The flood is coming, why should it be numbered?

　　Since flooding, numbered floods have occurred in the Yellow River, Taihu Lake, and the Yangtze River successively, and the Ministry of Water Resources has initiated emergency responses to flood and drought disasters several times.

　　Many people may notice the relatively unfamiliar word "number flood", what exactly is number flood? Under what circumstances should the flood and drought disaster emergency response be initiated? With these questions, a reporter from Science and Technology Daily interviewed industry experts.

　　Helps raise awareness of risk prevention

　　According to Yang Kun, deputy director of the Engineering Research Center for Flood Control, Drought Relief and Disaster Mitigation of the Ministry of Water Resources, numbering the floods and releasing them to the public has an important role in reminding everyone which rivers are currently in the process of flooding in order to improve the public’s prevention of flood risks. Consciousness.

　　"For the flood control department, the occurrence of numbered floods means that the water level of the key stations of the river reaches the warning level or other specific values. There may be dangers in the embankment, and it is necessary to strengthen the patrol inspection and do the flood prevention related work." Yang Kun said.

　　How to number the flood? Specifically, the flood number consists of three parts: the name of the river (lake), the year of the flood, and the serial number of the flood. For example, on July 2, the inflow of the Three Gorges Reservoir reached 50,000 cubic meters per second. .

　　There are different numbering standards depending on the specific situation

　　In response to changes in the flood situation in various river basins in recent years, in April 2019, the Ministry of Water Resources issued the revised “Regulations on the Numbering of Major Rivers and Floods in the Country” (hereinafter referred to as the “Regulations”).

　　“According to the “Regulations”, the warning level (flow) reached by the water level (flow) of major rivers and lakes across the country and the main rivers flowing into the sea alone across the province, and if there is no such indicator, a flood level of 2 to 5 years or Water levels (flows) that affect local flood control safety can be defined as flood numbering standards." Yang Kun pointed out.

　　As the water level gradually rises, dangerous situations may occur in the embankments of rivers and lakes. The water level that needs to be strengthened is called the warning water level.

　　Taking the Yangtze River flood number as an example, the "Regulations" clearly numbered the Yangtze River mainstream from Cuntan to Datong River. When the Yangtze River flood meets one of the following conditions, the flood number is required: the flow of the upstream Cuntan Hydrological Station or the inflow of the Three Gorges Reservoir reaches 50,000 cubic meters per second; the water level of the Lianhuatang Water Level Station in the middle reaches the warning level (32.50 meters, freezing Wusong elevation) Or the water level of the Hankou hydrological station reached the warning water level (27.30 meters, freezing Wusong elevation); the downstream Jiujiang hydrological station reached the warning water level (20.00 meters, freezing Wusong elevation) or the Datong hydrological station water level reached the warning water level (14.40 meters, freezing Wusong elevation).

　　Once a double flood occurs in the Yangtze River, when the flood reaches the numbering standard again and the time interval reaches 48 hours, it needs to be numbered separately. The compound flood mainly refers to the relatively rare flood "superimposition" phenomenon, which is mostly caused by the short rainfall interval in the upstream. For example, in the 1998 flood season, eight flood peaks appeared in the upper reaches of the Yangtze River and encountered floods in the middle and lower reaches, forming a large-scale flood.

　　Emergency response grading helps quick decision

　　According to the factors such as the nature, severity, controllability and impact range of flood and drought disasters, the Ministry of Water Resources' emergency response to flood and drought disasters is divided into four levels: level IV, level III, level II and level I.

　　"According to the work regulations, each level of flood and drought disaster emergency response has corresponding start conditions and procedures, as well as response actions." Yang Kun introduced that taking the current level Ⅲ emergency response as an example, the start conditions include the occurrence of a watershed Medium floods, small floods in multiple river basins, super-alarm floods in major rivers, major embankments in major rivers and rivers, major dangers in large and medium-sized reservoirs, or collapse of small reservoirs.

　　After starting the Level III emergency response, the Ministry of Water Resources will notify the relevant river basins and regions to inform the start of the response and make arrangements for the defense work; strengthen consultation and judgment, encrypted water regime monitoring and rolling forecast; send working groups and expert groups to the flood control frontline Guidance; According to the flood situation, danger situation and local needs, the Emergency Management Department is requested to do a good job in flood relief and emergency situation disposal. At the same time, the relevant units of the water conservancy department have entered the state of emergency duty, and do a good job in accordance with the division of responsibilities.

　　In Yang Kun's view, the start of the emergency response to flood and drought disaster prevention is mainly to notify relevant departments to enter the emergency state, and do the corresponding monitoring, forecasting and early warning, water engineering scheduling, mountain flood disaster prevention, dike inspection and emergency technical support and other defense work. For the public, it is necessary to pay attention to the release of relevant early warning information in a timely manner, avoid dangerous areas as much as possible, obey the risk-averse transfer command if necessary, and do personal safety protection.