Why has Dongting Lake become smaller? Why is Dongting Lake shrinking?

Why is Dongting Lake getting smaller?

Let's trace the history of Dongting Lake! It turns out that it is part of the famous Yunmengze in ancient China. In ancient times, Yunmengze was a large lake located between the two provinces of Hunan and Hubei, and it is said that it once covered an area of 40,000 square kilometers.

Later, due to the siltation of a large amount of sediment in the lake, most of the original lake became land, leaving only many relatively small lakes, the largest of which is Dongting Lake. After the formation of Dongting Lake, it still could not avoid the same encounter as Yunmengze, a large amount of sediment flowing into the lake continued to accumulate in the lake, and it became smaller and smaller.

After reading the above, you may want to ask such a question: Is it just Dongting Lake that has such an encounter?

Yes, there is sediment accumulation in general lakes, but the sediment accumulation in each lake varies according to the different conditions, some are fast, some are slow.

According to the statistics of the 50s of the 20th century, about 200 million tons of sediment are brought to Dongting Lake from various rivers in Hunan Province every year; However, the rivers in Jiangxi Province only bring more than 13 million tons of sediment to Poyang Lake. At the same time, Poyang Lake has only a narrow waterway that connects with the Yangtze River, and when the water in the lake flows into the Yangtze River, it has enough power to transfer more than 12 million tons of sediment to the Yangtze River, leaving only about 1 million tons of sediment in the lake every year. Dongting Lake and the Yangtze River are connected by many waterways, and the water flowing out of the lake not only cannot send a large amount of sediment into the Yangtze River, but on the contrary, because the Yangtze River has to pour into the lake when the water rises, it also pours part of the sediment from the Yangtze River into Dongting Lake. Therefore, the sediment accumulation rate of Dongting Lake is much faster than that of Poyang Lake.

In this way, Dongting Lake finally gave up the title of "China's largest freshwater lake" to Poyang Lake.

Why has Dongting Lake shrunk? Can't the satellites see it yet?

In ancient times, 800 Dongting gradually shrank with the movement of the earth's crust and the reclamation of fields around the lake, and Poyang Lake continued to expand in the crustal expansion zone, replacing the position of the largest freshwater lake in Dongting Lake.

Soil erosion in rivers has raised the lake bed.

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It is one of the five major freshwater lakes in China and an important throughput lake in the middle reaches of the Yangtze River. The lake area is located on the south bank of the Jingjiang River, spanning Hunan and Hubei provinces.

The main reason for the loss of the water area of Dongting Lake is climate change. From the 50s to the 70s of the last century, the drought in the middle reaches of the Yangtze River was heavier than the flooding, and the water area of Dongting Lake decreased most significantly. In the 80s and 90s, the slowdown in the decline of the water area of Dongting Lake was caused by the heavy waterlogging and drought in the middle reaches of the Yangtze River. In 2006, the precipitation in Hubei and Hunan in the middle reaches of the Yangtze River continued to be low, and the total precipitation in the Dongting Lake basin from May to September was less than that in the same period in history.

Another function of Dongting Lake is to absorb the floodwaters of the Jingjiang River. In 2006, Sichuan and Chongqing in the upper reaches of the Yangtze River.

There was a severe drought in other places, the precipitation from May to September was 3-5 percent less than that of the same period in history, and the water level from the upper reaches of the Yangtze River was sharply reduced, and the water level of Jianli Station in the middle reaches of the Yangtze River was only 25-28 meters in October, which was significantly lower than that in 2005. In addition, the Three Gorges Reservoir.

The impoundment of water at the gate has also reduced the Yangtze River's replenishment of Dongting Lake to a certain extent.

There are also human factors in the reduction of the water area of Dongting Lake, such as sediment accumulation, land reclamation and excessive reclamation.

The impact of the shrinking area of Dongting Lake.

The reduction of the water area of Dongting Lake will have an impact on the regional climate. Due to the decrease in the size of the lake, the ground is exposed to solar radiation.

The absorptive capacity of the room will have a serious impact on the local climate. The reduction in the water area of Dongting Lake will also affect Honghu Lake and the Jianghan Plain.

Wetland ecological environment. Climate experts believe that climate change and human activities will affect the reduction of the water area of Dongting Lake, and conversely, the reduction of the water area of Dongting Lake will affect climate change and the ecological environment. This interaction and interaction is a long and slow process.

The above content reference: ****.com - Climate change has led to a sharp decrease in the water area of Dongting Lake.

The main reasons for the continuous decrease in the area of Dongting Lake are:

1. The lake was enclosed to create fields, and the natural environment of Dongting Lake was destroyed.

2. Cage culture reduces the water flow velocity and accelerates sediment sedimentation.

3. The upstream water is reduced, which reduces the impact on sediment.

4. The Yangtze River burst southward several times, forming a situation of four divergent outlets, and the river carried a large amount of sediment into the lake, and the lake quickly silted up and shrunk.

5. Construction of illegal buildings around the lake.

1. Enclosing the lake to create fields;

2. Cage culture reduces the water flow velocity and accelerates sediment sedimentation.

3. The upstream water is reduced, which reduces the impact of celery on sediment.

4. The destruction of vegetation has caused sediment to accumulate in the upper reaches of Kina.

In fact, I think the biggest reason is human intervention, of course, natural factors are only a small part.

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How the reasons for the shrinkage of Qinghai Lake and Dongting Lake differ.

The reason for the shrinkage of Qinghai Lake: The warming climate has led to strong evaporation and shrinking of the lake.

The reason for the shrinkage of Dongting Lake: long-term enclosure of the lake and farming.

Dongting Lake, Poyang Lake and other lakes along the Yangtze River have shrunk, and the consequences may be why not.

1. Reasons. 1. The area of the lake area has been reduced due to the reclamation of land around the lake.

2. The increase in urban water and agricultural water use is the decrease in water volume.

3. The South-to-North Water Diversion Project has reduced the amount of water in the Yangtze River.

4. The climate is warming and the water evaporates greatly.

5. Indiscriminate deforestation leads to soil erosion, large sediment content in the water body, and serious siltation at the bottom of the lake.

Second, the way of governance.

1. Return farmland to lakes.

2. Plant trees on both sides of the Yangtze River to maintain water and soil.

3. Advocate water conservation and reduce water waste.

The decrease in flow during the dry season in the upper reaches is not a consequence but a cause.

What are the reasons for the shrinkage of Dongting Lake and Qinghai Lake?

The main reason for the Dongting Hidden Lake is the long-term enclosure of the lake and the cultivation of fields.

The main reason for the shrinkage of Qinghai Lake is that the climate is warming, the glacier reserves on the Qinghai-Tibet Plateau are decreasing, and the evaporation is relatively vigorous.

Why did Dongting Lake become the second largest freshwater lake?

The Xiangjiang and Yuanjiang rivers that flow through the lake have brought a large amount of sediment and sediment, and the lake has been reduced year by year due to the enclosing of the lake and the creation of fields. Dongting Lake has finally given up the position of the first freshwater lake to Poyang Lake.