What happened to the Yellow River?

Since 1972, the Yellow River has been frequently cut off. There are many reasons for disconnection, which can be summarized as follows:

1. Global Warming-With the intensification of global warming in recent years, on the one hand, the evaporation of river channels has increased greatly, and on the other hand, the glaciers in the upper reaches melt and absorb a lot of heat in spring and summer, which leads to the local temperature in the inland being lower than normal, and the temperature difference between the inland and the ocean is reduced, which in turn leads to the weakening of the monsoon and the lack of water vapor brought into the inland by the monsoon from the sea surface. Although global warming melts glaciers and increases the upstream water flow, it cannot offset the effects of increased evaporation and weakened monsoon. The water volume in the middle and lower reaches is decreasing year by year.

2. Vegetation destruction-The vegetation in the Loess Plateau is seriously destroyed, and the land lacking vegetation conservation is gradually desertified, with high evaporation. The dried-up groundwater needs to be continuously absorbed and replenished by flowing through rivers.

3. Backward irrigation methods-most of the middle and upper reaches of the Yellow River flow through economically underdeveloped border areas, old and young, lacking the technology and funds for water-saving irrigation, and most of them are flooded, resulting in serious waste of water resources in the Yellow River.

① The upper reaches belong to arid and semi-arid areas, and the middle reaches are the main recharge areas, but the soil erosion is serious, the seasonal variation is great, the downstream area is small, and the recharge is small;

(2) The population growth in the basin is fast, and the population growth rate far exceeds the grain growth rate;

In recent decades, with the development of society, the industrial and urban water consumption along the Yellow River has been increasing, and the irrigation area of the Yellow River has been expanding.

(4) The reservoir regulation capacity is low, and the water resources management is not unified;

⑤ Low water fee can't arouse people's awareness of water saving, and industrial and agricultural water is wasted;

⑥ Environmental pollution greatly reduces the utilization rate of the Yellow River water.

waterfall

Due to sediment deposition, in most sections of the Yellow River with a total length of 5,464 kilometers, the riverbed is higher than the cities and farmland in the basin, and it is constrained by dikes, so it is called "suspended river". So where did the Yellow River become a "hanging river"?

Dengkou County, southwest of Bayannur League, Mongolia, where the Yellow River is 4 to 6 meters higher than the county on average.

The Yellow River flows between Zhongtiaoshan Mountain and Qinling Mountains and passes through Jin Meng, Henan Province. From here, 30 kilometers away from the Yellow River, it is Luoyang, the famous capital of China. Luoyang is one of the eight ancient capitals in China. Since the Eastern Zhou Dynasty, the Eastern Han Dynasty, the Cao Wei Dynasty, the Western Jin Dynasty, the Northern Wei Dynasty, the Sui Dynasty (Yang Di), the Tang Dynasty (Wu Zetian), the Later Liang Dynasty and the Later Tang Dynasty have all established their capitals here, which is called the "Ancient Capital of Nine Dynasties".

After the Yin Dynasty was destroyed, Jiuding, the national treasure, moved to Luoyang with the intention of taking Luoyang as its capital. When the King of Wu died, Zhou and Zhao, who were the kings at that time, built Luoyi on a large scale, and established two cities, namely, Wangcheng and Zhoucheng. Between Jianshui East and Shuixi is Wangcheng, which is today's Wangcheng Park in Luoyang, Henan Province. In Shuidong, near the White Horse Temple today, is Chengzhou City. Move the capital to Wangcheng, and move the capital to Zhoucheng in Zhou. After Liu Xiu proclaimed himself emperor in the Eastern Han Dynasty, Luoyang became the capital.

Luoyang City in Han and Wei Dynasties was expanded on the basis of the ruins of Chengzhou City. The history of Luoyang City is "90 steps from north to south and 60 steps from east to west", so it is also called "96 City".

As early as five or six thousand years ago, there was "Yangshao culture" 50 miles west of Luoyang, which shows that the matriarchal clan commune system was quite developed at that time. This is the beginning, more and more brilliant.

