The Yangtze River Flood Control System in the Post Three Gorges Era
"China News Weekly" reporter / Yang Zhijie
Published in 2020.7.20, the 956th issue of "China News Weekly"
The Yangtze River's first flood red warning this year appeared in Poyang Lake.
At 13:00 on July 10, the Hydrographic Bureau of the Yangtze River Water Conservancy Commission (hereinafter referred to as the Yangtze River Commission) of the Ministry of Water Resources upgraded and issued a red early warning of floods in the river section near the mouth of Poyang Lake and in the Poyang Lake area. This is the highest level of flood warning signal. One day later, the red alarm sounded again, and the Hydrological Bureau of the Yangtze River Commission continued to issue red early warnings for floods in the section of the middle and lower reaches of the Yangtze River from the Jiujiang to Hukou and Poyang Lake areas at 12:00 on July 11. The warning was quickly verified. At 7:00 on July 12, the water level of the Poyang Station of the Rao River in Jiangxi exceeded the 1998 water level by 0.13 meters, breaking the historical extreme value since the hydrological record, and the flood control work of the whole province of Jiangxi entered a wartime state.
Poyang Lake was the last large-area "reservoir" before the Yangtze River entered the lower reaches. If the Poyang Lake is lost, the Yangtze River floods will be discharged directly, which will bring great pressure for flood control in the lower reaches of the Yangtze River. But now, this "reservoir" has been growing bigger and bigger. The National Satellite Meteorological Center has recently cooperated with the Jiangxi Meteorological Bureau to conduct scientific monitoring and assessment of the changes in the main body of Poyang Lake and the surrounding waters in Jiangxi Province, using satellite remote sensing monitoring results for nearly 10 years since 2010 and combining meteorological observation data for nearly 60 years. The results showed that the main body of Poyang Lake and the surrounding water area reached 4206 square kilometers, the largest in the past 10 years.
The flood control pressure of cities in the lower reaches of the Yangtze River is also increasing as the area of Poyang Lake expands. This year's torrential rains are extremely extreme and break through historical records, and are still prevalent in the middle and lower reaches of the Yangtze River. This inevitably raises worries. Will there be a flood in the Yangtze River similar to that in 1998? It was the worst flood in China in the past three decades, causing 4,150 deaths and leaving a very profound mark on China.
On July 13, the Ministry of Water Resources introduced at the State Council’s regular policy briefing that the water level below the Jianli River and the Dongting Lake, Poyang Lake and Taihu Lake are still in super-alarm status. Numerous predictions indicate that there will still be a large river basin flood this year, and the Yangtze River flood control system will once again face a severe test.
Be wary of major floods throughout the river basin
Poyang Lake is China's largest freshwater lake, and plays an important role in flood control and storage in the Yangtze River Basin.
The five major rivers in the Poyang Lake Basin merge into Poyang Lake, which is injected into the Yangtze River from the estuary after storage. At the same time, during the flood period of the main stream of the Yangtze River, Poyang Lake accepted that the Yangtze River floods poured into the lake, stored the Yangtze River floods, and relieved the upstream flooding pressure.
On the afternoon of July 7, Poyang Lake experienced the first river backwatering this year. At the foot of Shizhong Mountain at the intersection of the Yangtze River and Poyang Lake, the north of the lake turned into the south of the river, and the water of the Yangtze River poured into Poyang Lake. Chen Xianping, deputy director of the Hukou County Emergency Management Bureau, explained that the water level of the Yangtze River in Poyang Lake has risen rapidly by more than 40 centimeters due to heavy rainfall in recent days. Due to the large amount of incoming water from the Yangtze River, the Poyang Lake has been affected by the water level of the Yangtze River. The phenomenon of backflushing.
The backflow of river water will inevitably cause the water level of the Poyang Lake area to rise. According to the latest statistics from the Jiangxi Provincial Flood Control and Drought Relief Headquarters, as of 17:00 on the 11th, torrential rains, floods, waterlogging and other disasters have caused more than 5.21 million people in the Poyang Lake Basin, more than 430,000 people were resettled and 455 thousand hectares of crops were affected.
