The canyon is formed in hard gneiss, granite and Nanshan metamorphic rock, and the wide valley is formed in loose sand shale and red rock series. There are 20 canyons in this section, including Longyang Gorge, Jishi Gorge, Liujiaxia Gorge, Bapan Gorge and Qingtongxia. There are cliffs on both sides of the canyon, with narrow riverbed, steep river slope and rapid water flow. From Guide to Lanzhou, this section is one of the concentrated reaches of the three major tributaries of the Yellow River, and the inflow of important tributaries such as Taohe River and Huangshui River has greatly increased the water volume of the Yellow River. The reach from Longyangxia to Xiaheyan River in Ningxia is a "mine-rich" area of the Yellow River and one of the important hydropower bases in China. Qingtongxia in Ningxia to Hekou Town in Tuoketuo County, Inner Mongolia is an alluvial plain. After leaving Qingtongxia, the Yellow River flows northeast along the northwest boundary of Ordos Plateau, and then reaches Hekou Town eastward. Most of the areas along the river are deserts and desert grasslands, and there is basically no tributary injection. The river bed of the main stream is gentle and the water flow is slow. On both sides are large alluvial plains, namely the famous Yinchuan Plain and Hetao Plain. There are floods and ice disasters in the plain along the Yangtze River to varying degrees. Hetao Plain starts from Xiaheyan in Ningxia in the west and reaches Hekou Town in Inner Mongolia in the east, with a length of 900 kilometers and a width of 30-50 kilometers. It is a famous irrigation area for diverting water from the Yellow River with a long irrigation history. Therefore, there is a saying that "the harm of the Yellow River is only rich". 2. The middle reaches of the Yellow River are from Hekou Town, Tuoketuo County, Inner Mongolia to Jin Meng, Henan Province, with a river length of 1.206 km and a basin area of 344,000 square kilometers, accounting for 45.7% of the total basin area; The total drop in the middle reaches is 890 meters, with an average gradient of 0.74 ‰; This river has 30 major tributaries; The increased water volume accounts for 42.5% of the Yellow River water volume, and the increased sediment volume accounts for 92% of the whole Yellow River sediment volume, which is the main source of the Yellow River sediment. Hekou Town to Yumenkou is the longest continuous canyon on the main stream of the Yellow River-Shanxi Canyon. Most of the tributaries of this reach flow through the loess hilly and gully region, which is the main source of coarse sediment in the Yellow River. Among the 65.438+0.6 billion tons of sediment transport in the whole river for many years, 900 million tons come from this interval. This reach is the second largest hydropower base of the Yellow River with large gradient and abundant hydraulic resources. There is a famous Hukou Waterfall in the lower part of the canyon, with a deep trough width of only 30~50 meters and a low water level drop of about 18 meters, which is magnificent. From Yumenkou to Sanmenxia, the Yellow River flows through the Wei Fen Plain, the valley widens and the water flows slowly. The two banks of this river are Weibei and Jinnan loess tablelands, which are important agricultural areas in Shaanxi and Shanxi provinces. This reach has accepted Fenhe River, Luohe River, Jinghe River, Weihe River, Luo Yi River, Qinhe River and other important tributaries, and is one of the main sources of sediment in the lower reaches of the Yellow River, with an average annual output of 550 million tons. The reach is located in the channel from Yumenkou to Tongguan (that is, the small north main stream of the Yellow River) 132.5km, with drastic changes in erosion and deposition, and the channel is very unstable from side to side. Constrained by the mountains near Tongguan, the valley suddenly narrows, forming a natural bayonet with a width of only 1000 meters. The level of Tongguan river bed is closely related to the changes of erosion and deposition in the Xiaobei main stream of the Yellow River and the lower reaches of the Weihe River. Therefore, the reach from Sanmenxia to Taohuayu is divided into two parts by the hydrological term "Tongguan elevation": above Xiaolangdi, and the river is between Zhongtiaoshan and Yishan. The valley below Xiaolangdi gradually widens, which is the transition section of the Yellow River from mountainous area to plain. 3. The lower reaches of the Yellow River below Jin Meng, Henan Province, with a total length of 786 kilometers and a drainage area of only 23,000 square kilometers, accounting for 3% of the drainage area of major hydropower stations in the whole Yellow River basin; The total downstream drop is 93.6m, with an average gradient of 0.1.2 ‰; The increased water volume in the interval accounts for 3.5% of the water volume of the Yellow River. Due to the large amount of sediment in the Yellow River, the long-term sedimentation in the lower reaches has formed a world-famous "hanging river on the ground", and the Yellow River has become a watershed between the Haihe River Basin and the Huaihe River Basin. Except for the Dawen River flowing from Dongping Lake, there are no big tributaries in this section. Except for the low hills between Dongping Lake on the south bank and Jinan, the lower reaches depend on dikes, with a total length of 1.400 km. Historically, the lower reaches of the Yangtze River often burst, which brought heavy disasters to the Chinese nation. Because the lower reaches of the Yellow River flow from southwest to northeast, the north of the Yellow River freezes first in winter, forming ice flood. Ice dams are easily blocked by the overflow of ice, which leads to the overflow of dikes and poses a serious threat. Below the downstream Lijin is the Yellow River estuary. Due to sediment deposition, the mouth of the Yellow River keeps extending and swinging. At present, the Yellow River estuary is located at the intersection of Bohai Bay and Laizhou Bay, which is a new channel formed by the siltation of Qingshuigou after the artificial diversion of 1976. In recent 40 years, the average sediment transported by the Yellow River to the estuary area is about 654.38+100 million tons/year, extending to the Bohai Sea for 2.2 kilometers every year, with an average annual net land production of 25-365.438+0 square kilometers, which is equivalent to increasing the area of a football field every day.