Valley migration

The Yellow River is the second largest river in China, and it has been a sediment-laden river since ancient times. In the 4th century BC, the lower reaches of the Yellow River were called "turbid rivers" because of its turbid water. /kloc-at the beginning of the 0 th century, it was pointed out that "the river is heavy and turbid, and there are six buckets of mud for one stone". Sediment increased after Tang and Song Dynasties. Some of these sediments are accumulated on the downstream river bed, which is accumulated over time and highly silted, all of which are constrained by dikes and form a suspended river for a long time. During the flood season in autumn and summer, the defense is weak, and the river is diverted from the top to the river. According to historical records, in the three or four thousand years before 1946, the lower Yellow River burst 1593 times, the river changed its course 26 times and burst 1000 times. The flood starts from Haihe River in the north and reaches Huaihe River in the south, covering an area of 250,000 square kilometers, which has a great impact on the geographical environment of the Huang-Huai-Hai Plain in China.

As far as the characteristics of the changes in the lower reaches of the Yellow River are concerned, it can be roughly divided into the following stages.

(1) Dike before the Warring States Period

The upper limit began in the Neolithic age. At that time, the lower reaches of the Yellow River flowed through Hebei Plain and entered the sea on the west bank of Bohai Bay. Because there are no dikes on both banks, the river course is extremely unstable. According to documents, the Yellow River has made many trips, including three sections recorded in Gong Yu, Shan Hai Jing Bei Shan Jing and Han Shu Geography. The first two roads are in the west of Hebei plain, along the foothills of Taihang Mountain to the north. The lower reaches of the mountain pass generally flow northward to the southern edge of the alluvial fan of Yongding River, pass through Xiongxian County and Baxian County eastward, and enter the sea near Tianjin today. The lower reaches of the Gong Yu branch off from the Shanjing River in today's Shenxian County, passing through the middle of today's Hebei Plain and entering the sea east of Qingxian County. The great river in Han Zhi leaves the eastern foot of Taihang Mountain and flows through northeast Henan, northwest Shandong, southeast Hebei and northeast Huanghua County. Before the mid-Warring States period, these three rivers either dominated each other or existed at the same time, but it was common for them to flow through the big river in Han Zhi. In ancient times, "River" was the proper name of the Yellow River. According to the records in Hanshu and Shuijing Note, there are more than 10 waterways called "rivers" in Hebei Plain, which may all be the old roads of the Yellow River after some interruption and migration.

(2) the 4th century BC to early AD (from the middle of the Warring States Period to the end of the Western Han Dynasty)

In the middle of the Warring States period, after a large-scale embankment was built in the lower reaches, the fixed river course was the big river recorded in Hanshu 2 Geography, which ended the long-term situation of multi-stream diversion and frequent diversion, and we temporarily regarded it as the first major diversion of the Yellow River.

In the mid-Warring States period, the lower reaches of the Yellow River were sparsely populated. When the dike was first built, the width of the dikes on both banks was 50 Li Han (1 Li Han, equivalent to 414m today). Large streams (the mainstream of water) have to swim in dikes, and rivers have strong flood storage capacity and are not easy to burst. Since then, the number of teeth has increased day by day, and a large beach silted on both sides of the inland waterway of the levee has been reclaimed, and people's dikes have been built to defend themselves. Those who are far away are hundreds of steps away from the water. As a result, the riverbed is forced, the river body twists and turns, siltation is rapid, and dangers are repeated. At the end of the Western Han Dynasty, the river course in Xunxian County of Henan Province today, "The river is higher than the flat", has obviously become a "suspended river". This is the result of increased soil erosion in the middle reaches of the Yellow River since Qin and Han Dynasties. In 1 1 year, Wang Mang broke the Yellow River eastward, and the flood between the river and Huaihe River lasted for 60 years.

③1~10th century (from Eastern Han Dynasty to the end of Tang Dynasty)

In 1 1 year (the third year of Wang Mang's founding), the Yellow River burst above Yuancheng (now Daming East, Hebei Province), and the river flooded to several counties east of Qinghe County. At that time, because the river decided to flow eastward, Wang Mang did not advocate blocking the mouth, because his ancestral grave in Yuancheng was not threatened. It is recognized that the flood lasted for nearly 60 years, which led to the second major diversion in the history of the Yellow River.