Zhou Jianjun, chief researcher of the Institute of River and Ecology at the School of Civil Engineering and Water Conservancy, Tsinghua University, told China News Weekly that the backwatering of rivers in Poyang Lake during the flood season is normal. At present, the backwatering of rivers is not serious compared with previous years. He explained that the total water level of the Yangtze River is higher than the water level of Poyang Lake when backflow occurs. However, this year's data seems that the water level of Hankou upstream and downstream Datong water level, which is closer to the lake mouth, is about one meter away from the guaranteed water level, and the water level of the lake mouth has approached the guaranteed water level, which shows that only the single-point water level of the lake mouth is higher. The water level at the upstream and downstream observation stations has not exceeded the guaranteed water level.
At 16:00 on the 12th, the water level of the Poyang Lake and Hukou Station was close to the guaranteed water level of 22.50 meters. According to the relevant provisions of the "National Flood Control and Drought Relief Emergency Plan", after consultation and consultation, the National Defense General Administration decided to raise the flood response level Ⅲ emergency response to level Ⅱ. A day ago, on July 11, the Jiangxi Provincial Flood Control and Drought Relief Headquarters upgraded the flood control level II emergency response to level I, which was also the first time that Jiangxi initiated the response since 2010.
An expert on finger defense in the province said that in the face of rising floods, it is necessary to request the support of troops, armed police and other fresh troops in advance if necessary. Make preparations for organizing the transfer and resettlement of personnel in flood storage and detention areas, and blasting at flood diversion outlets. Activate flood diversion channels and flood storage detention areas in a timely manner. Once the commissioning order is issued, floods are immediately distributed to ensure the relief of pressure on important dikes. In response to the local government's demand for troops, the Jiangxi Military Region coordinated a certain army unit in the eastern theater, and 1,500 officers and soldiers arrived in Poyang County on the evening of July 11. In addition, the Rocket Army, Armed Police and Reserve Forces who have come to the rescue successively have gathered thousands of troops along the Poyang Lake.
"The Poyang Lake area is tense and must be taken seriously, but at present it seems that the main stream of the Yangtze River is not too serious." Zhou Jianjun told "China News Weekly" that the Hukou station has not exceeded the guaranteed water level, and the flow in the Poyang Lake area has increased. It is also slowing down, and more importantly, the water level of Datong in the lower reaches of Poyang Lake is still more than 1 meter lower than the design water level. "This shows that there is still room for the lower reaches of the Yangtze River (flood discharge). There are no major problems in Anhui and Nanjing, Jiangsu."
However, he reminded that what is most worrying now is the sudden rainstorm in the upper reaches of the Yangtze River and the occurrence of major floods. If the Three Gorges are not successfully intercepted, the upstream and downstream floods will overlap, and problems will easily occur. According to the weather forecast, from July 13th to 16th, the main heavy rainfall area will move southwards after a short northward movement, and then come to the middle and lower reaches of the Yangtze River again, with a large degree of coincidence with July 4th to 7th heavy rainfalls. At that time, heavy rain may still hit the Poyang Lake Basin. In this regard, Zhou Jianjun believes that even if there is heavy rainfall, as long as it does not overlap with the upstream flood, it will not be too serious. The Yangtze River channel below Datong can pass 80,000 cubic meters per second of flow, and the water beyond Poyang Lake can flow into the tributary of the Yangtze River. , Can also be safely discharged.
The Yangtze River Water Resources Commission predicted in April that the overall deviation of the meteorological landscape in the Yangtze River Basin in 2020 would be more likely to cause regional major floods in the Yangtze River, and even large river basin floods. In early July, the Yangtze River Commission stated that it still maintains this judgment based on the current status of meteorology and hydrology and supplementary analysis.
Cheng Xiaotao, a member of the Expert Committee of the National Disaster Reduction Committee and the former director of the Institute of Flood Control and Disaster Reduction of the China Institute of Water Resources and Hydropower Research, explained to China News Weekly that the major floods in the Yangtze River Basin are usually expressed in a variety of ways: ", the rain belt is mainly distributed in the middle and lower reaches of the Yangtze River, usually in June; the other is called the "big flood", mainly in the Sichuan and Chongqing areas on the upper reaches of the Yangtze River, usually in July and August.