From 3000 BC to 2000 BC (Yangshao culture in the Yellow River valley to Yinxu in Anyang), the geographical environment of the Yellow River valley was suitable for the growth of vegetation and the development of human production and living activities, and the climate environment about 2℃ higher created favorable conditions for the development of crops and vegetation. During this period, there were a large number of lakes such as Leixiaze and Onoze in the middle and lower reaches of the Yellow River. "On Mencius Teng Wengong" once recorded that the Yellow River valley was "lush with plants and animals", and the Guanzhong Plain still had "beautiful mountains and rivers, criss-crossing rivers and numerous talents" until the Warring States period in China (the forest in the middle reaches of the Yellow River in historical period, Shi Nianhai, 198 1 year).
After the Warring States period, with the extensive use of iron farm tools and the migration of Qin's economic center to Guanzhong, the vegetation in the Yellow River basin and the Loess Plateau began to be destroyed. Because the Yellow River Basin has been the center of Chinese civilization for a long time (China Historical Geography, Lan Yong, 2002), and the phenomenon of emphasizing agriculture over grazing in ancient China, the vegetation destruction in the Yellow River Basin has become a long-term and large-scale phenomenon. With the beginning of the cold climate in 1 1 century and the southward movement of the economic center of China, the ecological damage in the Yellow River basin began to decrease, but the forest coverage rate has been difficult to recover to the situation of the 3rd century BC. With the destruction of vegetation, the Loess Plateau began to be eroded by the Yellow River, and a large amount of soil was swept away, forming a surface morphology of thousands of valleys.
According to the research of scientists, the Yellow River has changed for two reasons. 1. Since the Qin Dynasty, the temperature in the Loess Plateau has turned cold and the rainstorm has been concentrated. Coupled with the loose structure of loess itself, it is easy to be eroded and collapsed, which contributes to soil erosion and makes a lot of sediment enter the Yellow River. Second, the rapid population growth, unrestricted land reclamation and grazing, caused the destruction of forests, grasslands, green vegetation, and the loss of natural protective layer on the Loess Plateau, resulting in serious soil erosion.
Every year, 4,000 tons of precious soil is eroded every square kilometer in the Yellow River Basin, which is equivalent to destroying 5.5 million mu of cultivated land a year! What's more, soil erosion has obviously reduced soil fertility, resulting in a large-scale reduction of crop production. The more production is reduced, the more people need to reclaim wasteland: the more land is reclaimed, the more serious soil erosion will be. In this way, the poorer the reclamation, the more sediment the Yellow River will have, and the number of breaches and diversions of the Yellow River will become more and more frequent. The key to harnessing the Yellow River is to control sediment and prevent it from flowing into the Yellow River at will. Recently, the problem of sandstorm has become more and more serious. Now, experts say that if humans cut down trees indiscriminately, the source of the Yellow River is likely to be submerged in sandstorms. 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.
After the founding of New China, scientists designed a scheme to control the Yellow River. They believe that the Loess Plateau should adhere to the management direction of animal husbandry and forestry. We must protect forest resources and restore lost vegetation as soon as possible. Let everyone know that deforestation is downright self-destructive, and it is necessary to rationally plan and use land and build a large number of water conservancy projects. This multi-pronged approach will certainly prevent soil erosion and make the dream of the Yellow River better realized.
The Yellow River is the second longest river in China, and it has been a muddy 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. In autumn and summer flood season, the defense is weak, ranging from flooding to water diversion. Historically, the Yellow River Basin has long been regarded as the political, economic and cultural center of China and the cradle of China culture. Frequent disasters in history also make the Yellow River known as "the worry of China". According to historical records, in the three or four thousand years before 1946, the lower reaches of the Yellow River burst 1593 times, and the river course was diverted 26 times, with more than a thousand breaches. 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. From 602 BC to 1938, the Yellow River burst 1590 times and the river moved 26 times. On average, there are two breaches in three years and a major diversion in a hundred years. 1938, the Yellow River changed its course, and the river went south to seize the Huai River, which flooded a large area of land in eastern Henan, northern Anhui and northern Jiangsu, with a population of12.5 million and 890,000 deaths. 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.