After nearly a thousand years, the lower reaches of the Yellow River were relatively stable, with occasional overflow and no large-scale diversion. The reason is:

First, during the Eastern Han Dynasty, a large number of nomadic people began to settle in the middle reaches of the Yellow River, returning farmland to graze, and secondary grasslands and shrubs replaced cultivated land, and soil erosion was relatively weakened.

Second, in 70 AD, under the leadership of Wang Jing, the flooded river in the late Western Han Dynasty was comprehensively controlled, and then a new river course was built, which roughly flowed through the Jilu border region, from Changshoujin (now in the area of West Wangbin, Puyang), from the great river in the Western Han Dynasty, along the Guluo River, through the south of Fan County today, diverted between yanggu county and Guluo River today, passed through the Yellow River and Ma Jiahe today, and then entered the sea in Lijin County, Shandong Province.

Thirdly, there were many tributaries in the lower reaches of the Yellow River at that time, either entering the sea alone or flowing into other rivers, and there were some lakes and swamps along the way, all of which played the role of flood diversion, sediment discharge and flow regulation.

④ 10 century ~ 1 127 (from the end of Tang Dynasty to the end of Northern Song Dynasty)

After nearly a thousand years of accumulation, the lower reaches of the Yellow River gradually silted up from the end of the Tang Dynasty. In 893 (the second year of Tang Jingfu), the estuary section was diverted for nearly a hundred miles. By the fifth generation, the frequency of crevasse increased obviously, with an average of less than three years.

By the beginning of 1 1 century, in today's Shanghe, Huimin and Binzhou cities and counties in Shandong, rivers are all "high-rise buildings". Since then, the location of the breach has moved up to Ganzhou (now Puyang, Henan) and Huazhou (now East Old Town, hua county). The general trend is that the river swings northward gradually. At the end of the Five Dynasties and the beginning of the Northern Song Dynasty, the Chihe River and the Henglong River were all located in the north of the big river in the Tang Dynasty.

1048, Shang (now Puyang dongchang lake Ji) burst its mouth, and its northward flow passed between Fuyang River and South Canal, while its downstream (now South Canal) and Boundary River (now Haihe River) entered the sea in Tianjin, which was called "Yellow River North School" in history. This is the third major diversion in the history of the Yellow River. (The Yellow River flows northward for three times: Shanghukun, Xiaowukun and Neihuangkou)

⑤1128 ~ 65438+the middle of the 6th century (from Jin Dynasty to Ming Jiajing Wanli)

1 128 (the second year of jianyan in the southern song dynasty), in order to prevent the nomads from going south, Du Chong, who was left behind by Song and Tokyo, was forced to break the river in the southwest of Huaxian County, Henan Province, making the Yellow River flow eastward through northeast Henan and southwest Shandong, enter Surabaya and seize Si into Huaihe River. Since then, the Yellow River has left the old road flowing through Xunhua and slippery areas since the Spring and Autumn Period and the Warring States Period, and no longer entered the Hebei Plain. In the following 700 years, it flowed into the Huaihe River in the southeast. This is an epoch-making event in the history of the changes in the lower reaches of the Yellow River, and it is also the fourth major diversion of the Yellow River.

The river between Jun and Slip used to be a narrow river in the lower reaches of the Yellow River. Due to the control of this section of the waterway, the swing range of the downstream waterway is basically limited to the Hebei Plain east of Taihang Mountain and north of Shandong Hill. After leaving this section of the river, the downstream river turns to the east or southeast and swings from northeast Henan to southwest Shandong. Among the 12 crevasses recorded in the Jin Dynasty, the river swings after the crevasse accounted for 10 in this area.

1286 (23rd year of Zhiyuan) 10 The Yellow River is located in Wu Yuan, Wu Yang, Zhongmou, Yanjin, Kaifeng, Xiangfu, Qixian, Suizhou, Chenliu, Tongxu, Taikang, Weishi, Weichuan, Yanling and Fugou. It can be roughly divided into three strands; One goes south in Zhongmou, passes through Weishi, Weichuan, Fugou, Yanling and other places, and enters the Huaihe River from Shui Ying; One is in Kaifeng, turns south, passes through Tongxu and Taikang, and flows from the vortex to the Huaihe River. We call it the fifth great diversion in the history of the Yellow River. From Jinyuan to the middle of Ming Dynasty, the changes of the Yellow River can be summarized as the following three points:

First, the position of the gap moves to the west. At first, the cracks were mostly in Shandong today (11950s and 1960s), and then moved westward to Jixian, Wu Yang (east of Yuanyang today) and Yanjin (11980s and 1990s). From the 1970s of 13 to the 40s of14, the crevasse moved to Xinxiang, Wu Yuan (now the west of Yuanyang) and Yingze (now Xiguxing Town, Zhengzhou City), almost reaching the top of the alluvial plain in the lower reaches of the Yellow River.