There is another kind of flood, like the 1998 flood, which was postponed to July and met with the "upper flood" to form a flood in the whole basin. "Floods also have multiple manifestations. One is that the peaks are extremely large and last a long time, such as the 1954 flood. The flood peaks of the 1998 flood were not that large, but they were one peak after another, eight consecutive." Cheng Xiaotao said.
"The latter half of the month is very important." Zhou Jianjun said that the flood season in the Yangtze River is more prone to "seven times and eight up". At present, the flood development is mainly concentrated in the middle and lower reaches of the south of the Yangtze River, and it is transferred to the north of the Yangtze River in early August. And upstream. This means that the upper reaches of the Yangtze River may still have worse flood conditions. The most important thing at present is to stabilize the upper reaches.
Over-reliance on the Three Gorges?
In order to reduce the downstream pressure, the Yangtze River Commission dispatched the Three Gorges Reservoir to reduce the average daily outflow from the current 25,000 cubic meters/second to 22,000 cubic meters/second from July 11th, so as to reduce the flood control pressure in the middle and lower reaches as much as possible. Nevertheless, Chen Guiya, deputy chief engineer of the Yangtze River Water Conservancy Commission of the Ministry of Water Resources, said that because the mouth of the Poyang Lake is far from the Three Gorges Reservoir, and the water from the Poyang Lake system is relatively large, the Three Gorges Reservoir Regulation has a great effect on the water level of the Poyang Lake. limited.
Zhou Jianjun further explained that the Three Gorges will block or release floods to a certain extent and will have little impact on the downstream. Even if the Three Gorges mostly passes through 10,000 cubic meters of water flow, because the distance is too far below Wuhan, the flow will not increase too much. It cannot be understood that the upstream flow rate is shifted down. For example, the flow rate that was originally 80,000 cubic meters per second is now superimposed to 90 million cubic meters per second.
"Objectively speaking, the middle and lower reaches of the Three Gorges Gang must have reduced certain burdens, but it is still debatable whether this is appropriate." According to Zhou Jianjun, according to the Three Gorges dispatching regulations, the Three Gorges should not manage the downstream too much, but only intercept the floods. , Mainly to keep Jingjiang safe. The Jingjiang River is another name for the Yangtze River from Zhicheng, Hubei Province to Chenglingji, Yueyang County, Hunan Province, with a total length of about 360 kilometers.
In May 2010, the State Flood Control and Drought Relief Headquarters pointed out in the "Response to the Three Gorges-Gezhouba Water Control Project 2010 Flood Season Dispatching and Operation Plan", "When small and medium floods occur in the upper reaches of the Yangtze River, according to real-time rain conditions and predictions, the Three Gorges Reservoir It is not necessary to implement flood control compensation and dispatch for the Jingjiang or Chenglingji River sections, and when the flood control safety is fully assured, the Three Gorges Reservoir can be dispatched and operated by the camera."
As of July 12, the water level of the Three Gorges was 152.16 meters. In principle, the water level of the Three Gorges Reservoir will be controlled according to the flood control limit water level of 145 meters during the flood season to ensure sufficient flood control reservoir capacity. Zhou Jianjun worried that the dispatch of the Three Gorges was a waste of flood control capacity. Although the current floods are mainly concentrated in the middle and lower reaches of the south of the Yangtze River, they will generally move to the north and upstream of the Yangtze River in early August. The upper reaches of the Yangtze River may still increase in flood conditions and cause major floods.
Before this, as an important part of the Yangtze River flood control system, the Three Gorges Reservoir has started flood control work. On June 29, the Three Gorges Dam opened its flood gates for the first time this year to free up storage capacity to meet the possible floods in the near future. On July 2, "Yangtze River Flood No. 1 in 2020" flowed into the Three Gorges Reservoir. At 14 o'clock that day, a peak flow of 53,000 cubic meters per second appeared. After interception, the peak cut rate reached 30%. Cheng Xiaotao believes that Hongfeng No. 1 on the Yangtze River has reached the critical point of 50,000 cubic meters per second. After interception, the downstream safety will be greater.
