What are the challenges of severe meteorological drought in the Yangtze River Basin?Cover News Interview with Xu Jijun

Cover news reporter Teng Yan

This summer, the most serious weather drought since 1961. At present, the water level of the Yangtze River and Dongting Lake and Poyang Lake are about 5-8 meters lower than the same period.

Earlier, a press conference related to the relevant situation of the Yangtze River River Basin held drought -resistant water supply and water supply in the Yangtze River Basin revealed that the water storage of Sichuan, Chongqing, and Anhui Reservoir was 10 % less than the same period of the year. 70 small and medium -sized reservoirs were lower than the dead water level. Still water running.

At 12 o'clock on August 16th, the Ministry of Water Resources launched the "Special Action for Joint Disputes of Drought and Water Supply and Water Supply for Drought and Water Supply for Drought and Water Supply for Drought and Water Supply for Water Supply and Preservation of Water Supply for Water Supply and Protection of the Yangtze River Basin, and the" Four Water "reservoir groups in Dongting Lake Xiangye, Xiangye Xiangye, and the" Four Water "reservoir groups, and the" Four Water "reservoir groups, and Poyang Lake Ganfun Rao Xiu Xiu Xiu's "Wuhe" reservoir group was hydrating downstream, and it plans to hydrate 1.48 billion cubic meters.

On August 21, the lakes were retreated in the mountains and rivers of the Yiyang, Poyang Hunan, and the large river bed was dry and naked (photography: cover journalist Yang Feng)

However, the drought resistance situation is still not optimistic. The National Climate Center pointed out that there is less likely to have less precipitation in the Yangtze River Basin in the autumn, and summer and autumn drought may occur in the middle and lower reaches.

What are the characteristics of drought in the Yangtze River Basin this year? What are the difficulty of drought resistance during the flood season? How to deal with drought in summer and autumn? Recently, the cover news interviewed Xu Jijun, director of the Institute of Water Resources of the Yangtze River Academy of Sciences.

Xu Jijun, Director of the Institute of Water Resources of the Yangtze Academy of Sciences

Character business card:

Xu Jijun, Director of the Institute of Water Resources of the Yangtze River Academy of Sciences, and Ph.D. in hydrological and water resources in Tsinghua University. He is also the director of the China Water Resources Strategic Research Association, a member of the Water Resources Professional Committee of the China Water Conservancy Society, and the director of the Yangtze River Economic Belt Protection and Development Research Center. In recent years, more than 30 scientific research projects including the National Natural Science Foundation of China, the national key R & D project, and the international science and technology cooperation project, including the evolution of water resources in the Yangtze River Basin, and the study of medium and long -term forecasting and evaluation planning methods. Participate in the water resources protection plan of the Yangtze River Basin, the special planning of water conservancy for the development of the Yangtze River Economic Belt.

Cover news: Drought in the flood season, is it rare in the history of the Yangtze River Basin? What challenges will it bring to the reservoir scheduling?

Xu Jijun: The drought in the main flood season is rare. A comparative feature of the Yangtze River Basin is that spring and autumn are easy to dry, and the floods are mainly floods in summer. Drought during the main flood season, it is difficult to scheduling the reservoir. Originally preparing flood prevention, some reservoirs were prepared to stop the floods in advance, but the flood did not come. Now I want to go to water supply and irrigation, and the pressure is relatively high. Many reservoirs are now running at low water levels, and even some have dried up.

Cover news: Which water conservancy measures will be applied to the current drought resistance?

Xu Jijun: The water conservancy facilities currently used for drought resistance are mainly reservoirs. Some pump stations pump from the river and the reservoir, as well as the water -boring project, that is, the water to diversion from the existing river lakes and reservoirs to another place. In addition, it also includes a well to meet the water supply and irrigation needs, which is an emergency measure.

Now the Yangtze River Basin, large and small reservoirs are undergoing drought resistance. The primary goal is to resist drought, fully ensure water supply and irrigation safety, and of course, it is necessary to prevent drought and flooding from rotating.

The flood and flood prevention and control, the water conservancy department has rich experience, but it is difficult to encounter such drought. Flood, like "acute disease", can be effective immediately after emergency treatment, but drought is like "chronic disease". It can be seen at first. After a few months, it will become more and more serious. It is difficult to judge how the next step will develop. The formation of drought disasters is a gradient process. The longer the duration, the greater the harm.

Cover news: What is the impact of drought on production and life deserves attention?

Xu Jijun: At present, in terms of living water, in the context of urban and rural water supply, most cities and towns and towns are basically guaranteed. However, some remote areas or mountainous areas and some places where water supply is not covered, living water is not guaranteed, and many places are actively transporting some water trucks.

For production, the main impact is still agricultural. It is reflected in the current disaster in some areas of crops. At present, places with better irrigation facilities can basically be irrigated through the limited water storage of the reservoir, but the situation is relatively severe because the reservoir storage in the early stage can be stained in the early stage of reservoir storage. There is not much water, and the rainfall is not enough now. If it lasts for two weeks (no effective rainfall), it will grow to the growth of crops, especially the growth of some medium rice and late rice in the Yangtze River Basin, which affects the production of autumn grain. This is now more worrying.

Cover news: Dongting Lake, Poyang Lake's water level is 5-8 meters lower than the same period of the same year, and the water body area is rapidly reduced. What does this mean?