Second, the main stream of the river gradually swings south. /kloc-After the middle of the 0/2nd century, the river passed through northeastern Henan and southwestern Shandong, and now it flows into Surabaya in Liangshan County, Shandong Province. Later, it gradually swung southward into Kaifeng and Shangqiu in eastern Henan, and then entered the beach through Dangshan, Xiaoxian and Xuzhou in Jiangsu. During the Jin and Yuan Dynasties, two man-made rivers burst, and they went blind from the river or entered the Huaihe River from the whirlpool. /kloc-In the late 3rd century, a river flowed from Yinghe River into Huaihe River and reached the southwest boundary of the fan-shaped plain in the lower reaches of the Yellow River.

Third, the lower reaches of the river are divided into several tributaries besides the main stream, and the change is uncertain. Since the second half of 12 century (during the reign of Jin Dading), there has been a situation of "two rivers diverging". After that, it is divided into three strands, all of which flow through the north of the abandoned Yellow River, merge into Surabaya and seize Si into the Huaihe River. By the second half of the13rd century (early Yuan Dynasty), there were several strands downstream, which seized water and whirled into the Huaihe River. Then it flows eastward to Si or southward to Huai River, and sometimes it flows northeast to Ma Jiahe and the North Qinghe River (now the Yellow River below Dongping, Shandong). Often several strands are parallel, overlapping is the main time, and the change is extremely chaotic. At the end of Yuan Dynasty (135 1), Jia Lu once managed a river from Fengqiu, Henan Province to Xuzhou, which was called Jia Luhe in history. It will be destroyed soon.

⑥ 65438+mid-6th century ~ 1854 (five years in Xianfeng, Qing Dynasty)

By the middle of16th century (the middle of Jiajing in Ming Dynasty), the situation of multi-stream diversion in the lower reaches of the Yellow River basically ended, and "the old road of Nanxi began to be blocked", "the whole river flowed out of Xu and Pi, and it took its place in Huai River." This is a major change in river regime. Later, in the early years of Wanli, Pan Jixun implemented the policy of "building dikes to control water and attacking sand with water", and the lower reaches of the river were basically fixed, which is the abandoned Yellow River on this map. Although there was an overflow later. But soon returned to the old road. Dams were built in the early Qing Dynasty. The rivers in Henan were relatively safe for a while, while the number of river breaches in Shandong and Jiangsu increased. The section from Xuzhou, Jiangsu Province to Huaiyin, which is also a canal, is "the most important throat". The key point of Pan Jixun's river management is in this reach, overhauling dikes, lattice dikes, moon dikes and remote dikes on both sides of the river, rebuilding Gaojiayan, raising the water level of Hongze Lake, storing water and brushing the Yellow River. In the early Qing Dynasty, the center of gravity of the river disaster moved from Huaiyin to the estuary because the Yellow River occupied the Huaihe River for a long time after Jinyuan, and a large amount of sediment was discharged into the estuary, which changed the slope and accelerated the siltation of the river above the estuary. Therefore, after18th century, the river disasters below Xuzhou are the most concentrated. /kloc-after the 0/9th century, the river channel was silted up and abandoned, and the breach occurred year after year. In addition, domestic political turmoil and ineffective river management make new diversions inevitable.

⑦ 1855 (five years of Qing Xianfeng) ~ before the 1950s.