Zhou Jianjun does not deny the role of the Three Gorges Project in flood control of the main stream of the Yangtze River, but he believes that judging from the water conditions on the 2nd day, there are no safety issues downstream and the Three Gorges should not stop the floods.
"The Three Gorges are used to prevent the Jingjiang River from floods and prevent possible devastating disasters." Zhou Jianjun believes that according to the Three Gorges flood control plan, when the upstream water flow is less than 56700 cubic meters per second, the Three Gorges Reservoir does not need to be intercepted. Directly vent. Over 56700 cubic meters per second, the Three Gorges Reservoir can start flood storage. He believes that the "Yangtze River No. 1 Flood" did not reach the standard. Such small and medium-sized floods should not be blocked by the Three Gorges at all. As long as the flood control standards and requirements are met in the middle and lower reaches, the floods can be resolved without particularly serious consequences. .
Zhou Jianjun once undertook scientific research topics such as sediment, flood control, ecological environment, dispatching operation and flood control of the Three Gorges Project. He has repeatedly called for safe floods in the middle and lower reaches of the Yangtze River to operate in accordance with the standards of the Three Gorges Plan. But in his view, the reality is, "In these years, we have very high requirements in the construction of water conservancy projects. We must raise the flood control standards to more than one hundred years or even more than one thousand years. Both are eliminated. Not only can the flood control goals not be achieved, but the river ecology is also greatly damaged."
Zhou Jianjun believes that the reason for this situation is related to the lack of professional knowledge in some middle and lower cities. A popular concept is that the Three Gorges interception of small and medium floods can reduce the local flood control pressure, resulting in local over-reliance on the Three Gorges Reservoir. In addition, the Three Gorges intercepting small and medium floods can ensure the economic benefits of dam power generation.
However, storing small and medium floods will occupy the flood storage capacity of the Three Gorges. "Whether the floods in the whole basin will come, no one is sure. If you really encounter the kind of big flood of 1954, the current flood storage capacity of the Three Gorges is very stretched." Zhou Jianjun said.
In addition, he reminded that blocking small and medium floods throughout the year will not only increase the risk of flood control in the Three Gorges, but because the middle and lower reaches have not been flooded for a long time, the river will shrink and further increase the risk of flood discharge. In the high water level of the dike of the Yangtze River, 4 to 5 meters of dikes have not been exposed to water for a long time. They need to go through safe flooding to allow the dikes to withstand certain tests and timely find hidden dangers and repair them in time. This is an effect that cannot be achieved by instrument detection. The so-called safe flood is the flood that is close to the design flow, often passing this kind of flood can guarantee the flood discharge capacity of the river.
Zheng Shouren, an academician of the Chinese Academy of Engineering and the general head of the Three Gorges Project Design, also said that the discharge of small and medium-sized floods in the annual flood season is below 45,000 cubic meters per second, which may lead to the shrinkage and degradation of the middle and lower reaches of the flood channel. Take a few years interval, discharge 55,000 cubic meters per second of flow, comprehensively test the embankment and flood discharge capacity of the Jingjiang river section to prevent the channel from shrinking.
In Zheng Shouren's view, the Three Gorges Reservoir is not unconditional for storing small and medium floods. In order to avoid the risk of flood control, the Three Gorges Project must be used to store small and medium floods, and three principles must be followed: First, the Three Gorges Reservoir is required to store small and medium floods to reduce disaster relief; Second, based on real-time rain conditions and forecasting, the Three Gorges Reservoir does not need to implement the Jingjiang or the city. The flood control compensation dispatch will be carried out in the Lingji area; the third is not to reduce the established flood control effect of the Three Gorges Project on the Jingjiang area and ensure the safety of the hub. Only when these conditions are met can the Three Gorges Project be able to activate the storage and storage function.
