The Yellow River is the second largest river in China. It flows through Qinghai, Sichuan, Gansu, Ningxia, Inner Mongolia, Shaanxi, Shanxi, Henan and Shandong provinces and regions, and into the Bohai Sea in Kenli County, Shandong Province. The Yellow River Basin is the main birthplace of Chinese civilization. Because of soil erosion in the Loess Plateau in the upper and middle reaches, it has become the most sediment-laden river in the world. Downstream from Mengjin, due to "good siltation", the river above the ground is formed; after the dyke is built, "good decision, good migration". Statistics show that in the past 2000 years, before 1949, there were two breaks in three years on average (statistical data are missing, actually about once a year). Without blockage, a diversion would take place. The Yellow River crevasse flooded the Changbei transgressive river system and entered the Huaihe River basin in the south, causing the river to migrate on the Huanghuaihai Plain. In view of its characteristics, water and sediment have been paid attention to since ancient times: water supply, irrigation, navigation, silting and silting with muddy water; water disasters should be eliminated, soil erosion should be prevented in the upper and middle reaches, and flood disasters should be prevented in the lower reaches. The development of the Yellow River accounts for almost half of China's water resources in history, especially for flood control in the lower reaches. The history of Yellow River water resources can be divided into four stages. The common features of the four stages are to develop farmland water resources in the upper and middle reaches of the Yellow River, and to control floods and disasters in the lower reaches of the Yellow River by repairing and blocking dikes.