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.
In the mid-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 Geography, which ended the long-term situation of multi-flow 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 blocked on both sides of the inland waterway of the levee has been reclaimed to build the people's dike for self-defense. 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.
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. First, since the Eastern Han Dynasty, a large number of nomadic people have moved into the middle reaches of the Yellow River, returning farmland to grazing, and secondary grasslands and shrubs have replaced cultivated land, resulting in relatively weak soil erosion. 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.
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 Shandong Shanghe, Huimin, Binzhou and other cities and counties, the river surface has been "high-rise buildings almost exceeded the height". 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)
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 characteristics of the Yellow River changes can be summarized as follows: First, the position of the breach moved westward. 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.
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.
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. 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.
The Ministry of Water Resources of China has set up the Yellow River Conservancy Committee, and all provinces, cities and counties where the Yellow River flows have set up the Yellow River Affairs Bureau. All county-level river affairs bureaus have set up management sections along the Yellow River levee to carry out the maintenance, survey and construction of the Yellow River levee.
654.38+0.8 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 of all, the Yellow River is not just a big river. Yellow River, Yellow Earth, Yellow Emperor, Yellow Skin and the legendary dragon, all these yellow symbols sublimate this turbid stream flowing through the heart of China into a holy 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." Second, the theory of loess weathering in the long geological age, in the desert Gobi in the interior of Asia, there are sand and gravel everywhere, which are decomposed and crushed in the harsh environment of sudden cooling and sudden heating until they form 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. Third, the deep and broad loess layer This is an unparalleled loess with an area of 4 1 10,000 square kilometers, and the thickness of loess coverage is generally above 1 10,000 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 loess plateau loses 2.2 billion tons of topsoil every year, most of which enters the Yellow River. Four or six thousand years ago, botanists in the Garden of Eden found that although the rainfall in the Loess Plateau was not as abundant as that in the south, the loss of nutrients was less, which was very suitable for the growth of poplar, birch, oak, Chinese pine, spruce, Zizyphus jujuba 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. V. Enlightenment of Ancient Civilization In the Houdu human activity site in Ruicheng, Shanxi, 6.5438+0.6 million years ago, burnt animal fossils and antler fossils were found, 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. Sixth, the historical account of the achievements in transforming nature has indeed bathed in the light of civilization at the earliest, and it is bound to accept the fire of civilization at the earliest. According to ancient legends, Shennong once taught people to grow crops. What is intriguing is that Shennong is Emperor Yan, that is, Vulcan. What he teaches is actually burning forests and practicing. 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 song of the ancestors when they cut down trees: "Kan Kan cuts sandalwood, the rivers are clear and the blue waves are rippling." "When logging is tintin, birds sing." Seven, 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.
1, single wood, yellow river in the sky. There was a Yellow River flow in ancient times, and now it is cultivated land. All roads are flexible, and the sea turns to dust. 3, the desert is lonely and straight, and the long river falls in yen. 4. The mountains cover the day, and the sea drains the golden river. By going up one flight of stairs, look further. Have you ever noticed how the water of the Yellow River flows out of heaven and into the ocean, never to return? 6. The Yellow River falls into the East China Sea, and Wan Li writes it in his mind. 7. The Yellow River is far above the white clouds. It is an isolated city, Wan Ren Mountain. Why use the elegy of willow to complain about the delay of spring, old Yumenguan, a spring breeze is not blowing! 8. I will cross the Yellow River, but the ice will suffocate and the ferry will climb the snowy Taihang Mountain. 9. There are nine meanders of Yellow River and Wan Li sand, and waves and strong winds are blowing from the horizon. 10, send Kunlun five-color stream, and a yellow turbid river runs through Zhongchuan. 1 1, Wangjing teacher in Baihua Garden, when the Yellow River gushes. There are no pedestrians in the wilderness in the poor autumn, and the horse's head comes to know who it is. 12, crossing the Yellow River, returning to Cornus for a few days. 13, the Haixi army on the north bank of the Yellow River, the war drum bells resounded all over the world. The south bank of the Yellow River is my country, Shu, and I have to support my family without millet. 14, see three doors, three doors open, the Yellow River does not return. 15, ordered Li Bai to change his poems, and the water of the Yellow River came. 16, the yellow river holds the soil, and the north wind hates rain and snow. 17, the Yellow River came to Kunlun from the west, and Wan Li roared and touched Longmen. 18, Xiyue is magnificent, and the Yellow River is like a silk sky. 19, and explore the tiger's den to the desert, whip the horse to the Yellow River. 20. The flowers are blue and the clouds are wide, and the Yellow River wants to be as yellow as the sky. 2 1, the Yellow River is white in autumn in Huang Yun, and pedestrians are relatively worried by the river. 22, the bright moon and the yellow river night, the cold sand is like a battlefield.