Entering the critical period, how to meet the big exam for flood prevention

【Economy Interface】

It is another year's flood season. Right now, heavy rains are hitting many places, and the warning is still continuing.

The Beijing-Tianjin-Hebei region ushered in the strongest rainfall during the flood season; heavy rains fell in many areas in Bazhong, Sichuan, and some areas encountered disasters such as waterlogging, mountain torrents, and mudslides; heavy floods occurred in the upper mainstream of Heilongjiang...

The latest data obtained by the reporter from the Ministry of Water Resources as of the 14th shows that since the flood season this year (April 1), there have been 20 heavy precipitation processes across the country, four more than the same period since 1998.

A total of 243 rivers in 22 provinces (autonomous regions and municipalities) experienced over-warning floods, of which 35 rivers had over-protection floods and 8 rivers had over-historical floods.

Severe is the current flood control situation in our country.

In the second half of July and the first half of August, the "seven lower and eight upper" flood control period, the development of the flood situation is even more touching.

Nowadays, in response to the flood prevention test, science and technology help us to show more "hard cards".

How is the flood situation going?

How to meet the big exam for flood prevention?

What are the weak links?

What are the long-term measures to keep the river safe and sound in the future?

In this regard, the reporter conducted an interview.

1. Over-alarm floods occurred in 40 rivers with intensive rainfall in 3 days

【phenomenon】

On July 13, the No. 1 flood of 2021 on the Jialing River smoothly passed through the central city of Chongqing.

Earlier, due to sudden heavy rains in Bazhong and Dazhou, Sichuan, the inflow of the Qujiang River, a tributary of the Jialing River, increased rapidly. At 19:00 on the 11th, the Hydrological Bureau of the Yangtze River Water Resources Commission of the Ministry of Water Resources officially announced that the Jialing River's No. 1 flood in 2021 was formed in the Qujiang River.

Turning the hour hand back, on June 21, the Nenjiang River's No. 1 flood of 2021 was formed. This is the first time a numbered flood has occurred in a major river in my country this year.

The two floods, one south and one north, reflect some of the characteristics of this year's flood situation.

　　On the whole, during this year's flood season, there were many heavy precipitation processes throughout the country.

Li Yan, the chief hydrology forecaster of the Ministry of Water Resources, said in an interview with our reporter that since the flood season, the national average rainfall has been slightly lower than that of the same period in normal years, but the rainfall is concentrated in time and space and the local rainfall intensity is high.

The rain areas are mainly concentrated in the south of the Yangtze River, the northeast of South China, the east of Huanghuai, most of North China, and the north of Northeast China. The location of rainbands is more norther than normal.

　　Under the influence of the rain area, the flood in the Northeast region occurred early, with a large magnitude, and a long duration, which became a major feature of the rainfall in this year's flood season.

"Since June, 23 rivers in Northeast China, including Heilongjiang, Nenjiang, and Songhua River Zhaoyuan River, have experienced over-warning floods, of which 11 rivers have over-protected floods, and 6 rivers have over-historical floods." Li Yan introduced, the middle and lower reaches of the Nenjiang River There have been two over-alarm floods in the main stream, and the Jiangqiao station in Qiqihar, Heilongjiang has accumulated over-alarm overtime for 9 days.

　　The flood situation does not only occur in the northeast. Since the flood season, floods have been concentrated in many rivers in the south.

How concentrated is it?

According to a report from the Ministry of Water Resources, from May 20 to 22, 42 rivers including Xiangjiang River in Hunan, Ganjiang River in Jiangxi, Minjiang River in Fujian, and Beijiang River in Guangdong had super-alarm floods; from June 28 to July 2nd, Xinjiang River and Raohe River in Jiangxi Province, Over-alert floods occurred in 46 rivers including Jianxi, Futunxi, and Qiantang River in Zhejiang. Among them, the Changshan and Sanhe sections of the Qiantang River experienced over-protection floods.

