What should we pay attention to during the critical period of flood prevention?, Rare Heavy Rainfall in Beijing Tianjin Hebei Yang Bang | Intelligence | Beijing Tianjin Hebei

Affected by Typhoon Du Suri, the Beijing Tianjin Hebei region has experienced extremely rare heavy rainfall. Now that three days have passed, although the rainfall is coming to an end, more flood control and disaster relief work has also entered a critical moment. How to deal with various challenges, what are the most important information to pay attention to at present? How is the related work progressing? Yang Bang, Deputy Director of the Information and Forecasting Department of the Hydrological Bureau of the Haihe Water Resources Commission of the Ministry of Water Resources; Wang Yong, Deputy Director of the Office of Tianjin Flood Control and Drought Relief Command and Deputy Director of the Emergency Management Bureau, continues to pay attention to the rare heavy rainfall in the Beijing Tianjin Hebei region!

Over 40 billion cubic meters

The 4-day rainfall in the Haihe River Basin is equivalent to 1/4 of the annual rainfall

Yang Bang, Deputy Director of the Intelligence and Forecasting Department of the Hydrological Bureau of the Haihe Water Resources Commission of the Ministry of Water Resources: In hydrology, precipitation refers to the total amount of precipitation received by the surface per unit area over a certain period of time, usually measured in millimeters. Simply put, it means spreading the total precipitation of a certain area over that area to form a height, which is defined in millimeters. The total amount of precipitation is equivalent to the height of precipitation multiplied by the area of the watershed or region, which is equivalent to the concept of a quantity. So, 40 billion cubic meters is actually a concept of quantity. Currently, the total area of the Haihe River Basin is 320000 square kilometers, and the recorded water volume is 41.9 billion cubic meters. Spreading over 320000 square kilometers in the Haihe River Basin, the height formed is 131 millimeters. There is a concept here that, from a multi-year average perspective, the average annual precipitation in the Haihe River Basin is only 525 millimeters. Therefore, the rainfall during these four days is equivalent to a quarter of the annual precipitation in the Haihe River Basin. In addition, precipitation in the Haihe River Basin is usually concentrated during the flood season from June to September, which is equivalent to 80% of the annual precipitation, about 409 millimeters. The precipitation during this process is equivalent to one-third of the total precipitation during the flood season. So, it is evident that the intensity and volume of this precipitation are quite significant.

Haihe River is experiencing the "most severe test since the 1996 flood"

Yang Bang, Deputy Director of the Information and Forecasting Department of the Hydrological Bureau of the Haihe Water Resources Commission of the Ministry of Water Resources: Currently, due to the impact of the typhoon, the Ziya River system, Daqing River system, and Yongding River system in the Haihe River Basin have experienced numbered floods, with multiple rivers exceeding the warning water level and some rivers exceeding the guaranteed water level. At present, the heavy rainfall has basically come to an end, but the flood control in the basin is undergoing the evolution process of floods, and the flood control engineering system is experiencing the most severe test since the 1996 flood in the basin. The upstream reservoirs are mostly operating at high water levels to retain floods, and there is an urgent need for large flow discharge. At the same time, the flood discharge capacity of downstream rivers is also limited, and the flood discharge pressure is very high. In addition, multiple flood storage areas have been put into operation one after another, with many personnel transfers and significant economic losses.

Six flood storage and detention areas have been activated in the Haihe River Basin

Involving 2 million people, with a total area of 3389.5 square kilometers

Yang Bang, Deputy Director of the Information and Forecasting Department of the Hydrological Bureau of the Haihe Water Resources Commission of the Ministry of Water Resources: With the development of flood conditions, up to now, the Haihe River Basin has opened up six flood storage and detention areas, including Ningjinpo, Dalu Ze, and Xiaoqing River flood diversion areas, as well as the Langouwa, Dongdian, and Xian County flood areas, involving a total of 2 million people. The total area of the flood storage and detention areas is 3389.5 square kilometers. The opening of flood storage and detention areas has strict procedures, which have a significant impact on society. Before the official opening, it is necessary to organize personnel to do a good job of transfer.

Beijing's first use of a flood detention reservoir built in 1998

How to mitigate downstream impacts?

Yang Bang, Deputy Director of the Information and Forecasting Department of the Hydrological Bureau of the Haihe Water Conservancy Commission of the Ministry of Water Resources: There is a Lugou Bridge hub in the upper reaches of the Yongding River, which includes a dam and a diversion gate. Among them, the diversion gate is the main channel for releasing floodwater to the downstream river channel. At the same time, in order to reduce the flood pressure on the downstream river channel, when encountering large floods, according to the Yongding River flood control plan approved by the National Flood Control Administration, some floodwater passes through the diversion gate, and the diversion gate of Lugou Bridge enters the Daning Reservoir and the Yongding River detention reservoir for temporary detention, which is equivalent to blocking a part of the water. Its total storage capacity is 80 million cubic meters. During this flood process, the Daning Reservoir and the Yongding River Detention Reservoir intercepted and stored over 74 million cubic meters of flood, playing an important role in flood detention and to some extent reducing the flooding losses in the downstream Yongding River floodplain.

After 60 years, the Yongding River floodplain will be reopened!

Tianjin has transferred over 35000 people

Wang Yong, Deputy Director of the Office of Tianjin Flood Control and Drought Relief Command and Deputy Director of the Emergency Management Bureau: ① Within Tianjin, the Yongding River flood area involves more than 35000 people, mainly concentrated in Wuqing District and Beichen District. ② The Yongding River floodplain has not been used for 60 years, and the people still have insufficient understanding of the harm of floods. In addition, the lives of the people in the pan region have made significant progress in recent years. Personal assets, including some other factors, also make the people have certain doubts about the transfer, which is also the biggest difficulty for us to transfer and evacuate personnel from the pan region Before using this pan area, we need to prepare in several aspects. Firstly, through various meticulous work, we need to safely transfer all the people within the pan area without leaving anyone behind. The second is that after the transfer, we need to conduct a thorough inspection of various facilities in the pan area, including electricity, pipelines, gas stations, etc. These facilities must be carefully deployed to prevent other secondary disasters from occurring during the use of the pan area. At the same time, once used in a pan area, the security risk is also relatively high. We need to strictly manage the pan area, strengthen control, and prevent the common people from mistakenly entering the pan area and causing life-threatening situations.

Typhoon "Kanu" is on its way, what should we pay attention to during the critical flood prevention period?

Yang Bang, Deputy Director of the Information and Forecasting Department of the Hydrological Bureau of the Haihe Water Conservancy Commission of the Ministry of Water Resources: ① We have already experienced a relatively heavy precipitation process in the early stage. If typhoon "Kanu" is added in the future, the soil in the early stage will be relatively wet, and rainfall will be more likely to form floods. ② What I want to remind is that we must have a sense of worry and risk, seize the gap period, and do a good job in scheduling some of our water conservancy projects. Because the water level stored in the early stage was relatively high, through certain scientific scheduling, the reservoir was lowered to a certain level to welcome the next flood Meanwhile, we need to make accurate predictions and forecasts In addition, do a good job in embankment rescue work and prepare the entire subsequent flood prevention in advance, because risk moments always exist.