On October 7, Jiangxi reported that the Yangtze River was irrigated for the first time this year, and the water level rose to more than 13 meters, which is a good thing that the people of Jiangxi have been waiting for for a long time.
As the largest freshwater lake in China, it has single-handedly fed the sons and daughters of Jiangxi, making it a famous land of fish and rice.
But the great drought in 2022 has turned this lake into a dry land of grass, the dry and cracked lake bed makes people look extremely sad, and the endless sea of grass has also become an Internet celebrity check-in place, and even some people secretly cut grass and sell it for profit.
In recent days, Poyang Lake has finally been poured back to the Yangtze River, and the once beautiful mountains and waters have gradually returned. So how important is Poyang Lake? Why does it dry up? What are the benefits of Yangtze River irrigation today?
What is the important role of Poyang Lake? What does it have to do with the Three Gorges?
Poyang Lake is located in the mainland Jiangxi Province, is the largest freshwater lake in China, because Poyang Lake is located in the middle and lower reaches of the Yangtze River, it plays an important role in the water flow and throughput of the Yangtze River, and is also greatly affected by the season. The area of the lake also changes with the water level, and when the water level is reached at a height of 22.59 meters, the lake area can reach 4070 square meters.
Poyang Lake is second to none for the people of Jiangxi, and Jiangxi's economic development has the indelible contribution of Poyang Lake.
The lakeside residents rely on it to build land around the lake, raise fish and rice, and establish a land of fish and rice that lives in peace and prosperity, giving birth to ancient and modern civilization, which is affectionately called "mother lake" by the people of Jiangxi, and the total grain output of 43.15 billion jin in Jiangxi in 2019 is the best gift of Poyang Lake.
In 2008, the "Ecological Economic Zone Around Poyang Lake" entered the eyes of the people of the whole country, and Jiangxi Province began to plan the ecological economic development of Poyang Lake, which is a demonstration of harmonious coexistence between man and nature, and a pioneer of China's low-carbon economic development.
Poyang Lake not only plays a vital role in the economic development of Jiangxi Province, but also irreplaceable in regulating water levels, storing water sources, maintaining ecology, improving climate and other natural aspects.
It is the largest freshwater wetland in Asia, rich in species, home to the most abundant freshwater fish and countless birds. Whenever the water level of the Yangtze River is abnormal, Poyang Lake can always replenish and regulate with it, and the water of the five rivers flows into the Yangtze River, which is known as the "kidney of the Yangtze River".
Poyang Lake and the Three Gorges are both lakes on the Yangtze River, and the Three Gorges are artificial lakes in the upper reaches, and their role is more focused on flood control, power generation and waterways; Poyang Lake is downstream, more than 600 kilometers from the Three Gorges Dam.
The reason why the two are related is that the Poyang Lake area suffered from floods in the middle and lower reaches of the Yangtze River in 2020, so the flood control capacity of the Three Gorges Dam living upstream has been questioned by many netizens.
Last year, Poyang Lake suffered a long-term drought, and netizens once again set their sights on the Three Gorges and proposed to release the Three Gorges water to relieve Poyang Lake, so the two were discussed together many times.
But in fact, the two are far apart, and the flood control effect of the Three Gorges Dam is more reflected in the speed of alleviating the turbulent water flow upstream, and it is necessary to "sharply collect and slow down" in the adjustment process, which cannot completely solve the downstream flood, especially the flood water source is in the lower reaches of the Three Gorges.
Similarly, for drought conditions, the Three Gorges itself needs water storage for power generation and shipping, and it is difficult to discharge more than 600 kilometers of floodwater to relieve Poyang Lake.
Why does Poyang Lake dry up? What are the consequences?
After clarifying the important role of Poyang Lake and the relationship between the Three Gorges, let's take a look at the causes and consequences of the great drought in Poyang Lake.
In July and August 2022, Poyang Lake, which should have been in the flood season, uncharacteristically experienced a major drought, and the water level of Kangshan Station dropped to 11.96 meters, the lowest water level in the 67 years since the station was established.
The water level has receded to a record low, the lake bed has become a gray cracked earth, the central island has not come out of the water for many years, and now it has to show the whole picture, and the lake bed is full of "dried fish", which is probably the best portrayal of "the vicissitudes of the sea into mulberry fields".
What exactly is the cause of this?
First of all, the direct reason is that there has been no rain for a long time, there is no precipitation to replenish, and the Yangtze River must be replenished.
According to statistics, in the past, the average precipitation in the Yangtze River Basin reached 1067mm, but since July 2022, the precipitation has decreased by 40% compared with the past, and the Poyang Lake Basin has reached 70%, and the number of invalid rainfall days has even exceeded 20 days, and the water volume in the entire Yangtze River Basin is less than 50mm.
Even if it doesn't rain, it continues to be hot, and the temperature hovers at 39 °C for 25 consecutive days, and the drought and high temperature have led to Poyang Lake not being replenished, but the drought is not only Poyang Lake, the entire Yangtze River basin has fallen into a big drought.