"On July 9-11, 15 rivers including the Qujiang River in Sichuan and its tributaries Datong River, the Ore River, a tributary of the Dadu River, and Sanmiao River, a tributary of the Jialing River in Chongqing, experienced over-alarm floods. Among them, the Qujiang River and its tributaries Datong River and Shentan River After 9 rivers have over-protection floods, the Datong River has over-historical floods." Li Yan said.

　　Heavy rain is still "intensive" on the scene.

From July 11 to 12, heavy rains in Beijing, Hebei and other places brought the unoptimistic flood control situation of the Haihe River Basin into the public eye.

At 14:00 on July 13, the No. 1 flood of 2021 occurred in the Luanhe River in the Haihe River Basin.

　　At present, the Songhua River is still over-alert. The Yangtze River, Huaihe River, Yellow River, Haihe River, Pearl River and other river basins have continued to experience heavy rains and floods. In addition, it has entered a critical period of "seven lower and eight upper" flood control periods. The future flood situation has attracted much attention.

The reporter learned from the Ministry of Water Resources that according to the comprehensive research and judgment of the Hydrometeorological Federation, during the "seven downs and eight ups" period, the country's rainfall was distributed as "more from the north to the south, but less in the middle". The north was mainly rainy; the rainy areas in the north were located in most of the northeast. North China, the northern part of the western part of Huanghuai, the eastern part of the northwest, and the northeastern part of the southwest. The rainy areas in the south are located in the southeast of the Jiangnan, the south of the east of South China, and the south of the southwest.

　　"The middle reaches of the Yellow River, the Haihe River Basin, Zhangwei River, Daqing River, Ziya, Hebei, Sanhe Luanhe, Nenjiang, Songhua River, Liaohe, Heilongjiang, etc. will have large floods. The upper reaches of the Yangtze River and the Han River, the upper reaches of the Yellow River, the Xijiang Beijiang, Qiantang River and Minjiang River in the Pearl River Basin Regional rainstorms and floods will occur in Jiang and others.” Li Yan revealed, “We will focus on the above-mentioned related rivers that are expected to have floods, and do a good job in monitoring, forecasting and early warning, scheduling of backbone water projects, dyke inspections and defenses, and technical support for emergency rescue. At the same time, prevent floods and flash floods in small and medium-sized rivers in areas where heavy rainfall may occur, and prevent small and medium-sized reservoirs from flooding safely."

2. Science and technology help major water conservancy projects to resolve violent waves

【Case】

"The whole of Beijing is waiting for rain. Some scenic spots have closed, flights have been cancelled, construction sites have been suspended, water pumps have been put in place, primary and secondary schools and kindergartens have stopped returning to school, the weather station has issued a rainstorm warning, and the atmosphere has been set here."7 On the evening of the 11th, Beijing netizens who received the rainstorm warning early joked.

The reason why citizens can wait so calmly for the heavy rain to arrive is inseparable from the early warning of the Meteorological and Hydrological Department, and the efforts of the people behind it-the Beijing Water Affairs Bureau dispatched the North Canal to suspend navigation in advance, and dispatch the urban rivers and lakes appropriately. Reduce the water level and free up about 22 million cubic meters of tank storage capacity; Drainage Group has increased the sewage treatment volume ahead of schedule, and the drainage pipe network has freed up 260,000 cubic meters; dispatched 57 pumping stations in the urban area to pump 3.42 million cubic meters of drainage...

　　As the “leading soldiers” and “eyes and ears” of flood control, early and accurate forecasting of water conditions can win more initiative for flood control and flood fighting.

At present, more accurate forecasts and forecasts are inseparable from the assistance of science and technology.

Technologies such as ground automatic measurement and reporting, aerospace remote sensing, satellite transmission, and wireless broadband network have been widely used, and a sky-ground integrated water regime information sensing network has been constructed.

The figures are sufficient to prove: before the flood in 1998, it took two hours to collect all the country's rain and water regime information; now it only takes about 15 minutes to collect all the country's rain and water regime information from more than 100,000 flood reporting stations.

