Why are there so many lakes in Jianghan Plain?

Jianghan Plain, located in Hubei Province, is a very important plain landform in China. It has been a land of plenty since ancient times. Because the local water area is large, more than 1000 lakes are connected everywhere, and people live a rich life. Why are there so many lakes in Jianghan Plain?

The waters surrounded by land are called lakes. The hufu lake (outflow lake) can not only maintain the balance of ecological environment and provide water, but also regulate river runoff, reduce or even avoid floods, and develop farming, aquaculture and tourism. They have inestimable natural ecological, economic and social values, so Hubei, a province with thousands of lakes, has become a land of plenty.

Why are there so many lakes in Hubei? Where did they come from? Speaking of lakes in Hubei, we can't avoid the vague "Yunmengze" or ancient cloud dream in history, so let's start with it.

"Yunmengze" in Ancient Books

There is no detailed description of the specific scope and form of "Yunmengze" in the vast ancient literature. Some people think that there are great lakes, some people refer to lakes, and some people say that lakes, swamps and floodplains are comprehensive landforms, which makes many future generations disagree.

It is generally believed that the earliest written records of ancient cloud dreams originated from "? As a part of the core area of Chu State, the ancient cloud dream in spoken language should appear earlier, and then appear in more documents, such as Li Zhou's Fang, Lv Chunqiu's Travel to Shi Lan, Huai Nan Zi Xing Xun and Er Ya Dishi.

Dongting Lake in High Water Season

Starting from Zi Xufu's "cloud dreamer, the square is 900 miles", later ancient books described the "cloud dreamer" as bigger and bigger, and even became a big lake across the Yangtze River, which was much bigger than "taking the distant mountains and swallowing the Yangtze River, making a vast soup and making a vast sky". This is either the need of ancient writing or hearsay, such as Fan Zhongyan's writing.

Ancient books make people doubt the ancient cloud dream. Therefore, in order to uncover the mystery of the ancient "Cloud Dream" or "Cloud Dream Ze", since the 1960s, people have drilled more than 1000 exploration holes in Jianghan Plain and obtained rich underground codes.

Prehistoric Jianghan

During the Yanshan movement, the geological subsidence of the two lakes and plains formed Jianghan-Dongting Depression. At this time, the Yangtze River and Hanshui River will come to Hubei, and high mineral salt lakes have appeared in the depressions, which have been eroded by the surrounding mountainous areas for thousands of years. After the Yangtze River broke through Wushan Mountain, it cut through thick sediment. Although swinging on the plains of the two lakes, it did not form a prehistoric giant lake.

After the neotectonic movement, the eastern part of Nanyang basin rose, and the Hanshui River went south smoothly, becoming a tributary of the Yangtze River. Huarong uplift appears in the middle of the two lakes and plains, which divides the great plains into Jianghan Plain and Dongting Lake Plain. The alternation of glacial and interglacial periods made the Yangtze River and Hanshui River alternately experience traceable erosion and traceable accumulation. In the process of traceable erosion, the river bed descended and the river bed was cut down, and the deep valleys of the Yangtze River and Hanshui River appeared in Jianghan Plain, forming a deep valley.

When tracing back to the source of accumulation, the river bed will be further silted by erosion carried by the river from the upstream, and the water surface of the river will be closer to the land surface. In flood season, the river will overflow the river channel, and lakes and swamps will develop in low-lying areas. The wandering and swinging of rivers will form meanders and oxbow lakes, so rivers will accumulate water to form lakes.

Because the bottom of the Yangtze River bed in Jianghan Plain is higher than the downstream, it is difficult for rivers to converge into prehistoric giant lakes here. Even if there is a big lake, it is a seasonal flood season lake. Therefore, the Quaternary strata in Jianghan Plain are many repetitions of river sedimentary cycles.

Geological drilling tells us that after the Quaternary, there has never been such a prehistoric giant lake crossing the river in Jianghan Plain. The landform in this area is a comprehensive landform including lakes, swamps, depressions, flood plains, terraces and residual hills. Only in this way will the ancestors of the Neolithic age settle here.