1In June, 855, the Yellow River burst in Tongwa Room, Yanglan, Henan Province, first flooded Fengqiu, Xiangfu County and Village in the northwest, then flowed eastward to Lanyi, Kaocheng and Changyuan counties, and then divided into three shares: one was transported from Zhaowanghe, east of Cao Zhou, to Zhangqiu; One stream flows through Changyuan County to Leijiazhuang, Dongming County, where it is divided into two streams, both of which flow northeast to Zhangqiu Town; After the confluence of the three rivers, it crosses the Zhangqiu Canal, enters the Daqing River through the salt-free river, and enters the sea through the Lijin oyster mouth. This is the sixth major diversion of the Yellow River. According to China's current administrative divisions, the route of the lower Yellow River flows through Xingyang, Zhengzhou, Yuanyang, Yanjin, Fengqiu, Zhongmou, Kaifeng, Lankao and Puyang in Henan, Cao Xian and Shan County in Shandong, Dangshan and Xiaoxian in Anhui, Fengxian, Peixian, Xuzhou, Pixian, Suining, Suqian and Jiangsu. However, after the diversion, the Yellow River broke through the original channel, changed to the northeast, and borrowed the Daqing River to flow into the Bohai Sea in Shandong. This breach ended the 700-year history of the lower Yellow River from Huaihe River to Bohai Bay. In the following 20 years, the flood freely overflowed on the delta alluvial fan with Tongwa room as its apex, reaching Jindi in the north, Cao Xian and Dangshan in the south and the Canal in the east. The water is scattered and falling. The whole riverbank was not completed until 1876, and now the lower reaches of the Yellow River have basically taken shape. In the lower reaches of the river, from Tongwa room to Taocheng port, breaches often occur, so it is called "tofu waist".

1June, 938, the Kuomintang government passively resisted Japan. Huayuankou levee was artificially opened in an attempt to stop the Japanese invaders from advancing westward with floods. This breach caused the Yellow River and the South River to flood the area between Jia Luhe, Heying and Guohe River, which caused serious disasters rarely seen in history. This is also the seventh major diversion in the history of the Yellow River.

Recently, the problem of weathering has become more and more serious. Now experts say that if human beings cut down trees indiscriminately, the source of the Yellow River is likely to be submerged in wind and sand. The Yellow River is the origin of the Chinese nation, but it is called the source of the mother river. Today, it is surrounded by barren hills and sandstorms everywhere.

Experts pointed out that illegal logging against the natural way of life is the main reason for destroying water resources, which makes this ecosystem with thousands of years of history face collapse and is likely to become another site of human civilization destruction.

It is the frequent flooding of the Yellow River that has created the Chinese nation's character of "being prepared for danger in times of peace". Chinese civilization also began with Dayu's arduous struggle to control water and divert rivers into the sea, so that many dynasties set up river management institutions, and the people of China also set up the "Yellow River Water Conservancy Commission", which is very rare in the world. It can be said that the Yellow River has played a decisive role in shaping the character of the Chinese nation and the direction of Chinese civilization.

tourist resources

The vibrant upstream reach-this reach is called the "rich mining area" of the Yellow River's hydraulic resources. Among them, from Longyang Gorge to Qingtongxia, rivers and canyons alternate with each other, with large riverbed gradient and rich hydraulic resources. The planned utilization gap exceeds 1.200m, and the installed capacity exceeds1.0 million kilowatts, accounting for nearly 50% of the whole river. The average annual power generation is nearly 60 billion kWh.

The tender and lingering Ningmeng reach-the Yellow River flows peacefully here, irrigating the farmland on both sides and benefiting the local people. Therefore, there is a saying that "Huang Hefu and Ningxia are the best in the world" and "the Yellow River risks only one side is rich". The land near Yinchuan, Ningxia is flat and has a vast area. For more than 2000 years, the Yellow River has been used for gravity irrigation. There are abundant products here, and the precious Chinese herbal medicines Lycium barbarum and Yinchuan rice are of good quality, which is known as "Jiangbei". Photo of Lycium barbarum The Hetao Plain in Inner Mongolia is very dry. In the west, the annual precipitation is less than 200mm. Here, "no water is a desert, and water is an oasis". The Yellow River water has created superior conditions for industrial and agricultural production here.