In Cheng Xiaotao's view, it is normal for different scholars to have different views. But the factors to be considered in the Three Gorges flood control are many, not just the reference flow. "Complexity also depends on one reason. The Yangtze River still has the problem of bank collapse. The levee basically rests on the side of the Yangtze River. In case of bank collapse, even if the water level is not so high, it will threaten the safety of the levee."
Therefore, Cheng Xiaotao believes that sometimes other factors such as flow rate may be considered, not just an indicator of flow rate. He agrees that too much interception of small and medium floods and smoothing out all of them will indeed cause the above problems. "The key is one degree."
Fragile "last insurance"
In the early morning of July 13, the Jiangxi Provincial Flood Control and Drought Relief Headquarters issued an emergency notice requesting that all single dike polders in the lake area must actively open the gate to clear the weir to store floods on July 13.
Chen Yunxiang, director of Jiangxi Provincial Rivers and Lakes Administration, told the media that since the water level in the Poyang Lake area and the five rivers exceeded the warning water level, and the water level at Xingzi Station even exceeded the historical extreme value, the flood control situation was more severe than in previous years. It is the first time that all the measures to open the gate to clear the weir and store floods in the dikes are all required.
Flood storage and detention areas are "actively affected areas" that the country has to demarcate to protect key areas from flooding. They are mostly depressions and lakes. They were mostly built during the lack of dams in the 1950s and 1960s and shared the pressure of the river. Flood control in the middle and lower reaches of the Yangtze River is mainly achieved through three systems: dikes, flood storage and detention areas, and reservoir groups. Embankments are fundamental. However, in the face of major floods or excessive floods, reservoir peak cuts and flood storage and detention are required to distinguish flood digestion. At present, there are 42 flood storage and detention areas in the main stream of the middle and lower reaches of the Yangtze River, with a total area of about 12,000 square kilometers and an effective flood storage volume of 58.97 billion cubic meters.
Flood storage and detention areas are the "last insurance" in the flood control system. For a long time, they have always been the weakest link. Zhou Jianjun noted that according to the Three Gorges plan, there are currently nearly 28 billion cubic meters of flood storage capacity in the vicinity of the Yangtze River's Lingji.
In 2016, Shen Huazhong, deputy director of the Flood Control and Drought Relief Office of the Yangtze River Commission, told the media that in addition to the construction of about 10 billion cubic meters of flood storage and detention areas near Chenglingji, the middle and lower reaches of the Yangtze River should be constructed in accordance with the requirements of the State Council  No. 12 document. Build 26.2 billion to 29.8 billion cubic meters of important and general flood storage and detention areas including the areas near Chenglingji, Wuhan, and Hukou. The construction of important flood storage and detention areas was originally planned to be completed by 2020, but due to inadequate investment, the progress was obviously lagging behind.
Existing flood storage and detention areas also have long-term management problems. At the end of August 2016, after the flood disaster in Anhui, Cheng Xiaotao, as the former executive deputy director of the Technical Research Center for Flood Control, Drought Relief, and Mitigation of the Ministry of Water Resources, led a team to investigate the severely affected areas. He noticed that after 1999, there were no major floods in the local area for 17 years. The flood prevention awareness of the people in the polder area was weak. The construction of the polder and the construction of new polders occupied the flood channel and the storage capacity of the lake. "The water system of rivers and lakes is crowded and blocked, and the drainage capacity of tributary rivers and the flood storage capacity of the inner lake are reduced, which was an important reason for the severe floods and disasters in the Huwei area of Anhui Province." Cheng Xiaotao said.
Many flood storage and detention areas have long been reclaimed into fields by the people. After the 1998 flood, the state called for returning farmland to the lake, which was divided into "single retreat" and "double retreat". "Single retreat" means that the land is not reclaimed, the people move out of the polder area, and the land can be cultivated, but flood gates should be opened during the flood period. "Double retreat" is to retreat people from the fields and restore the natural flood storage capacity of flood storage and detention areas.
In the disaster-stricken area, Cheng Xiaotao found that many of the "double retreat" became "single retreat". Even in the "single retreat" area, when the flood was encountered, none of the gates was opened, and the policy was difficult to advance. "The common people think that my place did not collapse during the flood in 1998 (the dam), as long as you persist, you can hold it. Why do you open the gate to release the water?"
