Our reporter Fu Lili
After entering the critical period of "seven lower and eight upper" flood control, my country's northern, northeastern, and eastern China have been hit by heavy rainfall one after another, causing many rivers in the Haihe, Huaihe, Nenjiang, Songhuajiang, Taihu and other river basins to be over-alarmed and over-protected. Even the largest flood since the actual measurement records occurred, and the flood control situation is very severe.
In the face of severe flood conditions, the Ministry of Water Resources has continued rolling consultations and comprehensive analysis to study and judge how to scientifically and finely dispatch water projects and play the "trump card" of reservoirs.
"Reservoir scheduling is the'trump card' for flood prevention and flood resistance. Playing this'trump card' and blocking floods and cutting peaks in time can gain the initiative of multiple levels of time and space for downstream flood control." Ministry of Water Resources Flood and Drought Prevention Deputy Director Wang Zhangli said.
Yuecheng Reservoir "eats" most of the upstream water
Since July 17, the Haihe River Basin has experienced the strongest rainfall since the flood season, and local heavy rains. The accumulated rainfall at Longshuiti Station in Huangshui Township, Huixian City, Xinxiang City, Henan Province has reached 1159 mm. Over-protection floods occurred in the Qi River and Anyang River.
In response to this flood, the Ministry of Water Resources scientifically and finely dispatched water projects such as the Yuecheng Reservoir, a controlling pivot project in the upper reaches of the Zhang River, to maximize the benefits of flood control and disaster reduction.
The No. 1 flood of 2021 occurred on the Zhangwei River on July 22, and the peak flow of the Yuecheng Reservoir reached 4860 cubic meters per second, all of which were stored in the reservoir, and the peak shaving rate reached 100%.
On the evening of July 28th, Li Guoying, deputy commander-in-chief of the State General Defense and Minister of Water Resources, had an emergency video meeting with the Haihe Water Resources Commission of the Ministry of Water Resources to carefully deploy the Haihe River Basin to prevent typhoon "fireworks" storm floods.
Facing the unfavorable situation of possible floods, waterlogging, and tide collisions in the lower reaches of Zhangwei River, it is decided to start from 23:00 on July 28th after comprehensive consideration of the forecast of rainfall and water in the next three days, the flood regulation capacity of the Yuecheng Reservoir, and the downstream channel flooding capacity. , Close the flood gate of Yuecheng Reservoir.
"If the Yuecheng Reservoir does not take discharge control measures, the Zhang River flood will be superimposed with the Wei River flood after it is discharged, increasing the Wei Canal flood discharge." Xu Helong, Director of the Flood and Drought Prevention Division of the Haihe Water Resources Commission of the Ministry of Water Resources, analyzed, "Therefore, The closure of Yuecheng Reservoir gates and staggered peaks is beneficial to flood discharge of the entire Zhangwei River system."
According to statistics, from July 17th to August 1st, the Yuecheng Reservoir held 280 million cubic meters of flood water. In this way, most of the inflow from the upper reaches of the Zhang River was "eaten" by the Yuecheng Reservoir, reducing the pressure on downstream flood control.
Nierji Reservoir minimizes the impact of floods on the main stream of the Nenjiang River
In the northeast, from July 17th to 20th, the middle and upper reaches of the Nenjiang River experienced heavy rains and local heavy rains.
Affected by this, at 8 am on July 18, the inflow of Nenjiang Nierji Reservoir was 4,110 cubic meters per second. Flood 2 of 2021 occurred on the Nenjiang River; on the same day, the Nuomin River, a tributary of the Nenjiang River at the lower reaches of the Nierji Reservoir, was extremely severe. flood.
As the only backbone project on the main stream of the Nenjiang River, the Nierji Reservoir plays a pivotal and irreplaceable role in regulating and storing floods in the Nenjiang River.
At 16:00 on July 18, the Songliao Water Resources Commission of the Ministry of Water Resources decided to take emergency measures-to close the spillway gate and generator set of the Nierji Reservoir at 16:45, and the outflow flow rate was reduced from 1,300 cubic meters per second to zero. For the Nuomin River flood peak, to minimize the impact of the flood on the main stream of the Nen River.
During the peak staggering period, the Nierji Reservoir lasted 27 hours with zero outflow, and a total of 284 million cubic meters of floodwater was blocked.
Ning Fanggui, director of the Flood and Drought Disaster Prevention Division of Songliao Water Resources Commission of the Ministry of Water Resources, believes that the Nierji Reservoir's emergency peak shift for 27 hours has reduced the water level of the river below the Nenjiang Mainstream Alliance by 0.37-0.60 meters, and avoided the Nenjiang Alliance to Fulare. The Jijiang section has exceeded the police and the Dalaijiang section has exceeded the security.
"In responding to the Nuomin River flood, Nierji Reservoir embodies the heroic qualities of the river basin." Ning Fanggui said.
This is just a microcosm of the scientific dispatch of reservoirs.
Data show that since the flood season this year, as of July 31, there were 2,718 sub-large and medium-sized reservoirs in the country that had blocked 70.9 billion cubic meters of flood water, 862 cities and towns were reduced inundation (times), 10.49 million mu of reduced arable land, and 5.72 million people were avoided. people.
Wang Zhangli said that reservoir operation has a huge impact. It is necessary to comprehensively consider hydrology, meteorology and the status of the reservoir itself, as well as upstream and downstream, main and tributary factors, to meet the needs of flood control, power generation, shipping and other aspects. It is a very complex process. Grasp the law and make scientific scheduling.