Xu Jijun: Under normal circumstances, the precipitation of Dongting Lake and Poyang Lake Basin mainly occur in April to July. During the period, the "two lakes" will remain at a relatively high water level. By July and August, if the water level of the Yangtze River is relatively high, the water rows of "two lakes" will not go out. After August and September, as the water level of the Yangtze River decreased, the water in the "two lakes" will gradually retreat to the dry flow of the Yangtze River, and the water level of the lake area will decrease.

The monitoring of Fengyun Meteorological Satellite shows that the water body area of ​​Poyang Lake has been significantly reduced since July. On August 21, the area of ​​water body and the water body area on July 10 were reduced by about 69%(picture source: National Satellite Meteorological Center)

However, in June this year, the dry current water level of the Yangtze River was not too high. In July, the water in the upstream of the upstream was significantly less, and the water level in the Yangtze River showed a downward trend. Although the two lakes were fine in the early stage, the water level in the Yangtze River was very low. When it flows, the water level has subsided for nearly a month earlier than the year in advance. In addition, the high temperature and the amount of evaporation are also large, and the water surface of the lake area has been reduced rapidly. "Two lakes" have no water, first of all, it will have a great impact on the surrounding water supply and irrigation. Secondly, the ecology of the lake area will also be affected to a certain extent. For example, some of the bottom live animals living on the mud beach may be exposed to high temperature and drought. There is a greater impact. In addition, some floating and aquatic plants are replaced by terrestrial plants.

The monitoring of Fengyun Meteorological Satellite shows that the water body area of ​​Dongting Lake has shown a decrease since July. On August 21, the area of ​​water body was reduced by about 67%compared with July 1 (picture source: National Satellite Meteorological Center)

Cover news: There is already a trend of removing high temperature. How long is it to relieve the drought in your opinion?

Xu Jijun: Although the high temperature has faded and the human body feels more comfortable, it is not much help for crops, because crops are now the most "thirsty", and the most needed precipitation. Now I am more worried that in September, if there is no particularly obvious precipitation in early September, the drought may last until mid -late September. July, August, and September are a critical period of crop growth. Continuous drought will cause production reduction, and even some areas will be harvested. Now in some places, if there are irrigation conditions, it can also ensure crop growth, but there are no good irrigation conditions. For example, some "Wangtiantian" will be reduced or even harvested.

If the drought can be relieved in 20 days, the loss of autumn grain may still be tolerated, but it may be very unfavorable for more than 20 days.

Cover news: The meteorological department predicts that the summer and autumn drought may occur. What are the preparations for related areas?

Xu Jijun: Now I am very worried about summer and autumn drought, and the possibility is still quite high. The water in the reservoir can irrigate and irrigated it. When the water supply can supply water, water supply, and the water source must be guaranteed. At the same time, some places of conditions can be adopted to ensure water supply, and some plain areas and mountainous areas should do a good job of groundwater emergency mining. The drought -deficient areas of the Yangtze River Basin must strengthen water -saving management. In some areas, measures such as manual rainfall should be implemented.

Cover news: Many people compare the heavy drought in the middle and lower reaches of the Yangtze River this year. What are the differences between these two major droughts?

Xu Jijun: 2006 Sichuan -Chongqing Drought is mainly concentrated in the upper reaches of the Yangtze River, Sichuan and Chongqing, as well as Yunnan. This time the drought covers a large range, not only Sichuan and Chongqing, but also the middle and lower reaches of the Yangtze River, including Hunan, Hubei, Jiangxi, Anhui, and downstream Jiangsu, and almost all the entire basin has suffered more severe drought.

On August 21, the rivers mussels were dried up and died in the mountains and rivers of Yiyang Hunan (Photography: Cover Journalist Yang Feng)

Furthermore, this year's drought occurred in the summer, called Fu dry, and the drought began to be earlier and lasting for a long time. There were obvious precipitation in the Yangtze River Basin in June. There were basically no significant precipitation in July. It continued until now. This situation is relatively rare, and it is accompanied by high temperature evaporation. At present, this year's drought is much more serious than 2006.

Cover news: Is the drought in the Yangtze River Basin also exposed some problems this year? What suggestions do you have?

Xu Jijun: This year's drought in the Yangtze River did expose some places that could be improved.

First, in terms of drought monitoring and early warning, the technology is relatively weak. There are many technical means of flood control in the Yangtze River, and it is very good. Drought monitoring and early warning should strengthen the corresponding basic research, technology research and development, and platform construction. For example, according to the current meteorological information, the development of drought in the future can be enhanced.

Second, for drought, the current engineering means are relatively weak. The construction of the reservoir is more considering flood control, water supply and irrigation. Water supply and irrigation are also under normal conditions. When encountering this extreme situation, there are not many measures. For example, this time, if the reservoir reserves a large amount of water in advance or has a reserve groundwater source, it will be much better.

Third, in the long run, we must strengthen the planning of drought resistance. Perhaps this year is just a warning, and now it should be considered scientific research and engineering planning that responds to climate change leading to extreme drought disasters.

Fourth, we must make a good overall planning between flood control and drought resistance, and adjust the scheduling regulations of the reservoir, and to do a good job of scheduling and operation from the perspective of flood control and drought resistance. A very critical point, how to control the flood limit of the reservoir, may leave some more water at a little bit. To leave more water, it will be beneficial to resist drought, but at the same time, it will bear a certain risk of flood prevention.

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