"The same polder area is now flooded differently than in the past." Cheng Xiaotao explained that a polder area was flooded in the past, which contained a few acres of land, lost one season of crops, the government has relief, civil affairs has insurance, and social donations, ordinary people You can quickly resume production and rebuild your home. However, now that the young and strong laborers have left the countryside, the land has begun to be intensively operated, and the initial investment in planting or breeding is very large. Once the disaster occurs, the losses are in the order of hundreds of thousands or even tens of millions, and it is difficult for civil relief and agricultural insurance to help these people get through Difficult.
In addition, the compensation methods of flood storage areas are also prone to wrangling. "Nuclear disasters first require nuclear capital and nuclear production. At the beginning of the year, the crops were not yet produced. After the flood, the government proposed to compensate for crops such as rice, but the people said that the crops are grown here as the yield is higher. Therefore, compensation methods for flood storage areas can no longer be done in accordance with the regulations of 20 years ago, and must be adjusted." Cheng Xiaotao told China News Weekly.
Dr. Yaowei Wei from the Institute of Water Conservancy Planning and Research of the Yangtze River Survey, Planning and Design Institute stated that the flood storage and detention area lacks a strict management system. Due to the low resettlement compensation standards and the low willingness of the people to relocate, it is difficult to control the population and economic development of the flood storage and detention area. It is difficult to meet the requirements of "divide into, save, and retreat". Once the flood diversion operation has huge losses, it is difficult to use the flood diversion.
Zhou Jianjun once counted that there are more than 50 million agricultural populations in such areas across the country, with poor conditions and high security risks. This is also an important shortcoming to achieve a comprehensive well-off this year.
In 2016, when the flood situation was severe, Anhui also took the initiative to enter the flood. In the "Report on the Investigation of Flood Disasters in the 2016 Yangtze River Basin in Anhui Province" completed by the team of Cheng Xiaotao, it was mentioned that in the flood control and flood control of Anhui, four active flood dikes have played the role of flood protection and embankment, but compared with 129 The number of dikes on the dike and the number of dikes on the initiative to enter the flood are still small. When the flood waters receded, these places pumped water out, but instead resumed production more quickly.
"We have a discussion with the local government. Everyone thinks that taking the initiative to enter the floods is the long-term security plan, but no one will take the initiative to choose this plan." Cheng Xiaotao told China News Weekly, the embankment on the lower reaches of the Yangtze River is so long. , No one wants. The reason is that, in the interest of local governments, it is better for local governments to take the initiative in flooding, rather than raising the entire embankment to get more funds from the state.
In Cheng Xiaotao's view, the construction of an eco-friendly and environmentally friendly flood control system is a systematic project, which requires the mandatory implementation of laws and regulations, the promotion and implementation of local governments, and the strong support of scientific and technological means. Today, 4 years later, in the face of a new round of floods, these problems are still hidden dangers of the Yangtze River flood control. Once it breaks, the consequences will be more serious than ever.
The short board of the Yangtze River flood control system
Prior to the arrival of the flood season exam this year, on May 28, the Ministry of Water Resources organized the 2020 Yangtze River flood control exercise. The flood control operation exercise was based on the Yangtze River flood in 1954. The content involved key decision-making processes such as joint operation of reservoir groups, operation of high water level of dikes, and use of flood storage and detention areas in the middle and lower reaches. An important goal of the exercise is that it hopes to give full play to the joint dispatching of the upper and middle reaches of the Yangtze River Reservoir with the Three Gorges Reservoir as the core, cooperate with flood storage and detention areas and other engineering applications, and make the best possible efforts to mitigate the loss of floods and floods by rationally tapping the flood control potential of the engineering system.
In fact, after the historic 1998 flood, as the Three Gorges Project was completed and put into operation in 2006, the Yangtze River flood control system was continuously strengthened.
