In general, the lower the river flows, the greater the flow, but the Yellow River is special, with fewer tributaries in the upper reaches. It flows through Ningxia Plain and Hetao Plain, where agriculture is developed, and the flow of the Yellow River decreases. After the middle reaches entered the Loess Plateau, the number of tributaries increased obviously, and the river flow also increased. Since the lower reaches of Henan Province entered Taohuayu, the flow from Taohuayu to the estuary has been declining due to the large population, developed agriculture and large water demand in North China.
The Yellow River is 5464 kilometers long and is the second longest river in China. The Yellow River is divided into upper, middle and lower reaches according to the harsh natural environment and hydrological conditions in the areas where the river flows.
The upper reaches of the Yellow River are 346 kilometers long, from Heyuan to Tuoketuo (Hekou Town) in Inner Mongolia Autonomous Region. Rivers cross the Qinghai-Tibet Plateau and flow through canyons, including more than 20 famous canyons. Here, the mountains are high and steep, with large drop and rich hydraulic resources. More water and less sediment, clearer river and even discharge are the hydrological characteristics of this reach. After the Yellow River flows out of Qingtongxia, the terrain is flat and open, and it enters Ningxia Plain and Inner Mongolia Hetao Plain. The canals crisscross here, making it one of the earliest agricultural development zones in the upper reaches of the Yellow River.
The middle reaches of the Yellow River 1234 km, from Hekou Town, Tuoketuo County, Inner Mongolia Autonomous Region to Taohuayu, Zhengzhou, Henan Province. Hydrological characteristics: Due to the heavy rain in summer and autumn, the reach is rich in sand sources, abundant in water and sediment, large in peak discharge and high in sediment concentration, and it is a world-famous sediment-laden river. River siltation and erosion alternate, and canyons and wide valleys alternate.
767 kilometers downstream of the Yellow River, from Taohuayu in Zhengzhou, Henan Province to Kenli County in Shandong Province, flows through the North China Plain from west to east. The river slope is small and the water flow is gentle. In addition, the river channel is wide, shallow and scattered, and the sediment deposition is serious, and the riverbed is gradually raised. Almost all banks rely on dikes as barriers.