The middle reaches of the Yellow River-Shaanxi-Gansu-Ningxia Gorge, where the Yellow River splits the Wan Ren Mountain like a bamboo, forming the longest continuous canyon section on the Yellow River. There are two famous places in this paragraph:

Hukou Waterfall-The Yellow River rushed here with thunderous momentum and roared away. Hukou Waterfall is not only a symbol of the Yellow River, but also a symbol of the Chinese nation's indomitable spirit of pioneering and forging ahead. "The wind is roaring, the horse is roaring, the Yellow River is roaring, and the Yellow River is roaring." A magnificent song sings the elegance of the Yellow River and the heroic spirit of the Chinese nation's invincible and hard struggle. (The lyrics are selected from The Yellow River Cantata)

Longmen-The story of "Carp yue longmen" originated from this. It is said that carp can jump over the dragon gate and become a dragon. This legend expresses people's good wishes to reach their ideal state after hard work, and also inspires Chinese children to strive for self-improvement and struggle. According to legend, it is a canyon dug by Dayu, so it is also called Yumenkou.

Related culture

654.38+0.5 million years ago, the Xihoudu ape-man appeared in Ruicheng County near the Yellow River in Shanxi Province. Later, Lantian ape-man 6.5438+0 million years ago and Dali ape-man 300,000 years ago fished and hunted along the Yellow River, and continued to work silently for the birth of the Yellow River civilization.

70,000 years ago, the early Homo sapiens in Ding Cun, Xiangfen, Shanxi Province, and the late Homo sapiens in Dagouwan, Uxin Banner, Inner Mongolia, 30,000 years ago played the prelude to the ancient Yellow River civilization.

The sites of microlithic culture from 10000 to 7000 years ago, Neolithic culture from 7000 to 3700 years ago, bronze culture from 3700 to 2700 years ago and ironware culture from 770 BC are almost all over the Yellow River basin. Since the Middle Stone Age, the Yellow River Basin has become the development center of ancient culture in China. Suirenshi, Fu and Shennongshi created and invented artificial fire technology, primitive animal husbandry and primitive agriculture, which opened the prelude to the development of the Yellow River civilization.

Qin Huang Hanwu, Tang Zong Song Zu, a generation of arrogant Genghis Khan, these emperors led the Chinese nation to push the ancient Yellow River civilization to the brilliant peak that attracted worldwide attention. Gunpowder, compass, papermaking, printing, Tang poetry and Song poetry, and Yuanqu are glittering treasures in the Yellow River civilization. Inventions and scientific achievements not only promoted the development of China, but also spread all over the world and promoted the progress of all mankind.

First, the second longest river in China.

The Yellow River, the second longest river in China, is a 5464-kilometer-long river that winds in the north of China. Seen from the sky, it is like a huge word "several", and it is also a unique totem of our nation.

Second, the characterization of the Yellow River

Not just a big river. The Yellow River, Yellow Earth, Emperor, Yellow Skin and the legendary dragon, all these yellow symbols sublimate this turbid stream flowing through the heart of China into a sacred river. Han Shu Gou Ji regards the Yellow River as the first of all waters: "China has the source of all rivers, and the Yellow River is its ancestor."

Third, the theory of loess weathering.

In a long geological time, in the desert Gobi in the interior of Asia, the sand everywhere is decomposed and crushed in the harsh environment of rapid cooling and rapid heating until it forms powder. The northwest airflow prevailing in the inland has blown them to the east for many years, and the coarse sand has fallen on the Mongolian plateau, and the most delicate powder has fallen to today's six provinces of Gansu, Shaanxi, Shanxi, Qinghai, Ningxia and Henan. After millions of years of transportation and accumulation, a loess plateau has finally formed, starting from the Great Wall in the north, reaching Qinling Mountain in the south, Sun Moon Mountain in the west and Taihang Mountain in the east.

Fourth, the deep and vast loess layer.

This is an unparalleled loess, with an area of 4 1 1,000 square kilometers, and the thickness of loess coverage is generally above 1 1,000 meters. The loess in Longdong, Shaanxi, Shanxi and other places is as deep as 100 to 200 meters, and the thickness in Lanzhou is more than 300 meters.

The Garden of Eden five or six thousand years ago.

