According to the Yellow River Net, the flow of Tongguan Hydrological Station on the middle reaches of the Yellow River rose to 5,090 cubic meters per second at 23:00 on October 5 due to the combined influence of the Wei River and the north main stream of the Yellow River. It is the “Yellow River No. 3 Flood in 2021”.
The Ministry of Water Resources maintains the third-level emergency response for flood and drought disaster prevention, intensive rolling consultations, finely dispatching Xiaolangdi and other main and tributary reservoirs, controlling the steady discharge of floods in the Yellow River, and guiding the inspection and defense of the middle and lower reaches of the Yellow River and tributary dikes such as the Weihe River to ensure flood control safety . At present, seven working groups dispatched by the Ministry of Water Resources are guiding the flood prevention work on the front line of flood control in the four provinces of Shaanxi, Shanxi, Henan, and Shandong.
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On September 27, the Yellow River experienced floods No. 1 and No. 2 in 2021 one after another.
During this year’s flood season, the Yellow River Basin has successively flooded and autumn floods. In the near future, the middle and lower reaches of the Yellow River will usher in a new round of rainfall. At the same time, from 12:00 on the 27th, the emergency response to flood and drought disaster prevention in the middle and lower reaches of the Yellow River was upgraded to Level III.
What does the ID flood mean? According to the “Regulations on Flood Numbering of Major Rivers in the Country”, the warning water level (flow) reached by the major rivers and lakes across the country and the major rivers that flow into the sea alone across the provinces can be defined as flood numbering standards.
The flood number is composed of three parts: the name of the river (lake), the year of the flood and the sequence number of the flood. As far as the Yellow River is concerned, when the upstream Tangnaihai Hydrological Station or Lanzhou Hydrological Station has a flow of 2500 cubic meters per second; the middle reaches of Longmen Hydrological Station or Tongguan Hydrological Station has a flow of 5000 cubic meters per second; the downstream Huayuankou Hydrological Station has a flow of 4000 cubic meters per second , When one of the above three conditions is met, flood numbering is required.
When the flood reaches the numbering standard again, the upstream flood time interval reaches 48 hours or the middle and downstream flood time interval reaches 24 hours, it is a compound flood.
Specifically, the recent continuous autumn rains in West China, the Yellow River Tongguan Hydrological Station had a peak discharge of 5,020 cubic meters per second at 15:48 on September 27, forming the first flood of the Yellow River in 2021. The interval between the No. 3 flood and the No. 1 flood is more than 24 hours, which is a compound flood.
Affected by rainfall, major floods occurred in the main branches and tributaries of the middle and lower reaches of the Yellow River. After the joint flood control operation of the reservoir group, the Yellow River Huayuankou Hydrological Station’s flow reached 4,020 cubic meters per second at 21 o’clock on the 27th, reaching the flood numbering standard, forming the second year of the Yellow River in 2021. No. flood.
Zhao Lianjun, director of the Institute of Sedimentation and Sediment of the Yellow River Hydraulic Research Institute, said in an interview: “The main purpose of the release of numbered floods is to raise public awareness of flood risk. For flood control departments, the occurrence of numbered floods means the Yellow River embankment. There is a possibility of danger, it is necessary to strengthen the inspection of the dykes and do a good job in flood prevention related work.”
(Source: Henan Daily Client)
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