Wei Shanzhong, the deputy minister of water resources, mentioned in the “General Strategy for Flood Control and Disaster Reduction of the Yangtze River in the New Period” published in February 2017 that there are currently about 34,000 kilometers of embankments in the Yangtze River Basin. Among them, more than 3,900 kilometers of main levees in the middle and lower reaches of the Yangtze River basically reached the planned flood control standards; in order to ensure the safety of flood control in key areas, 42 flood storage and detention areas that can store excess floods of about 59 billion cubic meters were arranged in the main stream of the middle and lower reaches of the Yangtze River. In the past ten years of flood control construction, the middle and lower reaches of the Yangtze River have basically formed a comprehensive flood control and disaster reduction system based on embankments, the Three Gorges Project as the backbone, other main and tributary reservoirs, flood storage and detention areas, river regulation projects and non-flood control measures."
However, Wei Shanzhong also pointed out that although the flood control capacity of the middle and lower reaches of the Yangtze River has been greatly improved, there are still many problems in the flood control of the middle and lower reaches of the Yangtze River. Although the Three Gorges Project has a flood control capacity of 22.15 billion cubic meters, the flood control capacity is still insufficient compared to the huge excess flood in the middle and lower reaches of the Yangtze River. In the case of the 1954 major flood, there will be 34 to 40 billion cubic meters of excess flood in the middle and lower reaches of the main stream, which needs to be properly arranged.
In addition, the flood control capacity of the tributaries and lakes in the middle and lower reaches is low, especially the levee input is small, and most of them do not meet the standard. After the operation of the controlled reservoirs in the Three Gorges and the upper reaches of the Yangtze River, the "clear water" discharge caused long-term erosion and silting adjustments in the mainstream and lower reaches of the river. The problem of bank collapse in some river sections is prominent, endangering the river regime and the safety of dikes; the management of small and medium-sized rivers and the prevention of mountain flood disasters are still in their infancy; small and dangerous reservoirs are extensive and urgently need to be removed and reinforced.
In July 2008, the State Council formally approved the "Yangtze River Basin Flood Control Plan" (hereinafter referred to as "Planning"). After the approval of the "Plan", a large-scale flood control project was launched in the Yangtze River Basin. However, many experts realized that in 2016, 505.8 million people were affected and 121 people were killed by heavy rains and floods in the middle and lower reaches of the Yangtze River, which revealed that there are still many shortcomings in the Yangtze River flood control system.
Zhong Zhiyu, chief engineer of the Yangtze River Water Resources Commission of the Ministry of Water Resources, proposed at the two national conferences in 2019 that the main problems of the current flood control and disaster reduction in the Yangtze River are: the lack of new planning guidance, the construction and management of flood storage and detention areas in the middle and lower reaches of the Yangtze River, and the mainstream channels in the middle and lower reaches of the Yangtze River. The bank collapse has intensified, and the flood prevention and security problems of the Zhoutan People's Embankment in the middle and lower reaches of the Yangtze River are prominent.
"As the Three Gorges and other upper reaches of the Yangtze River are successively completed, new and profound changes have taken place in the flood control situation in the middle and lower reaches of the Yangtze River." Zhong Zhiyu pointed out that it is necessary to systematically analyze the shortcomings of the Yangtze River's flood control and disaster reduction and re-examine the flood control standards of the Yangtze River Basin. Redefine the flood control system and formulate forward-looking plans.
Zhong Zhiyu suggested that we should accelerate the adjustment and construction of flood storage and detention areas in the middle and lower reaches of the Yangtze River, strengthen the treatment of bank collapse and emergency rescue in the main stream of the middle and lower reaches of the Yangtze River, and issue guidelines for the protection and utilization of continents in the middle and lower reaches of the Yangtze River as soon as possible.
People will never be able to eliminate the flood. How to coexist with the flood is an eternal topic. Cheng Xiaotao believes that at present, these problems are no longer achieved by simply adjusting the management methods of flood storage and detention areas, but the entire "Flood Control Law" must be adjusted. He admitted that the "Flood Control Law", formulated in the 90s of the last century, responded to the flood characteristics of traditional agricultural society, and it has been seriously lagging behind and must be revised as soon as possible.
China News Weekly Issue 26, 2020
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