Botanists have found that although the rainfall in the Loess Plateau is not as abundant as that in the south, the leaching loss of nutrients is also less, which is very suitable for the growth of poplar, birch, oak, Chinese pine, spruce, jujube and Vitex negundo. At that time, lush vegetation gave birth to a warm and rainy Garden of Eden. Today, Shanxi, Shaanxi, Gansu, Ningxia and other provinces have large areas of virgin forests. Henan Province, located in the Central Plains, is referred to as "Yu" for short. It can be seen that in the era of word-making in Cangjie, it was still a place where elephants haunted.

Six, the enlightenment of ancient civilization

Charred animal fossils and antler fossils were found in Houdu human activity site in Ruicheng, Shanxi, more than 6.5438+0.6 million years ago, and many carbon deposits were found in Lantian human site in Shaanxi, 6.5438+0.6 million years ago.

Since then, Lantian people, Dali people, Dingcun people and Hetao people have all thrived in the embrace of the Yellow River. Until 6000 years ago, matriarchal clan culture represented by Banpo civilization appeared on the yellow land.

Our ancestors hunted and gathered in such a green field and spent the golden childhood of Chinese civilization.

Seven, the historical account of the transformation of natural achievements.

It is indeed the first place to bathe in the light of civilization, and it must be the first place to be touched by the fire of civilization. According to ancient legends, Shennong once taught people to grow crops. What is intriguing is that Shennong is Emperor Yan, that is, Vulcan, and what he teaches is actually burning forests for farming. Mencius recorded the "achievements" of the three emperors and five emperors who burned the forest: "When Yao ... the vegetation was lush, the animals multiplied, the grain was not harvested, and the animals were threatened ... Yao was the only one who was worried, and he handled it well. Make good use of fire. The fierce mountain burned it, and the animals fled. "

In the Book of Songs, we heard the ancestors chanting when they cut down trees: "Kan Kan cut sandalwood, the river is dry, the river is clear, and the blue waves are rippling." "When logging is tintin, birds sing."

Eight, the vegetation on the Loess Plateau suffered great damage for the first time before the unification of the six countries by Emperor Wu of the Han Dynasty, and a large number of people entered Guanzhong, and the cultivated area increased greatly. At the same time, large-scale construction, the construction of the palace mausoleum, wantonly cut down the Guanzhong mountain forest. In the thirty-third year of the First Emperor (2 14 BC), Meng Tian defeated the Xiongnu and gained a large area of land in Hetao. Later, he settled in other places to defend the border and immigrated to the Ordos Plateau many times, with hundreds of thousands of people each time. The originally endless grassland has become a farming area.

Nine, uncover the bottom of the river

A few days ago, a century-old wonder "uncovering the bottom of the river" appeared in Dajinzui and Xiaoshizui sections of Shanxi Hejin section of the Xiaobei main stream of the Yellow River (Shanxi and Shaanxi sections), and the sediment at the bottom of the river was rolled up like a carpet by the current.

The phenomenon of "uncovering the bottom of the river" is a unique law of sediment movement in the Yellow River, which mainly occurs in Longmen, the main stream of Xiaobei, and Weihe, the tributary of the Yellow River. Its performance is that when the flood peak with high sediment concentration passes by, the riverbed is seriously washed in a short time, and the massive and flaky sediment at the bottom of the river is rolled up like a carpet, and then swept away by the current. Such intense scouring can make this section of riverbed several meters to more than ten meters deep in a few hours to dozens of hours. Due to the special conditions of the phenomenon of "uncovering the bottom of the river", "uncovering the bottom of the river" is called the century-old wonder of the Yellow River.

It is reported that the Yellow River was last "uncovered" on July 6, 1977 at/kloc-0. This "river bottom revelation" began at 8: 00 on July 5 and lasted until 8: 40. During this period, in the spur dike section of Xiaoshizui Reconstruction Project 1 in Hejin reach, two large-scale lifting objects 1 with a height of about 1 m and a length of about 7-9 m were hoisted successively with the turbulent underwater sound.

At the beginning of July, the tributaries from Wubao to Longmen in the middle reaches of the Yellow River were flooded with heavy rain, and the flood carried a lot of sediment south. On the evening of July 4th, the flood peak discharge of Longmen Hydrological Station at the source of Hejin reached 4600 cubic meters per second, and the maximum sediment concentration was more than 700 kilograms per cubic meter, which created conditions for the phenomenon of "uncovering the bottom of the river" in some areas.