Jianghan Lake Group

The comprehensive landform of land and water has seasonal changes. Ancestors can settle here on a small scale. Neolithic sites were found in Liuguan, Wulin and Hu Sha, and Western Zhou tombs were found in Honghu. King Chu used this place as a hunting ground. However, the inland of Jianghan Plain at that time was not suitable for large-scale gathering, and floods occurred frequently. Just like the "Mediterranean", the early cities were also distributed in a "Mediterranean pattern". Today, there are no big cities in the middle of Jianghan Plain.

Jianghan Plain was originally a comprehensive landform area such as lakes, swamps, depressions, floodplains, terraces and residual hills, and it is also the most suitable form for ancient cloud dreams or "cloud dreams". The "crossing the river" lake that the ancients once saw or heard was a short-lived sight of flooding in flood season. Such a scene appeared in 193 1 year, covering an area of 65438.

Jianghan Plain and Jianghan Lake Group are the result of the interaction between the initial terrain and the Yangtze River, Hanshui River and other rivers, and are not evolved from "Yunmengze". On the contrary, "Yunmengze" is a short-term "flood-season lake" in Jianghan Plain. In the ancient Jianghan Plain, there were no dams and levees. Whenever the flood season comes, the river will overflow the river and the low-lying areas will be submerged.

Jianghan Plain in Spring

Hubei became a province of thousands of lakes because the Jianghan Plain in the early days was low-lying, and tributaries such as the Yangtze River and Hanshui River wandered here, forming a great lake in the lowest place first. After the river is diverted, some ancient roads will still store water to form lakes. In the flood season, the flood will connect them, and after the flood season, they will return to a relatively independent state, only connecting with the external rivers through some waterways and unconditionally swallowing the river water.

Lake wetland

Due to different seasons and years, the sediment and biological debris brought by rivers are not equal, and the siltation in different areas is also unequal. Some lakes will become shallow due to siltation, some lakes will fade, some larger lakes will be divided into smaller lakes, and the smaller lakes will become smaller in the next siltation stage. Jianghan Lake Group is formed in this way. The new lake will be born, the old lake will disappear, the new lake will be born, it will expand, it will shrink and it will shrink.

Cold numbers

If human beings develop and utilize lakes unreasonably, natural lakes will disappear in one hundred or ten years. Taibai Lake, for example, has disappeared now, but it was still the largest lake in Jianghan Plain in the late Ming Dynasty, and it became a swamp in the19th century. Honghu Lake was born in the middle and early period of19th century, and it became the largest lake in Jianghan Plain by swamp process instead of Taibai Lake.

In 1950s, Jianghan Lake Group had more than 300 lakes 100, with an area of more than mu100 and a water area of more than 8,500 square kilometers. Hubei was worthy of the title of "province of thousands of lakes". By the 1980s, the number of lakes had become more than 800, and the water area was less than 3,000 square kilometers. Due to the reasons of reclaiming land from lakes, damming lakes, blocking rivers and lakes, lake pollution and so on, the number, area, volume and water quality of lakes are reduced.

There are only 755 lakes in Hubei Lake Protection List, which is a very cold number. Since the 20th century, Hubei has been deeply exploring the methods of lake protection, and various places have tried and practiced lake protection measures according to local conditions. The measures for returning the lake include: returning the dike to the lake, borrowing flood season, returning farmland to the lake, returning fishing to the lake, and leveling the dike to flood and improve the water network.

Honghu scenery

People's awareness of environmental protection is improved, and the ecological concept is updated, so the numbers will not be cold. The lake protection idea of "one lake, one policy" can also make Jianghan Plain retain the next beautiful lake with clear water, fish and rice fragrance. I believe that the children of Jingchu, who have changed their spiritual motivation, will certainly write the movement of "a province of thousands of lakes" and protect the clear waters and green mountains.