In addition, by analyzing the laws of floods that have occurred, transplanting similar river basin parameters, strengthening online plan revisions and real-time corrections, has also improved the accuracy of forecasting.

　　Since the flood season, as of July 14, the national water conservancy authorities have issued a total of 216,300 station forecasts for 1,605 rivers and 1,605 sections, and 655 water regime warnings.

In addition, the Ministry of Water Resources and the China Meteorological Administration launched a meteorological warning service for mountain flood disasters. The relevant regions issued a total of 92,700 county-level mountain flood disaster warnings, sent 7.9 million warning messages to the relevant persons in charge of flood prevention, and issued warning messages to the public in the threatened areas. 148 million, providing strong support for disaster prevention and avoidance and guaranteeing life safety.

　　Science is also reflected in reservoir operation.

At 20 o'clock on July 12, the Three Gorges Reservoir ushered in its first flood of the order of 40,000 cubic meters per second this year, and the Three Gorges Reservoir vacated 800 million cubic meters of flood control capacity in advance to intercept floods.

During the defense against the Nenjiang River No. 1 flood, the Songliao Water Resources Commission of the Ministry of Water Resources dispatched Nierji Reservoir to flood the reservoir before the flood; after the flood, the discharge flow was reduced and the peak was blocked, and the peak shaving rate reached 61.6%.

Through scientific research and judgment, timely dispatch of reservoirs and other projects, pre-discharge of water in advance, play the role of flood blocking and peak reduction, use the time difference of river flood discharge, effectively avoid the superposition of main and tributary streams or upstream and downstream flood peaks, and water conservancy projects will resolve turbulent waves and reduce flood control pressure.

As of July 12, since the flood season, 1,725 ​​(times) large and medium-sized reservoirs across the country have blocked a total of 32.8 billion cubic meters of floodwater, reduced flooding of 324 towns (times), reduced flooded arable land area of ​​2.8 million mu, and avoided the transfer of 1.63 million people.

Groups of figures and case by case confirm the importance of major water conservancy projects.

　　The "microscope" of flood prevention also focuses on every risk and hidden danger point.

As early as before the flood, the Ministry of Water Resources and the Emergency Management Department jointly conducted pre-flood inspections on the Yangtze, Yellow, Huai, Haihe, Pearl, Songliao, and Taihu Lakes, and urged all localities to promptly repair last year's water conservancy projects and restore flood control and drought resistance functions.

Formulate mountain flood disaster prevention, water engineering scheduling and flood limit water level implementation supervision and inspection plans, and guide local governments to prepare for the use of flood storage and detention areas.

　　"Since mid-June, the Ministry of Water Resources has concentrated on rectifying water conservancy projects under construction, operation projects, and potential flood prevention safety hazards. It has dispatched 12 inspection teams to monitor reservoirs, sluices, dikes, and silt dams, especially dangerous reservoirs, earthquake-damaged projects, and large-scale projects. Medium-sized reservoirs flood control dispatching and flood limit water level implementation, mountain flood disaster monitoring and early warning platform operation, etc. focus on conducting unannounced investigations and unannounced visits, urging localities to eliminate safety hazards in a comprehensive and timely manner. We have also published a list of 710 large-scale reservoirs and dams in the country responsible for safety, and urged all regions Implement the "three responsible persons" in the administration, technology, and inspection of small reservoirs during flood safety and those responsible for mountain flood disaster prevention, etc., and implement all responsibilities." Wang Wei, Director of the Technical Information Division of the Flood and Drought Prevention Department of the Ministry of Water Resources, told Ben Newspaper reporter.

3. Scientifically plan to accelerate the construction of a disaster prevention system

【Thinking】

Last year, major rivers such as the Yangtze River and the Yellow River experienced more numbered floods than in 1998, but major dikes of major rivers and flood control projects in key areas did not experience major dangers.

It can be said that after years of construction, my country has basically built a relatively complete flood and drought disaster prevention system, laying the foundation for defeating previous river basin floods, but every time we respond to the flood control exam, some problems have been exposed.