Because the terrain of Poyang Lake is higher than the middle and lower reaches of the Yangtze River, the only source of water flows into the Yangtze River, with no supply at the top and plunder below, and Poyang Lake soon fell into drought.
The second is the interception of various river reservoirs. It is already facing widespread heat and drought, and several main rivers are covered with reservoirs, cutting off the only source of water.
There are a total of 10,593 reservoirs in Jiangxi, most of which are located on the "five rivers system" of Poyang Lake, such as the Xia River and Wan'an Reservoir on the Gan River, the Hongmen and Liaofang Reservoirs on the Fu River, the Xunxikou Reservoir on the Changjiang River, and the Dayuan and Zhelin Reservoirs on the Xiuhe River, which makes Poyang Lake even more desperate, and it has no water and has to be cut off.
However, given the huge flood prevention effect of these reservoirs during flood years, it is impossible to dismantle them.
Finally, there are long-term causes, global warming and man-made overtaking. Global warming is a perennial issue, even the Arctic glaciers can not bear to melt, it is no wonder that there will be long-term drought and high temperature, the reasons for global warming will not be repeated here.
As for the unrestrained demand of human beings, it was also said before that Jiangxi's richness benefits from Poyang Lake, but long-term overfishing around the lake will inevitably backfire. If there is a drought in the Yangtze River basin, crops will also be short of water, and Poyang Lake will inevitably have an additional group of looters.
The drought in 2022 will undoubtedly be a devastating blow to the farming industry of the people of Jiangxi, with serious shortages of irrigation and drinking water sources, which will have a major impact on the local economy, and more importantly, the degradation of wetlands, the reduction of biomass, and the difficulty of habitat for migratory birds. It is a heavy blow to human development and natural ecology.
What are the benefits of Yangtze River water irrigation to Poyang Lake today?
With the prolonged drought unabated, people are beginning to worry that Poyang Lake may not return to its former past.
Some people say that they use seaweed to maintain health, some people say that they use the sea of grass for tourism, and some people secretly cut grass in the middle of the night and sell it for 25 yuan / bag as feed.
At this time, CCTV news came with good news, recently affected by continuous autumn rains, the overall water level of the Yangtze River gradually increased, the monitoring data of the hydrological department showed that on October 4, the flow of Poyang Lake was -2.77 cubic meters, and the flow of the lake on the 6th was -531 cubic meters, confirming the first Yangtze River water irrigation phenomenon this year.
Compared with 1,403 square kilometers monitored on September 18, the water area of Poyang Lake on October 5 has risen to 2,098 square kilometers, an increase of 49.5%.
If this is the precipitation situation in previous years, the Yangtze River water irrigation may not be a good thing, and even lead to flooding, but this time is a "long drought and Ganlin", let's take a look at what benefits will the Yangtze River water irrigation bring this time?
Needless to say, the most important thing is ecological restoration. At this time of year, there will be a flock of migratory birds migrating from East Asia to Australia, and Poyang Lake is an important wintering ground for migratory birds, and the infusion of river water at this time will greatly improve the habitat of animals and plants, and the foraging of finless porpoises and migratory birds does not need to be worried.
The second is the role of Jiangxi's overall economic recovery. This year's drought has caused irreparable crop losses, but it should improve the water supply of the surrounding residents.
In recent years, Jiangxi has also had the idea of building the Zhejiang-Jiangxi-Guangdong Grand Canal, and if the water level of Poyang Lake is stable, it is not ruled out that the project will be promoted to create an inland port for Jiangxi, after all, Jiangxi has not had any decent labels for so many years.
Of course, the water level of Poyang Lake is still rising, and relevant departments are also paying close attention to prevent sudden flooding.
epilogue
Poyang Lake from drought to river irrigation, teach us a deep lesson, even in the relatively stable climate in previous years, lake drought and flood will bring losses to people, not to mention the overall temperature of the earth is rising, changes in the environment will make local unexpected changes, which is more human can not intervene, so we should be more in awe of nature.
Similarly, we have seen nature's own ability to recover, even in severe drought and heat, nature, through its own regulation, can still restore Poyang Lake.
Compared with nature, human beings are very small, we take from nature without giving the earth a chance to breathe, and the earth may choose to renew and repair itself, and eliminate everything that does not conform to the law.
Resources:
1. "Yangtze River water poured into Poyang Lake for the first time this year: favorable for finless porpoises to inhabit and migratory birds to feed": https://www.chinanews.com/shipin/cns/2023/10-10/news972360.shtml
2. "What are the causes of the continuous drought in Poyang Lake": https://www.zhihu.com/question/356129877/answer/2617481527?utm_id=0
3. Analysis of the evolution characteristics of precipitation in the area around the lake of Poyang Lake, http://www.doc88.com/p-60129240454827.html
4. Analysis and Response Suggestions for Drought Disasters in the Yangtze River Basin in 2022, http://society.sohu.com/a/578184965_121123726
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