this heavy rainfall, Baisha Reservoir impounded 74 million cubic meters, discharged 94 million cubic meters, put in flood peak of 3,370 cubic meters per second, discharged 200 cubic meters per second at maximum, with peak clipping rate of 94%, and estimated flood control benefit of 2.27 billion yuan.

　　Panshitou Reservoir, the only large reservoir in Hebi City, played a great role in this flood control. Panshitou Reservoir is a key flood control project in Haihe River Basin, with a basin area of 1,915 square kilometers, which can effectively control the flood of Qihe River. Combined with the regulation and storage of downstream flood detention areas, the flood control standard of Weihe River is raised from once every 20 years to once every 50 years, ensuring the flood control safety of key areas, cities, farmland and important traffic trunk lines.

　　During this round of heavy rainfall, all the rainwater in the upper reaches of Qihe River was collected in Panshitou Reservoir. Affected by the heavy rainfall on July 11th and 18th and the flood discharge from Sanjiaokou and Gongshang reservoirs in the upper reaches of Qihe River, the inflow of Panshitou Reservoir has been increasing since 14: 30 on July 19th, and the water level of the reservoir has risen rapidly, which soon exceeds the flood limit. At 5 o’clock on July 22, the maximum storage capacity was 2710 cubic meters per second, and the water level of the reservoir rose at a speed of nearly 1 meter per hour. At 17: 00 on July 24, it reached an elevation of 257.9 meters. In just three days, the water level of the reservoir rose by nearly 33 meters, which is rare in history. In order to alleviate the huge flood control pressure in the downstream, from July 22nd to August 9th, the Provincial Water Resources Department conducted nine scientific operations successively, from the maximum flood discharge of 400 cubic meters per second, gradually reducing the pressure to 300 cubic meters per second, 200 cubic meters per second and 100 cubic meters per second … The flood discharge stopped at 15: 40 on July 29th, with the maximum flood interception of 270 million cubic meters and the peak clipping rate close to 100%.

　　"Most of the water coming from the upper reaches of Qihe River was’ eaten’ by Panshitou Reservoir, which controlled the flood discharge of Qihe River to the maximum extent. When Weihe River and Communist Canal exceeded the historical water level, it prevented the flood of the three rivers from overlapping, reduced the pressure of flood control in the lower reaches, and gained valuable time for flood control and disaster reduction in the lower reaches." Sun Yunfeng, director of the Provincial Water Resources Department, said.

　　"If Panshitou Reservoir does not take discharge control measures, Qihe River flood will be superimposed with Weihe River flood after discharge, which will increase the flood discharge of Weihe River, and Xunxian County and hua county County will face great threats." Feng Linsong, director of the Flood and Drought Disaster Prevention Department of the Provincial Water Resources Department, analyzed, "Therefore, the closure of the peak of Panshitou Reservoir has played a vital role in flood control of the entire Weihe River system."

　　From July 18 to July 24, there was continuous rainfall in the upper reaches of Qianping Reservoir, with the maximum inflow peak flow of about 800 cubic meters per second, and the flood detention and storage of the reservoir was about 74 million cubic meters, with a flood detention and detention rate of 98.73%. At 10: 00 on July 25th, Qianping Reservoir opened the floodgate for the first time, and the flood detention time was as long as 130 hours, which avoided overlapping with the downstream flood and reduced the downstream flood control pressure.

　　It is also the proper meaning of scientific scheduling to vacate the storage capacity. At 7: 00 on July 17th, the Provincial Water Resources Department dispatched Zhangwu Reservoir and Xiaonanhai Reservoir in Anyang City to start pre-discharge. By 17: 00 on the 18th, Zhangwu Reservoir vacated 1.28 million cubic meters more flood storage capacity than before pre-discharge, and Xiaonanhai Reservoir vacated 1.51 million cubic meters more flood storage capacity than before pre-discharge.

　　This is just the epitome of the scientific and precise operation of reservoirs by the Provincial Water Resources Department. At 7: 00 on July 20th, Zhaopingtai Reservoir had a maximum storage capacity of 8,300 cubic meters per second and a corresponding storage capacity of 532 cubic meters per second, with a peak clipping rate of 94%. At 17: 00 on July 21, Yanshan Reservoir put in 1120 cubic meters per second, corresponding to 15 cubic meters per second, and the peak clipping rate was 99%. At 8: 30 on July 20th, Gushitan Reservoir entered the reservoir with a maximum storage capacity of 314 cubic meters per second, corresponding to a storage capacity of 3.2 cubic meters per second, and the peak clipping rate was close to 100%. At 19: 00 on July 20th, the maximum storage capacity of Jiangang Reservoir was 1090 cubic meters per second, and the corresponding storage capacity was 64 cubic meters per second, with a peak clipping rate of 94%. At 18: 10 on July 20th, Changzhuang Reservoir received 905 cubic meters per second, corresponding to 430 cubic meters per second, and the peak clipping rate was 52% …

　　"Reservoir dispatching is a complicated process. Only by grasping the laws, accurately forecasting the flood process and scientifically dispatching water projects can we maximize the benefits of flood control and disaster reduction." Liu Zhengcai said, "In the next step, we will continue to firmly establish the concept of" people first, life first ",comprehensively consider the hydrological, meteorological and reservoir engineering conditions, as well as the upstream and downstream, left and right banks, main tributaries and other factors, comprehensively analyze and judge the rain, water, flood and engineering conditions, refine the practical dispatching response plan, and strengthen the" forecast, pre-judgment, early warning, rehearsal and pre-plan "