In addition, natural geography and climatic conditions determine that my country is one of the countries with the most frequent and severe floods and droughts and the most difficult defense in the world. Floods cannot be completely eliminated, and the long-term and arduous nature of the task of water control objectively exists.

Flood and drought disaster prevention needs to be planned and improved from a longer-term perspective.

　　"In terms of engineering systems, some rivers lack flood control control projects; large rivers and their important tributaries and a large number of small and medium-sized rivers have low embankment standards, or fail to meet the planned flood control standards, and further control needs to be strengthened; flood storage and detention areas, There are a large number of people on the beaches, the population is dense, the construction of safety facilities needs to be strengthened, the opening may cause large losses, and the decision-making is difficult; some areas have insufficient drainage capacity, and there are many obstacles to flooding in the river; the number of reservoirs, hydropower stations, and silt dams are large and common There are problems such as low engineering standards, insufficient investment in operation and management, and inadequate maintenance and maintenance. Some of them have disease risks and high pressure on safety during floods." Wang Wei said frankly.

　　There are also weak links in non-engineering systems.

From the perspective of early warning and forecasting, it is more difficult to forecast local sudden and short-duration heavy rainfall.

In addition, compared with the southern rivers, some rivers in the north have short source and rapid flow, short flood forecast period, lack of measured data, and insufficient forecasting capabilities; the level of monitoring and forecasting of mountain flood disasters and floods in small and medium-sized rivers also needs to be improved.

Wang Wei introduced that from the perspective of dispatching, some rivers and water engineering flood control and dispatching plans, over-standard flood prevention plans, and reservoir flood season dispatching and operation plans are not perfect; most of the basin water engineering disaster prevention joint dispatching is still in the exploratory stage, and overall planning The multi-objective dispatching mechanism for flood control, water supply, ecology, power generation, shipping, etc. is not yet complete, and the degree of informatization and intelligence of dispatching needs to be improved.

In addition, some river basins have not experienced major floods for many years, a small number of cadres and the masses have insufficient knowledge of the disasters of storms and floods, and lack practical experience in flood prevention and flood prevention. The awareness and ability of disaster prevention and avoidance needs to be enhanced.

　　How to make up for these shortcomings?

Liu Weiping, vice minister of the Ministry of Water Resources, emphasized that it is necessary to adhere to the idea of ​​"building more importantly than prevention, prevention more important than rushing, and rushing more importantly than rescue", and conform to the basic logic of flood and drought disaster risk prevention and resolution.

During the "14th Five-Year Plan" period, we will further accelerate the construction of flood control and control hubs, vigorously promote the reinforcement of dangerous reservoirs, the safety construction of flood storage and detention areas, the management of backbone flood channels, the management of small and medium rivers and mountain torrents, etc., to provide for flood control and disaster prevention Hard foundation.

Persist in moving the gate forward, and do a good job of "prevention" work such as monitoring, forecasting, early warning, dispatching and commanding, and solving problems before they start.

Do a good job inspection of the project, find that the danger is based on rushing to grab the small ones early, and make every effort to avoid and reduce disaster losses.

　　"During the '14th Five-Year Plan' period, we will also strengthen forecasting, early warning, rehearsal, and pre-plan'four-prevention' prevention methods, advance the construction of digital watersheds, promote the construction of a joint water engineering disaster prevention dispatch system, and comprehensively improve the analysis and processing of business information for water engineering Ability. Improve the modernization level of flood and drought disaster prevention, promote the establishment of an integrated monitoring system of "air, space and ground" for river basin floods, improve the basic area of ​​the river basin and the perception of water conservancy projects, improve the level of information collection, transmission, and processing, and improve the flood monitoring system of the river basin The coverage, density and accuracy of the project. Improve the forecast and early warning level of severe weather such as heavy rain, and make breakthroughs in the flood forecasting of northern rivers, floods of small and medium-sized rivers and flash flood disasters." Liu Weiping pointed out.

(Reporter Chen Chen)