What did the nomads do after they went south? Why did the Yellow River burst the least during this period?

The Yellow River is the second longest river in China. From the northern foot of Bayan Kara in Qinghai Province to the east, it flows through Sichuan, Gansu, Ningxia, Mongolia, Shaanxi and other eight provinces, and enters the sea in Shandong. As the mother river, the Yellow River nourishes Chinese civilization, but this mother river is also long enough to last. According to statistics, there are more than 500 breaches/kloc-0 in the lower reaches of the Yellow River, and there are 20 or 30 major diversions, including 6 major diversions.

The main tributary of the Yellow River.

First, the Yellow River before the Eastern Han Dynasty The Yellow River has been a muddy river since ancient times. In the pre-Qin period, the ancients used to call the Yellow River "turbid river". During the Qin and Han Dynasties, the Yellow River was recorded in the literature. Before the Tang Dynasty, the word "River" as a proper name only referred to the Yellow River today. It was not until the Tang Dynasty that "Yellow River" began to become its fixed name.

Since the Neolithic Age, the Yellow River has entered the sea from today's Hebei Plain. Because there were no dikes on both sides of the river at that time, the flow direction of the river was extremely unstable, which was generally called overflow. Because of the instability of the river, it often causes the river to burst its banks and flood the surrounding villages.

Before the Warring States Period, there were three ancient roads in the Yellow River, which were found in Shangshu Gong Yu, Shanhaijing and Hanshu Geography. The river flows recorded in these three documents are completely different. According to Shan Hai Jing, the river runs from the eastern foot of Taihang Mountain to the north, passing Julu, Shenzhou, xiong'an new area (Xiongxian County) and today's Bazhou to Tianjin Binhai New Area (namely Tanggu North). This is the northernmost old river course in the lower reaches of the Yellow River in history, and it is called "the mountain crosses the river".

According to Gong Yu's records, the Yellow River flows along the river course above Shenxian County, Hebei Province, and reaches the Bohai Sea in the southeast of Tianjin Binhai New Area in the southwest, which is called "Gong Yuhe".

Finally, the record of "Hanshu Geography" flows through Xukou, an ancient residence in the southwest of Xunxian County, Henan Province, and finally enters the Bohai Sea from Huanghua, Cangzhou, which is called "Han Zhihe" in history. Like Gong Yuhe and Shanjing River, they are all ancient Yellow Rivers that existed before the Warring States Period, but the recorded river flow time is different, so the flow direction of the Yellow River in the three documents is also different.

Autumn scenery in the Old Course of the Yellow River

During this period, because there was no flood control levee in the lower reaches of the Yellow River, rivers were never subject to any constraints, and many rivers often coexisted in the Yellow River. At that time, Hebei plain was vast and sparsely populated, so this situation had little impact on people at that time.

By the mid-Warring States period, dikes had been built in the lower reaches of the Yellow River. However, the good times did not last long. During the reign of Emperor Wendi of the Western Han Dynasty, the Yellow River broke again on a large scale, and then the sediment in the river gradually increased. By the end of the Western Han Dynasty, the phenomenon of hanging rivers on the ground had appeared in Hebi, Henan Province today. This is also the result of large-scale reclamation and agricultural development in the middle reaches of the Yellow River after Qin and Han Dynasties.

Throughout the Western Han Dynasty, the phenomenon of hanging river was particularly serious. The most serious breach was in the late Western Han Dynasty, when the Yellow River broke in Puyang today. The flood quickly invaded the old Huaihe River and spread to eastern Henan and western Shandong today, and the breach lasted for nearly 20 years.

The Yellow River burst its banks.

By 1 1 year, today's Daming area in Hebei Province was broken again and again, and Wang Mang usurped the Western Han regime and established a "new dynasty". In order to protect his ancestral grave from being affected, Wang Mang took a laissez-faire attitude towards the flood of the Yellow River, allowing the river to flood to the surrounding villages. The disaster lasted for more than 60 years.