Focus interview: What is the trump card in the eyes of experts to win the hard battle against floods?
CCTV News (Focus Interview): On July 17, "Yangtze River Flood No. 2 in 2020" formed in the upper reaches of the Yangtze River. What if Hong Feng is coming again? It is important to transfer and arrange people in the danger zone from various places; it is important to see the dike and find out the danger in time and deal with it; another important thing is how to proceed from the overall situation, scientifically arrange the key flood control projects, and make full use of the river channels and river basin reservoirs. And flood storage and detention areas, orderly blocking flood staggered peaks, flood flood storage, regulating water volume.
The Yaquehu River Embankment in Poyang County, Shangrao City was affected by the heavy rains in the early stage, so many of the embankment works reported to the police, and some embankments were in danger.
On July 11, an officer of the Rocket Army who arrived here to participate in the flood prevention and rescue operations used the area of a few kilometers away from the other side of the drone to conduct 24 hours of continuous observation to find the leak point. After the UAV accurately positions the pipe and bubble springs, the emergency unit immediately organizes the personnel to block the pipe flow by laying water basins and cofferdams.
With the help of scientific and technological means, this unit helped the area to find and eliminate 15 dangerous conditions of the pipeline in a few days, effectively protecting the safety of the embankment.
Like them, reinforcements and rescue forces that have arrived urgently from all over the country are on the levees of the Poyang Lake area to be highly vigilant and patrol and defend.
Over the past few days, due to heavy rainfall and the influx of the Yangtze River, Jiangxi has encountered super-historic floods, and the flood control situation in the Poyang Lake area and the Jiujiang section of the Yangtze River is extremely severe. On July 12, the working group of the Ministry of Water Resources rushed to the site in Poyang Lake to discuss flood prevention measures.
A single dike dyke is a dam built in a lake or river channel, with flood gates or flood diversion gates built on it. When the water level is low, agricultural production can be carried out in the dam, but no people are allowed to live, that is, only people are not returned. When the flood reaches the level of flood division, the single dike polder must be flood gated for flood storage. There are 185 single-retreat dikes in the Poyang Lake area. Since the flood season, due to the upright rice maturity season, only half of the single-retreat dikes have been used to harvest rice.
At 6 pm on July 13th, at the opening site of the three single-retreat dikes in Gongqing City, large excavators cleared the sandstone bags of the dam body, and the flood water dumped down the rolling dam. In Tushanxu and Hangzhouxu, the two single-retreat dikes, villagers and village committee cadres manually opened the floodgate valves, and the floodwaters flowed into the flood storage area. The use of all 185 single-retreat dikes in the Lake District, together with the flood storage of the upper and middle reaches of the reservoir, has effectively reduced the flood control pressure of the Poyang Lake and the Jiujiang section of the Yangtze River.
Play the card of flood control and flood control well, if the Dantuwei dike is the first card, the reservoir flood control is the trump card. The dam height of the Three Gorges Reservoir is 185 meters, and the flood control capacity in the flood season is 22.15 billion cubic meters. On July 2, the Three Gorges Reservoir was flooded. At that time, the No. 1 flood peak of the Yangtze River was formed, and the Three Gorges Reservoir moderately blocked the floods, reducing the pressure on the flood control in the middle and lower reaches.
A third of the peak was cut. Around July 2, the Three Gorges Reservoir was used to block the peaks of the lower reaches of the Yangtze River, which basically controlled the water level of the lotus pond not to exceed the warning level. However, the dispatch department received a rolling forecast that the rainfall in the upper reaches of the Three Gorges and the Dongting Lake area will continue, and the flooding process will continue to extend. The Three Gorges Reservoir itself also needs to free up some storage capacity to meet the larger floods.
This Yangtze River flood is characterized by a large peak height and a long duration. To reduce the pressure on the Three Gorges Reservoir, the dispatch department decided to enable the Yangtze River Reservoir Group to cooperate and operate in groups.
The Yangtze River Commission controls the discharge flow of the Three Gorges Reservoir, and dispatches Xiluodu, Xiangjiaba Reservoir and the cascade reservoirs in the middle reaches of the Jinsha River to increase the storage capacity and reduce the inflow of the Three Gorges Moderately; Peak cut. During the flooding, the huge reservoir groups participated in joint adjustment and joint control, and through joint control of 30 reservoir groups, the water levels of Shashi, Lianhuatang, Hankou, and Hukou were reduced by 3 meters, 0.8 meters, and 0.5 meters. 0.2 meters.
The Three Gorges Dam was originally designed to deal with major floods. At present, there are 41 reservoirs included in the joint operation plan in the Yangtze River Basin. In order to take advantage of the flood control and comprehensive benefits of the Three Gorges Reservoir, according to changes in the situation, changes in demand and scientific and technological progress, the Ministry of Water Resources 2009 An optimized dispatch plan was compiled, and trial storage was carried out for 12 consecutive years. The Three Gorges Reservoir was used for flood control 37 times and blocked 136 billion cubic meters.
At the same time as the floods in the Yangtze River occurred this year, there was also a major flood in the Qiantang River Basin, and the Xin'anjiang Reservoir in the basin also assumed the responsibility of flood storage.
At 9 a.m. on July 8, Xin'anjiang Reservoir officially launched a 9-hole flood discharge, which was the first time since the reservoir was built. The spillway was not suddenly decided to open to 9 holes, but first increased from 3 holes to 5 holes, then increased to 7 holes and 9 holes, and finally all opened. No matter how many holes are opened, it is based on the scientific demonstration of the dispatching expert group.
Before the arrival of this flood, through the pre-discharge, the water level of the reservoir dropped to nearly 2 meters below the flood control level. Although the reservoir is already flooding through openings, the upstream water is increasing at a faster rate, and the water level of the reservoir is still increasing.
The safety of the residents in the reservoir area needs to be guaranteed, and the safety of the reservoir dam is also important, which requires scientific and prudent decision-making.
The dispatching department accurately and dynamically grasps the amount of incoming water according to the reservoir water regime forecasting system, and then conducts "flood calculation" to accurately calculate the number of holes to be opened and the amount of flood discharge.
According to calculations, the Xin'anjiang Reservoir blocked 2.3 billion cubic meters of flood water this time, reducing the peak of 23,000 cubic meters per second to 7,670 cubic meters per second, with a peak cut rate of 67%, reducing the transfer of more than 400,000 people. The basis of scientific dispatching of water conservancy projects is accurate and timely forecasting, and the advantages of big data based on the Internet make the forecasting and dispatching systems tightly coupled and promote each other.
Flood control and flood fighting are a combination of punches. The Yangtze River Basin is included in the joint dispatch of reservoirs. In 2012, there were only 10 reservoirs, and now there are 41. These dozens of large and small reservoirs, up and down, together form a Yangtze flood. Defensive legion. In response to the No. 2 flood of the Yangtze River, the Ministry of Water Resources has formulated plans to block floods in the Three Gorges Reservoir and the upper and middle reaches of the reservoir group, and other flood control projects are also waiting in line. Flood control and flood control is a set of strength punches. Does the dike have a reinforced iron skeleton? The test is that the usual planning and construction are not in place. After the flood in 1998, about 3,900 kilometers of the main dykes in the middle and lower reaches of the Yangtze River basically reached the standard after being heightened and reinforced. Flood control and flood fighting are also a set of scientific punches. From the central to the local, all efforts are made to reduce disasters to the greatest extent with more scientific decision-making, scientific methods and scientific means.